Carbon Nanoparticle-Enhanced Immunoelectrochemical Detection for Protein Tumor Marker with Cadmium Sulfide Biotracers

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• 作者：Ja-an Annie Ho*^† ; ; Yeh-Chun Lin^† ; ; Li-Sheng Wang^† ; ; Kuo-Chu Hwang^‡ ; ; Pi-Tai Chou^§ ;
• 刊名：Analytical Chemistry
• 出版年：2009
• 出版时间：February 15, 2009
• 年：2009
• 卷：81
• 期：4
• 页码：1340-1346
• 全文大小：377K
• 年卷期：v.81,no.4(February 15, 2009)
• ISSN：1520-6882

文摘

We have developed a sensitive electrochemical immunoassay system for the detection of a protein tumor marker, carcinoembryonic antigen (CEA), that is based on a carbon nanoparticle (CNP)/poly(ethylene imine) (PEI)-modified screen-printed graphite electrode (CNP−PEI/SPGE) covered with anti-CEA antibodies. The signal amplification strategyusing CdS nanocrystals as biotracers and CNPs to enhance electron transferimproves the sensitivity and detection limit for CEA, suggesting that this system holds promise for development into a point-of-care or disposable home-care self-diagnostic tool. This biosensor is based on a sandwich complex immunoassay, which we assembled from sequential layers of the anti-CEA antibody (αCEA) on CNP−PEI/SPGE, the CEA sample, and the CdS nanocrystal quantum dots (QDs) sensitized with αCEA (αCEA−CdS QD). We used square wave anodic stripping voltammetry (SWASV) to amplify the signal current response obtained from the dissolved αCEA−CdS QDs. The calibration curve for CEA concentration was linear in the range of 0.032−10 ng/mL; the detection limit (estimated as the mean of the blank sample plus three times the standard deviation obtained on the blank sample) was 32 pg/mL (equivalent to 160 fg in a 5 μL sample). This method is suitably precise and sensitive to function as a means of determining urinary CEA, which is a better marker than serum CEA for the early detection of urothelial carcinoma.