It is demonstrated that carbon quantum dots derived from curcumin (Cur‐CQDs) through one‐step dry heating are effective antiviral agents against enterovirus 71 (EV71). The surface properties of Cur‐CQDs, as well as their antiviral activity, are highly dependent on the heating temperature during synthesis. The one‐step heating of curcumin at 180 °C preserves many of the moieties of polymeric curcumin on the surfaces of the as‐synthesized Cur‐CQDs, resulting in superior antiviral characteristics. It is proposed that curcumin undergoes a series of structural changes through dehydration, polymerization, and carbonization to form core–shell CQDs whose surfaces remain a pyrolytic curcumin‐like polymer, boosting the antiviral activity. The results reveal that curcumin possesses insignificant inhibitory activity against EV71 infection in RD cells [half‐maximal effective concentration (EC50) >200 µg mL−1] but exhibits high cytotoxicity toward RD cells (half‐maximal cytotoxic concentration (CC50) <13 µg mL−1). The EC50 (0.2 µg mL−1) and CC50 (452.2 µg mL−1) of Cur‐CQDs are >1000‐fold lower and >34‐fold higher, respectively, than those of curcumin, demonstrating their far superior antiviral capabilities and high biocompatibility. In vivo, intraperitoneal administration of Cur‐CQDs significantly decreases mortality and provides protection against virus‐induced hind‐limb paralysis in new‐born mice challenged with a lethal dose of EV71.

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Nanoparticle-assisted laser desorption/ionization mass spectrometry (LDI-MS) is a powerful tool for the analysis of a wide range of molecules. Many of the drawbacks in the matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) can be avoided with the application of nanomaterials as matrices as well as substrates for the LDI-MS to achieve a low background noise in low m/z region and high reproducibility. Surface-assisted LDI (SALDI)-MS, especially the nanoparticle-based LDI-MS, has emerged as a promising technique for the analysis of trace amounts of substances in various biological samples due to their high surface area for analyte enrichment, efficient desorption/ionization, and homogeneous crystallization of sample. Therefore, it is highly useful in clinical, forensic, medical, food and drug analyses, disease diagnosis, and various other fields. In this review, we briefly discuss the application of various nanomaterials, which include metal-based, carbon-based, silicon-based nanomaterials and nanocomposites, as matrices and substrates for LDI-MS based drug and metabolite analyses and possible detection strategies. Also, we discuss the idea of using "mass tag" for signal amplification for drug and metabolite detection using nanoparticle assisted LDI-MS.

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