title: Electrical detection of C-reactive protein using a single free-standing, thermally controlled piezoresistive microcantilever for highly reproducible and accurate measurements.
abstract: This study demonstrates a novel method for electrical detection of C-reactive protein (CRP) as a means of identifying an infection in the body, or as a cardiovascular disease risk assay. The method uses a single free-standing, thermally controlled piezoresistive microcantilever biosensor. In a commonly used sensing arrangement of conventional dual cantilevers in the Wheatstone bridge circuit, reference and gold-coated sensing cantilevers that inherently have heterogeneous surface materials and different multilayer structures may yield independent responses to the liquid environmental changes of chemical substances, flow field and temperature, leading to unwanted signal disturbance for biosensing targets. In this study, the single free-standing microcantilever for biosensing applications is employed to resolve the dual-beam problem of individual responses in chemical solutions and, in a thermally controlled system, to maintain its sensor performance due to the sensitive temperature effect. With this type of single temperature-controlled microcantilever sensor, the electrical detection of various CRP concentrations from 1 µg/mL to 200 µg/mL was performed, which covers the clinically relevant range. Induced surface stresses were measured at between 0.25 N/m and 3.4 N/m with high reproducibility. Moreover, the binding affinity (KD) of CRP and anti-CRP interaction was found to be 18.83 ± 2.99 µg/mL, which agreed with results in previous reported studies. This biosensing technique thus proves valuable in detecting inflammation, and in cardiovascular disease risk assays.
authors.affiliation: Institute of Applied Mechanics, National Taiwan University, Taipei 10617, Taiwan. ykyen@ntu.edu.tw
authors.forename: Yi-Kuang
authors.initials: YK
authors.lastname: Yen
authors.forename: Yu-Cheng
authors.initials: YC
authors.lastname: Lai
authors.forename: Wei-Ting
authors.initials: WT
authors.lastname: Hong
authors.forename: Yotsapoom
authors.initials: Y
authors.lastname: Pheanpanitporn
authors.forename: Chuin-Shan
authors.initials: CS
authors.lastname: Chen
authors.forename: Long-Sun
authors.initials: LS
authors.lastname: Huang
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D002097:C-Reactive Protein / Q000032:analysis*; D003217:Conductometry / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007118:Immunoassay / Q000295:instrumentation*; D055617:Micro-Electrical-Mechanical Systems / Q000295:instrumentation*; D008904:Miniaturization; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D002097:C-Reactive Protein
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