Synthetic peptide (DP1) functionalized graphene oxide: A biocompatible nanoformulation with broad-spectrum antibacterial and antibiofilm activity

Abstract

In the present scenario, clinical success of all existing antimicrobial regimes has been severely challenged by bacterial infections and emergence of multidrug-resistant strains necessitating the development of improved strategies with broad-spectrum bactericidal effects. With this objective, a multifunctional nanoformulation was synthesized by covalently coupling a novel synthetic antimicrobial peptide DP1 (RFGRFLRKILRFLKK) to graphene oxide (GO). This bioconjugated two-dimensional sheet (GO-DP1) with nanosized dimensions (32 nm) proficiently inhibited the growth of Gram-positive (Bacillus subtilis, Staphylococcus aureus) as well as Gram-negative (Escherichia coli, Salmonella typhi) bacteria along with multidrug-resistant bacterial strains namely Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus. The minimum inhibitory concentration (MIC) was 2 to 8 folds lower as compared to GO and in the effective range of peptide’s MIC. The conjugation between biotic (peptide) and abiotic (GO) surface combined the advantageous properties of these two classes of materials thereby signifying synergy. The biomedical applicability of GO-DP1 is also successfully demonstrated by evaluating its hemocompatibility and antibiofilm potency in a Pseudomonas aeruginosa contaminated hypodermic needle model. This is the first study of its kind that paves the way for future applications of this nanoformulation in environments and settings that serve as reservoirs of microbial contamination.