Wettability influences cell behavior on superhydrophobic surfaces with different topographies

Surface wettability and topography are recognized as critical factors influencing cell behavior on biomaterials. So far only few works have reported cell responses on surfaces exhibiting extreme wettability in combination with surface topography. The goal of this work is to study whether cell behavior on superhydrophobic surfaces is influenced by surface topography and polymer type. Biomimetic superhydrophobic rough surfaces of polystyrene and poly(l-lactic acid) with different micro/nanotopographies were obtained from smooth surfaces using a simple phase-separation based method. Total protein was quantified and showed a less adsorption of bovine serum albumin onto rough surfaces as compared to smooth surfaces of the same material. The mouse osteoblastic MC3T3-E1 cell line and primary bovine articular chondrocytes were used to study cell attachment and proliferation. Cells attached and proliferate better in the smooth surfaces. The superhydrophobic surfaces allowed cells to adhere but inhibited their proliferation. This study indicates that surface wettability, rather than polymer type or the topography of the superhydrophobic surfaces, is a critical factor in determining cell behavior

Development of a novel cell encapsulation system based on natural origin polymers for tissue engineering applications

Cells microencapsulated in biocompatible semi-permeable polymeric membranes are effective as cell delivery systems while protecting the host against immune responses. In this study, cell encapsulation membranes were prepared based on carrageenan and alginate, two natural cationic polymers. Different formulations/conditions were explored to optimize the microcapsules which were characterized with respect to their morphology, mechanical stability, and cytotoxicity. Spherical-shaped microcapsules were obtained from all the polymeric systems. The iota-carrageenan/sodium alginate microcapsules exhibited the best stability and permeability, and therefore, these were selected for the cell encapsulation. These capsules provided an environment that supported cell proliferation and have the potential for tissue engineering as well as other cell-based therapy applications.One of the authors (SML) acknowledges the support of the Programme Alssan-the European Union Programme of High Level Scholarships for Latin America (scholarship no. E04M041362CO). This work was partially supported by the European STREP HIPPOCRATES (NMP3-CT-2003-505758) and by the Fundacao para a Ciencia e Tecnologia (project PTDC/QUI/68804/2006) and carried out under the scope of European NoE EXPERTISSUES (NMP3-CT-2004-500283)

Multifunctional bioactive glass and glass-ceramic biomaterials with antibacterial properties for repair and regeneration of bone tissue

Bioactive glasses (BGs) and related glass-ceramic biomaterials have been used in bone tissue repair for over 30years. Previous work in this field was comprehensively reviewed including by their inventor Larry Hench, and the key features and properties of BGs are well understood. More recently, attention has focused on their modification to further enhance the osteogenic behaviour, or further compositional changes that may introduce additional properties, such as antimicrobial activity. Evidence is emerging that BGs and related glass-ceramics may be modified in such a way as to simultaneously introduce more than one desirable property. The aim of this review is therefore to consider the evidence that these more recent inorganic modifications to glass and glass-ceramic biomaterials are effective, and whether or not these new compositions represent sufficiently versatile systems to underpin the development of a new generation of truly multifunctional biomaterials to address pressing clinical needs in orthopaedic and dental surgery. Indeed, a number of classical glass compositions exhibited antimicrobial activity, however the structural design and the addition of specific ions, i.e. Ag(+), Cu(+), and Sr(2+), are able to impart a multifunctional character to these systems, through the combination of, for example, bioactivity with bactericidal activity. STATEMENT OF SIGNIFICANCE: In this review we demonstrate the multifunctional potential of bioactive glasses and related glass-ceramics as biomaterials for orthopaedic and craniofacial/dental applications. Therefore, it considers the evidence that the more recent inorganic modifications to glass and glass-ceramic biomaterials are able to impart antimicrobial properties alongside the more classical bone bonding and osteoconduction. These properties are attracting a special attention nowadays that bacterial infections are an increasing challenge in orthopaedics. We also focus the manuscript on the versatility of these systems as a basis to underpin the development of a new generation of truly multifunctional biomaterials to address pressing clinical needs in orthopaedic, craniofacial and dental surgery

