Efficient Synergistic Antibacterial Activity of α-MSH Using Chitosan-Based Versatile Nanoconjugates

Area of Science:

• Biochemistry
• Materials Science
• Microbiology

Background:

• Multidrug resistance in pathogenic organisms necessitates novel therapeutic strategies.
• Antimicrobial peptides, such as alpha-Melanocyte stimulating hormone (α-MSH), show potential against bacteria like Staphylococcus aureus, including MRSA.
• Challenges exist in the chemical stability and effective delivery of biopharmaceuticals like α-MSH.

Purpose of the Study:

• To develop a stable and effective delivery system for α-MSH to enhance its antimicrobial properties.
• To create chitosan-cholesterol α-MSH polymer-drug nanoconjugates using a simple chemical conjugation technique.
• To evaluate the antibacterial efficacy and safety of the developed nanoconjugates against Staphylococcus aureus.

Main Methods:

• A single-step, one-pot chemical conjugation was employed to synthesize chitosan-cholesterol α-MSH polymer-drug nanoconjugates.
• Staphylococcal growth inhibition experiments were conducted comparing nanoconjugates with individual controls (α-MSH and chitosan-cholesterol).
• Scanning electron microscopy (SEM) was used to observe phenotypic changes and cell lysis, and dose-response and hemolytic assays were performed.

Main Results:

• Chitosan-cholesterol α-MSH nanoconjugates achieved nearly 100% inhibition of Staphylococcus aureus growth.
• The nanoconjugates induced significant phenotypic alterations, cell lysis, and aggregation in bacterial cells.
• Even at a low concentration of 1 pM, α-MSH within the nanoconjugates showed substantial growth inhibition (∼40%), and the formulation was found to be non-hemolytic.

Conclusions:

• Nanoparticle-conjugated α-MSH, specifically chitosan-cholesterol α-MSH nanoconjugates, exhibit potent antimicrobial activity against Staphylococcus aureus.
• This novel formulation effectively overcomes the delivery and stability challenges associated with α-MSH.
• The developed nanoconjugates represent a promising future therapeutic candidate for treating multidrug-resistant Staphylococcus aureus and other bacterial infections.