The recognition of fingerprints has played an extremely important role in criminal investigations, due to its uniqueness. This paper reports on the recognition of sweat latent fingerprints using green-emitting, environment-friendly carbon dots prepared with DL-malic acid and ethylenediamine, and the exploration of impacting factors in the development process of fingerprints. The experiments showed that better fingerprint images could be obtained when the latent fingerprints are developed in green-emitting carbon dots with pH 9 for 30 min, at room temperature. The reported method was also effective for latent fingerprints on a variety of substrates, as well as for those water-immersed ones, where the developed fingerprint remained stable after long-term preservation. Furthermore, the fluorescent three-dimensional fingerprint image could provide direct and simple evidence on pressing habits. The objective of this paper was to present this method. The method may help to narrow the range of suspects during criminal investigations and in forensic science.

Fluorescence/temperature-sensitive hydrogels, thanks to their properties in fluorescence and temperature sensitivity, have shown a promising outlook in the fields of drug delivery, cell imaging, etc., and thus become the focus of present research. This paper reports the preparation of green-fluorescence/temperature-sensitive hydrogels through one-step radical polymerization with green fluorescence-emissioned carbon dots as fluorescence probes and N-isopropylacrylamide as a monomer. UV-vis spectra, fluorescence spectra, and fluorescence microscope imaging have been used to characterize the prepared hydrogel, and to study their optical and temperature-sensitive properties. It was discovered that the emission of prepared hydrogel is excitation wavelength-dependent, pH responding, and excellent temperature-sensitive, as well as having good biocompatibility. The prepared hydrogel can also be applied as fluorescence ink in the fields of anti-counterfeit identification and appraisal.

To avoid the side effects caused by nonspecific targeting, premature release, weak selectivity, and poor therapeutic efficacy of current nanoparticle-based systems used for drug delivery, we fabricated natural material-decorated nanoparticles as a multifunctional, membrane-controlled targeted drug delivery system. The nanocomposite material coated with a membrane was biocompatible and integrated both specific tumor targeting and responsiveness to stimulation, which improved transmission efficacy and controlled drug release. Mesoporous silica nanoparticles (MSNs), which are known for their biocompatibility and high drug-loading capacity, were selected as a model drug container and carrier. The membrane was established by the polyelectrolyte composite method from chitosan (CS) which was sensitive to the acidic tumor microenvironment, folic acid-modified CS which recognizes the folate receptor expressed on the tumor cell surface, and a CD₄₄ receptor-targeted polysaccharide hyaluronic acid. We characterized the structure of the nanocomposite as well as the drug release behavior under the control of the pH-sensitive membrane switch and evaluated the antitumor efficacy of the system in vitro. Our results provide a basis for the design and fabrication of novel membrane-controlled nanoparticles with improved tumor-targeting therapy.

Since biofilm infections could cause chronic diseases and drug resistance, posing a serious threat to human health, the development of antibiofilm nanomaterials has attracted the interest of researchers. In this study, a quaternized carbon dot–papain complex (qCD–P) was prepared, and the complex exhibited inhibiting and eliminating abilities against internal resident bacteria and external matrix biofilms, with a minimum inhibitory concentration against Staphylococcus aureus biofilms at 20 μg mL⁻¹. The morphology, particle size, surface potential, and groups of the prepared qCD–P were characterized through multiple characterization means, and the target and antibiofilm mechanisms were explored from the perspective of its two components qCDs and papain. Meanwhile, based on the optical properties of qCDs and catalytic properties of papain, a dual-channel detection platform (naked-eye visualization and ratio fluorescence) of hydrogen peroxide has been realized with o-phenylenediamine as the substrate. The multifunctional qCD–P would provide a foundation for research on the potential applications of nanomaterials for in-clinic treatment and biochemical detection.

Novel coupling membrane systems with thermoresponsive switches composed of two different polymers PAAM and PAAC have been successfully developed. The membranes show significant positive switch characteristics and higher thermoresponsive speeds.