Accurate regulation of cellular zinc signaling is imperative to decipher underlying zinc functions and develop new therapeutic agents. However, the ability to modulate zinc in a spatiotemporal manner remains elusive. We herein report an intelligent spiropyran-upconversion (SP-UCNPs) based nanosystem that enables near-infrared (NIR) light-controlled zinc release at precise times and locations. The magnitude of zinc release can be simply manipulated by varying the duration of NIR irradiation. Moreover, the utilization of NIR light not only showed little damage to cells but also significantly improved penetration depth. By evaluating activity of a model protein, phosphatase 2A, we further validated zinc signaling activation. Importantly, our strategy may be broadly applicable to other types of metal ions, like the ubiquitous second messenger calcium. More importantly, our strategy can potentially enable the precise control of specific signaling pathways of metal ions while minimizing cellular damage, facilitating the advanced manipulation of cellular dynamics.

A non-destructive, safe and practical strategy to produce high quality graphene in high yield is urgently required, since this would pave the way for a wide range of applications of graphene in the future. Here we present a pH-responsive water-dispersible method for the exfoliation and functionalization of graphene by using lysozyme. The pH-responsive dispersion of graphene may be useful for the reversible assembly of multicomponent/multifunctional nanohybrid materials and nanoscale electronic devices. More importantly, composites can be easily constructed through the interactions between disulphide groups in lysozyme and gold nanoparticles (AuNPs). The resulting graphene-AuNPs composites show excellent catalytic activity towards reduction of o-nitroaniline by NaBH₄. Since lysozyme is low cost and has antibacterial properties, and has been widely used in food preservation, medicine and the pharmaceutical industry, our approach may open a new scalable route for the manufacture of high-quality, nondestructive graphene for practical applications.

Luminescent carbon nanoparticles (CNPs) are newcomers to the world of nanomaterials and have shown great impact in health and environmental applications as well as being promising building blocks for future nanodevices because of their fascinating photoluminescence and potential to serve as nontoxic replacements for traditional heavy-metals-based quantum dots. Herein, fluorescent CNPs have been prepared from candle soot by refluxing with HNO₃ and subsequently separated by a single centrifugation. The CNPs can be represented by the empirical formula C₁H_0.677O_0.586N_0.015Na_0.069, and have a size of 20–100 nm, height of 3.0 nm, lifetime of 7.31 ns ± 0.06 ns and quantum yield of ~1.7%. Further studies demonstrate that: (1) the as-prepared CNPs exhibit excellent stability in biological media and their luminescence intensity does not change with ionic strength or pH in the physiological and pathological range of pH 4.5–8.8; (2) CNPs can act as electron donors and transporters and porphyrin can assemble onto CNPs through electrostatic and π-stacking interactions to form porphyrin–CNPs supramolecular composites; (3) CNPs have strong intrinsic peroxidase-like activity. Based on this intrinsic peroxidase activity, a simple, cheap, and highly selective and sensitive colorimetric and quantitative assay has been developed for the detection of glucose levels. This assay has been used to analyze real samples, such as diluted blood and fruit juice.