Selective and sensitive determination of neopterin in biological fluids using magnetic silica-supported molecularly-imprinted polymers.

Neopterin (NPT) is a key biomarker of immune system activation and holds significant importance in the diagnosis and monitoring of various clinical conditions. In this study, a novel magnetic silica-supported molecularly imprinted polymer (MIP-MS) was synthesized via surface imprinting and integrated with UV-vis spectrophotometry for the selective extraction and quantification of NPT in human serum and artificial cerebrospinal fluid. Comprehensive characterization was carried out and the results confirmed the successful fabrication of the MIP layer with well-defined structural and surface properties. Adsorption kinetics and isotherm studies were best fitted by the pseudo second-order (R = 0.9997) and Langmuir model (R = 0.9987), respectively and the results revealed the presence of specific recognition sites on the MIP-MS for NPT, resulting in adsorption capacity of 98.3 mg/g and imprinting factor of 4.77. Additionally, the MIP-MS exhibited outstanding reusability, retaining its performance over 10 adsorption-desorption cycles. The developed method demonstrated excellent sensitivity, with a wide linear range (3-300 nM), a detection limit of 1.18 nM and a recovery range of 97.6 %-100.4 %, accompanied by a relative standard deviation below 5.0 %. The findings suggest that the proposed MIP-MS coupled with UV-vis spectrophotometry provides a cost-effective, rapid, and highly selective alternative for NPT detection in biological samples.