Patent Application
20240315629
The present invention relates generally to the material science, and more particularly to conductive nanomaterials including acid crystallized PEDOT particles and composites thereof.
The background description provided herein is for the purpose of generally presenting the context of the invention. The subject matter discussed in the background of the invention section should not be assumed to be prior art merely as a result of its mention in the background of the invention section. Similarly, a problem mentioned in the background of the invention section or associated with the subject matter of the background of the invention section should not be assumed to have been previously recognized in the prior art. The subject matter in the background of the invention section merely represents different approaches, which in and of themselves may also be inventions. Work of the presently named inventors, to the extent it is described in the background of the invention section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the invention.
Bioelectricity is vital to many physiological processes in living organisms, such as the contraction of muscles, transmission of nerve impulses, regulation of heartbeats, and tissue regeneration, among others. The desire to implement bioelectricity to monitor or influence biological events has led to the emergence of bioelectronics, a discipline which aims to merge biology and microelectronics-typically through implantable or wearable devices. These medical technologies require a high-quality interface between tissue and electronics that enables both ionic and electronic communication. The first-generation of bioelectronic devices relied on inorganic interfaces which pose several disadvantages including 1) a strain mismatch which can lead to cell death and fibrosis at the tissue-device interface, 2) poor compatibility with magnetic fields used during magnetic resonance imaging (MRI), 3) challenges associated with translating both ionic and electronic signals, and 4) limited biodegradability. To overcome these challenges, researchers have been developing soft organic materials with mixed ionic and electronic conduction that can seamlessly integrate with cells and living tissues. Conductive hydrogels have gained significant attention as their structure mimics the extracellular matrix, the natural microenvironment of the cells, as such conductive hydrogels, have been aggressively explored for tissue engineering and regenerative medicine (TERM). The biological basis of such TERM applications is the facilitated transmission of endogenous or exogenous bioelectricity throughout the hydrogel, requiring charge percolation throughout the entire material.
Conductive hydrogels include hydrophilic polymeric networks with incorporated electroactive fillers, the most common of which include carbon nanotubes, graphene nanomaterials, conjugated polymers, and inorganics (gold, silver, metal oxides, etc.). Rationally designing hydrogels to promote homogeneous, 3D charge percolation for TERM and other bioelectronic applications remains a challenge. A significant limitation is the surface energy mismatch between the hydrophilic hydrogel precursor and the hydrophobic, typically carbon-based nanomaterial filler; this incompatibility requires laborious, multistep procedures to achieve sufficient loading for charge percolation. Of the available conductive fillers, conjugated polymers (CPs) have distinct advantages due to their enhanced chemical tunability, flexibility, biocompatibility, and solution processability. To achieve the necessary intrachain and interchain charge transport across long length scales for sufficient conductivity in thin-films, there are many processing methods such as spin-coating, blade-coating, or other facile techniques to obtain favorable packing with minimal polymer. However, as these processing methods cannot be translated to the tortuous, porous form factor of a hydrogel, achieving this same favorable packing is challenging, and has been traditionally limited to incorporating high loadings of CP filler.
Alternatively, CPs can be preorganized into colloidal dispersions which are stabilized by polyelectrolytes surfactants—enabling both solution processibility and high electrical conductivity. The most prominent CP dispersion is poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS) which can feature conductivities beyond 4000 S cm−1 when processed appropriately, leading to its widespread adoption within thin film applications such as chemical sensing, energy storage, and antistatic coatings. The commercial presence and biocompatibility of PEDOT:PSS has also inspired its use within conductive hydrogels for biomedical applications; however, as the ink is designed for 2D coatings, its direct incorporation within 3D hydrogels typically affords low conductivities between 10−3 and 10−1 S cm−1 (Table 2). While several groups have formulated conductive hydrogels directly out of PEDOT:PSS dispersions, many applications require the chemical and mechanical features of commonplace biomaterials to facilitate biocompatibility and biological outcomes such as cellular differentiation, necessitating a method to endow natural and synthetic biomaterials with conductivity.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.
In one aspect, the invention relates to a conductive nanomaterial comprising acid-crystalized poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) nanoparticles (ncrys-PEDOTX) with intrinsic dispersibility, wherein X represents an amount of an acid in a coagulation bath, and the amount is between 0 and 100%.
In one embodiment, the intrinsic dispersibility of the ncrys-PEDOTX enables its homogeneous incorporation at desired loading within diverse aqueous biomaterial solutions without additives or surfactants.
In one embodiment, the desired loadings is between 0-100%, preferably, varying within 0-5%, 5-10%, 10-20%, . . . up to 99%.
In one embodiment, the ncrys-PEDOTX is directly incorporable within a hydrogel, a scaffold, a film, a hydrophobic polymer, an elastomer, a thermoplastic, thermoset and/or an aqueous resin formation without sonication or external surfactants.
In one embodiment, the ncrys-PEDOTX is biocompatible, and hemocompatible.
In one embodiment, the ncrys-PEDOTX is usable in scalable, conductive, biocompatible, and modular platforms for bioelectronic applications.
In one embodiment, the ncrys-PEDOTX is synthesized with an acid-based nonsolvent induced phase separation (NIPS) method by coagulating a PEDOT:PSS solution into stable aggregates of concentrated PEDOT with tuneable PSS surfactant.
In one embodiment, the PEDOT:PSS solution comprises PEDOT:PSS added in a coagulation bath including acid in isopropanol (IPA). In one embodiment, the acid is a sulfuric acid. The sulfuric acid is adapted to remove the PEDOT from the PSS, while the IPA is used to act as a nonacidic solvent to wash away the removed PSS. It should be noted that many other acids and many other organic solvents can also be utilized to practice the invention.
In one embodiment, increasing the concentrations of the acid within the coagulation bath correlates with increasing a PEDOT/PSS ratio.
In one embodiment, the degree to which PSS is removed and PEDOT crystallizes within the ncrys-PEDOTX particles is directly related to the concentration of the sulfuric acid within the coagulation bath.
