Surface plasmon resonance (SPR) sensing technology is widely used in the field of biosensors due to its non-marking, high-sensitivity, and non-invasive characteristics. However, SPR technology is still limited to sensing analysis in twodimensional plane, axial detection, as the key of SPR application in three-dimensional medium spatial detection, has not been well studied and solved. In an angle-interrogation SPR sensing system, the spatial characteristics of evanescent wave-dielectric interaction at multiple wavelengths are studied, and the factors affecting the spatial distribution of surface plasmon resonance are also analyzed. An axial spatial resolution method based on the particle swarm optimization (PSO) algorithm with multi-wavelength angle-interrogation structure is proposed, the refractive index distribution in axial space is determined by analyzing the characteristic SPR signal. In addition, the calculation and analysis of the applicable range of wavelengths are carried out. In the reliable spectral range of the incident light wavelength of 600-900 nm, the average error of the axial refractive index spatial resolution increases from 10-5 RIU to 10-4 RIU as the number of axial layers increases. The proposed multi-wavelength angle modulation structure analysis method based on PSO algorithm extends the SPR detection range from two-dimensional plane to three-dimensional space, which provides a new and promising analysis model for molecular biology.
The throughput and label-free multianalyte interrogation ability provided by surface plasmon resonance imaging (SPRi) sensors has gained considerable interest in biochemical analysis. Here, we report an optical platform based on polarization contrast modulation, in which a three-dimensional plasmonic microwell array is used as a sensing chip to eliminate background resonance and greatly enhance the electromagnetic field response in the microwell structure by confining the SPR. In addition, the sensor can provide an extremely high contrast and signal-to-noise ratio and can achieve a very high sensitivity response (1.52 × 105 pixel / RIU). Additionally, the signal-to-background ratio is improved to 40. The low-concentration limit of detection can reach 5.38 × 10 − 7 RIU, which is 1 order of magnitude improvement. In biomolecular interaction analysis, the sensor can detect a 5.12 × 104-fold diluted bovine serum albumin antibody solution. The special chip architecture and high image quality introduce an array screening method using SPRi detection.
The throughput and label-free multianalyte interrogation ability provided by surface plasmon resonance imaging (SPRi) sensors has gained considerable interest in biochemical analysis. Here, we report an optical platform based on polarization contrast modulation, in which a three-dimensional plasmonic microwell array is used as a sensing chip to eliminate background resonance and greatly enhance the electromagnetic field response in the microwell structure by confining the SPR. In addition, the sensor can provide an extremely high contrast and signal-to-noise ratio and can achieve a very high sensitivity response (1.52 × 105 pixel / RIU). Additionally, the signal-to-background ratio is improved to 40. The low-concentration limit of detection can reach 5.38 × 10 − 7 RIU, which is 1 order of magnitude improvement. In biomolecular interaction analysis, the sensor can detect a 5.12 × 104-fold diluted bovine serum albumin antibody solution. The special chip architecture and high image quality introduce an array screening method using SPRi detection.
A bimetallic chip was designed to improve the performance of a surface plasmon resonance (SPR) sensor based on angular interrogation, which demonstrated a relatively low noise level and a high resolution compared with a single gold chip. The calculated refractive index resolution of the bimetallic chip is 5.3 × 10-7 RIU. In addition, the electric field intensity at the surface of the chip is enhanced. This can guarantee a high sensitivity in a larger sensing region for the measurement of macromolecules, especially in the field of biological sensing. The bimetallic chip SPR sensor was combined with molecularly imprinted polymer (MIP) film as artificial receptor to detect antibiotics. The molecularly imprinted polymer was prepared by photo-polymerization of ciprofloxacin capped with itaconic acid as functional monomer on the bimetallic chip. The thickness of the MIP film was 16 ±2 nm, which was measured with a stylus profiler. The MIP exhibited high selectivity to ciprofloxacin compared with dopamine and penicillin, and the selectivity coefficients of ciprofloxacin,penicillin, and dopamine were 1, 0.22, and 0.19, respectively. The SPR response was proportional to the concentration of ciprofloxacin, the limit of detection (LOD) of which was 0.1 pM or 0.04 ppt,while the LOD for a single gold chip was 0.5 pM. The adsorption of CIP by the MIP bimetallic-coated chip was reversible. Taking the reproducibility of MIP into consideration, a combination of SPR sensing with MIP is a promising method for the detection of ciprofloxacin.
Abstracts A method, based on particle swarm optimization (PSO) and finite-difference time-domain (FDTD) simulation, is proposed to optimize micro-well structural parameter of SPRi sensor with polarization contrast modulation. According to PSO algorithm, these six structural parameters are optimized. Following that, the electromagnetic field characteristics of the gold micro-well structure involving the background gold film thickness are simulated and optimized by FDTD. It is proved that the sensitivity of the optimized structure is four times higher than the traditional one, which shows the practicability of the home-built SPRi sensor, in addition, as a result of the high signal-to-noise ratio, the refractive index resolution of the sensor is two order of the magnitude lower. Besides that, optimization algorithm provides a new way for other SPR sensor optimization.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.