Multifunctional Biocompatible and Biodegradable Folic Acid Conjugated Poly(ε-caprolactone)–Polypeptide Copolymer Vesicles with Excellent Antibacterial Activities

Cancer patients after chemotherapy may also suffer bacterial attack due to badly decreased immunity. Although with high bacterial efficacy, conventional antibiotics are prone to inducement of drug resistance and may be not suitable for some cancer patients. In contrast, antibacterial peptides are highly effective in inhibiting bacteria without inducing resistance in pathogens. Presented in this article is a novel kind of highly effective antibacterial peptide-based biocompatible and biodegradable block copolymer vesicle. The copolymer is poly­(ε-caprolactone)-<i>block</i>-poly­[phenylalanine-<i>stat</i>-lysine-<i>stat</i>-(lysine-folic acid)] [PCL₁₉-<i>b</i>-poly­[Phe₁₂-<i>sta</i>t-Lys₉-<i>stat</i>-(Lys-FA)₆]], which can self-assemble into vesicles in aqueous solution. The biocompatible and biodegradable PCL forms the vesicle membrane, whereas the poly­[Phe₁₂-<i>sta</i>t-Lys₉-<i>stat</i>-(Lys-FA)₆] block constitutes the vesicle coronas. Compared to the individual polymer chains, the vesicles showed enhanced antibacterial activities against both Gram-positive and Gram-negative bacteria (16 μg mL^–1) due to the locally concentrated antibacterial poly­[Phe₁₂-<i>stat</i>-Lys₉-<i>stat</i>-(Lys-FA)₆] coronas, which may avoid the inducement of antibiotic-resistant bacteria and side effects of multidrug interactions. Furthermore, folic acid is introduced into the vesicle coronas for potential further applications such as cancer-targeted drug delivery. Moreover, the amino groups can be further functionalized when necessary. This low cytotoxic, biocompatible, biodegradable, and antibacterial vesicle (without antibiotic resistance) may benefit patients after tumor surgery because it is highly anti-inflammatory, and it is possible to deliver the anticancer drug to tumor cells simultaneously

Antibacterial Polypeptide-Grafted Chitosan-Based Nanocapsules As an “Armed” Carrier of Anticancer and Antiepileptic Drugs

Antibacterial polypeptides as ancient immune defense systems are effective against bacteria. Here we report a novel kind of “armed” carrier: an antibacterial polypeptide-grafted chitosan-based nanocapsule with an excellent antibacterial efficacy against both Gram-positive and Gram-negative bacteria. This nanocapsule also has excellent blood compatibility and low cytotoxicity. Patients after tumor surgery may benefit from this “armed” carrier because it is highly anti-inflammation and is able to deliver anticancer and antiepileptic drugs simultaneously