title: Fabrication of free-standing albumin-nanosheets having heterosurfaces.
abstract: Sheet-shaped carriers, having both obverse and reverse surfaces and thus a large contact area for targeting a site, have several advantages over spherical-shaped carriers, which have an extremely small contact area for targeting sites. Here, we proposed a novel method to prepare a free-standing ultrathin and biocompatible nanosheet having heterosurfaces, by a combination of four processes: (1) specific adsorption of recombinant human serum albumin (rHSA) molecules onto a patterned octadecyltrimethoxysilane self-assembled monolayer region (ODS-SAM), (2) preparation of nanosheets of rHSA molecules bearing thiol groups (SH-rHSA) via two-dimensionally disulfide crosslinking, (3) surface modification of the resulting nanosheet, and (4) preparation of the free-standing nanosheet by detachment from the ODS-SAM. The SH-rHSA molecules at pH 5.0 and a concentration of 1 microg/mL were specifically adsorbed on the patterned ODS-SAM regions by hydrophobic interaction, and were two-dimensionally crosslinked in the presence of copper ion as an oxidant. The rHSA-nanosheets were then simply detached from the ODS-SAM by treatment with surfactant. We succeeded in the preparation of rectangular (10 microm x 30 microm) and ultrathin (4.5 +/- 1.0 nm) rHSA-nanosheets on a patterned ODS-SAM, and could also obtain free-standing rHSA-nanosheets having heterosurfaces by surface modification with fluorescent latex beads. Thus, the rHSA-nanosheets having heterosurfaces could be regarded as a new biomaterial for drug carriers, hemostatic reagents, wound dressing for burn injury, and so forth.
authors.affiliation: Consolidated Research Institute for Advanced Science and Medical Care, Waseda University, Tokyo 169-8555, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Okamura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Goto
authors.forename: Daisuke
authors.initials: D
authors.lastname: Niwa
authors.forename: Yoshihito
authors.initials: Y
authors.lastname: Fukui
authors.forename: Masanobu
authors.initials: M
authors.lastname: Otsuka
authors.forename: Norikazu
authors.initials: N
authors.lastname: Motohashi
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Osaka
authors.forename: Shinji
authors.initials: S
authors.lastname: Takeoka
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D018625:Microscopy, Atomic Force; D008863:Microspheres; D049329:Nanostructures / Q000737:chemistry*; D012709:Serum Albumin / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D017655:Silicon Compounds / Q000737:chemistry; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D012709:Serum Albumin; D012821:Silanes; D017655:Silicon Compounds; C024779:octadecylsilane