The study of antimicrobial properties of film materials based on biopolymers and antiseptics

The development of new biomaterials with improved properties is becoming increasingly important in a wide range of applications. However, some of the most sought-after properties are anti-microbial properties, which can help prevent unwanted wound infections, especially in the face of growing antibiotic resistance of bacteria. The aim of the study was to study the effect of antimicrobial biomaterials based on calcium alginate, as a polymer system of local prolonged delivery of quaternary ammonium compounds, on reference and clinical strains of microorganisms. Samples of antimicrobial biomaterials contained decamethoxin (0.03-0.07 wt%), and polymers (polyvinyl alcohol and calcium alginate). Reference and clinical strains of Staphylococcus aureus, Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa were used for the study. The sensitivity of strains of microorganisms was determined by the disk-diffusion method according to the generally accepted method. The result of antimicrobial activity was assessed after 24 hours. The mean (M), the mean error of the mean (± m), and the criterion for the significance of differences (p) were calculated. The presence of differences between the research data was assessed by the Student's t-criterion. The results were considered reliable at p<0.05. High antimicrobial properties of the studied samples of antimicrobial biomaterials based on calcium alginate and decamethoxin have been established. It was revealed that the samples of polymeric biomaterials have a higher activity against gram-positive microorganisms compared to gram-negative strains. The composition is not inferior to the antimicrobial effect of a solution of decamethoxin and chlorhexidine in relation to all strains of microorganisms.

New Antimicrobial Biomaterials for the Reconstruction of Craniofacial Bone Defects

Reconstructive bone surgery of the head and neck could prove challenging in terms of postoperative healing and recovery. Fighting infection during the healing period is one of the critical factors of the long-term survival of an implant. The aim of the study was to develop an innovative composition suitable for an antibacterial craniofacial implant that should have the capacity to continuously and constantly release the amount of gentamicin necessary to prevent the post-surgical infections. For this purpose, a series of composite materials based on dimethacrylic monomers, hydroxyapatite and ZrO2, with (series B) or without the addition of polymethyl methacrylate (series A), reinforced with woven E-glass fibers (FRC) were obtained using the laminate lay-up process. Gentamicin was included in all FRC sample matrices to confer an antimicrobial effect. The results show that after extraction of the residual monomers from the FRC samples in different solvents (chloroform, acetone and ethyl alcohol), the cumulative amount of released gentamicin after 12 days was between 7.05–11.38 mg for A samples and 11.21–14.52 mg for B samples. The microbiological protocol showed that gentamicin induces a two weeks-lasting antimicrobial effect maintained over the minimal inhibitory concentration for P. aeruginosa and S. aureus.

Self-Assembling, Ultrashort Peptide Gels as Antimicrobial Biomaterials

Supramolecular antimicrobial hydrogels based on peptides are attractive soft materials for the treatment of infections, considering their ease of preparation and benign fate in biological settings and in the environment. In particular, stimuli-responsive systems that can be assembled/disassembled ad hoc could offer the opportunity to switch on/off their bioactivity as needed. Besides, the shorter is the peptide, the lower its cost of production. However, a structure-to-function relationship is yet to be defined and reported activities are generally not yet competitive relative to traditional antibiotics. Inspiration for their design can be found in host defense peptides (HDPs), which can self-assemble to exert their function. This article reviews research developments in this emerging area, and it examines features, differences and similarities between antimicrobial and amyloid peptides to open the avenue towards the next generation of supramolecular antimicrobial peptides as innovative therapeutic materials.