RESUMO
Starch is a natural material extracted from roots, seeds, stems and tubers of different plants. It can be processed as a thermoplastic to produce a variety promising products for biomedical applications, including foams, sheets and films. In the present work, we investigated the immunological properties of microfilms prepared with starches extracted from six different types of Andean potatoes and their relationship with the different film-surface features. We confirmed the biocompatibility of all the films using THP-1 human monocytes, noticing only slight decrease in cell viability in two of the tested starches. We also analyzed pro-inflammatory cytokine release and immune cell surface receptor modulation on THP-1 plated onto the films. Our data show differences in the immunological profile of the same cells cultured onto the different starch films. Furthermore, we examined whether the dissimilar stiffness or the nanometric roughness of the films might influence the immune stimulation of the THP-1 monocytes. Our results demonstrate no correlation between cultured THP-1 immune activation and surface film characteristics. We conclude that different Andean native potato starch films have specific ability to interact with cell membranes of immune cells, conceivably due to the different spatial localization of amylose and amylopectin in the diverse starches.
Assuntos
Fenômenos Mecânicos , Nanopartículas/química , Amido/química , Amido/imunologia , Materiais Biocompatíveis/farmacologia , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Citocinas/metabolismo , Humanos , Mediadores da Inflamação/metabolismo , Teste de Materiais , Microscopia de Força Atômica , Receptores Imunológicos/metabolismo , Propriedades de SuperfícieRESUMO
Different Andean crops were used to obtain starches not previously reported in literature as raw material for the production of biodegradable polymers. The twelve starches obtained were used to prepare biodegradable films by casting. Water and glycerol were used as plasticizers. The mechanical properties of the starch based films were assessed by means of tensile tests. Compost tests and FTIR tests were carried out to assess biodegradability of films. The results show that the mechanical properties (UTS, Young's modulus and elongation at break) of starch based films strongly depend on the starch source used for their production. We found that all the starch films prepared biodegrade following a three stage process and that the weight loss rate of all the starch based films tested was higher than the weight loss rate of the cellulose film used as control.
Assuntos
Produtos Agrícolas/química , Plásticos/síntese química , Amido/isolamento & purificação , Biodegradação Ambiental , Teste de Materiais , Peru , Plásticos/química , Espectroscopia de Infravermelho com Transformada de Fourier , Amido/química , Resistência à TraçãoRESUMO
Byssus fibres are tough biopolymer fibres produced by mussels to attach themselves to rocks. In this communication, we present the mechanical properties of the byssus from the South American mussel Aulacomya ater which have not been previously reported in the literature. The mechanical properties of the whole threads were assessed by uniaxial tensile tests of dry and hydrated specimens. Elastoplastic and elastomeric stress-strain curves were found for byssal threads from A. ater in the dry and hydrated state, respectively. The results obtained from mechanical tests were modelled using linear, power-law-type and Mooney-Rivlin relationships. These methods for dealing with tensile measurements of mussel byssus have the potential to be used with other stretchy biomaterials.