Testing is the key to product quality and safety. The quality of testing equipment determines the quality of testing results. In daily on-site testing, electrochemical sensors are usually single-use, so the material cost of the sensor determines the testing cost. Finding low-cost, high-throughput and scalable sensor materials is the key to reducing inspection costs.
With the development of material technology, carbon nanomaterials such as graphene have become potential choices for improving the performance of electrochemical sensors due to their unique material characteristics, such as high conductivity, large specific surface area, and biocompatibility. However, the production of traditional graphene devices based on chemical vapor deposition technology is limited, which is too expensive for one-time electrochemical detection applications. In addition, low-cost alternatives such as inkjet printing do not have sufficient control over the electrode geometry and cannot achieve good electricity. Chemical sensor performance.
Exploring new processes has become the key to the popularization and application of graphene electrochemical sensors. Recently, researchers at Iowa State University in the United States have realized low-cost manufacturing of graphene biosensors through high-resolution (line width ~ 40 μm) aerosol jet printing technology.
In this project, the graphene electrode is printed on a flexible polymer in an aerosol manner, which is converted into a histamine sensor by chemically combining the histamine antibody with the graphene. The antibody specifically binds to the histamine molecule, which prevents electron transfer And increase the resistance, and the resistance change can be measured and recorded by the sensor. The graphene electrochemical sensor prepared by this process can detect histamine in the range of 6.25 to 200 ppm, and the detection limit is as low as 3.41 ppm. (The test object is tuna broth)
It is reported that this type of histamine sensor is not only suitable for fish, it can also detect animal diseases such as salmonella, cancer or bird flu. In addition, by switching the antibody connected to the printing sensor, it can also be extended to various sensing applications, such as environmental toxin detection, food-borne pathogen detection, wearable health monitoring and health diagnosis.
Preparation and biofunctionalization scheme of AJP graphene biosensor
a) Printing graphene in IDE mode on polyimide (Kapton®) sheet;
b) Thermal annealing to increase the oxygen content of the printed graphene surface;
c) Immobilize histamine antibody on IDE by carbodiimide crosslinking chemical method;
d) Limit the unfunctionalized areas of IDE, and the buffer solution prevents non-specific adsorption in the biosensing process;
e) Histamine combined with IDE generates Nyquist potential maps in electrochemical bio-sensing.