Rapid and Selective Determination of Folate Receptor α with Sensitive Resonance Rayleigh Scattering Signal

International Journal of Analytical Chemistry, May 2017

A rapid, simple, and novel method for folate receptor α (FRα) determination is reported here. A probe of gold nanoparticles (Au NPs) modified with anti-FRα antibody was synthesized under the optimized conditions first. The antibody-modified Au NPs would aggregate when FRα was added to the probe for the specific interaction between antibody and antigen, resulting in the enhancement of resonance Rayleigh scattering (RRS) intensity. There is a linear relationship between the change of RRS intensity () and the concentration of FRα, with the detecting range of 0.50–37.50 ng·mL−1 and the limit of determination of 0.05 ng·mL−1. The determination of FRα in serum samples was realized with the advantages of high selectivity, high sensitivity, and easy operation.

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Rapid and Selective Determination of Folate Receptor α with Sensitive Resonance Rayleigh Scattering Signal

Rapid and Selective Determination of Folate Receptor α with Sensitive Resonance Rayleigh Scattering Signal Liping Wu,1,2 Yue Liu,2 Rong Huang,2 Huawen Zhao,2 and Weiqun Shu1 1Department of Environmental Hygiene, College of Preventive Medicine, Third Military Medical University, Chongqing 400038, China 2Department of Chemistry, College of Pharmacy, Third Military Medical University, Chongqing 400038, China Correspondence should be addressed to Huawen Zhao; moc.nuyila@whzdys and Weiqun Shu; moc.anis@0360mx Received 19 February 2017; Revised 13 April 2017; Accepted 7 May 2017; Published 25 May 2017 Academic Editor: Guannan Wang Copyright © 2017 Liping Wu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract A rapid, simple, and novel method for folate receptor α (FRα) determination is reported here. A probe of gold nanoparticles (Au NPs) modified with anti-FRα antibody was synthesized under the optimized conditions first. The antibody-modified Au NPs would aggregate when FRα was added to the probe for the specific interaction between antibody and antigen, resulting in the enhancement of resonance Rayleigh scattering (RRS) intensity. There is a linear relationship between the change of RRS intensity () and the concentration of FRα, with the detecting range of 0.50–37.50 ng·mL−1 and the limit of determination of 0.05 ng·mL−1. The determination of FRα in serum samples was realized with the advantages of high selectivity, high sensitivity, and easy operation. 1. Introduction Folate receptors (FRs) are a family of glycoproteins on cell membrane [1]. Folate in tissues could be specifically recognized by folate receptors. There are three subtypes of folate receptors expressed on cells, which are FRα (also called FR1), FRβ, and FRγ, respectively. Low level of folate receptors are expressed in normal cells or tissues. However, the expressing level of folate receptors, especially FRα, is greatly increased in most human tumors [2], to fulfill the need of massive folate for the proliferation of cancer cells [3, 4], indicating that the folate receptor could be served as a tumor biomarker for the initiation and progression of cancers and as a therapeutic target for cancer treatments [5]. The expressing level of folate receptor is extremely higher in colon cancers than in normal tissues [5]. Furthermore, the high expression of folate receptor is also associated with other tumors, such as lung cancer [6, 7], breast cancer [8], ovarian cancer [9–11], and brain tumor [5]. So the methodological basis could be provided for early diagnosis and monitoring of cancers by effective and quantitative determination of folate receptor. Currently, methods for folate receptor determination have been reported, such as fluorescence quenching or imaging [12, 13], electrochemical or electrochemiluminescence biosensors [14–17], and colorimetric detection [18–20]. For these methods, fluorescent dyes, electrochemical luminescent dyes, or expensive instruments are needed, terminal protection of small-molecule-linked DNA should be done first, or the detection is not sensitive enough. So it is still significant to set up simple and rapid ways to determine FRα for the early monitoring of cancers. In this contribution, FRα is determined using the distinctive resonance Rayleigh scattering (RRS) property of gold nanoparticles (Au NPs). RRS technology is well known for the high sensitivity and the convenience in performance and apparatus (common fluorophotometer). RRS method has been widely used to determine metal ions [21], biomolecules [22], medicines [23], pesticides [24], and so forth. Au NPs could be usually used as RRS probe for the special optical property. In our work, anti-FRα antibody was modified on the surface of Au NPs under optimized conditions, which was accomplished easily. In other words, Au NPs probe was made first. The antibody-modified Au NPs would aggregate when FRα was added to the probe, resulting in the enhancement of RRS intensity, for the specific interaction between anti-FRα antibody on the surface of Au NPs and FRα antigen. Meanwhile, there is a linear relationship between the change of RRS intensity () and the concentration of FRα, with the detecting range of 0.50–37.50 ng·mL−1, the limit of determination of 0.05 ng·mL−1, and the correlation coefficient of 0.9996. There are other methods reported for the determination of FRα. Compared to these methods, the advantages of our method are listed as follows. Firstly, the sensitivity of determination is guaranteed for RRS intensity is used as the response signal. Secondly, FRα could be determined with high selectivity, since it is based on the specific interaction between anti-FRα antibody and antigen in our method. Finally, the modification of anti-FRα antibody on the surface of Au NPs is simple t (...truncated)


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Liping Wu, Yue Liu, Rong Huang, Huawen Zhao, Weiqun Shu. Rapid and Selective Determination of Folate Receptor α with Sensitive Resonance Rayleigh Scattering Signal, International Journal of Analytical Chemistry, 2017, 2017, DOI: 10.1155/2017/1670812