An Improved Centroid Algorithm for a Surface Plasmon Resonance Bioanalyzer Using Microprocessors

We present an improved centroid algorithm designed for an economical, high-performance biomolecular interaction analyzer, which is based on the use of TSPRlk23 biosensors and composed of a microflow cell, a thermoelectric cooler (TEC), a clamp, a touch-screen monitor, three microprocessors and a photoelectronic conversion device. The proposed algorithm can be applied to asymmetric surface plasmon resonance (SPR) curves often obtained by a gold-based SPR biochemical analyzer and evaluated by the numerical calculations. The validity and efficiency of the algorithm were demonstrated by a comparison of the numerical calculation results with the experimental results obtained by using the SPR biochemical analyzer to measure the ethanol solutions with five concentrations of 10, 20, 30, 40, 50 wt.%. The sensitivity of the SPR biochemical analyzer was fairly enhanced by the improved centroid algorithm that we argued in this work even without the assistance of a laptop computer. In comparison with the first-order centroid algorithm, the experimental results further showed that the errors of measurement could be reduced when such an improved centroid algorithm was used.