Detection of biomolecules using optoelectronic biosensor based on localized surface plasmon resonance. Nanoimprint lithography approach (original) (raw)
Related papers
Localized surface plasmon resonance biosensors for real-time biomolecular binding study
A sensitive and low-cost microfluidic integrated biosensor is developed based on the localized surface plasmon resonance (LSPR) properties of gold nanoparticles, which allows label-free monitoring of biomolecular interactions in real-time. A novel quadrant detection scheme is introduced which continuously measures the change of the light transmitted through the nanoparticlecoated sensor surface. Using a green light emitting diode (LED) as a light source in combination with the quadrant detection scheme, a resolution of 10 −4 in refractive index units (RIU) is determined. This performance is comparable to conventional LSPR-based biosensors. The biological sensing is demonstrated using an antigen/antibody (biotin/ anti-biotin) system with an optimized gold nanoparticle film. The immobilization of biotin on a thiol-based selfassembled monolayer (SAM) and the subsequent affinity binding of anti-biotin are quantitatively detected by the microfluidic integrated biosensor and a detection limit of 270 ng/mL of anti-biotin was achieved. The microfluidic chip is capable of transporting a precise amount of biological samples to the detection areas to achieve highly sensitive and specific biosensing with decreased reaction time and less reagent consumption. The obtained results are compared with those measured by a surface plasmon resonance (SPR)-based Biacore system for the same binding event. This study demonstrates the feasibility of the integration of LSPR-based biosensing with microfluidic technologies, resulting in a low-cost and portable biosensor candidate compared to the larger and more expensive commercial instruments.
Microelectronic Engineering, 2009
The unique localized surface plasmon resonance (LSPR) property of gold nanoparticles has been used to design a label-free biosensor in a chip format. In this research, a sensitive and low-cost microfluidic integrated LSPR-based biosensor is developed. The gold nanoparticles were synthesized in solution and immobilized on quartz substrates by a silane layer as molecular glue. The gold nanoparticle-coated substrate was further integrated with a microfluidic chip. An automated sample introduction system was developed to perform a variety of processes including sample loading, chip washing and sample change. A refractive index resolution of 1 Â 10 À4 RIU (refractive index unit) was demonstrated by using the onchip biosensor combined with the automated sampling system. This developed microfluidic integrated system is capable of transporting a specific amount of bio-samples into the sensing chambers to achieve sensitive and specific biosensing with decreased reaction time and less reagent consuming. Proof-of-concept detection of antigen/antibody (biotin/anti-biotin) binding was performed and was quantitatively detected.
Sensors
In this work we present a surface plasmon resonance sensor based on enhanced optical transmission through sub-wavelength nanohole arrays. This technique is extremely sensitive to changes in the refractive index of the surrounding medium which result in a modulation of the transmitted light. The periodic gold nanohole array sensors were fabricated by high-throughput thermal nanoimprint lithography. Square periodic arrays with sub-wavelength hole diameters were obtained and characterized. Using solutions with known refractive index, the array sensitivities were obtained. Finally, protein absorption was monitored in real-time demonstrating the label-free biosensing capabilities of the fabricated devices.
Journal of Nanoscience and Nanotechnology, 2010
An enzyme-catalyzed precipitation reaction was employed as a means to increase the change in the LSPR signal after intermolecular bindings between antigens and antibodies occurred on gold nanodot surfaces. The gold nanodot array with an diameter of 175 nm and a thickness of 20 nm was fabricated on a glass wafer using thermal nanoimprint lithography. The human interleukin (hIL) 5 antibody was immobilized on the gold nanodot, followed by binding of hIL 5 to the anti-hIL 5. Subsequently, a biotinylated anti-hIL 5 and a alkaline phosphatase conjugated with streptavidin were simultaneously introduced. A mixture of 5-bromo-4-chloro-3-indolyl phosphate p-toluidine (BCIP) and nitro blue tetrazolium (NBT) was then used for precipitation, which resulted from the biocatalytic reaction of the alkaline phosphatase on gold nanodot. The LSPR spectra were obtained after each binding process. Using this analysis, the enzyme-catalyzed precipitation reaction on gold nanodots was found to be effective in amplifying the change in the peak wavelength of LSPR after molecular bindings.
Plasmonics in Biology and Medicine V, 2008
In this work, we aim at enhancing the sensitivity of surface plasmon resonance sensors towards the detection of biomolecule interactions by means of nanopatterning of the sensor surface. Use of nanostructured interfaces in combination with SPR is a promising step towards realizing biosensors with high efficiency and sensitivity. Nanopatterned surfaces enable multi-dimensional control over the behavior of surface-immobilized probe molecules. By means of a combination of self-assembled monolayer technology, colloidal lithography, and reactive ion etching, nanopatterns with either antibody confining or non-confining characteristics were produced and analyzed via photoelectron spectroscopy and infrared reflection absorption spectroscopy. Antibody immobilization on the patterns and subsequent specific binding of antigen was traced in real time by means of a surface plasmon resonance sensor. It was found that confining nanopatterns yield an increase in antibody activity towards antigen capture on surface of up to 120%, depending on the protocol used for their immobilization.
