The Technology Research Of Genetically Modified Rice Detection By Electrochemical Sensor

Simple,cost-effective and reliable methods for the quantification of the transgenic event Bt63 in rice are highly demanded due to the export event in recent years.The leading edge technology electrochemical DNA biosensors,which focuses on simple,rapid,automatic on-line,portable and inexpensive way of testing,has been achieved great progress and development in recent years.It represents a potential way in GMO detection.The presence of the transgene can be detected by a specific capture probe that is bound to the sensor surface.Thus,an electrochemical biosensor for screening genetically modified Bt63 event-specific sequences of DNA has been developed in our work.Square wave voltammetry(SWV)response of electrochemical marker MB was used to monitor the probe immobilization and target hybridization event.We also studied the influence of MB incubation and hybridization procedures on the responses of biosensor.The peak values of MB were linear with the logarithm of the target DNA concentrations from 1.0×10-10 to 1.0×10-5 M with a detection limit of 5.80×10-11 M.We also use the electrochemical biosensor to detect Bt63 transgenic rice leaves powder and various kinds of samples to verify whether it can be applied successfully in the real crop screening and distinguishes different amounts of DNA extracted from transgenic rice.The results showed that the proposed method provides accurate and sensitive Bt63 rice monitoring results compared to the PCR results,the applicability of the method as an effective and potential tool for GMO detection on market was confirmed by these findings.In order to improve the sensitivity of biosensor,a simple and reliable electrochemical biosensor based on an in-situ synthetic Au-reduced graphene oxide(Au-RGO)nanocomposite was constructed as well,which is considered a potential sensing platform for sensitive and selective Bt63 rice detection.UV-vis spectroscopy,transmission electron microscopy(TEM),raman spectra and cyclic voltammograms of the surface characterization showed that GO was reduced effectively and Au nanoparticles with an average size of 30 nm were well dispersed on the surface of RGO.Under optimum conditions,the peak values of MB were linear with the logarithm of the target DNA concentrations from 1.0×10-9 to 1.0×10-14 M with a detection limit of 3.36×10-5 M.Studies also showed that the DNA biosensor had good reproducibility and stability.At last,we used this biosensor to detect several rice samples,it showed good sensitivity and selectivity.Thus,the modified biosensor has great improvement in both sensitivity and selectivity,which laid the foundation for the development of commercial sensing devices for micro-rice testing.