ABSTRACT
Magnetic nanoparticles (MNPs) are widely applied in antibacterial therapy owing to their distinct nanoscale structure, intrinsic peroxidase-like activities, and magnetic behavior. However, some deficiencies, such as the tendency to aggregate in water, unsatisfactory biocompatibility, and limited antibacterial effect, hindered their further clinical applications. Surface modification of MNPs is one of the main strategies to improve their (bio)physicochemical properties and enhance biological functions. Herein, antibacterial ε-poly (L-lysine) carbon dots (PL-CDs) modified MNPs (CMNPs) were synthesized to investigate their performance in eliminating pathogenic bacteria. It was found that the PL-CDs were successfully loaded on the surface of MNPs by detecting their morphology, surface charges, functional groups, and other physicochemical properties. The positively charged CMNPs show superparamagnetic properties and are well dispersed in water. Furthermore, bacterial experiments indicate that the CMNPs exhibited highly effective antimicrobial properties against Staphylococcus aureus. Notably, the in vitro cellular assays show that CMNPs have favorable cytocompatibility. Thus, CMNPs acting as novel smart nanomaterials could offer great potential for the clinical treatment of bacterial infections.
ABSTRACT
Despite its importance, limited representations of the anthracite models have been developed. The first molecular representation of Chinese Jincheng anthracite with the incorporation of diverse molecular structures was constructed based on the available analytical data. Three hundred individual aromatic sheets were first built based on the aromatic fringe distribution obtained from high-resolution transmission electron microscopy. Alkyl chains and nitrogen, sulfur, and oxygen heteroatoms were added in the aromatic skeletons to form diverse anthracite structural units based on 13C NMR, X-ray photoelectron spectroscopy, and ultimate analyses. Fifty-five different anthracite molecules were formed by covalent cross-linking considering the constraint imposed by the molecular weight distribution of the Jincheng anthracite obtained from laser desorption time-of-flight mass spectrometry (LD-TOF MS). These molecules were packed into a three-dimensional cell to form a Jincheng anthracite model (C7730H3916O133N123S25). We showed that the proposed model can provide a reasonable representation of the Jincheng anthracite by comparing the simulated and experimental magnetic resonance spectroscopy, LD-TOF MS, density, and X-ray diffraction data. Because of the large, molecularly diverse structure, many anthracite behavioral processes can be further explored using this model in the future.
