Sol-gel chemistry for the design of living inorganic materials

SARA ALDABE BILMES; MERCEDES PERULLINI,; MATIAS JOBBAGY; ANA CECILIA SPEDALIERI; CARLA LLORENTE; ALEJANDRO CAMERA; PAULA VENA

Joao Pessoa

Congreso; XIII SBPMat meeting; 2014

Sol-gel chemistry provides a biomimetic mild approach for cell encapsulation with the advantages of chemical stability and enhanced mechanical properties. The basic idea behind is to take advantage of the fine biological machinery for producing specific molecules, either to recover them or to trigger or detect changes in the environment around. In this lecture, we present different pathways for the synthesis of silica based matrices for cell encapsulation oriented towards the design of bio-reactors, bio-sensors and devices for bio-remediation. The synthesis of a mineral cage around the cell requires full biocompatible precursors and pH. Osmoprotectors can be used for shielding microorganisms against silanol groups or excess of Na+ ions. For encapsulation of photosynthetic organisms good optical quality is required and UV-A is filtered with appropriate nanoparticles or dye molecules incorporated in the silica network. By the direct encapsulation cells are not able to divide and proliferate inside the matrix. Pre-encapsulation within alginate beads gives the possibility of macrocavities inside a mineral matrix where cells are able to duplicate and communicate, thus providing a long term living system producing both primary and secondary metabolites. The strategies developed in our group to synthesize these matrices are based in a deep knowledge of the molecular structure by combining SEM and SAXS characterizations, with measurements of the stress suffered by the organism, and mass transport through the pores. Several applications of these true living materials for sensors of herbicides by algae, bio-degradation of model dyes by fungi, and the bio-synthesis of metal nanoparticles by bacteria and algae will be discussed.