Patent Application
20060183261
The present disclosure relates generally to forming biological sensors. Genomic evaluation is often used for the detection of various genes or DNA sequences within a genome, specific gene mutation such as single nucleotide polymorphisms (SNP), and mRNA species in biological research, industrial applications, and biomedicine. Often, these large scale techniques include synthesizing or depositing nucleic acid sequences on DNA chips and microarrays. These chips and arrays may be used for detecting the presence of and identifying genes in a genome or evaluating patterns of gene regulation in cells and tissues.
A potential problem in forming such chips or arrays is the inability, in some instances, to form small, localized, unique drop chemistries via a controlled synthesis, which may allow for controlled reaction kinetics and/or controlled concentrations. Some current techniques for forming arrays include pin arrayers, pipettes, and bulk coatings. While pin arrayers may dispense relatively small volumes with good spatial resolution, they are generally not designed to dispense multiple fluids at the same location. Pipettes, in some instances, are generally not capable of dispensing the volumes of interest with accuracy in timing and placement. Bulk coatings generally do not allow for targeted functionalization of specific areas.
Still further, many current techniques use wet chemicals in forming arrays. A potential problem with wet chemicals is that they generally should be used substantially immediately, or they should be stored in refrigeration until use.
Arrays of sensors may also be used in microfluidic devices. These devices are generally capable of analyzing one or more samples for the particular parameter that the array is configured for. One potential problem with such an array may be the general inability to detect a variety of parameters from a single sample.
As such, it would be desirable to provide a substantially controlled method for forming a biological sensor having unique chemistries, wherein the sensor has the ability to be stored substantially stably in ambient conditions. Further, it would be desirable to provide a system in which a sensor may be used that is capable of detecting a variety of parameters from a single sample.
A method of forming a sensor on a predetermined area of a substrate is disclosed. The method includes dispensing a plurality of layers on the predetermined area of the substrate. Each of the plurality of layers is formed of a substantially different fluid having a substantially different function. The dispensing of the layers is accomplished by drop generating technology.
Objects, features and advantages will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to similar, though not necessarily identical components. For the sake of brevity, reference numerals having a previously described function may not necessarily be described in connection with subsequent drawings in which they appear.
Embodiment(s) of the biological sensor as defined herein may be used in a consumer-based diagnostic device or system, where the sensor is capable of advantageously diagnosing and/or monitoring a variety of wellness parameters.
The sensor(s) of the present disclosure may be used for detecting the presence of and identifying genes in a genome, and/or evaluating patterns of gene regulation in cells and tissues. Embodiment(s) of the present sensor may also advantageously be used for immunological marking (e.g. in connection with proteins, antibodies and immunoassays). The sensor(s) of the present disclosure may also be used for detecting small molecule antigens, hormones, pharmaceutics, and/or the like. Further, the sensor(s) may be used to form lab cards and/or lab chips using different, individual sensor dots to detect many different analytes of interest, for example from a single biological sample.
It is to be understood that embodiment(s) of the biological sensor may advantageously have small sizes and dried, stable chemistries. Without being bound to any theory, it is believed that the diagnostic test time of an embodiment of the diagnostic device disclosed herein may advantageously be quick, due in part to the small sensor size enabling substantially reduced chemical reaction time, substantially reduced incubation periods, and substantially fast mass transport. Further, an embodiment of the biological sensor has at least three layers, each of which is able to perform a specific, unique function. Still further, embodiments of the biological sensor are dehydrated, thereby advantageously allowing for substantially stable storage of the sensor under ambient conditions until use.
Embodiments of the method of making embodiment(s) of the biological sensor advantageously enable controlled dispensing (via a drop generating technique) of multiple fluids at substantially the same time with close spatial resolution (e.g. at substantially the same location). Without being bound to any theory, it is believed that this allows a user to control the unique chemical reactions that may take place between the dispensed materials. Further, embodiment(s) of the method may advantageously maintain protein conformation and orientation on a surface by allowing a user to control drying and/or evaporation rate(s). Still further, the drop generating technology advantageously allows for control over the synthesis, reaction kinetics, and concentration of the various droplets that make up embodiment(s) of the biological sensor.
