miércoles, 25 de abril de 2012

Micropatterning of Bioactive Glass Nanoparticles on Chitosan Membranes for Spatial Controlled Biomineralization

normal.img-000.jpgIn recent years, the biomaterials field has witnessed the rise of a third generation of materials able to stimulate specific cellular responses.Exposed to the right surface chemistry and topography, cells can adhere, proliferate, and differentiate.Microcontact printing (μCP) of biologically relevant ligands using a soft poly(dimethylsiloxane) PDMS stamp is the most common technique to generate specific patterns with different and well-defined chemistries. Patterns of proteins, molecules, polymers, nanoparticles, self-assembled monolayers, colloids, and metals have been reported.
Different methods can be applied to engineer culture substrates for guiding cellular responses with spatial control. Bioactive glass has been demonstrated to have a beneficial effect in bone regeneration, skin, articular regeneration, and angiogenesis applications as it binds to both bone and soft tissue.
Bioactive glass has been mainly applied in orthopedic and dental areas, since it promotes deposition of apatite under physiological conditions. A few works have reported the fabrication of substrates with spatial control of biomineralization. 
This team has been developed bioactive glass nanoparticles (BG-NPs) capable of inducing apatite precipitation upon immersion in simulated body fluid (SBF) were patterned on free-standing chitosan membranes by microcontact printing using a poly(dimethylsiloxane) (PDMS) stamp inked in a BG-NPs pad. Formation of the patterns was characterized by scanning electron microscopy (SEM). Mineralization of the bioactive glass patterns was induced in vitro by soaking the samples in SBF over different time points up to 7 days. The confined apatite deposition in the patterned regions with diameters of 50 μm was confirmed by Fouriertransformed infrared spectroscopy (FTIR), energy-dispersive X-ray (EDX) analysis, and SEM. In vitro tests confirmed the preferential attachment and proliferation of L929 cells to the areas printed with BG-NPs of the membranes. This approach permits one to spatially control the properties of biomaterials at the microlevel and could be potentially used in guided tissue regeneration for skin, vascular, articular, and bone tissue engineering and in cellular cocultures or to develop substrates able to confine cells in regions with controlled geometry at the cell’s length scale.

Micropatterning of Bioactive Glass Nanoparticles on Chitosan Membranes for Spatial Controlled Biomineralization
Gisela M. Luz, Luciano Boesel, Aranzazu del Campo, ́and Joao F. Mano 
3B’s Research Group-Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4806-909 Caldas das Taipas, Portugal
ICVS/3B’s-PT Government Associated Laboratory, Braga/Guimaraes, Portugal 
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany

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