Materials design at the nanoscale for biomedicine
Prof. Gianluca Ciardelli from Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy
Demand for medical implants is estimated to increase 9.3% annually to US$43.6 bln in 2011, according to a report by Freedonia Group. Cardiac implants are expected to remain the top-selling group, led by stents and defibrillators, with demand expanding 9%Pa to almost US$20 bln in 2011. Biodegradable plastics, that have found until now application in packaging, are slowly capturing newer markets, particularly medical products. Applications of biodegradable plastics have gained market acceptance in the medical sector in: medical implants, drug delivery, hernia repair devices. One reason for the rise in implant use is the performance and outcome advantages over alternative treatments, such as drugs. Another reason is the constant improvement and innovation of devices that keep getting smaller.
However, materials which were approved (e.g. polymers belonging to the polylactic or polyglycolic acids family) were originally designed for other applications and then proposed for
medical use. This approach usually results in various drawbacks in the final application, e.g. the release of acidic compounds during the degradation of polylactic acid results in a lowering of the local pH at the implant site, with consequent danger of inflammation reaction and adverse body response. Consequently, it is clear that a precise design at the nanoscale of the chemical and morphological structure, can open the way to a new generation of biomaterials tailor-made to the challenging applications of biomedicine and bionics, such as tissue regeneration, advanced diagnostics, cancer treatment.
In this context, this contribution will present the more recent research results of the Biomedical Laboratory at Politecnico di Torino on the application of proprietary, degradable block copolymers in the regeneration of the cardiac, nervous and bone tissue and in nanomedicine. Moreover, recent results in the translation of the lesson learned in the design of materials for tissue regeneration to the development of experimental models replicating the structure and function of healthy, ageing and pathological models will be illustrated. The rationale for polymer design illustrated in the figure here, where the different building blocks are used to provide the final product with the expected mechanical properties during use, cell-adhesion and - targeting motifs, hydrolytic and enzymatically activated degradation (enhanced in the presence of pathological conditions), providing non-toxic and bioactive degradation products. The polymers can be processed then in the suitable form (tubular structures, anisotropic scaffolds, nanoparticles, injectable gels) for the final application.