Skin2Tex Old peptides with new faces: A new strategy to develop non-toxic antimicrobial textiles for healthcare applications.

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Layer-by-Layer Deposition of Antibacterial Polyelectrolytes on Cotton Fibres

Publication . Gomes, Ana; Mano, João F.; Queiroz, João; Gouveia, Isabel C.

The introduction of molecules with biological properties on textile materials is essential for a number of biotechnological applications. With the purpose of testing new processes applied to textiles, in this study, we present the first results on the feasibility of using the Layerby-Layer (LbL) deposition process in natural fibers such as cotton, with natural polyelectrolytes like chitosan (CH) and alginic acid sodium salt (ALG), the durability of CH/ALG multilayer on cotton were evaluated. The increase of negative charges to the substrate cotton was made with NaBr and TEMPO, to ensure the success of the process of LbL. Three characterization methods to assess electrostatic LbL deposition were performed: the contact angle between a liquid (water) and the sample surface, in order to characterize the wettability of the samples with the different layers of CH and ALG; dyeing of the CH/ALG assembled cotton fabric with cationic methylene blue that shows regular changes in terms of color depth (K/S value), which indicate that the surface were alternately deposited with CH and ALG layers and, finally, the analysis by infrared spectroscopy using Fourier Transform with Attenuated Total Reflection (ATR-FTIR), to assess the changes in the interaction between CH and ALG deposited on cotton samples.

2012Journal article

Open access

Antimicrobial functionalization of wool: assessment of the effect of Cecropin-B and [Ala5]-Tritrp7 antimicrobial peptides

Publication . Mouro, Cláudia; Gouveia, Isabel C.

This investigation provides a new strategy to impart antimicrobial properties into wool-based materials using Cecropin-B and [Ala5]-Tritrp7 antimicrobial peptides (AMPs). The process was conducted using exhaustion method at 40 °C for 1–3 h. The presence of the AMPs in the modified-wool samples was confirmed by colorimetric assay of Bradford reagent and possible changes in the morphology of the fibers and damage to its surface were analyzed by scanning electron microscopy. Results showed that 1 h were long enough for the functionalization to occur effectively and that the morphology of the fibers was not influenced by the functionalization process. Furthermore, the antimicrobial activity of the AMPs applied on wool was assessment by JIS L 1902-2002 against Staphylococcus aureus (ATCC 6538) and Klebsiella pneumoniae (ATCC 4352). The results showed that both AMPs have a high reduction in bacterial growth (Cecropin-B resulting in 71.67% reduction against S. aureus and 85.95% against K. pneumoniae. While [Ala5]-Tritrp7 resulting in 66.74% reduction against S. aureus and 88.65% against K. pneumoniae).

2016Journal article

Open access

Péptidos antimicrobianos: uma nova estratégia na funcionalização bioativa de fibras de lã e poliamida

Publication . Mouro, Cláudia Filipa Duarte; Gouveia, Isabel Cristina Aguiar de Sousa e Silva

Os materiais têxteis em condições de humidade e temperatura adequadas são um excelente substrato para a proliferação de microrganismos, particularmente bactérias e fungos podendo, em ambiente hospitalar, contaminar doentes e profissionais de saúde. Assim, o uso de materiais têxteis antimicrobianos pode reduzir significativamente o risco de infeções especialmente quando usados em contacto direto com a pele. Para isso, várias substâncias com características antimicrobianas têm sido utilizadas, no entanto, preocupações devido aos seus efeitos colaterais têm levado a uma procura crescente de agentes antimicrobianos naturais, como soluções eficazes, ecológicas e não tóxicas. Consequentemente, neste trabalho, uma nova estratégia prevê o uso de péptidos antimicrobianos (AMPs) como agentes bioativos para a potencial biofuncionalização de materiais têxteis. A cecropina-B, o [Ala5]-Tritrp7 e o Cys-LC-LL-37 foram os AMPs selecionados para conferir propriedades antimicrobianas aos materiais têxteis. Neste trabalho, os AMPs foram usados no tratamento da lã (fibra natural) e da poliamida 6.6 (PA 6.6) (fibra sintética) e a sua ligação às fibras foi confirmada pelo teste do reagente de Bradford em solução e na amostra. Nesse sentido, pelos resultados obtidos, processos de funcionalização de apenas 1 hora foram estabelecidos para a biofuncionalização ocorrer de forma eficaz. Além disso, possíveis alterações nas características estruturais da lã e da PA 6.6 foram analisadas por difração de raio-x (DRX) e comprovou-se que a composição macromolecular das fibras não foi influenciada pelo processo de biofuncionalização, de forma prejudicial. Foram também obtidas imagens de microscopia eletrónica de varrimento (SEM) que comprovaram que a ligação dos AMPs nas fibras não alterou nem provocou danos na sua superfície. Entre os resultados obtidos, é de realçar que as amostras de lã e de PA 6.6 funcionalizadas com os AMPs apresentaram percentagens de redução bacterianas elevadas. No caso da lã, as amostras funcionalizadas apresentaram uma redução no crescimento bacteriano para o Staphylococcus aureus de 71,67% para a cecropina-B e de 66,74% para o [Ala5]-Tritrp7, enquanto para Klebsiella pneumoniae houve uma redução no crescimento bacteriano de 85,95% para a cecropina-B e de 88,65% para o [Ala5]-Tritrp7. Relativamente à PA 6.6, a redução de crescimento para o Staphylococcus aureus, das amostras de PA 6.6 funcionalizadas, foi de 68,81% para a cecropina-B e de 73,81% para o Cys-LC-LL-37. Por outro lado, para a Klebsiella pneumoniae reduções de crescimento de 85,25% para a cecropina-B e de 87,31% para o Cys-LC-LL-37 foram alcançadas. Apesar do efeito antibacteriano dos AMPs ser promissor, procedeu-se também à avaliação da sua citotoxicidade. Os resultados demonstraram que os AMPs não são tóxicos nas condições testadas e que os materiais funcionalizados podem ser utilizados com segurança. Assim, os resultados revelaram que os novos processos conferem propriedades antimicrobianas inequívocas às fibras tratadas. Esse efeito foi preferencialmente visível para as bactérias em estudo e foi avaliado pela norma JIS L 1902-2002.

