Sergio Madrigal-Carballo

This study reports for the first time the use of chitosan aerogels loaded with gentamicin sulfate as a model drug for biphasic release in wound dressings. Bacterial infections represent one of the main complications following injuries or burns, accounting for 75% of the mortality associated with such conditions. For this reason, the fundamental purpose of dressing is to restore the necessary environment for the healing of the injury. In this study, chitosan aerogels with gentamicin sulfate were developed using the lyophilization technique, incorporating antibiotic concentrations between 0.65 and 1.50 mg/ml. The dressings obtained showed an absorption capacity of 83%–92% of the exudate simulation buffer, which shows their swelling and liquid retention capacity. The drug release profiles showed a biphasic pattern, a rapid initial release, followed by a sustained phase, reaching between 70% and 80% release in 60 min. In vitro antimicrobial assays confirmed the efficacy of the dressings in inhibiting the growth of Staphylococcus aureus and Pseudomonas aeruginosa, with greater effectiveness at higher concentrations of the antibiotic (inhibition zone diameters up to ≈43 mm for S. aureus). Therefore, the developed dressing combines structural properties, fluid absorption, controlled release of a model molecule, and antimicrobial protection, presenting a promising option for wound treatment.

The interaction between A‐type interflavan bonds from cranberry proanthocyanidins (PAC) and surface virulence factors of extra‐intestinal pathogenic Escherichia coli (ExPEC) was studied. Electrospun nanofibers (ESNF) were fabricated using PAC and polycaprolactone (PCL) solutions and their physical and chemical properties were characterized. The ability of PAC:PCL composite ESNF to interact with and entrap ExPEC strain 5011 (ExPEC‐5011) was evaluated in vitro by plate culturing and when formulated as a biofilter and nanocoating. As a biofilter, the PAC:PCL ESNF exhibited a dose‐dependent ability to entrap ExPEC‐5011. Images from scanning electron and fluorescent microscopies revealed that ESNF sections with higher amounts of PAC led to higher bacterial entrapment. The effectiveness PAC:PCL ESNF to bind ExPEC when applied as a nanocoating was studied using ESNF‐coated polyvinyl chloride intermittent catheter. Results indicate that ExPEC‐5011 was entrapped well into the PAC:PCL ESNF coating on the catheter. Overall, our results suggest that incorporating the biomolecule PAC in ESNF is a potential means for applications requiring bacterial entrapment, such as biofunctionalization, biofiltration, and surface coating, among others.

Total polyphenol content (TPC), flavonoid content (TFC), anthocyanin content (TAC), and proanthocyanidin (PAC) content were determined in fruit from three tropical Vaccinium species (V. consanguineum, V. floribundum, and V. poasanum) from Costa Rica sampled at three stages of fruit development. Results show that TAC content increased as the fruit developed, while TPC, TFC, and PAC content decreased. Anthocyanin profiles were evaluated using ESI-MS/MS. Cyanidin and delphinidin glycosides were the predominant anthocyanins for the three tropical Vaccinium species. Proanthocyanidins were characterized using ATR-FTIR, NMR, and MALDI-TOF MS. Presence of procyanidin structures with B-type interflavan bonds were observed, but deconvolution of MS isotope patterns indicated that PACs with one or more A-type interflavan bonds accounted for more than 74% of the oligomers at each degree of polymerization.

Chitosan (CHT) has been reported to be biocompatible, bio-absorbable and particularly, is considered a good wound-healing accelerator. On the other hand, collagen (CGN) is one of the most widely used matrix biomaterial in tissue engineering. Highly porous CGN single 3D-scaffolds have been used to support