Magnetic Silicate Beads for the Immobilization of Molecules using Sol-gel Aqueous Route

V. TUTTOLOMONDO; G. J. COPELLO; L. E. DÍAZ

Villa Carlos Paz, Córdoba, Argentina

Congreso; XLIV Reunión Anual de la Sociedad Argentina de Investigación Bioquímica y Biología Molecular; 2008

Sociedad Argentina de Investigación Bioquímica y Biología Molecular

The use of biomolecules in clinical applications is limited due to their high cost, instability and low availability. This lead to an intense research in the field of immobilized biocatalysis. Immobilized biomolecules are reusable, more stable and less costly. Our aim was to develop a versatile biomolecule immobilization system for its recovery after a biological assay and its reutilization. For this purpose urease was immobilized onto magnetic silicate beads by the sol-gel aqueous route. A FeCl3 and FeCl2 aqueous mixture was coprecipitated with NaOH. The ferrofluid thus generated mixed with a sodium silicate solution was used as the aqueous phase of an inverse microemulsion where the magnetic beads were generated by the sol-gel process. The magnetic beads obtained were functionalized with APTES to provide NH2 groups and treated with glutaraldehyde, a bifunctional reagent that attaches to both APTES and urease free NH2 groups. These beads are recoverable by means of a magnet after an assay. Glutaraldehyde concentration was crucial for the immobilized enzyme activity and stability. The immobilized enzyme maintains its activity during at least 30 consecutive reaction-recovery cycles. The reutilization of this system after 30 days storage at 4ºC without losing its activity demonstrated its stability.