Further, a microfluidic device may contain thousands of biological sensors of the present disclosure, each of which is configured to detect a different parameter and/or analyte. Using such a device, a single sample may be divided (and prepared, if desired) upstream of each of the particular sensors, thus advantageously allowing various parameters to be detected from the single sample.
Referring now to
As depicted in both
In an embodiment, the biological sensor 14 includes at least one layer 18. In an alternate embodiment, sensor 14 includes a plurality of layers, non-limitative examples of which are depicted in
In both of the embodiments depicted in
The fluids dispensed to form the plurality of layers 16, 18, 20, 22, 24 may be biological or non-biological fluids. However, it is to be understood that the layer(s) generally are not formed of a sample to be analyzed. In the non-limitative example depicted in
The optional self-assembled monolayer 16, shown in both
The optional covalent attachment layer 22 may be deposited directly on some, or all, of the substrate surface 13 (not shown), or it may be deposited on some, or all, of the previously deposited self-assembled monolayer 16 (shown in
The detection molecule layer 18 is depicted in both
Embodiment(s) of the biological sensor 14 may optionally include a preservative layer 20 (shown in
Another example of another optional layer that may be used in the biological sensor 14 is a protective/passivation layer 24, as shown in
Generally, embodiment(s) of the biological sensor 14 may include a self-assembled monolayer 16 and/or a covalent attachment layer 22 to substantially enhance adhesion of the detection molecule layer 18 to the substrate 12. Further, it is to be understood that the addition of the preservative layer 20 and/or the protective layer 24 may advantageously allow the sensor 14 to remain substantially stable under ambient storage conditions. Still further, the preservative layer 20 and/or the protective layer 24 may serve to substantially preserve the function of the detection molecule layer 18 by substantially maintaining the functionality and conformation of the molecules of the detection layer 18.
Referring now to
Generally, an embodiment of a method for forming device 10/system 100 includes dispensing layer(s) on a substrate 12, for example, a plurality of layers 16, 18, 20,22, 24 on substrate 12. The embodiment of the method for forming the device 10 shown in
Each of the layers 16, 18, 20, 22, and 24 may be dispensed using drop generating technology. Drop generating technology may allow for substantially precise placement of the drops on the substrate 12. It is to be understood, however, that the precision of drop placement may be dependant, at least in part, upon the system used to hold and move the dispensed fluid. In a non-limitative example using drop generating technology, the precision of the drop placement is less than about 1 μm.
A non-limitative example of suitable drop generating technology includes an ejector head having one or more drop generators, which include a drop ejector in fluid communication with one or more reservoirs, and at least one orifice through which the discrete droplet(s) is eventually ejected. The elements of the drop generator may be electronically activated to release the fluid drops. It is to be understood that the drop generators may be positioned as a linear or substantially non-linear array, or as an array having any two dimensional shape, as desired.
An electronic device or electronic circuitry may be included in the ejector head as thin film circuitry or a thin film device that define drop ejection elements, such as resistors or piezo-transducers. Still further, the electronic device may include drive circuitry such as, for example, transistors, logic circuitry, and input contact pads. In one embodiment, the thin film device includes a resistor configured to receive current pulses and to generate thermally generated bubbles in response. In another embodiment, the thin film device includes a piezo-electrical device configured to receive current pulses and to change dimension in response thereto.
It is to be understood that the electronic device or circuitry of the ejector head may receive electrical signals and in response, may activate one or more of the array of drop generators. Each drop generator is pulse activated, such that it ejects a discrete droplet in response to receiving a current or voltage pulse. Each drop generator may be addressed individually, or groups of drop generators may be addressed substantially simultaneously. Some non-limitative examples of drop generating technology include continuous inkjet printing techniques or drop-on-demand inkjet printing techniques. Suitable examples of continuous inkjet printing techniques include, but are not limited to thermally, mechanically, and/or electrostatically stimulated processes, with electrostatic, thermal, and/or acoustic deflection processes, and combinations thereof. Suitable examples of drop-on-demand inkjet printing techniques include, but are not limited to thermal inkjet printing, acoustic inkjet printing, piezo electric inkjet printing, and combinations thereof.
