title: Immunosensors for C-Reactive Protein Based on Ultrathin Films of Carboxylated Cellulose Nanofibrils.
abstract: C-reactive protein (CRP) is an acute phase protein that has been widely used as a predictor of cardiovascular diseases. We report herein the synthesis of immunosensors based on carboxylated cellulose nanofibrils (CNF) for CRP detection, as demonstrated by quartz crystal microgravimetry (QCM). QCM sensors carrying ultrathin films of carboxylated CNF were prepared by using two protocols: (i) spin coating of CNF on the sensors followed by carboxylation via in situ oxidation with 2,2,6,6-tetramethylpiperidine 1-oxyl and (ii) carboxymethylation of CNF in aqueous dispersion followed by spin coating deposition on the sensors. Protein A was conjugated to the carboxylated CNF via N-(3-(Dimethylamino)propyl)-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide and used as a ligand for oriented immobilization of anti C-reactive protein (anti-CRP). The different carboxyl group density of the two oxidized CNF surfaces influenced Protein A binding and, subsequently, the available immobilized anti-CRP molecules. The detection efficiency for CRP, specificity, and concentration range displayed by the carboxylated CNF-based immunosensors coupled with oriented and unoriented anti-CRP were determined and compared.
authors.affiliation: Institute for Cardiovascular Science and Department of Cardiovascular Surgery of the First Affiliated Hospital, Soochow University , Suzhou, Jiangsu 215007, People's Republic of China.
authors.forename: Yanxia
authors.identifier: 0000-0002-1920-6709
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University , FI-00076 Aalto, Finland.|Departments of Forest Biomaterials and Chemical and Biomolecular Engineering, North Carolina State University , Raleigh, North Carolina 27695, United States.
authors.forename: Orlando J
authors.initials: OJ
authors.lastname: Rojas
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D002097:C-Reactive Protein / Q000032:analysis* / Q000276:immunology; D002264:Carboxylic Acids / Q000737:chemistry*; D002482:Cellulose / Q000737:chemistry*; D005340:Fibrinogen / Q000032:analysis / Q000276:immunology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay / Q000295:instrumentation* / Q000379:methods; D007074:Immunoglobulin G / Q000032:analysis / Q000276:immunology; D057139:Nanofibers / Q000737:chemistry*; D011791:Quartz; D012709:Serum Albumin / Q000032:analysis / Q000276:immunology; D013499:Surface Properties
chemical_list: D002264:Carboxylic Acids; D007074:Immunoglobulin G; D012709:Serum Albumin; D011791:Quartz; D005340:Fibrinogen; D002482:Cellulose; D002097:C-Reactive Protein