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Abstract Synthetic opioids, especially fentanyl and its analogs, have created an epidemic of abuse and significantly increased overdose deaths in the United States. Current detection methods have drawbacks in their sensitivity, scalability, and portability that limit field‐based application to promote public health and safety. The need to detect trace amounts of fentanyl in complex mixtures with other drugs or interferents, and the continued emergence of new fentanyl analogs, further complicates detection. Accordingly, there is an urgent need to develop convenient, rapid, and reliable sensors for fentanyl detection. In this study, a sensor is prepared based on competitive displacement of a fluorescent dye from the cavity of a supramolecular macrocycle, with subsequent fluorescence quenching from graphene quantum dots. This approach can detect and quantify small quantities of fentanyl along with 58 fentanyl analogs, including highly potent variants like carfentanil that are of increasing concern. Detection of these agents is possible even at 0.01 mol% in the presence of common interferents. This simple, rapid, reliable, sensitive, and cost‐effective approach couples supramolecular capture with graphene quantum dot nanomaterial quenchers to create a tool with the potential to advance public health and safety in the context of field‐based detection of drugs in the fentanyl class. 

Chirality, defined as “a mirror image,” is a universal geometry of biological and nonbiological forms of matter. This geometry of molecules determines how they interact during their assembly and transport. With the development of nanotechnology, many nanoparticles with chiral geometry or chiroptical activity have emerged for biomedical research. The mechanisms by which chirality originates and the corresponding synthesis methods have been discussed and developed in the past decade. Inspired by the chiral selectivity in life, a comprehensive and in-depth study of interactions between chiral nanomaterials and biological systems has far-reaching significance in biomedicine. Here, we investigated the effect of the chirality of nanoscale drug carriers, graphene quantum dots (GQDs), on their transport in tumor-like cellular spheroids. Chirality of GQDs (L/D-GQDs) was achieved by the surface modification of GQDs withL/D-cysteines. As anin-vitrotissue model for drug testing, cellular spheroids were derived from a human hepatoma cell line (i.e., HepG2 cells) using the Hanging-drop method. Our results reveal that theL-GQDs had a 1.7-fold higher apparent diffusion coefficient than theD-GQDs, indicating that theL-GQDs can enhance their transport into tumor-like cellular spheroids. Moreover, when loaded with a common chemotherapy drug, Doxorubicin (DOX), via π-π stacking,L-GQDs are more effective as nanocarriers for drug delivery into solid tumor-like tissue, resulting in 25% higher efficacy for cancerous cellular spheroids than free DOX. Overall, our studies indicated that the chirality of nanocarriers is essential for the design of drug delivery vehicles to enhance the transport of drugs in a cancerous tumor.