Membrane Penetrating-Cationic Peptide BP100 Functionalized Silver Nanoparticles as Efficient Antibacterial Agents

In the present scenario, resistance to antibiotics has become a threatening situation for public health. To find a solution for this, conjugation of a cationic peptide with silver nanoparticles is emerging as a promising route to attain enhanced antibacterial activity. In this direction, this work reports the synthesis of lysine-based cationic peptide (BP100: NH2–KKLFKKILKYL–amide) functionalized silver nanoparticles (BP100@AgNPs). The cationic peptide interacts electrostatically with the silver nanoparticles in an aqueous medium. The developed nanosystem followed green chemistry principles, owing to the use of water and a one-step strategy for the synthesis of peptide functionalized nanoparticles. Moreover, the developed BP100@AgNPs were characterized by UV–vis spectroscopy, zeta potential analysis, FTIR, transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). In addition to this, in order to have a deeper insight into the interaction between BP100 and silver nanoparticles, NMR analysis of the peptide (BP100) and the developed nanosystem (BP100@AgNPs) was carried out. This was further authenticated by 1D (1H,13C) NMR and 2D NMR (1H-COSY (correlation spectroscopy)), 13C-HSQC (heteronuclear single quantum coherence)). Moreover, the developed BP100@AgNPs were tested for antibacterial activity against Gram-negative (E. coli) and Gram-positive (S. aureus) bacterial strains. The nanosystem displayed good inhibition with MIC values of 3.60 and 13.20 μg/mL for E. coli and S. aureus, respectively. The destruction in the cellular membrane of the bacterial cells upon treatment with the nanosystem was observed via field emission scanning electron microscopy (FESEM) which confirmed the efficient antibacterial activity of the developed nanosystem. Hence, the synthesized nanosystem displayed considerable potential to be used as an excellent candidate for antibacterial applications

A Facile Approach for Synthesis and Intracellular Delivery of Size Tunable Cationic Peptide Functionalized Gold Nanohybrids in Cancer Cells

Peptide-based drug delivery systems have become a mainstay in the contemporary medicinal field, resulting in the design and development of better pharmaceutical formulations. However, most of the available reports employ tedious multiple reaction steps for the conjugation of bioactive cationic peptides with drug delivery vehicles. To overcome these limitations, the present work describes a one-step approach for facile and time efficient synthesis of highly cationic cell penetrating peptide functionalized gold nanoparticles and their intracellular delivery. The nanoconstruct was synthesized by the reduction of gold metal ions utilizing cell penetrating peptide (CPP), which facilitated the simultaneous synthesis of metal nanoparticles and the capping of the peptide over the nanoparticle surface. The developed nanoconstruct was thoroughly characterized and tested for intracellular delivery into HeLa cells. Intriguingly, a high payload of cationic peptide over gold particles was achieved, in comparison to conventional conjugation methods. Moreover, this method also provides the ability to control the size and peptide payload of nanoparticles. The nanoconstructs produced showed enhanced cancer cell penetration (μM) and significant cytotoxic effect compared to unlabeled gold nanoparticles. Therefore, this novel approach may also have significant future potential to kill intracellular hidden dreaded pathogens like the human immunodeficiency virus, Mycobacterium tuberculosis, and so forth