title collage
Photo of Mario Barbosa

Prof. Mario A. Barbosa


to his website
 
INEB- Institute for Biomedical Engineering, University of Porto, Porto, Portugal
http://www.ineb.up.pt/

Curriculum Vitae

Mário Barbosa, born in Vila do Conde on the 4th October 1950, is Professor Catedrático at the Faculty of Engineering since May 1992. Since September 2000 he is the Scientific Coordinator of INEB. INEB is a private non-profit institution set up in 1989 by the University of Porto, hospitals and other institutions to foster research in Biomedical Engineering. Mário Barbosa was one of the researchers of the University of Porto who promoted the constitution of INEB.

His main areas of research are cell and protein interactions with molecularly engineered surfaces, in particular self-assembled monolayers; injectable systems and 3D scaffolds for bone regeneration and enzyme delivery; surface chemistry of biomaterials.

Has been involved in research projects with financial support from the European Commission, European Science Foundation and Portuguese agencies. The most recent ones can be found at http://www.ineb.up.pt/ and involve collaborations with European, American and Chinese research groups, and also with hospitals and companies. They are related to protein adsorption, development of injectable materials for bone regeneration through minimally invasive surgery, development of artificial intervertebral disc substitutes capable of mimicking the natural disc, utilization of self-assembled monolayers as model surfaces to design materials with anti-clotting and anti-inflammatory properties, removal of heparin from dialyzed blood using selective surfaces to heparin, and the improvement of biomaterials through the analysis of explanted prostheses.

Has supervised 13 PhD theses (2 in co-supervision) and received several honors: in 2009 received, together with Profs. Alexandre Quintanilha and Sobrinho Simões, the “Corino de Andrade Prize”; in 2001 received the George Winter Award of the European Society for Biomaterials (ESB), the ESB award for outstanding work of an established researcher; in May 2000 was nominated Fellow of the International Union of Societies for Biomaterials Science and Engineering.

Belongs to several committees, boards and has positions in other institutions: since 2007 is the representative of the European Society for Biomaterials (ESB) for the Acta Biomaterialia Gold Medal award; since 2007 is the chairman of the awards committee of the ESB; since May 2006 is the Portuguese representative in the Mirror Group of the European Technology Platform on Nanomedicine of the European Commission.

Has published 120 papers in internationally refereed journals.

His Topic of Materials' Days 2010:

Cell-biomaterials Interactions at the nanoscale


Abstract:
Adsorbed proteins play a key role in many biological processes, including the interaction of cells with biomaterials surfaces. For instance, protein adsorption mediates cell adhesion, proliferation and differentiation. In general, the biomaterial surface is not selective towards protein adsorption. However, selective protein adsorption is crucial to guide biological behaviour on engineered materials, particularly those used for tissue regeneration. Selectivity is fundamental for cell behaviour and has become a major goal for biomaterials science, namely for guiding stem cell differentiation, inducing tissue regeneration, avoiding clot formation an controlling the inflammatory reaction. However, selective adsorption should not compromise the functionality of the adsorbed molecules and the conformational changes that occur upon adsorption should be such that they do not impair cell behaviour of anchorage-dependent cells.
Surface chemistry, particularly if designed at the nanoscale, is an essential parameter through which selective adsorption can be controlled. Various strategies have been proposed to induce and guide tissue regeneration, including the mimicking of the interactions between cells and the components of the extracellular matrix (ECM). Grafting of functional groups into polymeric materials, formation of polyelectrolyte polysaccharide- or protein-based complexes have been widely investigated. Exploiting the ability of some of these structures to self-assembly in the biological medium has been proposed in order to produce matrices that resemble the natural ECM.
To understand the fundamental processes occurring in some of these new materials self-assembled monolayers (SAMs) of alkanethiols produced on gold substrates have shown to be an ideal model, particularly when the objective is to study the influence of specific functionalities on protein adsorption and how it controls cell behaviour.
With the purpose of clarifying basic principles underlying the interaction of cells and proteins with surfaces SAMs have been used in our group, for instance to attract and bind proteins in a selective manner. For instance, we have used mixed SAMs (mixtures of OH and CH3 terminated thiols) and the immobilization of ligands to albumin (alkyl chains with 18 carbons) to selectively bind albumin. SAMs of alkanethiols on gold have been used also in the study of the influence of surface chemistry in the adhesion and activation of leukocytes (in vitro studies) and in acute inflammation. SAMs functionalized with transmembrane ligands capable to induce selective apoptosis of leukemic cells are being tested. An heparin-binding peptide, composed of L-lysine and L-leucine (pKL), was synthesized and immobilized, in different concentrations, onto SAMs terminated with tetra (ethylene-glycol) (EG4-SAMs) for the selective binding of heparin. SAMs exposing well-defined functional groups and promoting the adsorption of adequate proteins are expected to be a valuable alternative to other cell culture surfaces. They also provide a model for developing functionalized polymers.
These and other examples of the interaction between proteins and cells with surfaces at a molecular level will be given in this lecture.