Study Of Rapid Test Strips For Diagnosing Glycosylated Hemoglobin (HbA1c)

Diabetics is a global public health problem,characterized by hyperglycaemia.People with type II dibetes have many complications such as high blood pressure,cerebral infarction and nephrotic syndrome.In China,there are 114 million diabetics and 140 million pre-diabetics,and the prevalence rate of adult with diabetes is 10.9%which also accounts for a third of the world’s diabetics.Since 1969 Rahbar found that glycosylated hemoglobin in diabetics was elevated for the first time,after more than 40 years,glycosylated hemoglobin(HbA1c)has gradually become an indispensable indicators in the diagnosis and treatment for diabetics.Therefore,it is necessary to find an ideal,fast,low-cost and convenient analysis method to achieve rapid and accurate detection of HbA1c.The work of this study is as follows:(1)Based on the method of boric acid affinity chromatography,the affinity probe BSA-APBA was designed and constructed which could be immobilized on NC membrane.Bovine serum albumin(BSA)was used as the carrier and the 3-aminobenboric acid(3-APBA)was coupled with BSA to construct the affinity probe.Using the affinity probe as the test line on the test strips,semi-quantitative detection was conducted according to the color of the glycosylated hemoglobin on the test line.(2)With carboxyl polystyrene microspheres as raw material,based on methods such as swelling,covalent coupling and electrostatic adsorption,fluorescent microspheres coated with recombinant corestreptavidin(SA)were prepared.Fluorescent microspheres coupled with the monoclonal antibody for immunoassay were prepared based on avidin-biotin system.Fluorescent microspheres were utilized as the carrier,and traditional fluorescence immunochromatographic test strips were build,and test results were read by fluorescent reader NE 1700.(3)A rapid and easy to operate point-of-care testing strip based on fluorescent affinity immunochromatography to quantitatively determine the concentration of HbA1c in whole blood was developed.This assay based on a sandwich method performed on test strips effectively utilized the principle of affinity chromatography column which was commonly used in the detection of HbA1c.The test results were presented in a quantitative way by fluorescent signals with an assay time of 30min including hemolysis(10min),whole blood pretreatment(10min)and detection(10min).The test strips based on fluorescent affinity immunochromatography could quantitatively detect HbA1c in a wide range(3.0%~13.8%)with excellent linearity(R~2>0.99)and effectively differentiated negative or positive results(below or above 6.5%of HbA1c).The coefficients of variation for our test strips were both less than 15%and the accuracy was demonstrated compared with high performance liquid chromatography(HPLC)(R~2>0.95).There were no statistically significant differences between the lateral flow strips and HPLC.