Smartphone-Based Detection System For The Quantitative Detection Of Aflatoxin B1

Aflatoxin B1(AFB1) are a class of secondary metabolites produced by Aspergillus flavus and Aspergillus parasiticus, which are regularly found in maize, peanuts, wheat, soybeans, rice and other cereals. Due to AFB1 possesses the highest toxicity and carcinogenicity and have damaging effects to the liver tissue of humans or animals, AFB1 can lead to liver cancer, kidney cancer and even death, which seriously does harm to people’s health. Currently, the conventional methods for detecting AFB1 mostly require specialized equipment, complicated operation, which unable to meet the demand for on-site rapid detection, so the development of rapid, simple, low-cost method of detecting AFB1 is necessary. Smartphones-based biomolecular detection technique is expected to become a new generation of on-site rapid screening tools due to their portability, popularity, powerful data processing capabilities and the open source app development environment. In this paper, the assay is based on an indirect competitive immunoassay on a transparent plastic substrate. By using the smartphone detection system, we can achieve the simultaneous detection of multiple samples and directly display the concentrations of AFB1 in samples, which realize fast, simple, low-cost quantitative detection. The main research contents are as follows:1. Indirect competitive reaction was performed on a transparent plastic PC(Polycarbonate) sheet, with the assistance of PDMS(Polydimethylsiloxane) microchannel plate. After silver staining, the ODR(Optical darkness ratio) values of the binding strips presented on the PC are inversely proportional to AFB1 concentration.2. We have developed a smartphone detection system for rapid quantitative detection of AFB1. This system consists of two parts: smartphone application and portable optical device, the smartphone detection app is written to capture pictures of the reaction zone of the plastic chip firstly, then calculate the ODR value of each strip and fit calibration equation according to the concentrations of AFB1 standard solution and the corresponding ODR values, finally obtain the concentrations of AFB1 in samples on the basis of the calibration equation and the obtained ODR values of samples and directly display the results on the phone screen. To provide uniform illumination for the plastic biochip and eliminate the influence of ambient light, a portable optical device is designed by 3DMax and printed using a 3D printer. Then the white LED(Light Emitting Diode) lights, reflector, Light Guide Plate(LGP), diffuser and battery were put in the respective components.3. The presented smartphone detection system have achieved the detection of AFB1 in samples and provided a detection range of 0.5-500 ng/m L and lower detection limit of 0.5 ng/m L. The presented detection system was compared to commercial ELISA kits, the test results showed good consistency, which verify the accuracy and reliability of this method.