(WHS-P70) BIOMATERIALS FOR CONTROLLED-RELEASE OF AGENTS WITH ANTIMICROBIAL PROPERTIES
Friday, May 17, 2024
7:30 AM – 5:00 PM East Coast USA Time
Introduction Our compound, PEG-BPEI, counteracts (i) pathogens, (ii) biofilms, and (iii) toxins using electrostatic binding with the anionic components of each target. This occurs simultaneously and independently; and these multi-factor benefits are unlikely to be found with other compounds. Our research team, funded by the NIH, Department of Defense, and the University of Oklahoma, has carried out a productive multi-site collaboration evaluating the ability of PEG-BPEI, and the bioactive moiety 600 Da BPEI, to disable antibiotic resistance mechanisms, neutralize endotoxins, and disperse biofilms – factors linked to the dysregulation of wound healing. Developing PEG-BPEI products requires a delivery strategy. Candidate materials for delivery are gels, creams, and foams that are well-known non-immunogenic biomaterials. Product Development PEG-BPEI also differs from existing technology because it is not a peptide and thus resists proteolysis, unlike cationic peptides and peptide mimetics susceptible to rapid proteolytic degradation and/or protein binding. PEG-BPEI is a hydrophilic molecule that is completely miscible with water. We have demonstrated the ability to formulate PEG-BPEI with gels, creams, and polymers. We have used PEGylation to reduce the in vivo toxicity while retaining activity. Importantly, we also reduce toxicity issues by using very-low molecular-weight BPEI (600 Da) rather than higher molecular-weight BPEI (over 25,000 Da). Methods PEG-BPEI is cationic and uses electrostatics for binding with anionic sites on Gram-positive and Gram-negative bacteria. PEG-BPEI and the bioactive moiety 600 Da BPEI, have broad-spectrum activity to counteract (1) antimicrobial resistance (AMR) caused by the Gram-negative LPS layer; (2) AMR caused by Gram-positive cell wall and teichoic acids (3) AMR caused by metallo-β-lactamases; (4) Release of pro-inflammatory cytokines in response to the Gram-negative pathogen associated molecular pattern molecules (PAMPs) LPS and peptidoglycan; (5) Release of pro-inflammatory cytokines in response to the Gram-positive PAMPs teichoic acids and peptidoglycan; and (6) Biofilms formed by Gram-negative pathogens; and (7) Biofilms formed by Gram-positive pathogens. Results Checkerboard assays using microtiter plates demonstrate the antibiotic properties. Growth curves demonstrate bacteriostatic effects. Scanning electron microscopy (SEM) was used to confirm that the combination treatment leads to abnormal morphology. Data collected with isothermal titration calorimetry and fluorescence spectroscopy demonstrate a mechanism of action. ELISA was used to neutralize endotoxins (LPS, LTA, peptidoglycan) that otherwise stimulate pattern recognition receptors, leading the release of pro-inflammatory cytokines. Additional data show that PEG-BPEI can be absorbed onto, and released from, drug-delivery systems