Immunoassay for LMP1 in nasopharyngeal tissue based on surface-enhanced Raman scattering

Abstract

Yanping Chen1*, Xiongwei Zheng1*, Gang Chen1*, Chen He1, Weifeng Zhu1, Shangyuan Feng2, Gangqin Xi2, Rong Chen2, Fenghua Lan3, Haishan Zeng41Pathology Department of Fujian Provincial Tumor Hospital, Teaching Hospital of Fujian Medical University, 2Key Laboratory of OptoElectronic Science and Technology for Medicine, Ministry of Education, Fujian Normal University, 3Research Center for Molecular Diagnosis of Genetic Diseases, Fuzhou General Hospital, Clinical College of Fujian Medical University, Fuzhou, Fujian, People's Republic of China; 4Imaging Unit, Integrative Oncology Department, British Columbia Cancer Agency Research Centre, Vancouver, Canada*These authors contributed equally to this workBackground: Previous studies have shown that Epstein–Barr virus (EBV)-encoded latent membrane protein 1 (LMP1) is closely associated with the occurrence and development of nasopharyngeal carcinoma, and can be used as a tumor marker in screening for the disease. Here we report a new methodology based on highly specific and sensitive surface-enhanced Raman scattering (SERS) technology to detect LMP1 in nasopharyngeal tissue sections directly with no need of tedious procedures as with conventional immunohistochemistry methods.Methods: LMP1-functionalized 4-mercaptobenzoic acid (4-MBA)-labeled Au/Ag core-shell bimetallic nanoparticles were prepared first and then applied for analyzing LMP1 in formalin-fixed paraffin-embedded nasopharyngeal tissue sections obtained from 34 cancer patients and 20 healthy controls. SERS spectra were acquired from a 25 × 25 spot square area on each tissue section and used to generate SERS images.Results: Data from SERS spectra and images show that this new SERS-based immunoassay detected LMP1 in formalin-fixed paraffin-embedded nasopharyngeal tissue sections with high sensitivity and specificity. The results from the new LMP1-SERS probe method are superior to those of conventional immunohistochemistry staining for LMP1, and in excellent agreement with those of in situ hybridization for EBV-encoded small RNA (EBER).Conclusion: This new SERS technique has the potential to be developed into a new clinical tool for detection and differential diagnosis of nasopharyngeal carcinoma as well as for predicting metastasis and immune-targeted treatment of nasopharyngeal carcinoma.Keywords: surface-enhanced Raman scattering, immunoassay, LMP1, nasopharyngeal carcinoma, in situ hybridization, immunohistochemistry