Designing of a Test Tube Containing Aptamer-Immobilized Cholesteric Liquid Crystal Network-Based Optical Photonic Sensors for the Multiplex Detection of Doping Substances in Human Blood Serum

Abstract The detection of doping substances in human serum is a critical concern in both clinical diagnostics and anti-doping efforts. In this study, we present a novel, portable, and cost-effective biosensor system based on cholesteric liquid crystal networks (CLCN) for multiplexed drug detection. The system employs aptamer-immobilized CLCN-based optical sensors, fabricated on flexible polyethylene terephthalate (PET) substrates, for the onsite detection of cocaine, methamphetamine, heroin, tramadol, and salbutamol. The biosensor platform utilizes the unique optical properties of CLCNs, where the helical pitch change in response to analyte binding results in visible color shifts. These sensors are easy to fabricate, as all liquid crystals used are commercially available and inexpensive, making the technology highly accessible. Additionally, the sensors are easy to use, requiring minimal training, and the results can be quickly interpreted via a simple visual readout. The system was evaluated for its performance in spiked human serum samples, demonstrating high sensitivity, specificity, and accuracy in detecting low concentrations of doping substances. The inclusion of QR codes on the sensors allowed for convenient comparison with calibrated reference standards, ensuring reliable results. This biosensor system offers a promising solution for on-site and multiplexed detection of doping substances in human serum, with significant potential for monitoring in clinical and athletic settings.