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Ultrasensitive Detection of Biomarkers by Using a Molecular Imprinting Based Capacitive Biosensor
Published on: February 16, 2018
Molecularly Imprinted Polymer-Based Plasmonic Immunosandwich Assay for Fast and Ultrasensitive Determination of Trace
Xueying Tu1, Pir Muhammad1, Jia Liu1
1State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University , 163 Xianlin Avenue, Nanjing 210023, China.
Insights
We developed a novel antibody-free assay for detecting trace glycoproteins. This molecularly imprinted polymer (MIP)-based plasmonic immunosandwich assay (PISA) offers fast and ultrasensitive detection of biomarkers like erythropoietin (EPO).
Area of Science:
- Biochemistry
- Analytical Chemistry
- Materials Science
Background:
- Glycoproteins are crucial in biological processes, making their detection vital for clinical and research applications.
- Current immunoassays for glycoproteins face limitations due to antibody availability and reagent stability.
- There is a need for robust, sensitive, and specific methods for glycoprotein analysis in complex biological samples.
Purpose of the Study:
- To develop an antibody-free and enzyme-free assay for ultrasensitive glycoprotein detection.
- To establish a molecularly imprinted polymer (MIP)-based plasmonic immunosandwich assay (PISA) for trace glycoprotein analysis.
- To demonstrate the assay's efficacy using erythropoietin (EPO) as a model glycoprotein.
Main Methods:
- Utilized a gold-based boronate affinity MIP array for specific glycoprotein capture.
- Employed silver-based Raman nanotags for labeling captured glycoproteins, forming a sandwich complex.
- Integrated surface plasmon resonance (SPR) with surface-enhanced Raman scattering (SERS) for signal amplification.
- Developed a novel standard addition strategy for quantitative analysis in complex matrices like human urine.
Main Results:
- Achieved specific detection of erythropoietin (EPO) down to 2.9 × 10-14 M in solution.
- Successfully quantified EPO in human urine samples using the developed MIP-PISA method.
- The entire assay procedure, including sample analysis, was completed within 30 minutes.
Conclusions:
- The MIP-PISA offers a highly sensitive, specific, and rapid alternative to traditional immunoassays for glycoprotein detection.
- This antibody-free approach overcomes limitations associated with antibody production and reagent stability.
- The method shows significant potential for applications in biochemical research, clinical diagnostics, and antidoping analysis.
Abstract:
Glycoproteins play significant roles in many biological processes. Assays of glycoproteins have significant biological importance and clinical values, for which immunoassay has been the workhorse tool. However, immunoassay suffers from some disadvantages, such as poor availability of high-specificity antibodies and limited stability of biological reagents. Herein, we present an antibody-free and enzyme-free approach, called molecularly imprinted polymer (MIP)-based plasmonic immunosandwich assay (PISA), for fast and ultrasensitive detection of trace glycoproteins in complex samples. A gold-based boronate affinity MIP array was used to specifically extract the target glycoprotein from complex samples. After washing away unwanted species, the captured glycoprotein was labeled with boronate affinity silver-based Raman nanotags. Thus, sandwich-like complexes were formed on the array. Upon being shined with a laser beam, the gold-based array generated a surface plasmon wave, which significantly enhanced the surface-enhanced Raman scattering (SERS) signal of the silver-based Raman nanotags. The MIP ensured the specificity of the assay, while the plasmonic detection provided ultrahigh sensitivity. Erythropoietin (EPO), a glycoprotein hormone that controls erythropoiesis or red blood cell production, was employed as a test glycoprotein in this study. Specific detection of EPO in solution down to 2.9 × 10-14 M was achieved. Using a novel strategy to accommodate the method of standard addition to a logarithmic dose-response relationship, EPO in human urine was quantitatively determined by this approach. The analysis time required only 30 min in total. This approach holds promising application prospects in many areas, such as biochemical research, clinical diagnosis, and antidoping analysis.