In one embodiment, by tuning a volume ratio of sulfuric acid within the coagulation bath, the PEDOT/PSS ratio in the ncrys-PEDOTX is optimized to afford the ncrys-PEDOTX with high conductivity (σncrys-PEDOT20=410 S cm−1) rivaling all the existing conjugated polymer particles.
In one embodiment, the ncrys-PEDOTX has conductivities in a range of about 1-100 S cm−1, about 100-400 S cm−1, and/or about 400-800 S cm−1.
In one embodiment, the ncrys-PEDOT5 and ncrys-PEDOT20 have conductivities of about 87 and 410 S cm−1. The exemplary embodiment shows X=5% and =20% as two representative examples. It should be noted that many other concentrations of the acid, for example, X=1, 2, 3, 4%, . . . , or all the way to 100% acid concentration, can also be used to practice the invention. All these concentrations would change the final properties of the ncrys-PEDOTX particles. In one embodiment, crystallization of the ncrys-PEDOTX particles enhances with increasing the concentration of the sulfuric acid within the coagulation bath.
In one embodiment, a crystallite size of the ncrys-PEDOTX particles increases from about 1.26 to 1.58 nm upon treatment with more concentrated sulfuric acid.
In one embodiment, the ncrys-PEDOTX particles have not interfered with chemistries of crosslink hydrogels including hydrogen bonding, ionic bonding, Schiff-base chemistry, and radical photopolymerization.
In one embodiment, by directly adding the ncrys-PEDOTX to a hydrogel formulation, a highly conductive composite is achieved with a percolation threshold between 0-5, 5-10, 10-15, or 15-20 wt % loading of the ncrys-PEDOTX.
In one embodiment, the PEDOT:PSS is formed with one or more functional monomers to make the ncrys-PEDOTX particles to have greater functionality.
In another aspect, the invention relates to a method of synthesizing a conductive nanomaterial. The methods comprises dropwisely adding an aqueous solution of PEDOT:PSS into a coagulation bath including sulfuric acid in isopropanol (IPA) to form a mixture thereof; collecting particles from the mixture; and subsequently comminuting the collected particles into a fine powder to form the conductive nanomaterial comprising acid-crystalized ncrys-PEDOTX with intrinsic dispersibility while maintaining high conductivity, wherein X represents an amount of the acid in the coagulation bath, and the amount is between 0 and 100%.
In one embodiment, the IPA is a nonsolvent that dehydrates the colloidal dispersion, enabling the NIPS.
In one embodiment, the sulfuric acid is to stabilize segregation of insulating PSS from conductive PEDOT.
In one embodiment, conductivity enhancement from acid crystallization involves removal of PSS and enhanced crystallinity.
In one embodiment, increasing a concentration of the sulfuric acid within the coagulation bath correlates with increasing a PEDOT/PSS ratio in the ncrys-PEDOTX.
In one embodiment, the degree to which PSS is removed and PEDOT crystallizes within the ncrys-PEDOTX particles is directly related to the concentration of the sulfuric acid within the coagulation bath.
In one embodiment, by tuning a volume ratio of sulfuric acid within the coagulation bath, the PEDOT/PSS ratio in the ncrys-PEDOTX is optimized to afford the ncrys-PEDOTX with high conductivity (σncrys-PEDOT20=410 S cm−1) rivaling all the existing conjugated polymer particles.
In one embodiment, the ncrys-PEDOT5 and ncrys-PEDOT20 particles represent conditions with low and high concentrations of sulfuric acid in the coagulation bath, respectively.
In one embodiment, the ncrys-PEDOT5 and ncrys-PEDOT20 have conductivities of about 87 and 410 S cm−1.
In one embodiment, crystallization of the ncrys-PEDOTX particles enhances with increasing the concentration of the sulfuric acid within the coagulation bath.
In one embodiment, a crystallite size of the ncrys-PEDOTX particles increases from about 1.26 to 1.58 nm upon treatment with more concentrated sulfuric acid.
In a further aspect, the invention relates to a composite comprising an aqueous biomaterial solution; and acid-crystalized ncrys-PEDOTX loaded into the aqueous biomaterial solution, wherein the ncrys-PEDOTX acts as a filler with the highest conductivity of the particles while maintaining dispersibility, wherein X represents an amount of an acid in a coagulation bath, and the amount is between 0 and 100%.
In one embodiment, the aqueous biomaterial solution is devoid of additives or surfactants.
In one embodiment, the ncrys-PEDOTX is loaded into the aqueous biomaterial solution by vortexing, stirring, shaking, centrifugation, milling, and/or the likes.
In one embodiment, the aqueous biomaterial solution comprises a hydrogel synthesized from aqueous solutions of hydrophilic natural biopolymers including alginate, gelatin, collagen, and/or chitosan, or synthetic polymer formulations including pHEMA, PEO, and/or PEGDA.
In one embodiment, the composite has a significant increase in conductivity with a percolation threshold between 15 and 20 wt % loading of the ncrys-PEDOTX, with the highest loading displaying a remarkable conductivity of 1.1 S cm−1.
In one embodiment, the composite has about 8.2 S cm−1 with 5% particle loading, which is notably >400 fold higher than an EDOT postpolymerization in PEDGA alone (0.02 S cm−1).
In one embodiment, the ncrys-PEDOTX has no interfered with chemistries of the aqueous biomaterial solution.
In one embodiment, the ncrys-PEDOTX has no deleterious impact on the stability of the aqueous biomaterial solution.
In one embodiment, the composite comprises an aqueous photoprintable conductive resin is formulated through the addition of the ncrys-PEDOTX into a mixture of poly(ethylene glycol)diacrylate (PEGDA) and lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP) photoinitiator in water.
In one embodiment, the aqueous PEGDA resin is utilized for 3D printing of a soft matter with complex form factors with high fidelity complex biomedical structures for biomedical applications.
In one embodiment, the composite has high cell viability (>95%) at all loadings up to about 15% of ncrys-PEDOTX.
In one embodiment, the composite is biocompatible and/or hemocompatibible.
These and other aspects of the present invention will become apparent from the following description of the preferred embodiment taken in conjunction with the following drawings, although variations and modifications therein may be affected without departing from the spirit and scope of the novel concepts of the disclosure.
