Highly Sensitive Cholesterol Detection Using ß-Cyclodextrin and Graphene Oxide-Enhanced Surface Plasmon Resonance Sensor

This article researched a novel cholesterol sensor that leverages the power of reflective surface plasmon resonance (SPR). The sensor’s core principle relies on the highly specific interaction between cholesterol and ß-cyclodextrin (ß-CD). A complex is formed when cholesterol adsorbs onto the ß-CD molecules on the sensor surface. The measurable refractive index (RI) change on the surface of optical fibers is caused by this complex formation, which translates into a detectable shift in the wavelength of the SPR spectrum. The sensor’s effectiveness is further amplified by incorporating 2-D graphene oxide (GO) as a sensitizing material. This addition significantly enhances the sensor’s sensitivity, reaching an impressive 2910 nm/RIU (RI unit), representing a remarkable 75% improvement compared to its unsensitized counterpart. Meanwhile, the abundant functional groups on the GO surface provide a natural and efficient binding platform for the cholesterol-selective ß-CD probes. This sensor can detect cholesterol with a concentration of 0:1 µM, a response time of about 30 s, and a detection limit of 2 nM. In addition, the sensor achieves excellent selectivity for cholesterol in solution, minimizing interference from other biomolecules in solution. The compact size, plug-and play, and excellent stability of this sensor enable it to perform high-sensitivity cholesterol detection, and it is expected to be used in the future to detect human cholesterol levels.