Nanostructured Materials with biological activity

ALDABE BILMES, S

Lanzarote

Conferencia; Zing Conference Nanobiomaterials; 2013

Zing Conferences

Nanostructured Materials with biological activity Sara A. Bilmes INQUIMAE-DQIAQF, Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Ciudad Universitaria Pab. II, C1428EHA Buenos Aires, Argentina Encapsulation of cells in mineral matrices allow the design of materials with biological activity (MBA) that can work for long times if they are put in contact with appropriate nutrients in a physical space allowing cellular division. The main advantage of these matrices is that they are not easily biodegradable, and in consequence are stable, and can be used in natural systems without being predated nor released to the environment. Around 200 1012 moles of Si are processed in a year by diatoms in the oceans. From these living organisms producing hierarchical nanostructured silica we learned that life is possible within silica “cages” and silica structures can be built at room temperature by a sol-gel process. However, even the mild conditions in “chimie douce” the extension of this concept for encapsulating cells and microorganisms in the lab is a real challenge as the concentrations of precursors usually exceeds the toxicity limits accepted by living species. Here we present different strategies developed in our group for encapsulating living organisms (algae, fungi, bacteria, plants) in order to protect them from the toxicity of reagents, as well as against osmotic stress. The most successful way found for the design of MBAs is based on a pre-encapsulation of living species in Ca-alginate followed by sol-gel synthesis of the oxide matrix. Most of the work has been carried out with silica and silica-biopolymer hybrids starting from silicate, silica nanoparticles or silica alkoxydes. In addition, we have explored other oxides, such as zirconia and alumina whose precursors exhibit more detrimental effects. The matrix structure, optical and mechanical properties, as well as the stress suffered by microorganisms during encapsulation have been deeply analysed in order to provide a rationale for building MBAs oriented to the design of biosensors, bio-remediation devices and bio-reactors for the synthesis of metal nanoparticles with controlled size and shape.