Design Of A Colloidal-gold Strip Reader With High Accuracy

Gold-immunochromatographic assay (GICA) is a rapid immunoassay method rising in recent years. As it is simple, rapid, and low cost and has high sensitivity and stability, GICA has been widely used in various fields including disease detection, health care, epidemics monitoring, food inspection and quarantine.The research on colloidal-gold strip test mainly focuses on qualitative judgment, for the moment, which limits its application. Qualitative judgment is often prone to human error, and requires users with professional skills sometimes and even may produce false-positive or false-negative results in some instances; What’s more, with just qualitative results, we are unable to monitor the dynamitic process of target objects when chronic patients need long-term testing for a certain physiological index. As there is greater need for more detailed results, it has very significant practical value to develop quantitative analytical methods and instrument for colloidal-gold strips.According to investigation of the technology background analysis of the existing solutions, this paper proposes a novel detecting scheme for quantitative assay for colloidal-gold strips, based on the principle of photoelectric detection, with simple optical path, high accuracy, quick in measuring and low cost. It uses green LEDs as the emitting light source and a photodiode as the receiving device for obtaining reflected light, and utilizes a step motor to drive detection system for scanning the examining areas; Least squares method and wavelet transform are concerned for analyzing and processing the result waveform in order to get the concentration of sample. Under the produced solution, the paper designs a colloidal-gold strip reader with ultra-high precision. In the paper, the instrument of colloidal-gold strip reader is detailed introduced from the aspects of mechanical structure, optical path system, hardware circuits, software programming and algorithm research, and extensive experimental has been made to prove the feasibility of the proposed scheme and practical value of the instrument in the end.The experiment results indicate the instrument has high sensitivity and detection veracity rates with detecting errors less than1%, and good detection stability with coefficient variables less than8%o.