Substituted Borosilicate Glasses with Improved Osteogenic Capacity for Bone Tissue Engineering

Borosilicate bioactive glasses (BBGs) have shown capacity to improve the new bone formation when compared to silicate bioactive glasses. Herein, we assessed the capacity of BBGs to induce the osteogenic differentiation of bone marrow mesenchymal stem cells (BM-MSCs), as a function of their substituted divalent cations (Mg2+, Ca2+, Sr2+). To this purpose, we synthesized BBG particles by melt quench. The cell viability, proliferation and morphology, (i.e. PrestoBlue®, PicroGreen®, and DAPI and Phalloidin stainings, respectively) as well as protein expression (of ALP, osteopontin and osteocalcin) of BM-MSCs in contact with the BBGs were evaluated for 21 days. We observed an enhanced expression of bone-specific proteins (ALP, OP and OC) and high mineralization of BM-MSCs under BBG-Mg and BBG–Sr conditioned osteogenic media for concentrations of 20 and 50 mg/ml with low cytotoxic effects. Moreover, BBG-Sr at a concentration of 50 mg/ml was able to increase the mineralization and expression of bone-specific proteins even under basal media conditions. These results indicated that the proposed BBGs improved the osteogenic differentiation of BM-MSCs. Therefore, showing their potential as relevant biomaterials for bone tissue regeneration, not only by bonding to bone tissue, but also by stimulating new bone formation

Pervasive and intelligent decision support in Intensive Medicine – the complete picture

Series : Lecture notes in computer science (LNCS), vol. 8649In the Intensive Care Units (ICU) it is notorious the high number of data sources available. This situation brings more complexity to the way of how a professional makes a decision based on information provided by those data sources. Normally, the decisions are based on empirical knowledge and common sense. Often, they don’t make use of the information provided by the ICU data sources, due to the difficulty in understanding them. To overcome these constraints an integrated and pervasive system called INTCare has been deployed. This paper is focused in presenting the system architecture and the knowledge obtained by each one of the decision modules: Patient Vital Signs, Critical Events, ICU Medical Scores and Ensemble Data Mining. This system is able to make hourly predictions in terms of organ failure and outcome. High values of sensitivity where reached, e.g. 97.95% for the cardiovascular system, 99.77% for the outcome. In addition, the system is prepared for tracking patients’ critical events and for evaluating medical scores automatically and in real-time.(undefined

Effects of starch/polycaprolactone-based blends for spinal cord injury regeneration in neurons/glial cells viability and proliferation

Spinal cord injury (SCI) leads to drastic alterations on the quality of life of afflicted individuals. With the advent of Tissue Engineering and Regenerative Medicine where approaches combining biomaterials, cells and growth factors are used, one can envisage novel strategies that can adequately tackle this problem. The objective of this study was to evaluate a blend of starch with poly(ε-caprolactone) (SPCL) aimed to be used for the development of scaffolds spinal cord injury (SCI) repair. SPCL linear parallel filaments were deposited on polystyrene coverslips and assays were carried out using primary cultures of hippocampal neurons and glial cells. Light and fluorescence microscopy observations revealed that both cell populations were not negatively affected by the SPCL-based biomaterial. MTS and total protein quantification indicated that both cell viability and proliferation rates were similar to controls. Both neurons and astrocytes occasionally contacted the surface of SPCL filaments through their dendrites and cytoplasmatic processes, respectively, while microglial cells were unable to do so. Using single cell [Ca2+ ]i imaging, hippocampal neurons were observed growing within the patterned channels and were functional as assessed by the response to a 30 mM KCl stimulus. The present data demonstrated that SPCL-based blends are potentially suitable for the development of scaffolds in SCI regenerative medicine.Portuguese Foundation for Science and Technology through funds from POCTI and/or FEDER programs (Funding to ICVS, 3B's Research Group and post doctoral fellowship to A.J. Salgado-SFRH/BPD/17595/2004)