Biogenic porous silica and silicon sourced from Mexican Giant Horsetail (Equisetum myriochaetum) and their application as supports for enzyme immobilization

• Published in: Colloids and surfaces, B, Biointerfaces Vol. 166; pp. 195 - 202
• Main Authors: Sola-Rabada, Anna, Sahare, Padma, Hickman, Graham J., Vasquez, Marco, Canham, Leigh T., Perry, Carole C., Agarwal, Vivechana
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2018
• Subjects: arsenic; biocompatibility; biodegradability; cadmium; colloids; Coprinopsis cinerea; electronic circuits; energy-dispersive X-ray analysis; Enzyme activity; Enzyme immobilization; Enzymes, Immobilized - chemistry; Equisetum - chemistry; Equisetum spp; Equisetum telmateia; Fourier transform infrared spectroscopy; glutaraldehyde; immobilized enzymes; lead; Magnesiothermic reduction; mercury; peroxidase; Porosity; Porous silica; scanning electron microscopy; silica; silicon; Silicon - chemistry; Silicon Dioxide - chemistry; surface area; thermogravimetry; wet digestion method; X-ray diffraction; Porous silica; Enzyme immobilization; Equisetum spp; Enzyme activity; Magnesiothermic reduction
• ISSN: 0927-7765; 1873-4367; 1873-4367
• DOI: 10.1016/j.colsurfb.2018.02.047

[Display omitted] •Biosilica from Equisetum Myriochaetum converted to nanoporous silicon.•Biogenic silica and derived silicon usable as supports for enzyme immobilization.•Range of enzyme immobilization techniques for silica/silicon compared.•H. peroxidase effectively loaded on biogenic silica using glutaraldehyde coupling.•Active C. cinereus peroxidase loaded on porous silicon using carbodiimide method. Porous silica-based materials are attractive for biomedical applications due to their biocompatibility and biodegradable character. In addition, inorganic supports such as porous silicon are being developed due to integrated circuit chip compatibility and tunable properties leading to a wide range of multidisciplinary applications. In this contribution, biosilica extracted from a rarely studied plant material (Equisetum Myriochaetum), its conversion to silicon and the potential for both materials to be used as supports for enzyme immobilization are investigated. E. myriochaetum was subject to conventional acid digestion to extract biogenic silica with a% yield remarkably higher (up to 3 times) than for other Equisetum sp. (i.e. E. Arvense). The surface area of the isolated silica was ∼400m2/g, suitable for biotechnological applications. Biogenic silicon was obtained by magnesiothermic reduction. The materials were characterized by SEM-EDX, XRD, FT-IR, ICP-OES, TGA and BET analysis and did not contain significant levels of class 1 heavy elements (such as Pb, Cd, Hg and As). Two commercial peroxidases, horseradish peroxidase (HRP) and Coprinus cinereus peroxidase (CiP) were immobilized onto the biogenic materials using three different functionalization routes: (A) carbodiimide, (B) amine+glutaraldehyde and (C) amine+carbodiimide. Although both biogenic silica and porous silicon could be used as supports differences in behaviour were observed for the two enzymes. For HRP, loading onto biogenic silica via the glutaraldehyde immobilization technique (route B) was most effective. The loading of CiP showed a much higher peroxidase activity onto porous silicon than silica functionalized by the carbodiimide method (route A). From the properties of the extracted materials obtained from Equisetum Myriochaetum and the immobilization results observed, these materials appear to be promising for industrial and biomedical applications.