Lysozyme adsorption onto mesoporous materials: effect of pore geometry and stability of adsorbents.
In this paper, adsorption of lysozyme onto two kinds of mesoporous adsorbents (KIT-5 and AISBA-15) has been investigated and the results on the effects of pore geometry and stability of the adsorbents are also discussed. The KIT-5 mesoporous silica materials possess cage-type pore geometry while the AISBA-15 adsorbent has mesopores of cylindrical type with rather large diameter (9.7 nm). Adsorption of lysozyme onto AISBA-15 aluminosilicate obeys a Langmuir isotherm, resulting in pore occupation of 25 to 30%. In contrast, the KIT-5 adsorbents showed very small adsorption capacities for the lysozyme adsorption, typically falling in 6 to 13% of pore occupation. The cage-type KIT-5 adsorbents have narrow channel (4 to 6 nm) where penetration of the lysozyme (3 x 3 x 4.5 nm) might be restricted. The KIT-5 adsorbent tends to collapse after long-time immersion in water, as indicated by XRD patterns, while the AISBA-15 adsorbent retains its regular structure even after immersion in basic water for 4 days. These facts confirm superiority of the AISBA-15 as an adsorbent as compared with the KIT-5 mesoporous silicates. This research strikingly demonstrates the selection of mesoporous materials is crucial to achieve efficient immobilization of biomaterials in aqueous environment.
Vinu
Ajayan
A
Nano-ionics Materials Group, Fuel Cell Materials Center National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan.
Miyahara
Masahiko
M
Hossain
Kazi Zakir
KZ
Takahashi
Motoi
M
Balasubramanian
Veerappan Vaithilingam
VV
Mori
Toshiyuki
T
Ariga
Katsuhiko
K
D000327:Adsorption; D000538:Aluminum Silicates / Q000737:chemistry; D001672:Biocompatible Materials / Q000737:chemistry; D004800:Enzymes, Immobilized; D009113:Muramidase / Q000737:chemistry*; D053758:Nanoparticles; D036103:Nanotechnology; D012822:Silicon Dioxide / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D014961:X-Ray Diffraction
D000538:Aluminum Silicates; D001672:Biocompatible Materials; D004800:Enzymes, Immobilized; C049037:aluminosilicate; D012822:Silicon Dioxide; D009113:Muramidase