Metal–Organic Frameworks Modified Optical Fiber SPR Biosensor for DNA Detection

In order to deal with the issue of low sensitivity to biomolecules concentrations in traditional optical fiber surface plasmon resonance (SPR) biosensors, a fiber SPR deoxyribonucleic acid (DNA) biosensor was developed, which is based on an amino-functionalized Zr-based metal–organic framework (MOF) (UIO-66-NH2)-modified heterogeneous core structure. Porous material UIO-66-NH2 facilitates electron transfer and amplifies the SPR effect, resulting in a heightened sensitivity for the detection of DNA hybridization. This can be attributed to the material’s advantageous characteristics, including a substantial specific surface area, an excellent water stability, and a pronounced affinity for probe-DNA (pDNA). The DNA biosensor presented in this study demonstrates enhanced sensitivity as a result of the covalent attachment of MOFs to pDNA, hence increasing the number of binding sites available for target DNA (tDNA). The optical fiber SPR biosensor, which has been modified with UIO-66-NH2, exhibits remarkable capabilities in detecting DNA concentrations ranging from 1 pM to$1 ~\mu \text{M}$. It demonstrates a sensitivity of −7.72 nm/log ($\mu \text{M}$) and achieves a detection limit of 3 pM. In addition, the DNA biosensor has exceptional performance in terms of specificity and durability, rendering it a highly favorable option for utilization in several fields, such as drug delivery, protein identification, and environmental surveillance.