Journal of the American Chemical Society, 2009
Background on LSPR Sensing When the frequency of incident photons matches the collective oscillations of the conduction band electrons of noble metal nanoparticles, localized surface plasmon resonance (LSPR) occurs. 1-5 The result is a strong absorption band or multiple bands for metals such as Au and Ag in the visible region. The intensity and wavelength of the LSPR band depends on several factors, including the composition, size, and shape of the nanoparticles as well as the dielectric properties of the environment surrounding the metal and their local proximity to other metal nanoparticles. 1-5 There are three main types of sensing schemes based on the visible optical properties of metal nanoparticles. The first involves monitoring shifts in the LSPR band due to nanoparticle aggregation or changes in the nanoparticle-nanoparticle distance. This is usually performed with nanoparticles in solution, 6-9 but can be achieved in films. 10, 11 For example, researchers have detected polynucleotides, 6 proteins, 7, 9 solvents, 11 and metal ions 8, 10 through this scheme. Structural changes in DNA or other dynamic biophysical processes have also been probed by monitoring small changes in nanoparticle-nanoparticle distances optically, which is termed "molecular rulers". 12-14 A second approach involves using the nanoparticles as optical tags 15, 16 similar to fluorophores or other labels in an immunoassay or for cell imaging. 17, 18 In
Journal of Applied Physics, 2011
Localized surface plasmon resonance (LSPR) has emerged as a leader among label-free biosensing techniques in that it offers sensitive, robust, and facile detection. Traditional LSPR-based biosensing utilizes the sensitivity of the plasmon frequency to changes in local index of refraction at the nanoparticle surface. Although surface plasmon resonance technologies are now widely used to measure biomolecular interactions, several challenges remain. In this article, we have categorized these challenges into four categories: improving sensitivity and limit of detection, selectivity in complex biological solutions, sensitive detection of membrane-associated species, and the adaptation of sensing elements for point-of-care diagnostic devices. The first section of this article will involve a conceptual discussion of surface plasmon resonance and the factors affecting changes in optical signal detected. The following sections will discuss applications of LSPR biosensing with an emphasis on recent advances and approaches to overcome the four limitations mentioned above. First, improvements in limit of detection through various amplification strategies will be highlighted. The second section will involve advances to improve selectivity in complex media through self-assembled monolayers, "plasmon ruler" devices involving plasmonic coupling, and shape complementarity on the nanoparticle surface. The following section will describe various LSPR platforms designed for the sensitive detection of membrane-associated species. Finally, recent advances towards multiplexed and microfluidic LSPR-based devices for inexpensive, rapid, point-of-care diagnostics will be discussed.
Topographically Engineered Large Scale Nanostructures for Plasmonic Biosensing
Scientific Reports, 2016
We demonstrate that a nanostructured metal thin film can achieve enhanced transmission efficiency and sharp resonances and use a large-scale and high-throughput nanofabrication technique for the plasmonic structures. The fabrication technique combines the features of nanoimprint and soft lithography to topographically construct metal thin films with nanoscale patterns. Metal nanogratings developed using this method show significantly enhanced optical transmission (up to a one-order-ofmagnitude enhancement) and sharp resonances with full width at half maximum (FWHM) of ~15nm in the zero-order transmission using an incoherent white light source. These nanostructures are sensitive to the surrounding environment, and the resonance can shift as the refractive index changes. We derive an analytical method using a spatial Fourier transformation to understand the enhancement phenomenon and the sensing mechanism. The use of real-time monitoring of protein-protein interactions in microfluidic cells integrated with these nanostructures is demonstrated to be effective for biosensing. The perpendicular transmission configuration and large-scale structures provide a feasible platform without sophisticated optical instrumentation to realize label-free surface plasmon resonance (SPR) sensing.
A surface plasmon resonance array biosensor based on spectroscopic imaging
Biosens Bioelectron, 2001
We have developed a multi-element transduction system which combines conventional SPR spectroscopy with one-dimensional SPR microscopy to create an effective platform for monitoring binding events on macro-or micro-patterned receptor arrays created on disposable sensor chips. This creates an effective platform for monitoring simultaneous binding events on each of the regions patterned with the receptors. This system has been specifically designed with commercially available components to allow relatively easy duplication. Furthermore, this system can use a proven, simple method to compensate for changes in the bulk index of refraction of the solution containing the analytes due to changes in temperature or solute concentration with simple modifications to the sensor chips alone. Preliminary results demonstrate how this system can be used to monitor several independent biospecific binding events simultaneously.