The accompanying drawings illustrate one or more embodiments of the invention and together with the written description, serve to explain the principles of the invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment.
The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like reference numerals refer to like elements throughout.
The terms used in this specification generally have their ordinary meanings in the art, within the context of the invention, and in the specific context where each term is used. Certain terms that are used to describe the invention are discussed below, or elsewhere in the specification, to provide additional guidance to the practitioner regarding the description of the invention. For convenience, certain terms may be highlighted, for example using italics and/or quotation marks. The use of highlighting has no influence on the scope and meaning of a term; the scope and meaning of a term is the same, in the same context, whether or not it is highlighted. It will be appreciated that same thing can be said in more than one way. Consequently, alternative language and synonyms may be used for any one or more of the terms discussed herein, nor is any special significance to be placed upon whether or not a term is elaborated or discussed herein. Synonyms for certain terms are provided. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and in no way limits the scope and meaning of the invention or of any exemplified term. Likewise, the invention is not limited to various embodiments given in this specification.
One of ordinary skill in the art will appreciate that starting materials, biological materials, reagents, synthetic methods, purification methods, analytical methods, assay methods, and biological methods other than those specifically exemplified can be employed in the practice of the invention without resort to undue experimentation. All art-known functional equivalents, of any such materials and methods are intended to be included in this invention. The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention that in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the invention has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims.
Whenever a range is given in the specification, for example, a temperature range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the invention. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.
It will be understood that, as used in the description herein and throughout the claims that follow, the meaning of “a”, “an”, and “the” includes plural reference unless the context clearly dictates otherwise. Thus, for example, reference to “a cell” includes a plurality of such cells and equivalents thereof known to those skilled in the art. As well, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably.
It will be understood that when an element is referred to as being “on”, “attached” to, “connected” to, “coupled” with, “contacting”, etc., another element, it can be directly on, attached to, connected to, coupled with or contacting the other element or intervening elements may also be present. In contrast, when an element is referred to as being, for example, “directly on”, “directly attached” to, “directly connected” to, “directly coupled” with or “directly contacting” another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature.
It will be understood that, although the terms first, second, third etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the invention.
Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another element as illustrated in the figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. For example, if the device in one of the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower”, can therefore, encompasses both an orientation of “lower” and “upper,” depending of the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
It will be further understood that the terms “comprises” and/or “comprising”, or “includes” and/or “including”, or “has” and/or “having”, or “carry” and/or “carrying”, or “contain” and/or “containing”, or “involve” and/or “involving”, “characterized by”, and the like are to be open-ended, i.e., to mean including but not limited to. When used in this disclosure, they specify the presence of stated features, regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, regions, integers, steps, operations, elements, components, and/or groups thereof.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the invention, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
As used in the disclosure, “around”, “about”, “approximately” or “substantially” shall generally mean within 20 percent, preferably within 10 percent, and more preferably within 5 percent of a given value or range. Numerical quantities given herein are approximate, meaning that the term “around”, “about”, “approximately” or “substantially” can be inferred if not expressly stated.
As used in the disclosure, the phrase “at least one of A, B, and C” should be construed to mean a logical (A or B or C), using a non-exclusive logical OR. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Embodiments of the invention are illustrated in detail hereinafter with reference to accompanying drawings. The description below is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. The broad teachings of the invention can be implemented in a variety of forms. Therefore, while this invention includes particular examples, the true scope of the invention should not be so limited since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. It should be understood that one or more steps within a method may be executed in different order (or concurrently) without altering the principles of the invention.
Conductive hydrogels are promising materials with mixed ionic-electronic conduction to interface living tissue (ionic signal transmission) with medical devices (electronic signal transmission). The hydrogel form factor also uniquely bridges the wet/soft biological environment with the dry/hard environment of electronics. The synthesis of hydrogels for bioelectronics requires scalable, biocompatible fillers with high electronic conductivity and compatibility with common aqueous hydrogel formulations/resins. Despite significant advances in the processing of carbon nanomaterials, fillers that satisfy all these requirements are lacking.
In view of the foregoing, one aspect of the invention relates to intrinsically dispersible acid-crystalized PEDOT:PSS nanoparticles (ncrys-PEDOTX) which are processed through a facile and scalable nonsolvent induced phase separation method from commercial PEDOT:PSS without complex instrumentation. The particles feature conductivities of up to 410 S cm−1, and when compared to other common conductive fillers, display remarkable dispersibility, enabling homogeneous incorporation at relatively high loadings within diverse aqueous biomaterial solutions without additives or surfactants. The aqueous dispersibility of the ncrys-PEDOTX particles also allows simple incorporation into resins designed for microstereolithography without sonication or surfactant optimization; complex biomedical structures with fine features (<150 μm) are printed with up to 10% particle loading. The ncrys-PEDOTX particles overcome the challenges of traditional conductive fillers, providing a scalable, biocompatible, plug-and-play platform for soft organic bioelectronic materials.
Without intent to limit the scope of the invention, exemplary embodiments of the present invention are described below.
One aspect of the invention relates to a conductive nanomaterial comprising acid-crystalized ncrys-PEDOTX with intrinsic dispersibility, wherein X represents an amount of an acid in a coagulation bath, and the amount is between 0 and 100%.
In one embodiment, the intrinsic dispersibility of the ncrys-PEDOTX enables its homogeneous incorporation at desired loading within diverse aqueous biomaterial solutions without additives or surfactants.
In one embodiment, the desired loadings is between 0-100%, preferably, varying within 0-5%, 5-10%, 10-20%, . . . up to 99%.
In one embodiment, the ncrys-PEDOTX is directly incorporable within a hydrogel, a scaffold, a film, a hydrophobic polymer, an elastomer, a thermoplastic, thermoset and/or an aqueous resin formation without sonication or external surfactants.
In one embodiment, the ncrys-PEDOTX is biocompatible, and hemocompatible.
In one embodiment, the ncrys-PEDOTX is usable in scalable, conductive, biocompatible, and modular platforms for bioelectronic applications.
