Journal article
A novel fluorescent and electrochemical dual-responsive immunosensor for sensitive and reliable detection of biomarkers based on cation-exchange reaction
Analytica chimica acta, Vol.1096, pp.61-68
02/01/2020
PMID: 31883592
Abstract
Sensitive and reliable detection of biomarkers is of vital importance in tumor early detection and clinical therapy. A novel fluorescent/electrochemical dual-responsive immunosensing platform for reliable and sensitive quantification of biomarkers was designed based on cation-exchange reaction. To construct such a versatile platform, the model analyte, carcinoembryonic antigen (CEA), was captured by magnetic Fe3O4 nanoparticles bound with primary antibodies (Fe3O4-Ab1) and then recognized by the detection antibodies conjugated complex containing poly(amidoamine) (PAMAM), carbon nanotube (CNT) and carboxyl functionalized CdSe nanocrystals (NCs) (CNT-PAMAM-CdSe NCs-Ab2). Via ligand exchange, the stable CdSe nanocrystals were easily functionalized with carboxylate ion (CdSe–COO-) and showed high hydrophilicity. The CdSe–COO- was effectively and densely conjugated to CNT coated dendrimer PAMAM that possesses large specific surface area. Finally, the target CEA was detected based on cation-exchange reaction (CER) by adding Ag+ to release thousands of cations Cd2+, which were detected by fluorescence and electrochemistry simultaneously. The electrochemical measurement was performed by directly detecting Cd2+ through square wave voltammetry (SWV), which displayed an excellent correlation with CEA from 5 pg/mL to 50 ng/mL, with a limit of detection (LOD) of 1.7 pg/mL. The fluorescence detection was implemented since free Cd2+ could trigger the weak fluorescence metal-sensitive dyes (Rhod-5N) to generate extremely high fluorescence signal. The fluorescence results showed the LOD for CEA detection was 0.25 pg/mL with a calibration curve range from 1 pg/mL to 20 ng/mL. The dual signal outputs showed an attractively self-correcting ability, which provides the capability of avoiding false positive signal and making the detection result more reliable. The proposed dual-responsive platform holds great promises for biomarkers detection in clinical diagnostics and therapy.
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•The dual signal outputs showed an attractive self-correcting ability, which could make the detection result more accurate.•CER could release thousands of Cd2+, which could obtain hundreds of times signal amplification.•The Ab2-CdSe NCs-PAMAM-CNTs conjugate was adopted as amplification label, which could further enhance the detection signal.•The CdSe NCs were successfully functionalized with carboxyl groups, making them effectively conjugate with PAMAM.•Magnetic Fe3O4 NPs was used to conjugate the primary antibody, which provided an easy way to separate the immunocomplex.
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Details
- Title
- A novel fluorescent and electrochemical dual-responsive immunosensor for sensitive and reliable detection of biomarkers based on cation-exchange reaction
- Creators
- Yuting Zhao - Washington State UniversityXiaoli Cai - Washington State UniversityChengzhou Zhu - Washington State UniversityHaipeng Yang - Washington State UniversityDan Du - Washington State University
- Publication Details
- Analytica chimica acta, Vol.1096, pp.61-68
- Academic Unit
- School of Mechanical and Materials Engineering
- Publisher
- Elsevier B.V
- Number of pages
- 8
- Identifiers
- 99901227850101842
- Language
- English
- Resource Type
- Journal article