Sriyanti

Encapsulation of Alkaline Phosphatase in Mesoporous Methyl-Silica Hybrid by Sol-Gel Process

In recent years, the sol-gel technique has attracted increasing interest as a unique approach to immobilize biomolecules for bioanalitical applications as well as biochemical and biophysical studies. In this research, encapsulation of Alkaline Phosphatase (ALP) enzyme in mesoporous methyl-silica hybrid by sol-gel process has been carried out. Mesoporous methyl-silica hybrid has been synthesis by using tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as precursor and poly(ethylene) glycol (PEG) as a polymer dopant. The preparation of methyl-silica hybrid was carried out at various mol ratios of precursors and PEG concentration. Encapsulation was emphasized by mixing sol solution and tris-HCl buffer containing ALP. The Surface Area Analyzer analysis data showed that the pore diameter and surface area of methyl-silica hybrid tended to increase as the PEG dopant concentration increases. Result showed that ALP encapsulated in the methyl-silica hybrids with PEG dopant gave enzymatic activity as 0.112 U/mg enzyme, higher than ALP encapsulated in copolymerization of TEOS with MTES or in silica from TEOS precursor only (0.098 U/mg enzyme and 0.069 U/mg enzyme, respectively). It was shown that copolymerization of TEOS with organosilane precursor and the entrapment of polymer additives into sol-gel processed materials are useful methods for modifying the internal environment and hence the activity of biomolecules entrapped in sol-gel derived biomaterials.

Bilangan Oksidasi dan Reaksi-Reaksi Mangan

Telah dilakukan pembuatan tris (2,4-pentanadionato) Mangan (III), Kalium manganat dan Kalium permanganat untuk mempelajari bilangan oksidasi mangan. Dilakukan pula reaksi-reaksi sederhana terhadap mangan untuk mengamati mangan pada berbagai keadaan tingkat oksidasi. Hasil yang diperoleh menunjukan bahwa Mangan (II) stabil dalam suasana asam, Mangan (III) tidak stabil dan dapat distabilkan dengan pembentukan kompleks mangan-acetylacetonat, Mangan (IV) stabil dalam bentuk oksidanya (MnO 2 ), Mangan (VI) atau manganat stabil dalam suasana basa kuat dan Mangan (VII) atau permanganat hanya stabil dalam suasana asam.