A highly sensitive tapered fiber biosensor modified by PDMS combustion product and graphene oxide for MUC1 detection

It is a critical challenge to develop reliable, stable, and sensitive biosensors for specific detection of mucin 1 (MUC1). In this paper, a label-free biosensor based on polydimethylsiloxane (PDMS) combustion product and graphene oxide (GO) functionalized tapered fiber (PGTF) was proposed and demonstrated for high sensitivity MUC1 detection. The PDMS combustion product is mainly composed of SiO2, which can be firmly bonded to the surface of the fiber, effectively increasing the specific surface area of the fiber. At the same time, the combination of the PDMS combustion product and the fiber cladding material will generate defects in the cladding, resulting in easier leakage of light inside the fiber core. Therefore, a strong evanescent field and interference effect can be obtained without drawing the tapered fiber waist very thin, which contributes to improving the sensitivity of fiber biosensor. In addition, GO has good biological affinity, a large specific surface area, and abundant functional groups, which can provide more binding sites for the attachment of biomolecule. The detection limit of the PGTF is 0.11 pM when the diameter of the fiber taper is 50 mu m and modified with five layers of PDMS combustion product. Experimentally demonstrated sensor specificity and reproducibility, indicating that the sensor has a practical value for real applications. The PGTF has great potential as a simple, sensitive, and label-free assay in the field of cancer marker detection.