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Volumn 120, Issue 34, 1998, Pages 8587-8598

Encapsulation of biologicals within silicate, siloxane, and hybrid sol- gel polymers: An efficient and generic approach

Author keywords

[No Author keywords available]

Indexed keywords

GLYCEROL DERIVATIVE; POLYMER; SILICATE; SILOXANE;

EID: 0032475402     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja9814568     Document Type: Article
Times cited : (637)

References (115)
  • 60
    • 3543144511 scopus 로고    scopus 로고
    • note
    • 1a-c to our knowledge, the polyol ester precursors presented here have not been previously reported, nor have similar compounds been utilized for bioencapsulation purposes.
  • 61
    • 3543119782 scopus 로고    scopus 로고
    • note
    • Silicate and polysilicate esters of ethylene glycol, propylene glycol, diglyterol, triethylene glycol, etc., were readily accessed via transesterification.
  • 63
    • 3543073160 scopus 로고    scopus 로고
    • note
    • FTIR analysis indicated complete hydrolysis, with no trace of glycerol being observed in the xerogels. Also, the monoliths were found to be mechanically and optically stable to repeated cycles of wetting with aqueous or organic media, followed by drying.
  • 64
    • 3543061382 scopus 로고    scopus 로고
    • note
    • Direct evidence for the diffusion of substrates into xerogels and their reaction with the internalized enzymes was obtained by incubating monoliths with chromogenic substrates. Thus, when silicas containing C. rugosa lipase, β-glucosidase, and horseradish peroxidase were respectively contacted with aqueous solutions of 4-nitrophenyl palmitate, 4-nitrophenyl β-D-glucopyranoside or hydrogen peroxide, and 1,4-hydroquinone, the generation of colored products and accompanying color development was observed throughout the sol-gel matrix. Control reactions where xerogels were placed in solutions of the products were used to distinguish the simple diffusion of these compounds into the gel interiors.
  • 70
    • 3543102329 scopus 로고    scopus 로고
    • note
    • 1a and in extreme cases lead to gelation-resistant products.
  • 74
    • 3543090654 scopus 로고    scopus 로고
    • note
    • 1,20 the reported methods are too aggresive for bioencapsulation.
  • 77
    • 3543112888 scopus 로고    scopus 로고
    • note
    • 23 and takes into account ionic interactions and adsorption effects between the inhibitor and the charged silica framework.
  • 79
    • 3543130364 scopus 로고    scopus 로고
    • note
    • m* of 0.13 ± 0.01 mM.
  • 82
    • 3543117461 scopus 로고    scopus 로고
    • note
    • The half-lives at 70 °C were as follows (times for free enzyme, GPS-encapsulate, and PMS-encapsulate, respectively): β-glucosidase (12.7 ± 0.8, 673 ± 51, and 756 ± 65 h), acid phosphatase (0.12 ± 0.01, 11.3 ± 1.4, and 15.1 ± 1.3 min), and C. rugosa lipase (23 ± 1.8 min, 12.3 ± 0.9 h, and 14.6 ± 1.7 h).
  • 84
    • 3543073159 scopus 로고    scopus 로고
    • note
    • The initiation, rate and extent of phase separation could be controlled by varying the sol-gel mix. Thus, macroporous methylsiloxanes and allylsiloxanes were formed at water:precursor ratios above about 0.60 and 0.35 w/w, respectively. SEM studies of the materials demonstrated three-dimensional fused globule architectures with continuous pore networks. The frameworks showed transitions from approximately 1-3 μm spherical/ oblate/prolate structures in the small pore (approximately 1 -15 μm) materials to 1-3 × 3-20 μm solid threadlike elements in the large pore (approximately 15-50 ,μm) polymers.
  • 85
    • 3543129127 scopus 로고    scopus 로고
    • note
    • Initial NA and TPA examinations of the metallosilicate and mesoporous alkylsiloxane sol-gels indicated respective pore distributions of 8.6-12.9 and 8.1-11.3 nm and pore volumes of 1.751-1.820 and 0.860-1.601 mL/g.
  • 86
    • 3543092955 scopus 로고    scopus 로고
    • note
    • 2O:MeOH, then primed with TMOS, GPTMS, or APTES. The moderate viscosity of the precursors limited the minimal dimensions of printed/molded structures down to about 30 μm.
  • 97
    • 0000251275 scopus 로고
    • Enzymes in Synthetic Organic Chemistry
    • Elsevier Science: Oxford, U.K.
    • (a) Wong, C.-H.; Whitesides, G. M. Enzymes in Synthetic Organic Chemistry, Tetrahedron Organic Chemistry Series, Vol. 12; Elsevier Science: Oxford, U.K., 1994.
    • (1994) Tetrahedron Organic Chemistry Series , vol.12
    • Wong, C.-H.1    Whitesides, G.M.2


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.