Low-cost Surface Plasmon Resonance Research Articles

An innovative plastic optical fiber-based biosensor for new bio/applications. The case of celiac disease

Abstract In this work an innovative and low cost surface plasmon resonance (SPR) biosensor, based on the utilization of plastic optical fibers (POF), is presented and experimentally tested for the diagnosis and/or follow-up of celiac disease. In particular, the POF-based sensor was used to monitor the formation of the transglutaminase/anti-transglutaminase antibodies formation, a new hallmark for the diagnosis of celiac disease. In particular, on the gold layer surface of the POF sensor, the guinea pig transglutaminase was immobilized. The ability of the POF-sensor to detect the binding of anti-transglutaminase antibodies to the immobilized transglutaminase was studied. The obtained results showed that the POF-sensor is able to sense the transglutaminase/anti-transglutaminase complex in the range of concentrations between 30 nM and 3000 nM. Importantly, the proposed sensing method could be easily expanded to different target compounds.

A polycarbonate based surface plasmon resonance sensing cartridge for high sensitivity HBV loop-mediated isothermal amplification

In this study, we report a simple, low-cost surface plasmon resonance (SPR)-sensing cartridge based on a loop-mediated isothermal amplification (LAMP) method for the on-site detection of the hepatitis B virus (HBV). For LAMP detection, a SPR based LAMP sensing system (SPRLAMP) was constructed, including a novel SPRLAMP sensing cartridge integrating a polymethyl methacrylate (PMMA) micro-reactor with a polycarbonate (PC)-based prism coated with a 50 nm Au film. First, we found that the change of refractive index of the bulk solution was approximately 0.0011 refractive index (RI) units after LAMP reaction. The PC-based prism's linearity and thermal responses were compared to those of a traditional glass prism to show that a PC-based prism can be used for SPR measurement. Finally, the HBV template mixed in the 10 μl LAMP solution could be detected by SPRLAMP system in 17 min even at the detection-limited concentration of 2 fg/ml. We also analyzed the correlation coefficients between the initial concentrations of HBV DNA templates and the system response (ΔRU) at varying amplification times to establish an optimal amplification time endpoint of 25 min ( R 2 = 0.98). In conclusion, the LAMP reaction could be detected with the SPRLAMP sensing cartridge based on direct sensing of the bulk refractive index.

Exchangeable low cost polymer biosensor chip for surface plasmon resonance spectroscopy

An exchangeable low cost surface plasmon resonance biosensor chip for real-time monitoring of biochemical interactions has been developed. It is based on a simple patented prism design, fabricated from a cyclic-olefin co-polymer (COC), which thus allows for high throughput fabrication, using injection molding techniques. The sensor chip can be operated in both, angular and wavelength interrogation modes, and ray tracing simulations have investigated the light beams focalization.

Design and validation of a low cost surface plasmon resonance bioanalyzer using microprocessors and a touch-screen monitor

An economical and high-performance bioanalyzer, with no use of laptop computer, based on the use of TSPR1k23 biosensors was systematically designed, and validated experimentally for its high performance. The analyzer is composed of a micro-flow cell, a thermoelectric cooler (TEC), a clamp, a touch-screen monitor, and an electronic control unit (ECU) incorporated with photoelectric conversion device. The micro-flow cell is made of stainless steel with high thermal conductivity, and the micro-flow system is based on PID temperature-controlled algorithm to keep the constant temperature (25°C) of the liquid sample via thermal exchange with the clamp. With a peristaltic pump implemented by an injection loop flow system, the bioanalyzer allows the core sensor to be completely exposed to samples. The touch-screen monitor displays the normalized response signal values updated every 0.25s, with a typical noise level less than 5RU (response unit) within 2h. The bioanalyzer was validated using hepatitis B surface antigen (HBsAg) as an example. Anti-HBsAg monoclonal antibody is adhered to the surface of the sensor chip by a bifunctional cross-linker with the technology of self-assembly. The duration of the HBsAg measurement only lasts 5min with a dilution factor ranging from 200 to 1200, optimized with a R-squared value 0.998. The results suggested that the bioanalyzer has higher selectivity, lower cost, expanded detection limit, and shorter measuring time as compared with the HBsAg ELISA kit, especially for low concentrations of analyte.

高精度单光束自参照相位灵敏表面等离子体共振传感器

A versatile and low-cost single-beam self-referenced phase-sensitive surface plasmon resonance (SPR) sensing system with ultra-high resolution performance is presented. The system exhibits a root-mean-square phase fluctuation of +-0.0028 angle over a period of 45 min, i.e. a resolution of +-5.2*10^(-9) refractive index units. The enhanced performance has been achieved through the incorporation of three design elements: a true single-beam configuration enabling complete self-referencing so that only the phase change associated with SPR gets detected, a differential measurement scheme to eliminate spurious signals not related to the sensor response, and the elimination of retardation drifts by incorporating temperature stabilization in the liquid crystal phase modulator. Our design should bring the detection sensitivity of non-labeling SPR biosensing closer to that achievable by conventional fluorescence-based techniques.

A low-cost surface plasmon resonance instrument based on detection of resonance excitation wavelength

A laboratory-made surface plasmon resonance (SPR) instrument based on the detection of resonance excitation wavelength has been successfully fabricated. The performance and workability of the SPR instrument was demonstrated as a DNA biosensor. Biotinylated single-stranded oligonucleotides (ssDNA) were chemically immobilized on a gold-film surface of the SPR instrument as a DNA probe for the detection of its fully complementary, half-complementary and non-complementary ssDNA. The immobilization of the ssDNA probe was done by avidin–biotin linkage. The ssDNA used were 12-mer oligonucleotides. The sensing mechanism was based on the shift in resonance wavelength of an excitation light beam as the target ssDNA hybridized with the ssDNA on the gold-film surface. The linear dynamic ranges of the DNA biosensor for fully complementary and half-complementary ssDNA are 0.04–1.2 pM and 0.08–1.1 pM, respectively. The DNA biosensor showed higher sensitivity to fully complementary ssDNA than to half-complementary ssDNA. But no shift of resonance wavelength to the non-complementary ssDNA was observed.