Development And Improvement Of A Miniature Lateral Flow Test Strip Detection Equipment

Nowadays, gastric carcinoma is the common tumor in China. Mostpatients were diagnosed with advanced gastric cancer, while only less than10%patients were diagnosed with early gastric cancer (EGC). However,patients with EGC compared with those suffering with advanced gastriccancer have higher survival rate, so early diagnosis of gastric carcinoma isof significant importance. It has been demonstrated that HelicobacterPylori CagA protein is closely related with the development of gastriccancer.In the past few decades, immunochromatographic assay, due to itssimple, rapid and low-cost detection, has been widely used in many fields,such as environmental monitor, food safety and medical diagnosis etc.Though this technology has so many merits, the limit of low sensitivitydetection and qualitative detection still confine its extensive applications.For the reason, some group researchers begin to study immune biosensors for quantitative detection. At the same time, as the development ofnanotechnology, some novel nanomaterials are applied toimmunochromatographic assay for further improving detection sensitivity.In this paper, we designed a CCD-based immune biosensor. Itconsists of sample module, light source module, acquisition module, powermodule, radiator module and PC module. By changing the light source,this instrument could realize quantitative detection of colloidal goldlabeled lateral flow test strips or quantum dots labeled lateral flow teststrips. In addition, a software system was also developed in order toanalyze data and diagnose diseases, which was a user-friendly interface. Inthe system, two image algorithms were used for processing test stripimages. Moving K-means method based on HSI color space was appliedon colloidal gold labeled lateral flow test strip images, and revised WTHEalgorithm was used for quantum dots labeled lateral flow test strip images.Both methods have led to satisfying results with extracting usefulinformation.In the end, CagA samples of different concentrations were detectedby using two kinds of lateral flow test strips. It turned out that theinstrument based on colloidal gold labeled lateral flow test strips reached a sensitivity of0.5ng/mL, while the device employing quantum dots labeledlateral flow test strips had a limit of detection with20pg/mL.