Background: Fatty liver disease and obesity are among the most prevalent health conditions in modern society and have recently garnered significant attention. Semaglutide, a well-known anti-obesity drug, has been widely used for diabetes and obesity treatment; however, nanotherapeutics utilizing semaglutide have not yet been developed. Methods: A novel statin–lipid conjugate was synthesized using rosuvastatin and ursodeoxycholic acid, a liver-protective agent. This conjugate was then formulated with semaglutide through hydrophobic interactions to create a new nanoparticle system. The physicochemical properties of the nanoparticles were analyzed, and their therapeutic efficacy was evaluated in a high-fat diet (HFD)-induced animal model. Results: The statin–lipid conjugate was successfully synthesized, forming novel nanoparticles with semaglutide in an aqueous solution. These nanoparticles exhibited distinct properties compared to conventional semaglutide formulations. In animal experiments, the treatment group demonstrated a 30.24% reduction in body weight and a 46.80% improvement in liver function markers compared to the control group. Conclusions: This study introduces a novel semaglutide-based nanoparticle (SRLC NP) system that overcomes key limitations of conventional semaglutide therapy by providing enhanced bioavailability, extended circulation time, and improved cellular uptake. These findings highlight the potential of SRLC NPs as a clinically translatable nanotherapeutic approach for more effective, sustained, and patient-friendly obesity and fatty liver disease treatment.

In cancer therapy, photodynamic therapy (PDT) has attracted significant attention due to its high potential for tumor-selective treatment. However, PDT agents often exhibit poor physicochemical properties, including solubility, necessitating the development of nanoformulations. In this study, we developed two cationic peptide-based self-assembled nanomaterials by using a PDT agent, chlorin e6 (Ce6). To manufacture biocompatible nanoparticles based on peptides, we used the cationic poly-L-lysine peptide, which is rich in primary amines. We prepared low- and high-molecular-weight poly-L-lysine, and then evaluated the formation and performance of nanoparticles after chemical conjugation with Ce6. The results showed that both molecules formed self-assembled nanoparticles by themselves in saline. Interestingly, the high-molecular-weight poly-L-lysine and Ce6 conjugates (HPLCe6) exhibited better self-assembly and PDT performance than low-molecular-weight poly-L-lysine and Ce6 conjugates (LPLCe6). Moreover, the HPLCe6 conjugates showed superior cellular uptake and exhibited stronger cytotoxicity in cell toxicity experiments. Therefore, it is functionally beneficial to use high-molecular-weight poly-L-lysine in the manufacturing of poly-L-lysine-based self-assembling biocompatible PDT nanoconjugates.