Ultrasensitive Quantum Weak Measurement Biochemical Sensor via a Porous Anodic Alumina Nanostructure

In this paper, an ultrasensitive quantum weak measurement biochemical sensor based on porous anodic alumina (PAA) was first proposed and realized. The PAA film has the advantages of a regular hexagonal arrangement of pores, a high specific surface area, and low cost, which is a significant biosensing platform. By optimizing the structure parameters such as pore size and thickness of the PAA film, the biochemical sensor achieves a refractive index sensitivity of as high as 25 326 nm/RIU with a corresponding resolution of as low as 1.4 × 10^-7 RIU. The combination of the PAA film and weak measurement technology amplifies the sensing changes of small phase differences, thus realizing a highly sensitive response to the changes of the sensing medium. The biochemical sensor is capable of detecting biomolecules, such as glucose and proteins, with low detection limits and high specificity. Molecular testing validates that the sensor has a limit of detection as low as 3.9 mg/L for glucose small molecules and 112 pM for bovine serum albumin (BSA) biomacromolecules. The specificity testing validates that the biosensor is capable of specifically recognizing IgG proteins with high sensitivity, and a limit of detection as low as 8.4 ng/mL was achieved. As a result, the proposed PAA-based reflection-type quantum weak measurement biochemical sensor has the advantages of robustness and simplicity of structure, providing a versatile platform for the next generation of high-sensitivity biochemical sensing technology.