Bioactive silica

Keywords silicon dioxide, medicinal chemistry, surface chemistry, sorbent, efferent therapy, enteosorption, medicinal preparation, infectious diseases, detoxication, bioactive silica, purulent wound, pyoinflammatory diseases, diarrhea... 

In collaboration with various medical institutions of Ukraine and Russia, the Institute of Surface Chemistry of the NAS of Ukraine has developed a novel medicinal preparation Silics (the term silics is derived from silica and the institute of Chemistry of Surface), and designed a nanotechnology for its production.2,3 This bioactive silica (BAS) is distinguished for its extended surface and high adsorption properties. 

Results of the above-outlined research into physico-chemical and medico-biological properties of BAS, conducted at the Institute of Surface Chemistry of the NAS of Ukraine in collaboration with Vinnitsa State Medical University, named after N.I. Pirogov, and other medical institutions of Ukraine and Russia give reasons to infer that Silics is an active medicinal substance which on its own can function as a therapeutic agent. Sorptive detoxication with the aid of the bioactive silica brings about a profound effect in the case of acute intestinal infections, diarrheas of various origins, viral hepatitis, as well as for local treatment for pyoinflammatory diseases and purulent wounds. 

Serra, J., Gonzalez, P., Liste, S., Serra, C., Chiussi, S., Leon, B., Perez-Amor, M., Ylanen H. 0. Hupa, M. (2003). FTIR and XPS studies of bioactive silica based glasses. Journal of Non-Crystalline Solids, 332(1-3), 20-27. 

Poologasundarampillai, G., Yu, B., Tsigkou, O., Valliant, E.M., Yue, S., Lee, P.D. et al. (2012) Bioactive silica-poly (y-glutamic acid) hybrids for bone regeneration effect of covalent coupling on dissolution and mechanical properties and febrication of porous scaffolds. Soft Matter, 8, 4822-4832. 

Preparation of a bioactive and degradable poly(epsilon-caprolactone) / silica hybrid through a sol-gel method. Biomaterials, 23, 4915-4921. 

Although the biocompatibility and biodegradability of these materials were rapidly determined, the bioactivity of Si02-PCL hybrid materials was not studied until recently [99]. In order to provide bioactivity to Si02-PCL hybrid materials, Rhee prepared triethoxysilane end-capped poly(s-caprolactone) which was then cocondensed with tetraethyl orthosilicate and calcium nitrate via the sol-gel method. The Ca-containing PCL/silica hybrid so obtained showed in vitro bioactivity and biodegradability. The hybridization procedure between the a,co-hydroxyl PCL and silica phases was proposed to be as follows ... 

Regardless of the composition, the synthesis conditions also play an important role in the bioactivity and mechanical properties [ 101 ]. When PCL/silica hybrid materials... 

Bioactive glasses are currently used as granulate for bone and dental grafting in small defects, or as powder incorporated into toothpaste. Although silica-based bioactive glasses meant an extraordinary advance in the field of bone tissue regeneration, their application as pieces for medium and large defects is not possible due to their very poor mechanical properties. 

Aburatani, Y., Tsuru, K., Hayakawa, S. and Osaka, A. (2002) Mechanical properties and microstructure of bioactive ORMOSILs containing silica particles. Materials Science and Engineering C, 20, 195-198. 

Rhee, S. and Choi J. (2002) Preparation of a bioactive poly(methyl methacrylate) /silica nanocomposite. Journal of the American Ceramic Society, 85, 1318-1320. 

Chen, Q Miyata, N. and Kokubo, T. (2003) Bioactivity and mechanical properties of poly (dimethylsiloxane) modified calcia-silica hybrids with added titania. Journal of the American Ceramic Society, 86, 806-810. 

Yoo, J.J. and Rhee S.H. (2004) Evaluations of bioactivity and mechanical properties of poly (e-caprolactone) silica nanocomposite following heat treatment. Journal of... 

Thick-layer silica gel chromatography can also be employed [7], although most separations are now accomplished by high-performance liquid chromatography. Resolution of complex mixtures often requires both normal and reverse phase modes [19]. A further dimension is added, when bioactivity is correlated with spectroscopically-monitored chromatographic profiles. 

Ordered mesoporous silica have already been studied as carriers for drug delivery [1,2] recently, their use has also been proposed in bone tissue engineering [3,4], in combination with bioactive glass-ceramic scaffolds [5,6]. The kinetics of ibuprofen release in SBF [7] from MCM-41 silica with similar pore diameter has shown puzzling discontinuities [3,6,8] aim of the present work is to assess whether these anomalies may be related to structural changes in the MCM-41 mesoporous spheres under the adopted conditions. 

Some non-silica sol-gel materials have also been developed to immobilize bioactive molecules for the construction of biosensors and to synthesize new catalysts for the functional devices. Liu et al. [33] proved that alumina sol-gel was a suitable matrix to improve the immobilization of tyrosinase for detection of trace phenols. Titania is another kind of non-silica material easily obtained from the sol-gel process [34, 35], Luckarift et al. [36] introduced a new method for enzyme immobilization in a bio-mimetic silica support. In this biosilicification process precipitation was catalyzed by the R5 peptide, the repeat unit of the silaffin, which was identified from the diatom Cylindrotheca fusiformis. During the enzyme immobilization in biosilicification the reaction mixture consisted of silicic acid (hydrolyzed tetramethyl orthosilicate) and R5 peptide and enzyme. In the process of precipitation the reaction enzyme was entrapped and nm-sized biosilica-immobilized spheres were formed. Carturan et al. [11] developed a biosil method for the encapsulation of plant and animal cells. 

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