Investigation of the antibacterial activity of Temporin-Ba loaded chitosan nanoparticles

The primary objective of this study is to evaluate chitosan nanoparticles as potential carrier systems to overcome the limited stability and bioavailability of antimicrobial peptides and to investigate their potential as an alternative to conventional irrigation solutions in endodontics. In this context, the Temporin-Ba (TemBa) peptide was loaded onto chitosan nanoparticles, and the obtained formulations were physicochemically characterized and evaluated for their biological activities. The loading capacity and encapsulation efficiency confirmed the system's ability to incorporate the peptide; however, these parameters remained limited due to the structural characteristics of chitosan. DLS analyses revealed that blank nanoparticles exhibited a monodisperse and stable structure, while peptide loading resulted in increased particle size and heterogeneity. SEM and TEM findings supported these results, FT-IR confirmed peptide–chitosan interactions, and TGA demonstrated that peptide incorporation provided partial thermal stability to the structure. Antimicrobial evaluations showed that the free peptide was effective against both Gram-negative and Gram-positive bacteria, whereas the nanoparticle formulations were partially effective against Gram-negative and showed limited activity against Gram-positive bacteria. MIC analyses indicated that the free peptide possessed the potential to inhibit bacterial growth; however, this activity decreased in nanoparticle formulations due to restricted peptide release. In conclusion, chitosan nanoparticles were successfully demonstrated as potential carriers for antimicrobial peptides such as TemBa. In endodontics, this approach offers a promising, biocompatible, and targetable alternative to overcome the limitations of conventional irrigation solutions. Nevertheless, improving encapsulation efficiency, optimizing release behavior, and enhancing efficacy against Gram-positive bacteria are considered critical for future clinical applications.