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In this chapter, a full overview of the main characterization techniques of biopolymer membranes and films is presented, focusing on the fundamentals and methods of analysis of each technique applied to biopolymers. First, a complete publications search on the main characterizations of biopolymer films and membranes is reported, specifying the number of published papers per technique from 1999 to 2018. Then, the characterizations are sorted by type. In the physicochemical characterization section, microscopy techniques, Fourier transform infrared spectroscopy, Raman spectroscopy, nuclear magnetic resonance spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermal analysis are addressed. Then, physical characterizations, such as swelling, degradation/erosion degree, mechanical and barrier properties, contact angle, and textural analysis applied to biopolymer membranes and films are elucidated. Finally, the main biological characterizations are reported, such as cytotoxicity, sensitization capacity, and irritation potential.

Silk fibroin (SF) is a promising and versatile biodegradable protein for biomedical applications. This study aimed to develop a prolonged release device by incorporating SF microparticles containing dyes into SF hydrogels. The influence of dyes on incorporation and release kinetics in SF based devices were evaluated regarding their hydrophilicity, molar mass, and cationic/anionic character. Hydrophobic and cationic dyes presented high encapsulation efficiency, probably related to electrostatic and hydrophobic interactions with SF. The addition of SF microparticles in SF hydrogels was an effective method to prolong the release, increasing the release time by 10-fold.

In this study, we proposed the use of the biopolymer alginate to produce membranes with diclofenac sodium incorporated as model-drug aiming at wound dressing application with drug delivery. The membranes were prepared by casting and the drug was incorporated directly into alginate solution, being retained within the membrane. Morphological, chemical, mechanical and barrier properties were evaluated, as well as the release kinetics in vitro using simulated exudate fluid at 37 °C. Results show that the membranes are malleable in the glycerol presence and more resistant to water after crosslinking. The incorporation of diclofenac sodium did not affect barrier properties, but influenced the mechanical properties, increasing the total thickness (from 0.108 to 0.209 mm) and reducing tensile strength (from 40.85 to 21.76 MPa). Drug release evaluation shows that anomalous transport is the major rate-controlling mechanism, where the swelling or erosion of the alginate matrix is the major responsible for the diclofenac sodium release, with a small contribution of Fickian diffusion mechanism. The results show the potential of application of the alginate membranes for wound dressings with drug delivery for enhancing healing process.

RESUMO A fibroina de seda e um polimero natural presente nos casulos dos bichos-da-seda da especie Bombyx mori e apresenta um grande potencial para utilizacao como biomaterial, devido a sua resistencia mecânica, biocompatibilidade e biodegradabilidade. Uma das maneiras de utilizacao da fibroina de seda como biomaterial e na forma de membrana densa, que pode ser explorada para usos na cicatrizacao de ferimentos e queimaduras. A possibilidade de incorporacao de outros materiais na membrana, tais como farmacos e nanoparticulas, aumenta a gama de aplicacoes da membrana de fibroina de seda, possibilitando o preparo de um dispositivo de liberacao controlada. O objetivo desse trabalho e o estudo de metodos de incorporacao de um farmaco modelo (diclofenaco de sodio) em membranas densas de fibroina de seda, para usos futuros como dispositivo de liberacao controlada, especialmente na area de curativos de alto desempenho. Como metodos de incorporacao foram estudados: 1) incorporacao da solucao de farmaco diretamente na solucao de fibroina, antes do preparo da membrana; 2) incorporacao por adsorcao da solucao de diclofenaco na membrana de fibroina. Foram analisadas as caracteristicas visuais e de solubilidade das membranas obtidas pelos diferentes metodos, bem como feitas caracterizacoes por FTIR e MEV, que permitiram a escolha do melhor metodo de incorporacao do farmaco.