title: Spectroscopic and electrochemical characterization of cytochrome c encapsulated in a bio sol-gel matrix.
abstract: Sol-gel technique represents a remarkably versatile method for protein encapsulation. To enhance sol-gel biocompatibility, systems envisaging the presence of calcium and phosphates in the sol-gel composition were recently prepared and investigated. Unfortunately, the low pH at which solutions were prepared (pH < 2.5) dramatically limited their application to proteins, because the acidic environment induces protein denaturation. In this paper we apply a new protocol based on the introduction of calcium nitrate to the inorganic phase, with formation of a binary bioactive system. In this case protein encapsulation results versatile and secure, being achieved at a pH close to neutrality (pH 6.0); also, the presence of calcium is expected to enhance system biocompatibility. To determine the properties of the salt-doped sol-gel and the influence exerted on entrapped biosystems, the structural and functional properties of embedded cytochrome c have been investigated. Data obtained indicate that the salt-doped sol-gel induces no significant change in the structure and the redox properties of the embedded protein; also, the matrix increases protein stability. Interestingly, the presence of calcium nitrate appears determinant for refolding of the acid-denatured protein. This is of interest in the perspective of future applications in biosensoristic area.
authors.affiliation: Department of Experimental Medicine and Biochemical Sciences, University of Rome Tor Vergata, Via Montpellier, 1, Rome, Italy. daniela.deriu@uniroma2.it
authors.forename: Daniela
authors.initials: D
authors.lastname: Deriu
authors.forename: Sara Emanuela
authors.initials: SE
authors.lastname: Pagnotta
authors.forename: Roberto
authors.initials: R
authors.lastname: Santucci
authors.forename: Nicola
authors.initials: N
authors.lastname: Rosato
mesh_terms: D000818:Animals; D017610:Calcium Compounds / Q000737:chemistry*; D002942:Circular Dichroism; D045304:Cytochromes c / Q000737:chemistry* / Q000378:metabolism; D004339:Drug Compounding; D004563:Electrochemistry; D005782:Gels / Q000737:chemistry*; D006736:Horses; D006863:Hydrogen-Ion Concentration; D009566:Nitrates / Q000737:chemistry*; D010084:Oxidation-Reduction; D044367:Phase Transition; D011487:Protein Conformation; D011489:Protein Denaturation
chemical_list: D017610:Calcium Compounds; D005782:Gels; D009566:Nitrates; D045304:Cytochromes c; C059948:calcium nitrate