Encapsulation of Hemoglobin in Mesoporous Silica (FSM)—Enhanced Thermal Stability and Resistance to Denaturants

Abstract

Hemoblogin (Hb), which is a typical oligomeric protein, was introduced into the pores of mesoporous silica (FSM: folded-sheet mesoporous material) that had a diameter of 7.5 nm. Soret CD spectra of Hb-FSM-7.5 conjugates showed a peak that was identical to that of free Hb. This suggests that Hb retained its highly ordered structure in the mesoporous silica. In addition, the UV-visible absorption spectrum showed that Hb had an increased resistance to heat denaturation in the silica. Even after heat treatment at 85 degrees C, Hb-FSM-7.5 retained its ligand-binding activity. The stability of Hb-FSM-7.5 was examined further by measuring its peroxidase-like activity. Encapsulation of Hb resulted in the retention of activity in the presence of high NaCl or Gdn-HCl levels. This suggests that encapsulation prevented dissociation and denaturing. Thus, it seems that the mesopores created a favorable environment for the oligomeric protein to perform its function, even under harsh conditions.

Membrane Fusion Mediated Intracellular Delivery of Lipid Bilayer Coated Mesoporous Silica Nanoparticles

“…Compared to native cytC, the encapsulated cytC in the MSNs revealed a slight broadening of the adsorption peak in the UV-Vis spectrum, but no blue shift was observed, suggesting that the interaction between the protein and pore surface did not change the structure of cytC ( Figure S1a, Supporting Information). [40] Since cytC has a positive charge at pH 7.4 its adsorption is mainly driven by electrostatic interactions with the negatively charged silanol groups on the surface of MSNs. [41,42] Therefore, we studied the influence of ionic strength on the release profile of cytC.…”

Encapsulation of PEG-modified Myoglobin in Hydrophobic Mesoporous Silica as Studied by Optical Waveguide Spectroscopy

“…[1][2][3][4][5][6][7] Among various inorganic nanoporous materials, surfactant-templated mesoporous silica materials have been considered an ideal host due to their uniform and ordered pore structures suitable for accommodating enzymes. [1][2][3][4][5][6][7] The pore diameter of mesoporous silica can be tuned within a range from 2 nm to tens of nanometers and the pore size distribution is narrow. [8][9][10][11][12] Artificial enzymatic materials have been developed by encapsulating enzymes into the mesoporous silica host using these characteristic features.…”

“…[8][9][10][11][12] Artificial enzymatic materials have been developed by encapsulating enzymes into the mesoporous silica host using these characteristic features. [1][2][3][4][5][6][7][13][14][15][16][17][18][19][20] Encapsulation efficiency of enzymes within mesoporous silica is mainly influenced by two factors: size matching of the enzyme and the pore diameter; and surface characteristics of the mesoporous silica. 1 These two factors are also considered essential for stabilizing the enzyme activity within the mesoporous silica host.…”

“…1 The size matching can be achieved by preparing mesoporous silica with a desirable pore diameter accommodating a size-matched enzyme. [1][2][3][4][5][6][7] As for the surface characteristics, the surface charge of mesoporous silica play an important role for adsorption of enzymes inside the silica mesopores. 1,[3][4][5][6][7] In addition to the surface charge, the hydrophobic or hydrophilic property of the mesopore surface is also considered an important factor for enzyme adsorption.…”

“…[1][2][3][4][5][6][7] As for the surface characteristics, the surface charge of mesoporous silica play an important role for adsorption of enzymes inside the silica mesopores. 1,[3][4][5][6][7] In addition to the surface charge, the hydrophobic or hydrophilic property of the mesopore surface is also considered an important factor for enzyme adsorption. 21,22 The regulation of the surface characteristics of the silica mesopores has usually been attempted by controlling the dissociation of surface silanols and/or by derivatizing the surface silanol groups with functional organic silanes.…”