Clinical applications of current photodynamic therapy (PDT) agents are often limited by their low singlet oxygen (1O2) quantum yields, as well as by photobleaching and poor biocompatibility. Here we present a new PDT agent based on graphene quantum dots (GQDs) that can produce 1O2 via a multistate sensitization process, resulting in a quantum yield of ~1.3, the highest reported for PDT agents. The GQDs also exhibit a broad absorption band spanning the UV region and the entire visible region and a strong deep-red emission. Through in vitro and in vivo studies, we demonstrate that GQDs can be used as PDT agents, simultaneously allowing imaging and providing a highly efficient cancer therapy. The present work may lead to a new generation of carbon-based nanomaterial PDT agents with overall performance superior to conventional agents in terms of 1O2 quantum yield, water dispersibility, photo- and pH-stability, and biocompatibility.

Novel red‐emissive carbon‐dots (C‐dots) with broad absorption in the region from 400 to 750 nm are prepared from polythiophene phenylpropionic acid. Upon near infrared laser irradiation, the red‐emissive C‐dots show strong photoacoustic response and high photothermal conversion efficiency (η ≈ 38.5%). These unique properties enable the C‐dots to act as multifunctional fluorescent, photoacoustic, and thermal theranostics for simultaneous diagnosis and therapy of cancer.

Single‐atom catalysts (SACs), as homogeneous catalysts, have been widely explored for chemical catalysis. However, few studies focus on the applications of SACs in enzymatic catalysis. Herein, we report that a zinc‐based zeolitic‐imidazolate‐framework (ZIF‐8)‐derived carbon nanomaterial containing atomically dispersed zinc atoms can serve as a highly efficient single‐atom peroxidase mimic. To reveal its structure–activity relationship, the structural evolution of the single‐atom nanozyme (SAzyme) was systematically investigated. Furthermore, the coordinatively unsaturated active zinc sites and catalytic mechanism of the SAzyme are disclosed using density functional theory (DFT) calculations. The SAzyme, with high therapeutic effect and biosafety, shows great promises for wound antibacterial applications.

Nitrogen and sulfur codoped carbon dots (CDs) were prepared from garlic by a hydrothermal method. The as-prepared CDs possess good water dispersibility, strong blue fluorescence emission with a fluorescent quantum yield of 17.5%, and excellent photo and pH stabilities. It is also demonstrated that the fluorescence of CDs are resistant to the interference of metal ions, biomolecules, and high ionic strength environments. Combining with low cytotoxicity properties, CDs could be used as an excellent fluorescent probe for cellular multicolor imaging. Moreover, the CDs were also demonstrated to exhibit favorable radical scavenging activity.

As next-generation artificial enzymes, nanozymes have shown great promise for tumor catalytic therapy. In particular, their peroxidase-like activity has been employed to catalyze hydrogen peroxide (H 2 O 2 ) to produce highly toxic hydroxyl radicals ( • OH) to kill tumor cells. However, limited by the low affinity between nanozymes with H 2 O 2 and the low level of H 2 O 2 in the tumor microenvironment, peroxidase nanozymes usually produced insufficient • OH to kill tumor cells for therapeutic purposes. Herein, we present a pyrite peroxidase nanozyme with ultrahigh H 2 O 2 affinity, resulting in a 4144-and 3086-fold increase of catalytic activity compared with that of classical Fe 3 O 4 nanozyme and natural horseradish peroxidase, respectively. We found that the pyrite nanozyme also possesses intrinsic glutathione oxidase-like activity, which catalyzes the oxidation of reduced glutathione accompanied by H 2 O 2 generation. Thus, the dual-activity pyrite nanozyme constitutes a self-cascade platform to generate abundant • OH and deplete reduced glutathione, which induces apoptosis as well as ferroptosis of tumor cells. Consequently, it killed apoptosis-resistant tumor cells harboring KRAS mutation by inducing ferroptosis. The pyrite nanozyme also exhibited favorable tumor-specific cytotoxicity and biodegradability to ensure its biosafety. These results indicate that the high-performance pyrite nanozyme is an effective therapeutic reagent and may aid the development of nanozyme-based tumor catalytic therapy.

The FeO nanozyme was the first reported nanoparticle with intrinsic peroxidase-like activity and has been widely used in biomedicine. To optimize its catalytic activity, we introduced histidine residues onto the FeO nanoparticle surface in order to mimic the enzymatic microenvironment of natural peroxidase enzymes. Our results show that modification with a single amino acid could more than ten-fold improve the apparent affinity (K) of the FeO nanozyme for the substrate HO and enhanced its catalytic efficiency (k/K) up to twenty fold. Thus we not only optimized the activity of the FeO nanozyme, but also provide a new rationale for improving the efficiency of nanomaterial-based catalysts by utilizing strategies observed in nature.

ExperimentalOpals shown in this work have been prepared following a method described previously [1,24]. This sol±gel method provides size-controlled spheres for further sedimentation by gravity. The sediments are sintered (thermal annealing at 950 C for 3 h) to control the lattice parameter (a), and to strengthen the structures for consequent infillings. The usual size of the opal bits used for infiltration is 5±9 mm 2 in surface area by 0.5 mm thickness. The sphere diameter is 410 nm and, accordingly, the lattice parameter a = 580 nm.Fixed-Flow Reactor: Sb 2 O 3 -silica composites were placed in the bottom bed of an upflow fixed-bed quartz reactor at atmospheric pressure. The gas flow rate was kept constant at 34 mL min ±1 . The composition of the reactant gas from cylinders controlled by mass flow controllers was 20 vol.-% H 2 S in N 2 .Operating temperature and reaction time were the variables affecting the sulfide growth. Temperatures around 280±300 C are considered optimal for the sulfidation. Samples cracks are apparent as the operating temperature rises up to 550 C (melting point of Sb 2 S 3 ). Sulfidation times of 10 h resulted in almost complete oxide conversion (96 %).Band structure calculations were carried out by using the MIT package software. In this program, the fully vectorial Maxwell equations are solved for plane-wave propagation in a periodic dielectric medium. The system is characterized by the dielectric functions of the voids and backbone, the crystalline structure, and the value of the lattice parameter.Optical Characterization: The measurements were performed with a Fourier transform infrared spectrometer (FTIR), IFS 66S from Bruker with a IRScope II microscope attached. A 36 X Cassegrain objective was used to focus and collect the light. The incident and collected light cover external angles from 15 to 30 from normal incidence with respect to (111) family of planes.The X-ray powder diffraction (XRD) study was carried out in a Siemens 5000 diffractometer using Cu Ka radiation.The reference sample is the commercial product from Aldrich, Antimony trisulfide 99 %+.

Cancer nanotheranostics combining therapeutic and imaging functions within a single nanoplatform are extremely important for nanomedicine. In this study, carbon dots (C-dots) with intrinsic theranostic properties are prepared by using polythiophene benzoic acid as carbon source. The obtained C-dots absorb light in the range of 400-700 nm and emit bright fluorescence in the red region (peaking from 640 to 680 nm at different excitations). More importantly, the obtained C-dots exhibit dual photodynamic and photothermal effects under 635 nm laser irradiation with a singlet oxygen ((1)O2) generating efficiency of 27% and high photothermal conversion efficiency of 36.2%. These unique properties enable C-dots to act as a red-light-triggered theranostic agent for imaging-guided photodynamic-photothermal simultaneous therapy in vitro and in vivo within the therapeutic window (600-1000 nm).