Bioadhesive Polymeric Films Containing Rhamnolipids, An Innovative Antimicrobial Topical Formulation.

Acne affects most of the world's population, causing an impact on the self-esteem of adolescents and young adults. One of the causes is the presence of the bacteria Cutibacterium acnes which are part of the natural microbiota of the skin. Topical treatments consist of anti-inflammatory and antibiotics, which could select resistant strains. Alternatives to the antibiotic are biocomposites that have antimicrobial activity like biosurfactants which are produced by bacteria. An innovative way of applying these compounds is bioadhesive polymeric films that adhere to the skin and release the active principle topically. Rhamnolipids have great potential to be used in the treatment of acne because they present antimicrobial activity against C. acnes in low and safe concentrations (MIC of 15.62 µg/mL, CBM of 31.25 µg/mL and CC50 of 181.93 µg/mL). Four films with different rhamnolipids concentrations (0.0; 0.1; 0.2; and 0.3%, w/w) were obtained as to visual appearance, mass variation, thickness, density, solubility, pH, water vapor transmission, mechanical properties (folding endurance, bioadhesion strength, tensile strength, elongation at break and Young's modulus), scanning electron microscopy and infrared. The results show that these formulations had a homogeneous appearance; elastic mechanical properties; pH similar to human skin and bioadhesive. The polymeric films containing rhamnolipids were effective against C. acnes, in the in vitro test, at the three concentrations tested, the film with the highest concentration (0.3%, w/w) being the most promising for presenting the highest antimicrobial activity. Thus, the polymeric film containing rhamnolipids has the potential to be used in the treatment of acne.

Antibacterial Activity of Biodegradable Films Incorporated with Biologically-Synthesized Silver Nanoparticles and the Evaluation of Their Migration to Chicken Meat.

The food industry has been exploring the association of polymers with nanoparticles in packaging production, and active products are essential to increase the shelf life of food and avoid contamination. Our study developed starch-poly (adipate co-terephthalate butyl) films with silver nanoparticles produced with Fusarium oxysporum components (bio-AgNPs), intending to control foodborne pathogens. The bio-AgNPs showed activity against different Salmonella serotypes, including multidrug-resistant Salmonella Saint Paul and Salmonella Enteritidis, with minimum bactericidal concentrations ranging from 4.24 to 16.98 µg/mL. Biodegradable films with bio-AgNPs inhibited the growth of up to 106Salmonella isolates. Silver migration from the films to chicken was analyzed using electrothermal atomic absorption spectrophotometry, and the results showed migration values (12.94 mg/kg and 3.79 mg/kg) above the limits allowed by the European Food Safety Authority (EFSA) (0.05 mg/kg). Thus, it is necessary to improve the technique to avoid the migration of silver to chicken meat, since these concentrations can be harmful.

Metal Nanoparticles against Viruses: Possibilities to Fight SARS-CoV-2.

In view of the current Coronavirus Disease 2019 (COVID-19) pandemic outbreak, the research community is focusing on development of diagnostics, treatment, and vaccines to halt or reverse this scenario. Although there are already various vaccines available, adaptive mutations in the SARS-CoV-2 genome can alter its pathogenic potential and, at the same time, increase the difficulty of developing drugs or immunization by vaccines. Nanotechnology carries a potential to act in all stages in fighting this viral disease, with several possibilities of strategies such as applying nanoparticles directly as antivirals in delivery systems against these viruses or incorporating them in materials, with power of achievement in therapeutics, vaccines and prevention. In this paper, we review and bring insights of recent studies using metal nanocomposites as antivirals against coronavirus and structurally similar viruses.

Antiphage activity of natural and synthetic substances: a new age for antivirals?

Viruses are considered biological entities that possess a genome and can adapt to the environment of living organisms. Since they are obligate intracellular parasites, their cycle of replication can result in cell death, and consequently, some viruses are harmful to mammalian cells and can cause disease in humans. Therefore, the search for substances for the treatment of viral diseases can be accomplished through the use of bacteriophages as models for eukaryotic cell viruses. Thus, this review highlights the main studies identifying substances with antiphage activity in comparison assays involving phages and eukaryotic viruses, in order to explore the potential of these substances as antivirals. As a future perspective, this approach may help at the beginning of an Antiviral Age.