Physico-chemical characterisation of Silk-based materials

Physico-chemical characterisation is essential to define and to assure quality, safety and efficacy of silk-based materials when intended for pharmaceutical and biomedical use. In fact, the possible interconversion and interactions between the various conformations of the fibroin and sericin, and the transitions from the most stable crystalline forms to the metastable amorphous ones, can modify (i) the release properties of the drugs from the silk-based delivery systems, (ii) the silk-based carrier's superficial properties, determining the targeting mechanisms to the site of action. Thermal analysis and spectrophotometric methods, supported by X-ray diffraction analysis and microscopic techniques, are useful to characterise the main crystal structures and the three conformations, Silk I, Silk II and unstable Silk III, of proteins. This chapter reports some applicative examples of the analyses performed with these techniques concerning the characterisation of silk proteins and silk-based micro/nano-drug delivery systems.