Alessandro Sannino

Progress and Perspectives in the Management of Wound Infections

The progress in nanotechnology and the medical application of novel generations of nanomaterials have opened new horizons in the definition of non-conventional approaches against multiple diseases. Biomaterials coated with antimicrobial metal nanoparticles, along with the topical applications of zinc, silver or copper-based formulations have demonstrated huge potential in prevention from infections associated with implantable medical devices and in biofilm eradication. In wound healing, in particular, the increasing healthcare costs and the antibiotic resistance demonstrated by several microorganisms have encouraged researchers and companies in the development of innovative wound dressings with antibacterial properties and capability to promote and enhance the healing process. Supported by scientific evidence, many formulations have been proposed and a large number of works involves the use of hybrid metal nanoparticles/polymer products, which have demonstrated encouraging results both in vitro and in vivo. In this chapter, recent progress in the development of novel wound dressings based on antibacterial metal nanoparticles is presented, along with the most interesting results achieved by the authors, mainly devoted to the application of silver nanocoatings in wound management.

A tissue engineered osteochondral composite for cartilage repair: an in vivo study

This work aimed to validate the efficacy of a tissue engineered osteochondral composite for the treatment of cartilage lesion produced in adult pigs. The osteochondral composite was manufactured by combining an osteo-compatible cylinder and a neocartilagineous tissue obtained by seeding swine articular chondrocytes into a collagen scaffold. Articular cartilage was harvested from the trochlea of six adult pigs and was enzymatically digested to isolate the chondrocytes [Deponti D.et al. 2005]. The cells were then expanded in monolayer culture in chondrogenic medium and seeded onto a collagen scaffold. The collagen scaffold was preintegrated in vitro, macroscopically and microscopically, to a an osteo-compatible cylinder. The seeded osteochondral scaffolds were left in standard culture condition for 3 weeks with the addition of growth factors. At the end of culture time the osteochondral scaffolds were surgically implanted in osteochondral lesion performed in the trochlea of the same pigs from which the cartilage was initially harvested. As control, some osteochondral lesions were treated with acellular scaffolds and others were left untreated. After 3 months, the repair tissue of the three experimental groups was macroscopically analyzed and processed for histological and biochemical analysis. The hystologic ICRS II scale showed a statistically significant difference between the three experimental groups only in the parameters regarding the cell morphology and the surface/superficial assessment: the lesion treated with the unseeded osteochondral scaffolds showed higher values in chondrocytes morphology and in the superficial layer recovery, with respect to the lesions treated with the seeded scaffolds or left untreated. The biochemical analysis showed a higher DNA content in the lesion repaired with cellular scaffold and a higher GAGs/DNA ratio in the lesions with a spontaneous repair. The result of this study demonstrate that an osteochondral scaffold was able to repair an osteochondral lesion in an in vivo model of adult pigs, showing a good integration with the surrounding tissue. The quality of the repair was higher when the scaffold was not seeded with chondrocytes, but filled with cells migrated from subchondral bone. This tissue engineered osteochondral composite could represent a valuable model for further in vivo studies on the repair of chondral/osteochondral lesion.