Regeneration Ability of Aptamer-coated Piezoelectric Quartz Crystal Chips / 中华医院感染学杂志

OBJECTIVE To study the optimal reagent for regeneration of aptamer-coated piezoelectric quartz crystal chips and detect storage ability of aptamer-coated chips. METHODS Anti-IgE aptamers were immobilized on the gold surface of piezoelectric quartz crystal biosensor with biotin-avidin method. The reaction between anti-IgE aptamers and IgE was monitored in time on piezoelectric sensor. We tried to regenerate the sensor surface after binding IgE by rinsing the aptamer-coated chips with HCl, NaOH, EDTA, urea and formamide individually. Aptamer-coated chips were stored in PBS with 0.1% sodium azide and the stored chips were used to detect IgE in 35 days. RESULTS Of the five reagents, EDTA was the best one for regeneration of aptamer-coated chips and the sensor could retain 91.5% of the original detecting signals after five regeneration cycles. Moreover, the aptamer-coated chips could be stored in the binding buffer for 21 days without obvious loss of activity. CONCLUSIONS Compared with antibody-based piezoelectric sensor, aptamer-based sensor has lower cost, more regeneration cycles and longer time for the storage of chips. This series of experiments shows the superiority of aptamer detection.

Aptamer-based Piezoelectric Quartz Crystal Biosensor / 中华医院感染学杂志

OBJECTIVE To establish an aptamer-based piezoelectric sensor assay to detect human immunoglobulin E (IgE) and acquire the parameters about this kind of biosensor. METHODS Anti-IgE aptamers were immobilized on the gold surface of piezoelectric quartz crystal sensor with biotin-avidin method. The reaction between anti-IgE aptamers and IgE was monitored in time on piezoelectric sensor. Different concentrations of IgE were detected and the calibration curve of IgE was drawn. Non-specific response signals of BSA, IgG and IgE were monitored to show the detecting specificity of aptamer-based sensor. RESULTS For the aptamer-based sensor, the lowest limit of detection was 0.055mg/L and the linear range was 0.1-2.5mg/L. Non-specific signals of this sensor were less than 5% of specific signals of IgE at the same concentration. CONCLUSIONS The aptamer-based piezoelectric sensor can detect 5.5 ng IgE while the non-specific signals are very low. So this aptamer-based sensor is hopeful to be applied to clinical laboratory diagnosis.

Immobilization Method on Piezoelectric Quartz Crystal DNA Sensors Based on Monolayer SAM / 中华医院感染学杂志

OBJECTIVE To discuss a highly effective method to immobilize probe on the surfaces of piezoelectric DNA sensors.METHODS Pseudomonas aeruginosa probe was immobilized on the gold surface of gene sensor(array) with routine self-assembly method(SAM)(non-reduction method) and SAM with deoxidized probe((reduction) method),respectively.The changes in frequency and time-cost were compared in reactions with(different) concentrations of probe.RESULTS Reduction method had the advantage of more probe immobilization;less time consumed in testing and higher changes in frequency during the reaction than non-reduction method.CONCLUSIONS Reduction method has a better ability to immobilize probe on the surfaces of piezoelectric DNA sensors.