A new strategy for battling bacterial resistance: Turning potent, non-selective and potentially non-resistance-inducing biocides into selective ones

Antibiotic alternatives are in great need for combating antibiotic resistance. Selective delivery of a potent non-selective non-resistance-inducing biocide (C17) to MRSA was achieved by encapsulating it in solid lipid nanoparticles (SLNs) conjugated with a MRSA-specific antibody (termed as "Ab"). The C17-loaded Ab-conjugated SLNs (C17-SLN-Ab) demonstrated significantly better antimicrobial activity than its antibody free counterpart (C17-loaded SLN) and C17-loaded SLN with a non-specific IgG antibody. In a new MRSA/fibroblast co-culture assay, C17-SLN-Ab showed selective toxicity toward MRSA than fibroblast cells. C17-SLN-Ab possesses double selectivity, exhibiting higher toxicity to MRSA than to Pseudomonas aeruginosa. This same strategy was used to successfully increase C17's selectivity against E. coli K12 by switching the conjugated anti-MRSA antibody to an anti-E. coli antibody, demonstrating versatility of this new strategy. This proof-of-concept research can be extended to other non-selective antimicrobials, against which bacterial resistance is unlikely to develop, to generate a new group of promising antibiotic alternatives.

Dynamic mechanical behaviour of nanoparticle loaded biodegradable PVA films for vaginal drug delivery

In this study, we investigated the viscoelastic and mechanical behaviour of polyvinyl alcohol films formulated along with carrageenan, plasticizing agents (polyethylene glycol and glycerol), and when loaded with nanoparticles as a model for potential applications as microbicides. The storage modulus, loss modulus and glass transition temperature were determined using a dynamic mechanical analyzer. Films fabricated from 2% to 5% polyvinyl alcohol containing 3 mg or 5 mg of fluorescently labeled nanoparticles were evaluated. The storage modulus and loss modulus values of blank films were shown to be higher than the nanoparticle-loaded films. Glass transition temperature determined using the storage modulus, and loss modulus was between 40-50℃ and 35-40℃, respectively. The tensile properties evaluated showed that 2% polyvinyl alcohol films were more elastic but less resistant to breaking compared to 5% polyvinyl alcohol films (2% films break around 1 N load and 5% films break around 7 N load). To our knowledge, this is the first study to evaluate the influence of nanoparticle and film composition on the physico-mechanical properties of polymeric films for vaginal drug delivery.