"Ilie Murgulescu" Institute of Physical Chemistry of the Romanian Academy, 060021 Bucharest, Romania.
Faculty of Biology, "Alexandru Ioan Cuza" University, 700505 Iasi, Romania.
Molecules. 2018 Jun 5;23(6):1362. doi: 10.3390/molecules23061362.
A wide range of hybrid biomaterials has been designed in order to sustain bioremediation processes by associating sol-gel SiO₂ matrices with various biologically active compounds (enzymes, antibodies). SiO₂ is a widespread, chemically stable and non-toxic material; thus, the immobilization of enzymes on silica may lead to improving the efficiency of biocatalysts in terms of endurance and economic costs. Our present work explores the potential of different hybrid morphologies, based on hollow tubes and solid spheres of amorphous SiO₂, for enzyme immobilization and the development of competitive biocatalysts. The synthesis protocol and structural characterization of spherical and tubular SiO₂ obtained by the sol gel method were fully investigated in connection with the subsequent immobilization of lipase from . The immobilization is conducted at pH 6, lower than the isoelectric point of lipase and higher than the isoelectric point of silica, which is meant to sustain the physical interactions of the enzyme with the SiO₂ matrix. The morphological, textural and surface properties of spherical and tubular SiO₂ were investigated by SEM, nitrogen sorption, and electrokinetic potential measurements, while the formation and characterization of hybrid organic-inorganic complexes were studied by UV-VIS, FTIR-ATR and fluorescence spectroscopy. The highest degree of enzyme immobilization (as depicted from total organic carbon) was achieved for tubular morphology and the hydrolysis of p-nitrophenyl acetate was used as an enzymatic model reaction conducted in the presence of hybrid lipase⁻SiO₂ complex.
为了通过将溶胶-凝胶 SiO₂ 基质与各种生物活性化合物（酶、抗体）结合来维持生物修复过程，设计了广泛的混合生物材料。SiO₂ 是一种广泛存在、化学稳定且无毒的材料；因此，将酶固定在二氧化硅上可能会提高生物催化剂在耐久性和经济成本方面的效率。我们目前的工作探索了基于无定形 SiO₂ 的空心管和实心球的不同混合形态的潜力，用于酶固定和竞争性生物催化剂的开发。通过溶胶-凝胶法合成球形和管状 SiO₂ 的合成方案和结构表征与随后的脂肪酶固定进行了充分研究。固定在 pH 6 进行，低于脂肪酶的等电点，高于二氧化硅的等电点，这意味着支持酶与 SiO₂ 基质的物理相互作用。通过 SEM、氮气吸附和动电电位测量研究了球形和管状 SiO₂ 的形态、结构和表面性质，同时通过 UV-VIS、FTIR-ATR 和荧光光谱研究了杂化有机-无机配合物的形成和特性。管状形态的酶固定程度最高（从总有机碳来看），并在存在杂化脂肪酶-SiO₂ 复合物的情况下，使用 p-硝基苯乙酸酯的水解作为酶模型反应进行。