In one embodiment, the ncrys-PEDOTX is synthesized with an acid-based nonsolvent induced phase separation (NIPS) method by coagulating a PEDOT:PSS solution into stable aggregates of concentrated PEDOT with tuneable PSS surfactant.
In one embodiment, the PEDOT:PSS solution comprises PEDOT:PSS added in a coagulation bath including acid in isopropanol (IPA). In one embodiment, the acid is a sulfuric acid. The sulfuric acid is adapted to remove the PEDOT from the PSS, while the IPA is used to act as a nonacidic solvent to wash away the removed PSS. It should be noted that many other acids and many other organic solvents can also be utilized to practice the invention.
In one embodiment, increasing the concentrations of the acid within the coagulation bath correlates with increasing a PEDOT/PSS ratio.
In one embodiment, the degree to which PSS is removed and PEDOT crystallizes within the ncrys-PEDOTX particles is directly related to the concentration of the sulfuric acid within the coagulation bath.
In one embodiment, by tuning a volume ratio of sulfuric acid within the coagulation bath, the PEDOT/PSS ratio in the ncrys-PEDOTX is optimized to afford the ncrys-PEDOTX with high conductivity (σncrys-PEDOT20=410 S cm−1) rivaling all the existing conjugated polymer particles.
In one embodiment, the ncrys-PEDOTX has conductivities in a range of about 1-100 S cm−1, about 100-400 S cm−1, and/or about 400-800 S cm1.
In one embodiment, the ncrys-PEDOT5 and ncrys-PEDOT20 have conductivities of about 87 and 410 S cm−1. The exemplary embodiment shows X=5% and =20% as two representative examples. It should be noted that many other concentrations of the acid, for example, X=1, 2, 3, 4%, . . . , or all the way to 100% acid concentration, can also be used to practice the invention. All these concentrations would change the final properties of the ncrys-PEDOTX particles. In one embodiment, crystallization of the ncrys-PEDOTX particles enhances with increasing the concentration of the sulfuric acid within the coagulation bath.
In one embodiment, a crystallite size of the ncrys-PEDOTX particles increases from about 1.26 to 1.58 nm upon treatment with more concentrated sulfuric acid.
In one embodiment, the ncrys-PEDOTX particles have not interfered with chemistries of crosslink hydrogels including hydrogen bonding, ionic bonding, Schiff-base chemistry, and radical photopolymerization.
In one embodiment, by directly adding the ncrys-PEDOTX to a hydrogel formulation, a highly conductive composite is achieved with a percolation threshold between 0-5, 5-10, 10-15, or 15-20 wt % loading of the ncrys-PEDOTX.
In one embodiment, the PEDOT:PSS is formed with one or more functional monomers to make the ncrys-PEDOTX particles to have greater functionality.
Another aspect of the invention relates to a method of synthesizing a conductive nanomaterial. The methods comprises dropwisely adding an aqueous solution of PEDOT:PSS into a coagulation bath including sulfuric acid in isopropanol (IPA) to form a mixture thereof; collecting particles from the mixture; and subsequently comminuting the collected particles into a fine powder to form the conductive nanomaterial comprising acid-crystalized ncrys-PEDOTX with intrinsic dispersibility while maintaining high conductivity, wherein X represents an amount of the acid in the coagulation bath, and the amount is between 0 and 100%.
In one embodiment, the IPA is a nonsolvent that dehydrates the colloidal dispersion, enabling the NIPS.
In one embodiment, the sulfuric acid is to stabilize segregation of insulating PSS from conductive PEDOT.
In one embodiment, conductivity enhancement from acid crystallization involves removal of PSS and enhanced crystallinity.
In one embodiment, increasing a concentration of the sulfuric acid within the coagulation bath correlates with increasing a PEDOT/PSS ratio in the ncrys-PEDOTX.
In one embodiment, the degree to which PSS is removed and PEDOT crystallizes within the ncrys-PEDOTX particles is directly related to the concentration of the sulfuric acid within the coagulation bath.
In one embodiment, by tuning a volume ratio of sulfuric acid within the coagulation bath, the PEDOT/PSS ratio in the ncrys-PEDOTX is optimized to afford the ncrys-PEDOTX with high conductivity (σncrys-PEDOT20=410 S cm−1) rivaling all the existing conjugated polymer particles.
In one embodiment, the ncrys-PEDOT5 and ncrys-PEDOT20 particles represent conditions with low and high concentrations of sulfuric acid in the coagulation bath, respectively.
In one embodiment, the ncrys-PEDOT5 and ncrys-PEDOT20 have conductivities of about 87 and 410 S cm−1.
In one embodiment, crystallization of the ncrys-PEDOTX particles enhances with increasing the concentration of the sulfuric acid within the coagulation bath.
In one embodiment, a crystallite size of the ncrys-PEDOTX particles increases from about 1.26 to 1.58 nm upon treatment with more concentrated sulfuric acid.
A further aspect of the invention relates to a composite comprising an aqueous biomaterial solution; and acid-crystalized ncrys-PEDOTX loaded into the aqueous biomaterial solution, wherein the ncrys-PEDOTX acts as a filler with the highest conductivity of the particles while maintaining dispersibility, wherein X represents an amount of an acid in a coagulation bath, and the amount is between 0 and 100%.
In one embodiment, the aqueous biomaterial solution is devoid of additives or surfactants.
In one embodiment, the ncrys-PEDOTX is loaded into the aqueous biomaterial solution by vortexing, stirring, shaking, centrifugation, milling, and/or the likes.
In one embodiment, the aqueous biomaterial solution comprises a hydrogel synthesized from aqueous solutions of hydrophilic natural biopolymers including alginate, gelatin, collagen, and/or chitosan, or synthetic polymer formulations including pHEMA, PEO, and/or PEGDA.
In one embodiment, the composite has a significant increase in conductivity with a percolation threshold between 15 and 20 wt % loading of the ncrys-PEDOTX, with the highest loading displaying a remarkable conductivity of 1.1 S cm−1.
In one embodiment, the composite has about 8.2 S cm−1 with 5% particle loading, which is notably >400 fold higher than an EDOT postpolymerization in PEDGA alone (0.02 S cm−1).
