ABSTRACT
Self-assembled peptide hydrogels have emerged as alternatives to the conventional approaches employed in controlled drug release, wound-healing, and drug delivery, and as anti-infective agents. However, peptide hydrogels possessing antibacterial properties are less explored. In this work, we have designed three ultrashort antibacterial peptide hydrogels: Fmoc-FFH-CONH2, Fmoc-FHF-CONH2, and Fmoc-HFF-CONH2. The rheological study showed the higher storage modulus of Fmoc-FFH-CONH2 (30.43 kPa) compared to Fmoc-FHF-CONH2 and Fmoc-HFF-CONH2, which may be attributed to the enhanced aromatic interaction in Fmoc-FFH-CONH2 compared to the other two variants, resulting in more mechanical rigidity. Further, the prepared hydrogels were evaluated for their inherent antibacterial potency against Gram-positive (Staphylococcus aureus, strain MTCC 96) and Gram-negative (Pseudomonas aeruginosa, strain PA01) bacteria. Antibacterial experiments demonstrated the potency of the hydrogels in the order of Fmoc-FFH-CONH2 > Fmoc-FHF-CONH2 > Fmoc-HFF-CONH2. The antibacterial effect of the hydrogels was predominantly due to the osmotic stress and membrane disruption, which was verified by reactive oxygen species (ROS) generation and outer membrane permeabilization assays. Our findings point to the scope of using the synthesized peptide hydrogels as agents for topical applications.
Subject(s)
Fluorenes , Hydrogels , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Fluorenes/chemistry , Hydrogels/chemistry , Peptides/chemistry , Pseudomonas aeruginosaABSTRACT
The utilization of peptide-based drug delivery systems has been suboptimal due to their poor proteolytic susceptibility, poor cell permeability, and limited tumor homing capabilities. Earlier attempts in using d-enantiomers in peptide sequences increased proteolytic stability but have compromised the overall penetration capability. We designed a series of peptides (STRAPs) with a syndiotactic polypeptide backbone that can potentially form a spatial array of cationic groups, an important feature that facilitates cellular uptake. The peptides penetrate cell membranes through a combination of active and passive modes. Furthermore, the cellular uptake of the peptides was unaffected by the presence of or treatment with bovine serum and human plasma. The designed peptides successfully delivered methotrexate, an anticancer drug, to the in vitro and in vivo models of breast cancer, with the best performing peptide STRAP-4-MTX conjugate having an EC50 value of 1.34 µM. Peptide drug delivery in mouse xenograft models showed a greater reduction of primary tumor and metastasis of breast cancer, in comparison to methotrexate of the same dose. The in vivo biodistribution assay of the STRAP-4 peptide suggests that the peptide accumulates at the tumor site after 2 h of treatment, and in the absence of tumors, the peptide gets metabolized and excreted from the system.
Subject(s)
Antineoplastic Agents , Breast Neoplasms , Cell-Penetrating Peptides , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/therapeutic use , Breast Neoplasms/pathology , Cell Line, Tumor , Cell-Penetrating Peptides/chemistry , Drug Delivery Systems , Female , Humans , Methotrexate/chemistry , Methotrexate/pharmacology , Methotrexate/therapeutic use , Mice , Peptides/chemistry , Tissue DistributionABSTRACT
A complete peptide-based drug delivery unit has been designed with a tumor homing domain chemically linked to a syndiotactic cell-penetrating domain. The designed peptides were synthesized, characterized, and tested in vitro for cellular uptake and cytotoxicity evaluation. The differential uptake, cellular internalization, negligible hemotoxicity, selective toxicity to MDA-MB-231 breast cancer cells, and the superior penetration in three-dimensional MDA-MB-231 tumorospheres confirm their utility as a promising delivery vector.
