Carbon-based nanoparticles (CNPs) have gained recognition because of their good biocompatibility, easy preparation, and excellent phototherapy properties. In biomedicine applications, CNPs are widely applied as photodynamic agents for antibacterial purposes. Photodynamic therapy has been considered a candidate for antibacterial agents because of its noninvasiveness and minimal side effects, especially in the improvement in antibacterial activity against multidrug-resistant bacteria, compared with conventional antibiotic medicines. Here, we developed CNPs from an active polyhydroxy phenolic compound, namely, gallic acid, which has abundant hydroxyl groups that can yield photodynamic effects. Gallic acid CNPs (GACNPs) were rapidly fabricated via a microwave-assisted technique at 200 °C for 20 min. GACNPs revealed notable antibacterial properties against Gram-positive and Gram-negative bacteria, including Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The minimum inhibitory concentrations of GACNPs in S. aureus and E. coli were equal at approximately 0.29 mg/mL and considerably lower than those in gallic acid solution. Furthermore, the GACNP-loaded hydrogel patches demonstrated an attractive photodynamic effect against S. aureus, and it was superior to that of Ag hydrofiber^®, a commercial material. Therefore, the photodynamic properties of GACNPs can be potentially used in the development of antibacterial hydrogels for wound healing applications.

Currently, fused deposition modeling (FDM) is a 3D printing technology that has been most widely used to develop innovative drug delivery approaches for overcoming the limitations of oral drug administration. Propranolol has a short plasma half-life and is well soluble in acidic environments. Thus, this study aimed to develop a gastro-floating 3D printed device (GFD) to sustain the release of propranolol in the stomach as a gastro-retentive drug delivery system. The polylactic acid (PLA) was selected to fabricate the GFD. An air chamber was included in the interior construction of the GFD design for buoyancy. The number of open channels on the side wall of GFD was modified to regulate release. The propranolol gel formulation was composed of a mixture of propranolol and polyvinylpyrrolidone (PVP) at the weight ratio of 6:5 and was then loaded into GFDs using a syringe. GFD exhibited a floating ability of more than 24 h with low standard deviation (SD) values of weight variation and shape dimension. The propranolol release from GFD shows sustained release properties in the simulated gastric environment without lag time. The 4 and 5 channels of GFD exhibited sustained drug release for 6 h. In addition, the duration of sustained release for 8 h was achieved from the GFD with 2 and 3 channels. The kinetic release of propranolol from GFDs was the best fit with zero-order. Thus, the GFDs could be designed to control the drug release according to each patient, which has the potential for applying personalized gastro-retentive drug delivery in various medications. Graphical abstract

Carbon dots (CDs) are among the famous nanoparticles that have been widely developed due to high biocompatibility, low toxicity, ease of preparation, excellent photoluminescent properties, and outstanding application in biomedicine. Among the various biomedical activities of CDs, they can be applied as antibacterial agents because of their photodynamic properties. Photodynamic therapy (PDT) has been considered an alternative antibacterial agent because of its non-invasive nature and minimal side effects, especially in terms of improving antibacterial activity against multidrug resistant bacteria when compared with traditional antibiotics. In this research, we developed CDs from o-phenylenediamine (OP). The o-phenylenediamine CDs (OPCDs) were synthesized via a hydrothermal method at 180°C for 3 h. After that, they revealed a spherical shape with a size range of 16.38 ± 2.64 nm. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of OPCDs against Staphylococcus aureus (S. aureus) for both light exposure and without light exposure groups were significantly greater than the OP solution because the OPCDs could generate reactive oxygen species (ROS) via a photodynamic mechanism leading to the bacteria cell death. Therefore, the created OPCDs may have the capability to be utilized for treating skin infections caused mainly by S. aureus. In conclusion, OPCDs could be proposed as nanomaterials that enhance antibacterial activity and provide photodynamic properties.

Wound infections pose a significant challenge in healthcare settings due to prolonged healing times and the emergence of antibiotic-resistant bacteria. Traditional wound dressings often fail to provide sustained drug release, optimal moisture retention, and effective antibacterial protection, leading to suboptimal therapeutic outcomes. This study aimed to optimize and develop neomycin-integrated hydrogels crosslinked via tannic acid (TA) for the treatment of infectious wounds. The hydrogels were optimized using a central composite experimental design. The amounts of polyvinyl alcohol (PVA, 10–20% w/w) and polyvinylpyrrolidone (PVP, 5–20% w/w) were varied and mixed with a fixed concentration of TA (1% w/w) as a crosslinker. The water content (%), water absorption (%), erosion (%), water vapor transmission rate (WVTR), and the mechanical properties of the hydrogels were evaluated. Neomycin was integrated in the optimized hydrogel, and the antibacterial activity against Staphylococcus aureus was studied using a time-kill analysis method. The optimal hydrogel formula contained PVA and PVP at a ratio of 20:19.89 by weight. The resulting hydrogel possessed good physical and mechanical properties and had a water content of 71.86%, water absorption of 124.96%, minimal erosion of 33.08%, and optimal WVTR of 5567 g/m²/24 h. Furthermore, the hydrogel showed desirable elasticity, with a Young’s modulus of 474.81 Pa and a tensile strength that could resist breakage upon application. The neomycin-integrated hydrogels inhibited bacterial growth comparably to the neomycin solution (0.5% w/v). Therefore, TA was proven to be a promising natural crosslinker and the optimized hydrogel was demonstrated to be a propitious platform for neomycin cutaneous application, and which could be used to treat infected wounds in the future.