Ultra-low fouling and functionalizable zwitterionic coatings grafted onto SiO2 via a biomimetic adhesive group for sensing and detection in complex media.
Non-specific protein binding from human plasma and serum has severely hindered the full capabilities of biosensors concerned with cancer biomarker detection. Currently, there is a strong desire for developing new materials which allow for the convenient attachment of an ultra-low fouling and functionalizable surface coating which can be used for highly sensitive and label-free detection of target analytes directly from complex media. In this work, a short 20 min in situ "graft to" protocol using Tris pH 8.5 buffer was developed for zwitterionic carboxybetaine methacrylate (CBMA) polymer conjugates containing the adhesive biomimetic moiety, 3,4-dihydroxy-L-phenylalanine (DOPA), on SiO(2) substrates. Using a surface plasmon resonance (SPR) biosensor, different buffers, pH values, salt concentrations, and temperatures were investigated for determining the "graft to" conditions that yield dense polymer films which both minimize non-specific protein adsorption and maximize antibody immobilization. The optimized surface coatings were shown to be highly protein resistant to 100% human blood plasma and serum. Subsequent antibody functionalized surfaces without any blocking agents enabled the specific detection of the cancer biomarker ALCAM directly from undiluted human serum down to 64 ng/mL. The successful use of this zwitterionic surface coating for detection from complex media on SiO(2) surfaces indicates its potential for broad impacts in the development of implantable medical devices, in vivo diagnostics, and nano-scale biosensors.
Brault
Norman D
ND
Department of Chemical Engineering, University of Washington, Seattle, WA 98195-1750, USA.
Gao
Changlu
C
Xue
Hong
H
Piliarik
Marek
M
Homola
Jirí
J
Jiang
Shaoyi
S
Yu
Qiuming
Q
D000269:Adhesives / Q000737:chemistry; D015703:Antigens, CD / Q000097:blood*; D040761:Biomimetic Materials / Q000737:chemistry*; D015374:Biosensing Techniques / Q000295:instrumentation*; D001774:Blood Chemical Analysis / Q000295:instrumentation*; D015816:Cell Adhesion Molecules, Neuronal / Q000097:blood*; D020099:Coated Materials, Biocompatible / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005326:Fetal Proteins; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D020349:Surface Plasmon Resonance / Q000295:instrumentation*; D013499:Surface Properties; D020410:Activated-Leukocyte Cell Adhesion Molecule
D000269:Adhesives; D015703:Antigens, CD; D015816:Cell Adhesion Molecules, Neuronal; D020099:Coated Materials, Biocompatible; D005326:Fetal Proteins; D012822:Silicon Dioxide; C105613:ALCAM protein, human; D020410:Activated-Leukocyte Cell Adhesion Molecule