Adsorption of β-amyloid oligomers on octadecanethiol monolayers.
OBJECTIVE
β-Amyloid oligomers of different aggregation and physiological functions exhibit distinct adsorption behavior allowing them to be discriminated in preparations.


METHODS
Two forms of amyloid oligomers, small 1-4 nm and large 5-10nm were formulated using synthetic 42 amino acids β-amyloid peptide. Forms differ in their size and physiological function. A systematic study of adsorption of these amyloid species on self-assembled monolayers of octadecanethiol on gold was performed. Structural changes upon adsorption of oligomers were interrogated by the reflection absorption infrared spectroscopy.


RESULTS
The amount of adsorbed peptide material, as detected by surface plasmon resonance spectroscopy, is similar in case of both small and large oligomers. However, adsorption of small oligomers leads to a transformation from beta sheet rich to beta sheet depleted secondary structure. These changes were accompanied by the unique morphology patterns detectable by atomic force microscopy (AFM), while the quartz microbalance with dissipation indicated a formation of a compact adsorbate layer in case of small oligomers. These effects may be integrated and utilized in bioanalytical systems for sensing and detection of Alzheimer's disease related peptide forms in artificial, and possibly, real preparations.
Institute of Biochemistry, Vilnius University, Mokslininku 12, LT-08662 Vilnius, Lithuania. Electronic address: tadas.ragaliauskas@bchi.stud.vu.lt.
Tadas
T
Ragaliauskas
Institute of Biochemistry, Vilnius University, Mokslininku 12, LT-08662 Vilnius, Lithuania. Electronic address: mindaugas.mickevicius@bchi.vu.lt.
Mindaugas
M
Mickevicius
Institute of Biochemistry, Vilnius University, Mokslininku 12, LT-08662 Vilnius, Lithuania. Electronic address: rima.budvytyte@bchi.vu.lt.
Rima
R
Budvytyte
Institute of Biochemistry, Vilnius University, Mokslininku 12, LT-08662 Vilnius, Lithuania. Electronic address: gniaura@ktl.mii.lt.
Gediminas
G
Niaura
Institut de Chimie et des Matériaux Paris-Est, Université Paris-Est, 2 rue Henri Dunant, 94320 Thiais, France. Electronic address: carbonnier@icmpe.cnrs.fr.
Benjamin
B
Carbonnier
Institute of Biochemistry, Vilnius University, Mokslininku 12, LT-08662 Vilnius, Lithuania. Electronic address: gintaras.valincius@bchi.vu.lt.
Gintaras
G
Valincius
D000327:Adsorption; D016229:Amyloid beta-Peptides / Q000737:chemistry*; D058266:Dielectric Spectroscopy; D018625:Microscopy, Atomic Force; D013055:Spectrophotometry, Infrared; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D020349:Surface Plasmon Resonance
D016229:Amyloid beta-Peptides; D013438:Sulfhydryl Compounds
Adsorption; Alzheimer’s; Amyloid; Atomic force microscopy; Hydrophobic surfaces; Oligomers; Quartz microbalance; RAIRS; Self-assembled; Surface plasmon resonance spectroscopy