In one embodiment, the ncrys-PEDOTX has no interfered with chemistries of the aqueous biomaterial solution.
In one embodiment, the ncrys-PEDOTX has no deleterious impact on the stability of the aqueous biomaterial solution.
In one embodiment, the composite comprises an aqueous photoprintable conductive resin is formulated through the addition of the ncrys-PEDOTX into a mixture of poly(ethylene glycol)diacrylate (PEGDA) and lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP) photoinitiator in water.
In one embodiment, the aqueous PEGDA resin is utilized for 3D printing of a soft matter with complex form factors with high fidelity complex biomedical structures for biomedical applications.
In one embodiment, the composite has high cell viability (>95%) at all loadings up to about 15% of ncrys-PEDOTX.
In one embodiment, the composite is biocompatible and/or hemocompatibible.
These and other aspects of the present invention are further described below. Without intent to limit the scope of the invention, exemplary instruments, apparatus, methods and their related results according to the embodiments of the present invention are given below. Note that titles or subtitles may be used in the examples for convenience of a reader, which in no way should limit the scope of the invention. Moreover, certain theories are proposed and disclosed herein; however, in no way they, whether they are right or wrong, should limit the scope of the invention so long as the invention is practiced according to the invention without regard for any particular theory or scheme of action.
In this exemplary study, we report intrinsically dispersible acid-crystalized PEDOT:PSS nanoparticles (ncrys-PEDOTX) to enable 3D charge percolation within hydrogels for organic bioelectronic applications. Using an acid-based nonsolvent induced phase separation (NIPS) method, commercial PEDOT:PSS inks were coagulated into stable aggregates of concentrated PEDOT with tuneable PSS surfactant to enable dispersion within prototypical hydrogels. Compared to other common conductive fillers ncrys-PEDOTX displays enhanced dispersibility, enabling homogeneous incorporation at relatively high loadings within diverse aqueous biomaterial solutions without additives or surfactants. To demonstrate the plug and play nature of the particles ncrys-PEDOT20 was directly incorporated within both natural biomaterial derived hydrogels and an aqueous resin designed for projection microstereolithography without sonication or surfactant optimization. With only a single step for conductive filler incorporation, hydrogels were endowed with significant conductivity (>1 S cm−1) rivaling other reported systems in performance and simplicity. Furthermore, high fidelity complex biomedical structures were printed with up to 10% loading of conductive particles with fine features (<150 μm), biocompatibility, and hemocompatibility. The ncrys-PEDOTX particles overcome the challenges of traditional conductive fillers, offering a scalable, conductive, biocompatible, and modular platform for soft organic bioelectronic materials.
Materials: PEDOT:PSS aqueous solution (Clevios PH1000) was purchased from Heraeus Electronic Materials. PEDOT:PSS dry redispersible pellets, sulfuric acid (ACS reagent, 95.0-98.0%), gelatin from porcine skin (gel strength 300, Type A), chitosan (medium molecular weight), agarose (Type I, low EEO), sodium alginate, and poly(ethylene glycol) diacrylate (PEGDA, Mn=575 g mol−1) were purchased from Sigma-Aldrich and used as received. Rat tail collagen (Type I, 2.05 mg mL−1 in 0.6% acetic acid) was purchased from First Link (UK) Ltd. Glutaraldehyde (≈50% in water, ≈5.6 mol L−1) and lithium phenyl(2,4,6-trimethylbenzoyl)phosphinate (LAP) were purchased from TCI.
Preparation of ncrys-PEDOTX Nanoparticles: Acid crystallized PEDOT:PSS nanoparticles (ncrys-PEDOTX) were synthesized by dropwise addition of PEDOT:PSS aqueous solution into a coagulation bath including sulfuric acid in isopropanol under stirring for 12 h. Subsequently the particles were filtered, washed with isopropanol, deionized water, and acetone. The particles were then dried in vacuo and milled (Freezer/Mill SPEX Cryogenic Grinder) for three cycles where one cycle included 5 min of precool time, 15 min of grinding, and 2 min of rest. The speed was maintained at a rate of 15 counts per second (cps). Crystallization of 100 mL of ink within a 20% acid bath yielded 802 mg of ncrys-PEDOT20.
Size Analysis: To probe the size distribution and morphology of the PEDOT nanoparticles, scanning electron microscopy was conducted using a Hitachi S-4800 SEM operated at 5 kV. Nanoparticles were dispersed in methanol and were drop cast and air-dried on carbon-coated tapes prior to imaging. The high conductivity of the particles precluded the need for a secondary conductive coating. The resulting images were analyzed using ImageJ, data were collated from over 200 individual particles.
X-Ray Photoelectron Spectroscopy: Measurements were performed with a NEXSA G2 XPS instrument, using a 15 keV Al-Kα X-ray source. Survey and high-resolution spectra of C 1s and S 2p core levels were recorded. All spectra were adjusted to the C is level of 284.8 eV. Data analysis was performed using the Thermo Fisher Avantage software.
X-Ray Diffraction: PXRD data were collected at room temperature on a STOE-STADI-P powder diffractometer equipped with an asymmetric curved Germanium monochromator (Cu Kα1 radiation, λ=1.54056 Å) and 1D silicon strip detector (MYTHEN2 1K from DECTRIS). The line focused Cu X-ray tube was operated at 40 kV and 40 mA. Powder was packed in an 8 mm metallic mask and sandwiched between two polyimide layers of tape. Intensity data from 1.5° to 70° two theta were collected over a period of 120 min. Instrument was calibrated against a NIST Silicon standard (640d) prior the measurement.
Conductivity Measurements: For particle conductivity measurements 50 mg of ncrys-PEDOTX or commercial lyophilized PEDOT:PSS was pressed into a pellet with an 8 mm diameter by pressing under a hydrostatic pressure of 3500 kg cm−2 for 2 min. Four-point conductivity measurements were performed using a Lucas Labs Pro4 four-point probe head with a Keithley 9 2400 source meter. Samples were measured in triplicate and the average pellet or gel thickness was determined via caliper.
