This application claims priority to Korean Patent Application No. 10-2011-0013641, filed on Feb. 16, 2011, and all the benefits accruing therefrom under 35 U.S.C. §119, the content of which in its entirety is herein incorporated by reference.
1. Field
The disclosure relates to a sensor, which detects molecular binding with high-sensitivity by enhancing the mass of gold nanoparticles through light-irradiation, and a method thereof.
2. Description of the Related Art
A sensor such as a biosensor typically causes a change in an electrical or optical signal using, for example, a specific binding, reaction, etc. between a biomolecule, such as a protein, deoxyribonucleic acid (DNA), virus, bacteria, cell, and tissue, and a surface of the biosensor, thereby quantitatively and qualitatively analyzing and diagnosing the biomolecule.
A method of increasing the size of a gold nanoparticle using gold ions or silver ions together with a chemical reducing agent on the gold nanoparticle to enhance the mass of the gold nanoparticle, which is referred to as staining, is known. Since the method of enhancing the mass of a gold nanoparticle can cause binding of the gold nanoparticle after an antigen-antibody reaction of biomolecules and amplify a signal by enhancing gold or silver, complex preprocessing is not required. However, staining requires a catalyst, such as hydroxylamine or hydroquinone, to enhance the mass of the gold nanoparticle. Thus, gold or silver may be extracted from a solution as well as the gold nanoparticle, which deteriorates selectivity and sensitivity.
A method of enhancing the mass of a gold nanoparticle by increasing the size of a gold nanoparticle without using a reducing agent is disclosed.
Also, a method of detecting molecular binding and a sensor capable of improved sensitivity through a change in a mass, optical property, and/or electrical property of a gold nanoparticle is disclosed. The method may be used to detect biomolecular binding.
According to an aspect, a method of enhancing mass of a gold nanoparticle through light irradiation, including irradiating a composition comprising a gold nanoparticle and a metal-enhancing component with a wavelength of light effective to reduce the metal-enhancing component on a surface of the gold nanoparticle to increase the mass of the gold nanoparticle, is provided.
In the method, the light may be ultraviolet (“UV”) light.
In the method, the metal-enhancing component may be metal ions.
In this case, the metal ion may be selected from silver (Ag) ions, copper (Cu) ions, gold (Au) ions, and palladium (Pd) ions.
In the method, the gold nanoparticle may have a diameter of about 5 nm to about 200 nm.
According to another aspect, disclosed is a method of detecting molecular binding, including binding a target molecule to a sensor for detecting a change in a property of a gold nanoparticlebound to the target molecule; binding a gold nanoparticle to the target molecule; contacting the sensor including the bound gold nanoparticle and bound target moleculewith a composition including a metal-enhancing component; irradiating the composition and the bound gold nanoparticle with a wavelength of light effective to reduce the metal-enhancing component on a surface of the gold nanoparticle to change the property of the gold nanoparticle; and detecting the change in the property of the gold nanoparticle to detect the molecular binding of the target molecule.
In the method, the change in the properties of the gold nanoparticle may be selected from a change in mass, optical property, and electrical property.
In the method, the light may be UV light.
In the method, the metal-enhancing component may be a metal ion selected from a silver (Ag) ion, copper (Cu) ion, gold (Au) ion, and palladium (Pd) ion.
In the method, the gold nanoparticle may have a diameter of about 5 nanometers (nm) to about 200 nm.
In the method, the sensor may be a biosensor and the target molecule may be a biomolecule.
Thus, also disclosed is a method of detecting molecular binding of a target antigen or a target antibody to a sensor. The method includes binding the target antigen or target antibody to a surface of a sensor for detecting a change in a property of a gold nanoparticle bound to the antigen or antibody; binding a gold nanoparticle to the antigen or antibody bound to the sensor; contacting the sensor with the bound gold nanoparticle and bound target antigen or target antibody with a composition comprising a metal-enhancing component; irradiating the contacted composition with a wavelength of light effective to reduce the metal-enhancing component on a surface of the gold nanoparticle to change the property of the gold nanoparticle, wherein reducing is in the absence of a reducing agent; and detecting the change in the property of the gold nanoparticle to detect the molecular binding of the target antigen or target antibody to the sensor.
The target antigen or antibody may be directly or indirectly bound to the sensor and/or the gold nanop article.
According to another aspect, a sensor including a sensor, a gold nanoparticle, a composition, and a light irradiation device is provided. A target molecule binds to a surface of the sensor, and the sensor detects a change in a property of a gold nanoparticle bound to the target molecule. The gold nanoparticle is bound to the target molecule on a surface of the sensor. The composition includes a metal-enhancing component which changes the property of the gold nanoparticle, and the sensor is contacted with the composition. The light irradiation device irradiates the composition in contact with the sensor and the gold nanoparticle-bound target molecule. In the sensor, the metal-enhancing component is reduced on a surface of the gold nanoparticle by light from the light irradiation device to change the property of the gold nanoparticle, and the sensor detects the change in the property of the gold nanoparticle.
The sensor may be a biosensor and the target molecule may be a biomolecule.
In the sensor, the sensor may be selected from a mass sensor, an optical sensor, and an electrical sensor.
In the sensor, the change in the property of the gold nanoparticle may be selected from a change in mass, optical property, and electrical property.
