Attachment of Ampicillin to Expanded Poly(tetrafluoroethylene): Surface Reactions Leading to Inhibition of Microbial Growth

Abstract

The broad spectrum antibiotic, ampicillin (AM), was reacted to expanded poly (tetrafluoroethylene) (ePTFE) surfaces and resulted in the formation of antimicrobial surfaces effective against gram-positive, Staphylococcus aureus, Bacillus thuringiensis, and Enterococcus faecalis, and gram-negative, Escherichia coli, Pseudomonas putida, and Salmonella enterica bacteria. These ePTFE surface modifications were accomplished by utilization of microwave maleic anhydride (MA) plasma reactions leading to the formation of acid groups, followed by amidation reactions of heterofunctional NH 2/COOH-terminated polyethylene glycol (PEG). The final step, the attachment of AM to the PEG spacer, was achieved by amidation reactions between COOH-terminated PEG and NH 2 groups of AM. This approach protects the COOH-AM functionality and diminishes the possibility of hydrolysis of the antimicrobial active portion of AM. These studies also show that approximately 90% of AM molecules are still covalently attached to PEG-MA-ePTFE surfaces after exposure to the bacteria solutions. Even after a 24 h period, the AM volume concentration changes only from 2.25 to 2.04 microg/m3, and depending upon the bacteria type, the bacteria suspensions containing AM-PEG-MA-ePTFE specimens retain 85-99% of their initial optical density.

Covalent immobilization of antimicrobial peptides (AMPs) onto biomaterial surfaces

“…However, many of these compounds are associated with anaphylaxis, cytotoxicity or low efficiency [5,13]. These limiting aspects prompt the use of true antibiotics such as vancomycin, tobramycin, cefalozin, teicoplanin, carbenicillin, amoxicillin, penicillin, ampicillin and gentamicin [3,[34][35][36][37], through two different strategies: substance-releasing coating and substance covalent immobilization. The release strategy offers the potential for extended activity, but has to date failed to achieve delivery of a sustained and effective dosage over a relatively prolonged period of time.…”

“…For example, vancomycin has been successfully attached to titanium and proven to be bactericidal to Staphylococcus aureus and Staphylococcus epidermidis [5,7]. In addition, Aumsuwan et al [34,37] reported the covalent attachment of penicillin and ampicillin to expanded polytetrafluoroethylene (ePTFE). When these drugs were immobilized through a PEG-spacer, the surfaces displayed high antimicrobial efficiency among their spectrum of activity, indicating that antibiotic mobility is essential to activity.…”

“…Covalent immobilization of AMP can increase their long-term stability while decreasing their toxicity, as compared to incorporation approaches on leach-or releasebased systems [11,35,36,69,[72][73][74][75]. Furthermore, the proper orientation of the peptide may result in enhanced activity [34]. Towards this goal, the effect of AMP chemical immobilization on antimicrobial activity has been studied by several investigators [3,4,6,[25][26][27]29,48,49,71] (Table 1).…”

Cationic Antimicrobial Peptides

“…Examples of these surfaces are ampicillin and penicillin attached to expanded poly(tetrafluoroethylene) [99,100]. However, the growing emergence of bacterial resistance towards classical antibiotics is a major drawback to their applicability for the production of antibiotic surfaces.…”

Antibiofilm Properties of Interfacially Active Lipase Immobilized Porous Polycaprolactam Prepared by LB Technique

“…[4]. Penicillin and ampicillin are covalently attached to expanded polytetrafluoroethylene through a PEG-spacer to develop antimicrobial surface [2], [5]. 2-Methoxy-2′, 4′-dichloro chalcone when mixed with marine paint and coated on polycarbonate, glass fiber reinforced plastic and polymethylmethacrylate prevents the formation of Vibrio natriegens biofilm [6].…”