title: Fabrication of calix[4]arene derivative monolayers to control orientation of antibody immobilization.
abstract: Three calix[4]arene (Cal-4) derivatives which separately contain ethylester (1), carboxylic acid (2), and crownether (3) at the lower rim with a common reactive thiol at the upper rim were synthesized and constructed to self-assembled monolayers (SAMs) on Au films. After spectroscopic characterization of the monolayers, surface coverage and orientation of antibody immobilized on the Cal-4 derivative SAMs were studied by surface plasmon resonance (SPR) technique. Experimental results revealed that the antibody could be immobilized on the Cal-4 derivatives spontaneously. The orientation of absorbed antibody on the Cal-4 derivative SAMs is related to the SAM's dipole moment. The possible orientations of the antibody immobilized on the Cal-4 derivative 1 SAM are lying-on or side-on, while on the Cal-4 derivative 2 and Cal-4 derivative 3 head-on and end-on respectively. These experimental results demonstrate the surface dipole moment of Cal-4 derivative appears to be an important factor to antibody orientation. Cal-4 derivatives are useful in developing site direct protein chips.
authors.affiliation: Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, China. hxchen@shu.edu.cn.
authors.forename: Hongxia
authors.initials: H
authors.lastname: Chen
authors.affiliation: Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, China. liufeng825@tom.com.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: Laboratory of Biosensing Technology, School of Life Sciences, Shanghai University, Shanghai 200444, China. stefanieqfj@163.com.
authors.forename: Fangjie
authors.initials: F
authors.lastname: Qi
authors.affiliation: College of Nanoscience and Nanotechnology, Pusan National University, Pusan 609-735, Korea. koh@pusan.ac.kr.
authors.forename: Kwangnak
authors.initials: K
authors.lastname: Koh
authors.affiliation: Department of Oncology, the Second Affiliated Hospital of Nanjing Medical University, Nanjing 210011, China. wkmys@sohu.com.
authors.forename: Keming
authors.initials: K
authors.lastname: Wang
mesh_terms: D055910:Antibodies, Immobilized / Q000276:immunology*; D015374:Biosensing Techniques; D047250:Calixarenes / Q000138:chemical synthesis*; D002264:Carboxylic Acids / Q000737:chemistry; D043844:Crown Ethers / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D010169:Palmitic Acids / Q000276:immunology; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: C450319:16-mercaptohexadecanoic acid; D055910:Antibodies, Immobilized; D002264:Carboxylic Acids; D043844:Crown Ethers; D010169:Palmitic Acids; D047250:Calixarenes; D006046:Gold