Synthesis and characterization of tri(ethylene oxide)-attached poly(amidoamine) dendrimer layers on gold.
This paper describes the synthesis of a tri(ethylene oxide)-attached fourth-generation poly(amidoamine) dendrimer (EO3-dendrimer) and the characterization of its layers on gold. NMR analysis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry revealed that about 61 amine groups of a G4 PAMAM dendrimer were covalently conjugated with tri(ethylene oxide) units, accounting for a 95% modification level. Layers of the EO3-dendrimer were formed on gold, and the resulting surface was characterized by infrared reflection absorption spectroscopy, ellipsometry, and contact angle goniometry. The EO3-dendrimer resulted in more hydrophilic and less compact layers with no substantial deformation of the molecule during layer formation by virtue of the EO3 units, compared to a PAMAM dendrimer. Interestingly, the specific binding of avidin to the biotinylated layers of the EO3-dendrimer approached a surface density of 5.2 +/- 0.2 ngmm-2, showing about 92% of full surface coverage. The layers of the EO3-dendrimer were found to be more resistant to nonspecific adsorption of proteins than PAMAM dendrimer layers when bovine serum albumin and serum proteins were tested.
Hong
Mi-Young
MY
Department of Biological Sciences, Korea Advanced Institute of Science and Technology 373-1, Kusung-dong, Yusung-ku, Taejon 305-701, South Korea.
Kim
Young-Ja
YJ
Lee
Jae Wook
JW
Kim
Kimoon
K
Lee
Jung-Hwa
JH
Yoo
Jong-Shin
JS
Bae
Sung-Hun
SH
Choi
Byong-Seok
BS
Kim
Hak-Sung
HS
D000327:Adsorption; D000818:Animals; D001360:Avidin / Q000737:chemistry; D001710:Biotin / Q000737:chemistry; D001798:Blood Proteins / Q000737:chemistry; D002417:Cattle; D016650:Fluorescein-5-isothiocyanate; D006046:Gold / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011108:Polymers / Q000737:chemistry*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D001798:Blood Proteins; D011108:Polymers; D001360:Avidin; D012710:Serum Albumin, Bovine; D001710:Biotin; D006046:Gold; D016650:Fluorescein-5-isothiocyanate