Sedimentation Analysis: Dispersions were prepared using 10 mg mL−1 concentrations of either ncrys-PEDOT5 or ncrys-PEDOT20 in either DI H2O and 2 wt % sodium alginate in DI H2O. Dispersions (10 mg mL−1) of ncrys-PEDOT20 were also prepared in 2 wt % chitosan in 1% acetic acid and 0.2 wt % collagen in 0.6% acetic acid. At predetermined time intervals, aliquots of the supernatants were carefully collected from just below the surface of the meniscus and analyzed via UV-Vis at 633 nm. The ratio of the absorbance at a given time point compared to that of the initial time point was used to measure the stability of the suspensions.
Hydrogel Preparation: Gelatin: 400 mg of gelatin was added to 20 mL of DI H2O and stirred at 45° C. for 1 h. A solution of ncrys-PEDOT20 (10 mg mL−1) was prepared using the gelatin stock solution and stirred at 45° C. for 1 h. For the vial tilt experiment, 4 mL of particle-loaded gelatin dispersion was slowly cooled to room temperature. For the reinforcement experiment, 6 mL of the particle-loaded gelatin dispersion was poured into a polystyrene dish and slowly cooled to room temperature. Discs were punched using an 8 mm biopsy punch and washed with DI H2O. Alginate: 400 mg of sodium alginate was added to 20 mL of DI H2O and stirred at room temperature overnight. A solution of ncrys-PEDOT20 (10 mg mL−1) was prepared using the alginate stock solution and stirred at room temperature for 1 h. For the alginate worm experiment, particle-loaded alginate dispersion was injected into an aqueous solution of 1 M CaCl2. For the reinforcement experiment 6 mL of the particle-loaded alginate dispersion was poured into a polystyrene dish lined with a filter paper soaked with 0.05 M CaCl2 and incubated for 24 h at room temperature according to previously reported procedures. Discs were punched using an 8 mm biopsy punch and washed with DI H2O. Chitosan: 2 g of chitosan was added to 100 mL of aqueous acetic acid (1% v/v) and stirred at room temperature until homogeneous. A solution of ncrys-PEDOT20 (10 mg mL−1) was prepared using the chitosan stock solution and stirred at room temperature for 1 h. For the vial tilt experiment 1 mL of aqueous glutaraldehyde (50%) was added to 4 mL of particle loaded chitosan dispersion at room temperature. For the reinforcement experiment 6 mL of the particle loaded chitosan dispersion was poured into a polystyrene dish lined with a filter paper soaked in 25% aqueous glutaraldehyde and incubated for 24 h at room temperature. Discs were punched using an 8 mm biopsy punch and washed with DI H2O.
Mechanical Characterization: The mechanical properties of the hydrogels were investigated in the compression mode using a DMA (850, TA Instruments) with a 0.05 N preload force, at 25° C. under immersion in DI H2O. The elastic modulus was determined from slope of the stress-strain curve within the elastic region. The elastic modulus, compressive strength, and compressive strain were calculated from five hydrogels discs.
Printing of ncrys-PEDOT20 Incorporated Resins: A home-made μCLIP printer was used to print all structures utilized throughout the study. Conditions used for printer setup and operation followed previously reported procedures. Focal plane pixel resolution was set at 3.98×3.98 μm, and 5 μm layer thickness was used. The system is similar to those previously described, with updates to the light projector and light path. A hydrogel resin including PEGDA (39.5 wt %), LAP (0.5 wt %), and water (60 wt %) was used with varying loading of ncrys-PEDOT20. Particles were loaded into the resin at 1, 5, or 10 wt %, initially vortexed for 2 min, and vortexed for 1 min immediately both before use and between each print. Using the μCLIP printer, esophageal stents and square form factors were printed. Esophageal stents were designed to be 10.93 mm long with supports and have struts 133 μm in diameter. Squares were 8 mm in length and height and were 1 mm in thickness, with 1 mm tall supports on one side to adhere prints to the platform. Inks with 1 wt % ncrys-PEDOT20 were printed with 0.0008 mJ mm−2 power, 5 wt % loading with 0.2188 mJ mm−2 power, and 10 wt % loading with 0.3063 mJ mm−2 power. In situ polymerization of particle loaded prints with EDOT followed previously reported procedures.
Biocompatibility Analysis: In vitro cytotoxicity tests were performed on particle-loaded PEGDA hydrogels based on the ISO 10993-5 protocol. 3D printed hydrogels with square (8 mm×8 mm×1 mm) form factors were assessed with either 1, 5, 10, or 15 wt % ncrys-PEDOT20. Indirect Extract Tests: Before performing cytotoxicity experiments, each hydrogel was washed with ethanol, DPBS, and Dulbecco's Modified Eagle Medium/Nutrient Mixture F-12 (DMEM/F-12) media (Gibco; Cat no. 11 320 033). DMEM/1F-12 media supplemented with both 10% fetal bovine serum (FBS) and 1% antibiotic-antimycotic (2 mL) was added directly onto 0.15 g of hydrogel and incubated at 37° C. with 5% CO2 in a humidified incubator for 24 h to create extracts. Separately, a suspension of L929 cells was prepared at a concentration of 5×104 cell mL−1 and 100 μL of the suspension was dispensed into each well of a 96-well plate. The plate was incubated at 37° C. with 5% CO2 in a humidified incubator. After 24 h, culture media was removed from the wells and replaced by 100 μL of extract media from the hydrogels. Following 48 h, the cell viability was assessed via alamarBlue assay (Invitrogen; Cat no. A50101). Samples were repeated in quintuplicate. Direct Tests: L929 cells were prepared at a concentration of 5×104 cell mL−1 and 200 μL of this suspension was added directly on the particle-incorporated hydrogels within a 24-well polystyrene tissue culture plate. The plate was incubated at 37° C. with 5% CO2 in a humidified incubator for 4 h for cell attachment, and 300 μL of DMEM/F-12 media supplemented with both 10% fetal bovine serum (FBS) and 1% antibiotic-antimycotic was carefully added into each well. Following 48 h, a live/dead solution was prepared from the LIVE/DEAD Viability/Cytotoxicity Kit (Invitrogen; Cat no. L3224) with 0.5 μL of calcein AM and 2.0 μL of ethidium homodimer-1 (EthD-1) in 1 mL of DPBS. Each hydrogel was stained with live/dead solution (200 μL), incubated for 30 min, and imaged with a Nikon confocal microscope. The cell viability percentage was calculated using Fiji (ImageJ).
