RESUMO
Two major aspects of functional colloidal nanoparticles are their colloidal stability (dispersion) and controlled assembly of nanoparticles into ordered structures. Simplifying colloidal nanoparticles as isotropically interacting spheres is unsuitable for small nanoparticles capped with hydrocarbon chain ligands in which the ligand-ligand interaction plays a prominent role in the assembly processes. However, experimentally characterizing the ligand shell structure in solution presents significant challenges, and computer simulations yield divergent results without effective validation. Moreover, the connection between detailed information regarding ligand shell structures and interparticle interactions, in relation to the diverse dynamical behaviors of colloidal nanoparticles, remains poorly understood. In this study, we reveal the relationship between the ligand shell structures, interparticle interactions, and dynamical behaviors of few-nm-sized near-spherical nanoparticles capped with hydrocarbon chain ligands immersed in nonpolar solvents. Our study shows a transformation of the interparticle interactions from anisotropic attractions to isotropic repulsions as a result of the change in the ligand shell structures from order to disorder caused by varying temperature and other factors. The interplay between anisotropic attractions from ligand bundles and isotropic repulsions from disordered ligands dictates the nanoparticle dynamical behaviors of dispersion, uncontrolled aggregation, and controlled assembly.
RESUMO
Photosensitizers (PSs) have greatly flourished as a promising tool for photodynamic therapy owing to their integration of both in situ diagnosis and treatment in a single nanoplatform. However, there is still a need to explore synthesis pathways that can result in high-performance PSs with good reproducibility, high yield, less dark toxicity, and an attractive therapeutic index. Therefore, by exploiting the precise molecular engineering guideline, this work unveils a straightforward protocol to fabricate three homologous PSs (TPA-T-RS, TPA-Ts-RS, and TPA-Ts-RCN) with aggregation-induced emission (AIE) characteristics. Through slight structural tuning, the PSs are capable of anchoring to the cell membrane, mitochondria, and lysosome, and effectively generating reactive oxygen species (ROS). More importantly, TPA-Ts-RCN proved an intuitively appealing imaging-guided photodynamic therapy (PDT) effect. This work is expected to add a promising dimension to the field of architecting AIE PSs for image-guided photodynamic therapy.