2013Master thesis

Open access

Antimicrobial and antioxidant surface modification toward a new silk-fibroin (SF)-l-Cysteine material for skin disease management

Publication . Nogueira, Frederico; Granadeiro, Luiza Breitenfeld ; Mouro, Cláudia; Gouveia, Isabel C.

A novel dressing material – silk fibroin fabric (SF)-l-Cysteine (l-Cys) – is here developed to be used asstandard treatment for atopic dermatitis (AD), which combines comfort, thermic, and tensile strengthproperties of silk materials with antioxidant and antimicrobial effects of l-Cys. A careful understand-ing about the linking strategies is needed in order not to compromise the bioavailability of l-Cys anddeplenish its bioactivity. Durability was also addressed through washing cycles and compared with hos-pital requirements, according to international Standard EN ISO 105-C06:2010. The present research alsoanalyze the interactions between Staphylococcus aureus and SF-l-Cys under simulating conditions of ADand demonstrated the effectiveness of a double covalent grafting, with the importance of SF tyrosine(Tyr) covalent linkage with l-Cys (SF-g-l-Cys/Tyr-g-l-Cys) even after several washing cycles, twenty five,whereas for a disposable application a single covalent mechanism of grafting l-Cys proved to be suffi-cient (SF-g-l-Cys). Results showed effective antimicrobial activities exhibiting higher inhibition ratios of98.65% for SF-g-l-Cys after 5 washing cycles, whereas 97.55% for SF-g-l-Cys/Tyr-g-l-Cys after 25 washingcycles, both at pH 9.5 grafting strategy. Furthermore, it is also reported a non-protumoral effect of l-Cys. Anew advance is herein achieved at the world of medical antimicrobial textiles tailored to address woundmoisture environment and exudate self-cleaning, which may open novel applications as complementarytherapy for AD disease.

2016Journal article

Open access

Incorporation of antimicrobial peptides on functionalized cotton gauzes for medical applications

Publication . Gomes, Ana; Mano, João F.; Queiroz, João; Gouveia, Isabel C.

A large group of low molecular weight natural compounds that exhibit antimicrobial activity has been isolated from animals and plants during the past two decades. Among them, peptides are the most widespread resulting in a new generation of antimicrobial agents with higher specific activity. In the present study we have developed a new strategy to obtain antimicrobial wound-dressings based on the incorporation of antimicrobial peptides into polyelectrolyte multilayer films built by the alternate deposition of polycation (chitosan) and polyanion (alginic acid sodium salt) over cotton gauzes. Energy dispersive X ray microanalysis technique was used to determine if antimicrobial peptides penetrated within the films. FTIR analysis was performed to assess the chemical linkages, and antimicrobial assays were performed with two strains: Staphylococcus aureus (Gram-positive bacterium) and Klebsiella pneumonia (Gram-negative bacterium). Results showed that all antimicrobial peptides used in this work have provided a higher antimicrobial effect (in the range of 4 log-6 log reduction) for both microorganisms, in comparison with the controls, and are non-cytotoxic to normal human dermal fibroblasts at the concentrations tested.

2015Journal article

Open access