Hemocompatibility Analysis: 12 mL of the blood samples were collected from three female rabbits and pooled together in anticoagulant vials. The hemocompatibility of ncrys-PEDOT20 was assessed using a 50 mg mL−1 stock solution in DI water. The hemolysis assay protocol was adapted from prior literature procedures. Briefly, 300 μL of particle solution was added to 4 mL of 0.9% saline solution and equilibrated for 30 min at 37° C. 200 μL of diluted blood (4 mL of blood diluted in 5 mL of 0.9% saline solution) was added to the sample. A negative control was prepared by adding 200 μL of diluted blood to 4 mL of 0.9% saline solution (0% hemolysis) and a positive control was prepared by adding 200 μL of diluted blood to 4 mL of DI water (100% hemolysis). The sample was then incubated at 37° C. for 1 h, centrifuged at 1000 rpm for 5 min, and the absorbance of the supernatant was measured at 545 nm. The hemolysis experiment was performed in triplicate.
Dispersible and Tunable ncrys-PEDOTX—Preparation and Characterization: The synthesis of PEDOT nanoparticles is typically achieved through bottom-up, template-, or emulsion-based methods which suffer from limited tunability, low yields, and particles that lack aqueous processability, the latter of which is a critical requirement when working with biomaterial dispersions. While reactors have been reported to afford submicron PEDOT particles via aerosol vapor polymerization and electrochemistry, such methods require sophisticated instrumentation and, as the afforded particles lack a polyanionic surfactant such as PSS, have both limited aqueous dispersibility and require external dopants (Table 1). Alternatively, commercial PEDOT:PSS can be concentrated via lyophilization and redispersed within a biomaterial; while this top-down approach is scalable and accessible due to the commercial availability of PEDOT:PSS, the afforded composites demonstrate limited conductivity as well as leeching over time due to the excess insulating PSS dispersant. Recently an acid-based nonsolvent induced phase separation (NIPS) approach was applied to coagulate PEDOT:PSS into stable, microparticles to both partially remove insulating PSS and enhance the crystallinity of the PEDOT assemblies, however this method afforded porous systems with size features too large for dispersion within conductive hydrogels. Acid treatment has also been recently implemented to improve and investigate mixed conduction within thin film devices.
In this exemplary example, we leverage a top-down NIPS-based processing approach to commercial PEDOT:PSS (Heraeus Electronic Materials, 1.1-1.3% solid content, Clevios PH1000) to prepare tuneable PEDOT:PSS nanoparticles with intrinsic dispersibility for conductive hydrogel applications, as shown in panel a of
Commercial PEDOT:PSS (1-1.3 wt %) was added dropwise into a coagulation solution including both isopropanol (IPA) and sulfuric acid. Collected particles were subsequently comminuted into a fine powder using a cryogenic grinder to afford nanoparticles with an average diameter of 81.5 nm, as shown in panel c of
PEDOT:PSS films processed via acid crystallization typically display enhancements in conductivity—to investigate the conductivity of ncrys-PEDOTX, disc-shaped pellets were formed by applying hydrostatic pressure to the particles and were subsequently analyzed via four-point probe measurements, as shown in panel f of
Conductive ncrys-PEDOTX Incorporated Hydrogels: Conductive hydrogels are typically synthesized directly from aqueous solutions of hydrophilic natural biopolymers (alginate, gelatin, collagen, chitosan) or synthetic polymer formulations (pHEMA, PEO, PEGDA). Hydrophobic carbon-based nanomaterials such as carbon nanotubes (CNTs) and graphene (G) are common fillers for conductive hydrogels but lack stability in water, requiring complex surfactants and/or harsh oxidation to disperse, thus complicating their application within conductive hydrogels. The residual PSS within ncrys-PEDOTX can act as an internal surfactant to stabilize their dispersion within aqueous biomaterial solutions, overcoming this limitation. The tunability with which this internal surfactant remains within the particle can therefore act as a handle to promote aqueous dispersibility. The kinetic stability of ncrys-PEDOTX was investigated by monitoring the absorbance of 1 wt % (10 mg mL−1) ncrys-PEDOTX aqueous dispersions over time, a common method to profile the sedimentation kinetics of nanomaterial dispersions. Both ncrys-PEDOT5 and ncrys-PEDOT20 were first dispersed via stirring in either DI H2O or 2% aqueous sodium alginate, the latter of which is a common precursor for conductive biomaterials, as shown in
We then investigated if ncrys-PEDOT20 impacted the prototypical chemistries that are utilized to crosslink biomaterials into hydrogels. Many natural aqueous biomaterial dispersions are crosslinked thermally, covalently, ionically, or via pH. Representative biomaterial dispersions of polysaccharides (agarose, chitosan), protein (gelatin), and synthetic resin (PEGDA) were loaded with 1 wt % (10 mg mL−1) of ncrys-PEDOT20, stirred and subsequently crosslinked, as shown in panel b of
For bioelectronic applications conductive hydrogels require sufficient electronic conductivity to facilitate the transmission of endogenous or exogenous bioelectricity throughout the material, requiring 3D charge percolation. Prior experiments have suggested that as the loading of conducting filler is increased, a dramatic enhancement in conductivity is observed which is attributed to the formation of percolation pathways for charge carriers. The filler volume required to achieve percolation is related to the aspect ratio; for fillers of roughly spherical shape, similar size, and random orientation, a loading of 16% has been found—known as the Sher-Zallen invariant. While 1D and 2D materials such as CNTs or G would require reduced loadings to achieve percolation, these materials have limited aqueous dispersibility and the relatively high surface area of their form factor compared to spherical particles promotes aggregation. As high loadings of conductive filler are typically incompatible with hydrophilic hydrogel precursors, this challenge has been circumvented by processing hydrogels directly out of conjugated polymers, typically PEDOT:PSS. However, many applications require the chemical and mechanical features of hydrogels with a natural or synthetic biomaterial base, rather than a CP base to facilitate biocompatibility and biological outcomes such as cellular differentiation. To observe the endowed percolation behavior of ncrys-PEDOT20 within a prototypical hydrogel, particles were systematically loaded within the aqueous PEGDA resin—this resin was chosen due to its widespread use for 3D tissue engineering constructs, biosensing media, and drug-controlled release matrices. As anticipated, a significant increase in conductivity was observed between 15% and 20% incorporation, with the highest loading displaying a remarkable conductivity of 1.1 S cm−1, as shown in panel a of
