Potential Application of Protamine for Antimicrobial Biomaterials in Bone Tissue Engineering

Area of Science:

• Biomaterials Science
• Orthopedic Engineering
• Microbiology

Background:

• Bacterial infections of biomaterials pose significant challenges in medical devices.
• Developing novel biomaterials with bactericidal properties is crucial.
• Antimicrobial peptides and proteins (AMPs) offer a promising alternative to antibiotics to combat bacterial resistance.

Purpose of the Study:

• To develop an intelligent biomaterial for bone tissue engineering using protamine-loaded hydroxyapatite (protamine/HAp).
• To evaluate the antimicrobial activity and biocompatibility of protamine/HAp as a potential bone substitute.

Main Methods:

• Protamine adsorption onto hydroxyapatite (HAp) was analyzed using the Langmuir adsorption model.
• In vitro studies assessed bacterial adhesion, growth inhibition, and morphological changes on protamine/HAp.
• Cytotoxicity of protamine/HAp was evaluated in vitro and in vivo.

Main Results:

• Protamine adsorption to HAp followed the Langmuir model, driven by electrostatic and/or hydrophobic interactions.
• Protamine/HAp demonstrated dose-dependent inhibition of bacterial adhesion and growth in vitro.
• High protamine concentrations (>1000 μg·mL⁻¹) induced in vitro cytotoxicity but showed no apparent in vivo cytotoxicity.

Conclusions:

• Protamine/HAp exhibits significant antimicrobial activity and biocompatibility at concentrations below 1000 μg·mL⁻¹.
• This material is a promising candidate for bone substitutes in orthopedic applications.
• Protamine/HAp offers a novel, antibiotic-free approach to prevent biomaterial-associated infections.