The increasing demand for organ replacements in a growing world with an aging population as well as the loss of tissues and organs due to congenital defects, trauma and diseases has resulted in rapidly evolving new approaches for tissue engineering and regenerative medicine (TERM). The extracellular matrix (ECM) is a crucial component in tissues and organs that surrounds and acts as a physical environment for cells. Thus, ECM has become a model guide for the design and fabrication of scaffolds and biomaterials in TERM. However, the fabrication of a tissue/organ replacement or its regeneration is a very complex process and often requires the combination of several strategies such as the development of scaffolds with multiple functionalities and the simultaneous delivery of growth factors, biochemical signals, cells, genes, immunomodulatory agents, and external stimuli. Although the development of multifunctional scaffolds and biomaterials is one of the most studied approaches for TERM, all these strategies can be combined among them to develop novel synergistic approaches for tissue regeneration. In this review we discuss recent advances in which multifunctional scaffolds alone or combined with other strategies have been employed for TERM purposes.
The widespread occurrence of nosocomial infections and the emergence of new bacterial strands calls for the development of antibacterial coatings with localized antibacterial action that are capable of facing the challenges posed by increasing bacterial resistance to antibiotics. The Layer-by-Layer (LbL) technique, based on the alternating assembly of oppositely charged polyelectrolytes, can be applied for the non-covalent modification of multiple substrates, including medical implants. Polyelectrolyte multilayers fabricated by the LbL technique have been extensively researched for the development of antibacterial coatings as they can be loaded with antibiotics, antibacterial peptides, nanoparticles with bactericide action, in addition to being capable of restricting adhesion of bacteria to surfaces. In this review, the different approaches that apply LbL for antibacterial coatings, emphasizing those that can be applied for implant modification are presented.
1 November 2017 in Materials Science and Engineering: C
The interfacial two-dimensional spreading dynamics of quasilinear Vero cell colony fronts in methylcellulose (MC)-containing culture medium, under a constant average front displacement velocity regime, was investigated. Under comparable experimental conditions, the average colony front displacement velocity becomes lower than that reported for a standard culture medium. Initially, the presence of MC in the medium hinders both the colony spreading, due to a gradual change in the average size and shape of cells and their distribution in the colony, and the cell motility in the gelled medium. Furthermore, at longer culture times enlarged cells appear at random in the border region of the colony. These cells behave as obstacles (pinning sites) for the displacement of smaller cells towards the colony front. The dynamic scaling analysis of rough fronts yields the set of exponents , and , which is close to that expected for a quenched Kardar-Parisi-Zhang model.