3D Printing of ncrys-PEDOTX Incorporated Resins: 3D printing has matured into a promising technique for rapidly generating soft matter with complex form factors for biomedical applications, such as stents, scaffolds for tissue regeneration, implants, and soft robotics, among others. Printing conductive hydrogels while maintaining structural control of fine (<200 μm) features remains a challenge, as the incorporation of electroactive fillers into printable resins can dramatically impact the rate of photopolymerization or clog the printing nozzle due to particle aggregation during the printing process—arising from poor particle dispersibility. Alternatively, 3D printed insulating hydrogels can be endowed with electrical conductivity through 1) soaking the part in monomer solution, and 2) subsequently polymerizing the monomer in situ to generate a double network hydrogel—however such systems have limited control of the final CP loading, and can lack homogenous distribution of incorporated CP. While a growing literature has adopted making 3D printable resins directly from PEDOT:PSS, many biomedical applications require the high water content, mechanical properties, and biocompatibility of widely utilized synthetic biomaterials which mimic the native extracellular matrix microenvironments. It would be attractive to simply add a dispersible conductive filler to a pre-existing aqueous resin to directly print conductive hydrogels.
An aqueous photoprintable conductive resin was formulated through the addition of ncrys-PEDOT20 into a mixture of poly(ethylene glycol)diacrylate (PEGDA) and lithium phenyl (2,4,6-trimethylbenzoyl) phosphinate (LAP) photoinitiator in water (panel a of
Biocompatibility is an important and often overlooked property of materials intended for bioelectronic applications. The biocompatibility of ncrys-PEDOT20 was assessed by proxy of particle-loaded 3D printed PEGDA gels. Following a modified ISO 10993-5 protocol, in vitro cytotoxicity tests were performed both on extracts from the particle-loaded hydrogels and through direct contact via alamarBlue (panel d of
To demonstrate the capability to print complex, biomedically relevant geometries, particle incorporated aqueous PEGDA resins were printed. Complex tubular scaffolds resembling esophageal stents with 133.33 μm diameter struts were printed (panel j of
A simple, scalable acid-based nonsolvent induced phase separation (NIPS) approach was leveraged to afford acid crystalized PEDOT nanoparticles (ncrys-PEDOTX) from commercial PEDOT:PSS with dispersibility arising from an internal surfactant. By tuning the volume ratio of sulfuric acid within the coagulation bath, the PEDOT/PSS ratio was optimized to afford particles with conductivity rivaling all reports of conjugated polymer particles to date (σncrys-PEDOT20=410 S cm−1). Evidence from spectroscopy and scattering suggest that both the removal of insulating PSS and a decrease in the interchain π-π stacking distance of PEDOT lead to enhanced conductivity within the crystallized particles, similar to reports of acid crystalized thin films of PEDOT:PSS, but in solution. Sedimentation and conductivity analyses suggests there is a fine balance when removing PSS via acid crystallization to achieve enhanced conductivity, while maintaining dispersibility.
When incorporated within aqueous dispersions of both natural (polysaccharides and proteins) and synthetic biomaterials, ncrys-PEDOT20 demonstrated high compatibility without the need of external surfactants or sonication—this was observed at concentrations orders of magnitude higher than what is possible with pure graphene or carbon nanotubes. Furthermore, the particles did not interfere with the toolbox of chemistries typically used to crosslink hydrogels (hydrogen bonding, ionic bonding, Schiff-base chemistry, and radical photopolymerization). By directly adding ncrys-PEDOT20 to common hydrogel formulations, highly conductive composites were achieved with a percolation threshold between 15 and 20 wt % loading. The observed conductivity (>1 S cm−1) is remarkable considering the base of the hydrogel was not derived from a CP. Given the aqueous dispersibility and kinetic stability at high loadings (100 mg mL−1), the ncrys-PEDOT20 incorporated PEGDA resin was utilized for microstereolithography. The afforded hydrogels demonstrated biocompatibility and structural fidelity with complex, small (<150 μm) features. Such fine features are incredible considering the high loading of conductive filler, and that both sonication and surfactants were not required for resin preparation. As the reported particles display enhanced aqueous dispersibility, high conductivity, biocompatibility, and scalable access from a common commercial ink (PEDOT:PSS), we anticipate ncrys-PEDOTX offers a robust platform toward conductive hydrogels for TERM and other bioelectronic applications. Unlike other conductive hydrogel formulations which require complex multistep procedures and additives, ncrys-PEDOTX can be directly added to endow already existing and commonplace hydrogel formulations for biomedical applications with conductivity.
The foregoing description of the exemplary embodiments of the invention has been presented only for the purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in light of the above teaching.
The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to enable others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.
Some references, which may include patents, patent applications and various publications, are cited and discussed in the description of this invention. The citation and/or discussion of such references is provided merely to clarify the description of the present invention and is not an admission that any such reference is “prior art” to the invention described herein. All references cited and discussed in this specification are incorporated herein by reference in their entireties and to the same extent as if each reference was individually incorporated by reference.
This application claims priority to and the benefit of U.S. Provisional Application Ser. No. 63/491,753, filed Mar. 23, 2023, which is incorporated herein in its entirety by reference.
This invention was made with government support under grant number N00014-20-1-2777 awarded by the Department of Defense. The government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63491753 | Mar 2023 | US |
