Rapid Detection Of Food Safety Based On Paper-Based Microfluidic Bionanosensor Technology

As one of the most basic livelihood,food safety is closely related to our life.Mycotoxin poisoning and food allergy are two important factors that affect food safety,which seriously threaten people's lives and health,and bring great pressure to our medical and health system.At present,the mainstream detection methods in food safety testing field need large equipment and trained operators,and it is difficult to get out of the laboratory in general,so it can not be applied to daily life.In order to overcome the shortcomings of traditional food safety detection methods,it is of great theoretical significance and application value to study a more specific,faster,sensitive and low-cost portable detection method.The paper-based analytical equipment provides a way for food safety departments to develop miniaturized,simplified and low-cost analytical methods.In this paper,a rapid food safety detection platform based on paper-based microfluidic chip is constructed.By using electrochemical detection method,the sample operation,paper supported microelectrode,nano electrochemical sensor,aptamer-antigen immune reaction mechanism are integrated together to achieve the real significance of convenience,so as to achieve low-cost and mass production.The details are as follows.(1)The paper-based microfluidic chip based on origami technology is designed.On the one hand,the chip can realize the detection of dual target sources,on the other hand,it is made into origami structure to avoid cross contamination in the process of working electrode modification.Then the chip was functionalized to construct peanut allergen Ara h1 aptamer biosensor.In this paper,the working electrode modified with black phosphorus nanosheets was used to realize the high sensitivity detection of peanut allergen Ara h1.The results showed that the best conditions for the detection of peanut allergen Ara h1 were as follows: the immobilization time of the aptamer was 1 h,the concentration of the aptamer was 5 ?M,and the binding time of the aptamer-Ara h1 was20 min.Under these conditions,the dynamic concentration range of Ara h1 is 50-1000 ng / ml,and the detection limit of the paper-based microfluidic nano aptamer sensor is21.6 ng /m L.(2)A paper-based microfluidic chip with common counter electrode and reference electrode is designed,and two working electrodes are placed separately in a twodimensional structure,which can also realize the detection of dual target source.Subsequently,the chip was functionalized to construct an aptamer biosensor for simultaneous detection of aflatoxin B1(AFB1)and ochratoxin A(OTA).The performance of the sensor was enhanced by using BP-Au composite nanomaterials.The optimal conditions were as follows: the concentration of AFB1 aptamer was 2 ?M and OTA aptamer was 1 ?M,the immobilization time of aptamer was 4 h,and the reaction time was 20 min.Then differential pulse voltammetry(DPV)was used to detect AFB1 and OTA standard solutions with concentration of 0.5-10 ng/ml.The detection limits of AFB1 and OTA were calculated to be 0.23 ng/ mL and 0.39 ng/ mL respectively.