To form the sensors 14 depicted in
In an embodiment, the layers 16, 18, 20, 22, 24 may be dispensed as drops/droplets on the substrate surface 13 and/or on the other layer(s). In an embodiment, the drop sizes may be sub-pico liter volumes of fluid established with a spatial resolution that varies depending, at least in part, on the accuracy of the equipment used. In an embodiment, the spatial resolution may be up to about 3000 dpi. In one non-limitative example, the spatial resolution is about 2400 dpi. Generally the drops have a size ranging between about 10 femto liters and about 200 pico liters. The drops of fluid in one layer may be a build-up of a fluid to achieve the desired density and/or surface coverage. In an embodiment of the sensor 14 having multiple layers, each layer 16,18, 20, 22, 24 may have a different volume of a different fluid, the volumes defined, in part, by the number of dispensed drops and the volume of each drop.
The small volume of drops contained in each layer 16, 18, 20, 22, 24 advantageously substantially reduces chemical reaction and incubation periods typical of traditional assays, in part, because the distance through which the molecules diffuse is small (e.g. the mass transport through pico liter sized drops is substantially faster than through a micro liter sized drop).
It is to be understood that each layer 16, 18, 20, 22, 24 is dispensed at a predetermined area(s) on the substrate surface 13. In an embodiment, the predetermined area is defined so the layers 16, 18, 20, 22, 24 are dispensed on the substrate 12 such that they touch and/or overlap, as depicted in the figures. The digital image control of drop generating technology (a non-limitative example of which is inkjet printing) advantageously permits for dispensing multiple fluids in various channels 26 on the substrate surface 13 in a pattern, at a single or specific area, or across substantially the entire surface 13, as desired. Non-limitative examples of suitable patterns that the biological sensors 14 may be formed in on the surface 13 include stripes, text patterns, graphical images, and/or combinations thereof. One example of an array has hundreds of biological sensors 14 on a device that is the size of a credit card.
The inkjet printing allows for the dispensing of the multiple layers of the same or different fluids onto the same physical location (predetermined area) of the substrate 12 at controlled times. For example, the selected layers 16,18, 20, 22, and/or 24 may be dispensed substantially simultaneously with or without drying time between dispense processes. In an alternate embodiment, the selected layers 16, 18, 20, 22 and/or 24 may be dispensed sequentially. The time between drop dispensing may be modulated between substantially simultaneous to time periods (non-limitative examples of which include seconds, minutes, hours, days, etc.) lapsing between dispenses. The time for dispensing may be dependant, at least in part, upon the application and equipment configuration used.
Further, the controlled timing of drop generator dispensing allows the chemical reaction kinetics and synthesis to also occur in a controlled manner on the substrate 12, in part, because the first order concentration of reactants and products is controlled with substantially minor mass transport limitations.
Sensor 14 conformation and orientation on the surface 13 may advantageously be controlled, in part, by controlling the drying and/or evaporation rate. In an embodiment, drop drying may be controlled, in part, by dispensing the different layers at advantageous times. A non-limitative example of advantageously timing the dispensing of the layers 16, 18, 20, 22, 24 includes first dispensing the self-assembled monolayer 16 and the covalent attachment layer 22 on the substrate 12 and allowing them to sit for a desired time. It is to be understood that the self-assembled monolayer 16 and the covalent attachment layer 22 may be substantially wet or substantially dry when the detection molecule layer 18 is dispensed thereon. After the detection molecule layer 18 is dispensed, and as it is drying, the preservative layer 20 may be dispensed thereon. After a desired time, the protective layer 24 may then be deposited. It is to be understood that the sensor 14 may be substantially wet or substantially dry as the protective layer 24 is added.
The drying rate(s) of the layers 16,18, 20, 22, 24 may be controlled, for example, by formulating the dispensed liquids (e.g. adding humectants) and by controlling the surrounding environment (e.g. temperature, humidity).
