Owing to merging antibiotic resistance, the synthesis of novel antibacterial agents becomes increasingly important. Carbon dots (CDs) belong to a new class of carbon-based nanomaterials that have shown great potential in combating emerging and drug-resistant infections due to their unique optical properties, such as excellent biocompatibility and easy surface modification. Herein, light-treated CDs (LCDs) with enhanced antibacterial activity and low drug resistance were synthesized by using a simple one-pot hydrothermal method. LCDs can generate reactive oxygen species (ROS) under the light-emitting diode light, which kill two pathogenic bacteria, including methicillin-resistant Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). In addition, in vitro experiments show that the liquid crystal displays excellent biocompatibility. Due to the visible photo-oxidative activity, LCDs can be used as photodynamic therapy agents, providing efficient bactericidal activity. This study provides a simple way to modify CDs that lead to new properties. important (CDs carbonbased carbon based drugresistant resistant properties modification Herein lighttreated light treated (LCDs onepot one pot method ROS (ROS lightemitting emitting bacteria methicillinresistant methicillin S. S (S E. E (E coli. . coli) addition photooxidative photo oxidative

Abstract As one of the most promising formulations for poorly water-soluble drugs, nanocrystals have been attracting increasing attention in recent years. Isoliquiritigenin (ISL) is a flavonoid with a chalcone structure, and possesses many biological activities. However, its clinical application is significantly limited mainly due to its low oral bioavailability caused by poor hydrophilicity. To address this, ISL nanocrystals were developed in this study to improve its oral bioavailability. Three types of nanocrystals with differing particle size; R1, R2, and R3, were prepared by anti- solvent precipitation or anti-solvent precipitation combined with sonication, which was optimized by single-factor experiments. These nanocrystals were characterized based on their physical properties, in vitro release, and in vivo absorption performance. The mean particle size of R1, R2, and R3 was 555.7, 271.0, and 46.2, respectively. The dissolution ratio of ISL in the nanocrystals was significantly improved, with the quickest rate recorded in R2. Peak concentration and area under the concentration-time curve of R2 after oral administration in rats was 5.83- and 2.72-fold higher than that of the ISL solution, respectively. These findings indicate that the dissolution and absorption of ISL can be significantly enhanced by nanocrystals, and the dissolution behavior and pharmacokinetic properties of nanocrystals is significantly influenced by particle size. watersoluble water soluble drugs years (ISL structure activities However hydrophilicity R1 R anti antisolvent sonication singlefactor single factor experiments release performance 5557 555 7 555.7 2710 271 0 271.0 462 46 2 46.2 respectively improved concentrationtime time 5.83 583 5 83 2.72fold 272fold fold 2.72 72 solution 55 555. 27 271. 4 46. 5.8 58 8 72fold 272 2.7 5. 2.