ABSTRACT
Objective To construct an immunosensor for detecting CD4+ T lymphocytes without labeling .Methods The staphy-lococcus protein A(SPA) method was adopted to conduct the oriented immobilization of CD4 monoclonal antibodies on the gold in-terdigitated microelectrode surface for capturing CD4+ T lymphocytes .Then cyclic voltammetry(CV) method was used to conduct the representation of modification situation on the gold interdigitated microelectrode surface .Finally the electrochemical impedance spectroscopy(EIS) was used to detect the impedance of CD4+ T lymphocytes captured by the immunosensor .The standard curve was drawn by the impedance values change obtained by the equivalent electric circuit fitting .Results The linear range of this im-munosensor for detecting CD4+ T lymphocytes was (5 × 103 -5 .0 × 106 )/mL ,with lower detection limit of 5 .0 × 102/mL .Conclu-sion The constructed immunosensor has accurate and reliable detection results uhidn is simple to operate accurate ,convenient and cheap ,which might be expected to be used in the real-time detection system ,and offers help for realizing rapid ,accurate and inex-pensive CD4+ T lymphocyte count .
ABSTRACT
Objective To investigate the similarities and differences of 3 methods for detecting hepatitis B virus S 1(PreS1) ,and select the appropriate method for detecting clinical samples .Methods The PreS1 of the serum samples from chronic hepatitis B pa-tients were tested with enzyme immunoassay analyzer ,time-resolved method and the manual method .To compare the repetition rate ,select PreS1 antigen strongly positive serum and weak positive serum were detected 15 times by three methods ;To compare the explicit rate ,the reaction temperature was raised or lowered by 3 ℃ .Results The positive rate of three methods was 93 .53% , 92 .81% ,92 .81% .Automated ELISA reproducibility CV strong positive CV3 .62% ,weakly positive CV was 13 .42% ,CV of time-resolved method for the 2 kinds of samples were 5 .10% ,7 .92% ,manual methods CV 11 .10% 29 .88% ;changing the reaction incu-bation temperature 3 ℃ ,automatic detection ELISA all specimens S/CO value decreased ,increasing the chance of a false negative . The manual methods and time-resolved detection method for all specimens S/CO values increased ,increasing the chance of a false positive .Conclusion The detection rate and repeatability of automated ELISA were better .The time-resolved method followed and the manual methods were poor .