In the sensor, the light may be UV light.
In the sensor, the metal-enhancing component may be metal ions, and the metal ions may be selected from silver (Ag) ions, copper (Cu) ions, gold (Au) ions, and palladium (Pd) ions.
In the sensor, the gold nanoparticle may have a diameter of about 5 nm to about 200 nm.
According to an embodiment, the mass of a gold nanoparticle may be enhanced by increasing the size of the gold nanoparticle without using a reducing agent, and thus selectivity or sensitivity may be improved.
Also, a gold-nanoparticle-based metal enhancement reaction by light-irradiation not only increases the mass and size of the gold nanoparticle but also changes optical and electrical properties, and thus it may be applied to a variety of sensors.
Further, sensitivity of detection may be improved due to a change in various properties of a gold nanoparticle due to the metal-enhancement reaction by light irradiation.
The above and other aspects, advantages and features of this disclosure will become more apparent by describing in further detail embodiments thereof with reference to the accompanying drawings, in which:
The invention now will be described more fully hereinafter with reference to the accompanying drawings, in which a non-limiting embodiment is 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 disclosure 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.
It will be understood that when an element is referred to as being “on” another element, it can be directly on the other element or intervening elements may be present therebetween. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
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.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” or “includes” and/or “including,” when used in this specification, specify the presence of stated regions, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other regions, integers, steps, operations, elements, components, and/or groups thereof.
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 term “lower,” can therefore, encompasses both an orientation of “lower” and “upper,” depending on 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 terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
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 disclosure, and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
One or more embodiments are described herein with reference to cross section illustrations that are schematic illustrations of idealized embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments described herein should not be construed as limited to the particular shapes of regions as illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, a region illustrated or described as flat may, typically, have rough and/or nonlinear portions. Moreover, sharp angles that are illustrated may be rounded. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region and are not intended to limit the scope of the claims.
Referring to
The gold nanoparticle-based metal enhancement reaction by light-irradiation not only increases the mass and size of the gold nanoparticle 13 but may also change one or more optical and/or electrical properties of the gold nanoparticle 13. Thus, the gold-nanoparticle-based metal enhancement reaction may be utilized in a variety of sensors. That is, the sensor 10 may be any one of a mass-based sensor, an optical sensor, and an electrical sensor. For example, as the mass-based sensor, a quartz crystal microbalance (“QCM”), a cantilever sensor, a surface acoustic wave (“SAW”) sensor, and the like may be used. As the optical sensor, a sensor using UV-visible spectrophotometry, colorimetry, surface plasmon resonance (“SPR”), and the like may be used. As the electrical sensor, an electrochemical sensor, a field effect transistor (“FET”) sensor, and the like may be used.
The gold nanoparticle-based metal enhancement reaction by light irradiation illustrated in
Referring to
Next, the sensor with the gold nanoparticle-bound target molecule is contacted, for example immersed, in a composition including a metal-enhancing component.
Next, the composition is irradiated with light. Upon irradiation of the composition, the metal-enhancing component is reduced on a surface of the gold nanoparticle. As a result, a change in a property of the gold nanoparticle occurs.
Thereafter, the change in the property of the gold nanoparticle is detected.
To confirm a change in a property of the gold nanoparticle, a composition obtained by combining gold nanoparticles having an average size of about 20 nm and a silver nitrate (or in another embodiment chloroauric acid (HAuCl4)) solution at a volume ratio of about 1:9 of gold nanoparticles to metal source is irradiated with UV light having a wavelength of about 254 nm for 10 minutes to reduce silver (or gold) ions in the composition on the surfaces of the gold nanoparticles.
Without being bound by theory, it is believed that the reduction of the metal-enhancing component, for example, silver ion, causes the metal (e.g., silver) to physisorb or chemisorb on the gold nanoparticles. As the metal is adsorbed, the surface sites of the gold nanoparticle may saturate so that additional reduced metal forms a metal adlayer on the adsorbed metal that is adsorbed on the gold nanoparticle.
Subsequently, absorbance is measured by UV-visible spectrophotometry. As a result of modification of the gold nanoparticle by the metal-enhancing component, absorbance is significantly varied as shown in
In an embodiment, the breadth of the absorption peak in the visible wavelength range that corresponds to modification of the gold nanoparticle by the metal-enhancing component (e.g., silver or gold) may be varied by controlling the amount of the metal-enhancing component that adsorbs onto the gold nanoparticle. In another embodiment, the breadth of the peak may be controlled by an identity of the metal-enhancing component. In a further embodiment, the peak wavelength of the absorption spectrum may be tuned by controlling the amount of the metal-enhancing component adsorbed onto the gold nanoparticle. In yet another embodiment, the peak wavelength of the absorption spectrum may be tuned by controlling the identity of the metal-enhancing component adsorbed onto the gold nanoparticle. In yet a further embodiment, a hybrid component may be formed on the gold nanoparticle from reducing a metal-enhancing component containing multiple types of metal ions, for example, gold and silver ions.
Referring to
Referring to
While the invention has been particularly shown and described with reference to embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit or scope of the present invention as defined by the following claims.
Number | Date | Country | Kind |
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10-2011-0013641 | Feb 2011 | KR | national |