Inorganic hydrogels for whole-culture encapsulation

MERCEDES PERULLINI; CECILIA SPEDALIERI; MATÍAS JOBBÁGY; SARA A. BILMES

Advances in Biosensor Research

Nova Publishers

Año: 2015; p. 57 - 76

Sol-gel encapsulation of living cells within inorganic hydrogels, mainly silica, is a promising technology for the design of biosensors. These host-guest functional materials maintain specific biologic functions of their guest while the properties of the host can be tuned to fulfill the requirements of particular applications. Inorganic immobilization hosts exhibit several advantages over their (bio)polymer-based counterparts. While both hosts provide tailored porosity, the former offers enhanced chemical stability towards biodegradation as well as higher physical stability (low swelling). However, along one-pot encapsulations, the direct contact of cells with precursors during the sol-gel synthesis and the constraints imposed by the inorganic matrix during operating conditions may influence the biological response. In order to prevent this, an alternative two-step procedure was proposed. Living cells are pre-encapsulated in biocompatible carriers based on biopolymers such as alginates that confer protection during the inorganic and more cytotoxic synthesis. By means of these carriers, whole cultures of microorganisms remain confined in small liquid volumes generated inside the inorganic host, providing near conventional liquid culture conditions. Moreover, this approach allows the encapsulation of multicellular organisms and the co-encapsulation of multiple isolated cultures within a single common monolithic host, creating an artificial ecosystem in a diminished scale isolated inside a nanoporous matrix that would allow ecotoxicity studies to be carried out in portable devices for on-line and in situ pollution level assessment.