Mesoporous materials with pore sizes between 2 and 50 nm have elicited widespread interest in catalysis, separation, adsorption, sensors, and drug delivery applications due to its highly ordered pore size along with high hydrothermal stability and easily modifiable surface functionalities. Fabricating these mesoporous materials as continuous fibers offers exciting vistas for biomedical applications especially in tissue engineering. The aim of the present study was to fabricate, characterize, and evaluate the cellular and gene expression of mesoporous silica with a long ordered fibrous morphology to support regeneration of bone tissue. Tetraethyl orthosilicate, polyvinyl pyrrolidone, and the tri-block copolymer P-123 were subjected to electrospinning to fabricate continuous ordered mesoporous silica nanofibers by optimizing solution and operation parameters. Mesoporous silica fibers with an average diameter of 470 nm and mesopores of dimension 5.97 nm were obtained. The combination of micropores, mesopores, macropores, and the nanofibrous morphology imparted excellent bioactivity to the mesoporous silica fibrous scaffolds as demonstrated by the proliferation of human osteoblast-like cells (MG63) and by the maintenance of its phenotype. The upregulation of collagen I, alkaline phosphatase, osteocalcin, osteopontin, and bone sialoprotein signifies the maturation of MG63 cells on the silica scaffold. Hence, these novel scaffolds are promising new biomaterials for orthopaedic applications.

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Mesoporous silica has attracted attention in recent years due to its high surface area, tunable ordered narrow pores and easily modifiable functional groups. In the present work, iron oxide nanoparticles (Fe 2 O 3 ) were incorporated into the pores and surface of mesoporous SBA-15 (Santa Barbara Amorphous) via a thermal pre-synthesis method. The textural and surface properties were characterized using electron microscopy, X-ray diffraction and nitrogen adsorption-desorption analysis. Due to a reduction in thermal pressure during the synthesis, the textural property of the magnetic silica remained highly ordered. The superparamagnetic property of the synthesized material was confirmed using SQUID-VSM. Cell viability studies were carried out with MC3T3 fibroblast cell lines in the presence and absence of magnetic silica and our results showed no significant change in the cell viability between the concentration range of 31.3 mg mL À1 and 250 mg mL À1 . The magnetic resonance properties of the iron oxide doped mesoporous silica was determined using MRI and showed excellent longitudinal (R 1 ) and transverse relaxivities (R 2 ) with an R 2 /R 1 ratio close to 1, indicating the potential of this material as a magnetic contrast agent.

Fe(3)O(4) nanoparticles covalently linked to a gold electrode have been used for immobilizing catalase (CAT) enzyme to sense the presence of various concentrations of H(2)O(2). These nanoparticles ranging from 20 to 30 nm were synthesized by thermal co-precipitation of ferric and ferrous chlorides. SEM and XRD have been used for morphological and structural characterization of Fe(3)O(4) nanoparticles. CAT enzyme was linked covalently to the surface of iron oxide using carbodiimide in phosphate buffer (pH 7.4) at 4 °C. The enzyme-iron oxide link was confirmed by FT-IR spectroscopy. Sensing studies carried out using cyclic voltammetry showed a linear response of the CAT/nano Fe(3)O(4)/Au bioelectrode towards H(2)O(2) between 1.5 and 13.5 µM with a very sharp response time of 2 s.