The dehydration of the drops advantageously forms layers 18 (and optionally 16, 20, 22, 24) that may advantageously be stable and stored under ambient conditions. This is unlike assays/devices that include wet chemicals that may require immediate use or refrigeration storage. Further, the preservation and/or protective layers 20, 24 may allow for rapid rehydration of the sensor 14 upon exposure to a desired fluid/solution/sample.
Generally, drop generating techniques are non-contact techniques. Non-contact techniques, e.g. inkjet printing, may advantageously enable surface shape and material independence and may also enable substantially contamination-free dispensing.
Referring now to
In an embodiment, the fluid passage 30 is divided into one or more fluid conduits 32, 34, 36. It is to be understood that the three conduits 32, 34, 36 depicted in
Each conduit 32, 34, 36 has an area 33, 35, 37 at which an embodiment of the biological sensor 14 may be positioned. It is to be understood that area 33, 35, 37 may be at any desirable location in/adjacent to conduit 32, 34, 36. It is to be further understood that any embodiment of the biological sensor 14 as disclosed herein may be used. Each of the biological sensors 14 located at the areas 33, 35, 37 may be adapted to detect a parameter from a sample to which it is exposed. In an embodiment, each sensor 14 may be configured to detect one or more parameters that is/are different from the one or more parameters detectable by each of the other sensors 14. In a non-limitative example, a first sensor 14 is adapted to detect complementary DNA strands; while a second sensor 14 is adapted to detect a desired antibody.
It is to be understood that the sample that is introduced into the housing 28 may be divided within the housing 28 such that each portion of the sample flows through a different conduit 32, 34, 36. Further, each conduit 32, 34, 36 may be configured to prepare each portion of the sample separately, if desired. The sample preparation (if performed) in each conduit 32, 34, 36 generally occurs upstream of the sensor 14. This advantageously may allow each portion of the sample to have a specific preparation process that corresponds to each sensor 14, such that the portion of the sample may chemically react with the particular sensor 14 to detect the desired parameter(s). In an embodiment, sample preparation in each conduit 32, 34, 36 may be different from the preparation that occurs in each of the other conduits 32, 34, 36, due, in part, to the different sensors 14.
It is to be understood that each biological sensor 14 is substantially isolated in/adjacent to conduits 32, 34, 36 such that a different portion of the sample may be exposed to each sensor 14. Upon being exposed to the previously prepared sample portions, each of the biological sensors 14 detects the specific parameter for which they are configured to detect.
In a non-limitative example, the microfluidic device 1000 contains thousands of different sensors 14 located in thousands of corresponding conduits. This advantageously allows a single sample to be introduced, divided, prepared, and tested for a variety of (e.g. wellness) analyte(s)/parameter(s).
Embodiment(s) of the biological sensor 14 have many advantages, including, but not limited to the following. Embodiments of the biological sensor 14 have multiple layers 16,18,20, etc. each of which is able to perform a specific, unique function. Further, embodiments of the biological sensor 14 are dispensed to permit dehydration, thereby advantageously allowing for ambient stable storage of the sensor 14 until use. The biological sensors 14 may advantageously be used in a consumer-based diagnostic device 10 or system 100 where each sensor 14 is substantially isolated in a channel 26 and is capable of detecting a parameter that is different from each of the other sensors 14. This may advantageously allow for diagnosing and/or monitoring a variety of wellness parameters. Further, embodiment(s) of the method of forming embodiments of the biological sensor 14 allow for controlled dispensing of multiple fluids in a desired amount, on a desired area, and at a desired time. Still further, embodiments of the biological sensor 14 may be used in a microfluidic device 1000. The microfluidic device 1000 may advantageously contain a plurality (a non-limitative example of which is a thousand or more) of biological sensors 14, each of which is configured to detect a different parameter(s). Using such a device 1000, a single sample may be divided and prepared upstream for each of the particular sensors, thus advantageously allowing various parameters to be detected from the single sample.
While several embodiments have been described in detail, it will be apparent to those skilled in the art that the disclosed embodiments may be modified. Therefore, the foregoing description is to be considered exemplary rather than limiting.
