Hollow micro- and nano-particles by gas foaming

This paper presents the results of a first successful attempt to produce hollow micro- and nano-particles of a large variety of materials, dimensions, shapes and hollow attributes by using an environmentally friendly and cheap technology, common in polymer processing and known as gas foaming. The central role played by ad hoc polymeric hollow micro- and nano-particles in a variety of emerging applications such as drug delivery, medical imaging, advanced materials, as well as in fundamental studies in nanotechnology highlights the wide relevance of the proposed method. Our key contribution to overcome the physical lower bound in the micro- and nano-scale gas foaming was to embed, prior to foaming, bulk micro- and nano-particles in a removable and deformable barrier film, whose role is to prevent the loss of the blowing agent, which is otherwise too fast to allow bubble formation. Furthermore, the barrier film allows for non-isotropic deformation of the particle and/or of the hollow, affording non-spherical hollow particles. In comparison with available methods to produce hollow micro- and nano-particles, our method is versatile since it offers independent control over the dimensions, material and shape of the particles, and the number, shape and open/closed features of the hollows. We have gas- foamed polystyrene and poly-（lactic-co-glycolic） acid particles 200 ~m to 200 nm in size, spherical, ellipsoidal and discoidal in shape, obtaining open or closed, single or multiple, variable in size hollows.

Silk-ELR co-recombinamer covered stents obtained by electrospinning

In the field of tissue engineering the choice of materials is of great importance given the possibility to use biocompatible polymers produced by means of biotechnology.A large number of synthetic and natural materials have been used to this purpose and processed into scaffolds using Electrospinning technique.Among materials that could be used for the fabrication of scaffold and degradable membranes,natural polymers such as collagen,elastin or fibroin offer the possibility to design structures strictly similar to the extracellular matrix(ECM).Biotechnology and genetic engineering made possible the advent of a new class of biopolymers called protein-based polymers.One example is represented by the silk-elastin-proteins that combine the elasticity and resilience of elastin with the high tensile strength of silk-fibroin and display engineered bioactive sequences.In this work,we use electrospinning technique to produce a fibrous scaffold made of the corecombinamer Silk-ELR.Obtained fibres have been characterized from the morphological point of view.Homogeneity and morphology have been explored using Scanning Electron Microscopy.A thorough study regarding the influence of Voltage,flow rate and distance have been carried out to determine the appropriate parameters to obtain the fibrous mats without defects and with a good distribution of diameters.Cytocompatibility has also been in vitro tested.For the first time we use the co-recombinamer Silk-ELR for the fabrication of a 2.5 angioplasty balloon coating.This structure could be useful as a coated scaffold for the regeneration of intima layer of vessels.