Functionalization of wool with L‐cysteine: Process characterization and assessment of antimicrobial activity and cytotoxicity

Abstract

This investigation reports a new biotechnological process that uses L-cysteine (L-Cys) which provides a permanent, nontoxic and effective antimicrobial effect over wool-based materials. This process is simple and carried out via widespread exhausting methods. Typically, wool fabrics are incubated with L-Cys for 50 min at 60 C in a pH 4.8 acetate buffer solution 25 mM, under mild agitation to give a good absorption rate. The minimal inhibitory concentration (MIC) of L-Cys was evaluated by the NCCLS M07-A6 standard method, and the results showed a good antibacterial activity against S. aureus and K. pneumoniae within the range of 6.0 Â 10 À3 À 4.8 Â 10 À2 g/mL [MIC 0.6% (w/v)] and 6.0 Â 10 À3 À 4.8 Â 10 À2 g/mL [MIC 0.6% (w/v)], respectively. In addition, the antimicrobial activity of the functionalized wool was assessed by the international standard JIS 1902JIS -2002 showing a good inhibition of bacterial growth for an L-Cys concentration of 1% over the weight of fabric, both against Staphylococcus aureus and Klebsiella pneumoniae. Moreover, the biocidal mechanism was found to be related with the increase of sulfhydryl's groups onto wool fibers, which were quantified by the Ellman's reagent (5,5 0 -Dithio-bis(2-nitrobenzoic acid) method. The new process is easy to perform, non toxic, preserve wool quality and is a novel biomimetic approach that uses antimicrobial amino acids and may open new avenues for the design of biomedical textiles with a broad range of applications in healthcare.

Comparison of the antibacterial activity of modified‐cotton with magainin I and LL‐37 with potential as wound‐dressings

“…When in contact with LL-37 at concentrations of 4.17 and 5.00 mg/mL, which were the concentrations chosen for the functionalization of the cotton gauzes, there was an increase in cellular viability of 23%, but in contrast a decrease of 6% in fibroblast viability was observed, when in contact with magainin I at concentrations of 0.20 and 4.17 mg/mL. These results mean that none of the magainin I and LL-37 concentrations caused cytotoxic effect in the normal human dermal fibroblasts, since according to Gouveia et al (2011), 16 only an alteration above 30% in comparison with control is considered cell-toxic. 16 Consequently, these AMPs were considered safe to be applied as antimicrobial agents to contact with the human skin without ARTICLE WILEYONLINELIBRARY.COM/APP causing any cutaneous adverse reaction in the tested concentrations.…”

“…Samples were then dried at room temperature. The soaping procedure was performed over the samples treated with the AMPs prior to further investigation and assessment of antibacterial activity, in order to give evidence of the fastness of the functionalization process …”

“…The soaping procedure was performed over the samples treated with the AMPs prior to further investigation and assessment of antibacterial activity, in order to give evidence of the fastness of the functionalization process. 16 Effectiveness of the Functionalization Process on Cotton Color Strength Values (K/S). A color strength test was performed using Coomassie brilliant blue reagent to assess the presence of the antimicrobial peptides, magainin I, and LL-37, in the modified-cotton samples and the K/S values were determined.…”

New biomaterial based on cotton with incorporated Biomolecules

“…This further ionized to TNB −2 . This last ion showed a yellow color that could be detected by visible light at 405 nm …”

“…This last ion showed a yellow color that could be detected by visible light at 405 nm. 30,40 Attenuated Total Reflectance (ATR)-Fourier Transform Infrared (FTIR) Spectra ATR-FTIR spectra of samples were acquired on a Thermo-Nicolet is10 FTIR spectrophotometer with OMNIC software with wavelengths of 500-4000 cm 21 . The spectra were collected at a resolution of 4 cm 21 with 64 scans per spectrum.…”