Zhihong Xu

Nasopharyngeal carcinoma detection by tissue smears using surface-enhanced Raman spectroscopy

ABSTRACT Nasopharyngeal carcinoma is one of the most common malignant neoplasms in head and neck. In this work, surface-enhanced Raman spectroscopy technique was used to study the molecular differences between cancerous and noncancerous smear samples which were obtained after clinical biopsy by smearing the tissue on the slides. Principal component analysis combined with linear discriminant analysis provided a sensitivity of 79.4% and a specificity of 81.8% for differentiation between cancerous and noncancerous nasopharyngeal tissue smears. This work provides a good basis for the methodology of nasopharyngeal tissue smear based on surface-enhanced Raman spectroscopy technique and is worth further studying.

Discrimination of Nasopharyngeal Carcinoma from Noncancerous Ex Vivo Tissue Using Reflectance Spectroscopy

Reflectance spectroscopy is a low-cost, nondestructive, and noninvasive method for detection of neoplastic lesions of mucosal tissue. This study aims to evaluate the capability of reflectance spectroscopy system under white light (400–700 nm) with a multivariate statistical analysis for distinguishing nasopharyngeal carcinoma (NPC) from nasopharyngeal benign ex vivo tissues. High quality reflectance spectra were acquired from nasopharyngeal ex vivo tissues belonging to 18 noncancerous and 19 cancerous subjects, and the combination of principal component analysis-linear discriminant analysis (PCA-LDA) along with leave-one-spectrum-out cross-validation (LOOCV) diagnostic algorithm was subsequently employed to classify different types of tissue group, achieving a diagnostic sensitivity of 73.7% and a specificity of 72.2%. Furthermore, in order to distinguish NPC from nasopharyngeal benign ex vivo tissues based on reflectance spectra simply, spectral intensity ratios of oxyhemoglobin (540/576) were used as an indicator of the carcinogenesis associated transformation in the hemoglobin oxygenation. This tentative work demonstrated the potential of reflectance spectroscopy for NPC detection using ex vivo tissue and has significant experimental and clinical value for further in vivo NPC detection in the future.

A potential method for non-invasive acute myocardial infarction detection based on saliva Raman spectroscopy and multivariate analysis

Raman spectroscopy (RS) was employed for human saliva biochemical analysis with the aim to develop a rapidly non-invasive test for acute myocardial infarction (AMI) detection. High-quality Raman spectra were obtained from human saliva samples of 46 AMI patients and 43 healthy controls. Significant differences in Raman intensities of prominent bands were observed between AMI and normal saliva. The tentative assignment of the observed Raman bands indicated constituent and conformational differences between the two groups. Furthermore, principal component analysis (PCA) combined with linear discriminant analysis (LDA) was employed to analyze and classify the Raman spectra acquired from AMI and healthy saliva, yielding a diagnostic sensitivity of 80.4% and specificity of 81.4%. The results from this exploratory study demonstrated the feasibility and potential for developing RS analysis of human saliva into a clinical tool for rapid AMI detection and screening.

Autofluorescence and white light imaging-guided endoscopic Raman and diffuse reflectance spectroscopy for in vivo nasopharyngeal cancer detection

Nasopharyngeal cancer (NPC) is an endemic with high incidence in Southern China and Southeast Asia countries. Screening for NPC under conventional white light imaging (WLI) nasopharyngoscope examination remains a great clinical challenge due to its poor sensitivity. Here, we developed an integrated 4-modality endoscopy system combining WLI, autofluorescence imaging (AFI), diffuse reflectance spectroscopy and Raman spectroscopy technologies for in vivo endoscopic cancer detection for the first time. A pilot clinical test of the system for NPC detection was conducted, in which 283 in vivo Raman and diffuse reflectance spectral data sets from 30 NPC patients and 30 healthy subjects were acquired under the guidance of AFI and WLI. Both high diagnostic sensitivity (98.6%) and high specificity (95.1%) for differentiating cancer from normal tissue sites were achieved using this system combined with principal component analysis-linear discriminant analysis diagnostic algorithm, demonstrating great potential for improving real-time, in vivo diagnosis of NPC at endoscopy.

Saliva surface-enhanced Raman spectroscopy for noninvasive optical detection of nasopharyngeal cancer

The early cancer detection is of great significance to increase the patient’s survival rate and reduce the risk of cancer development. Surface enhanced Raman spectroscopy (SERS) technique, a rapid, convenient, nondestructive optical detection method, can provide a characteristic “fingerprint” information of target substances, even achieving single molecule detection. Its ultra-high detection sensitivity has made it become one of the most potential biochemical detection methods. Saliva, a multi-constituent oral fluid, contains the bio-markers which is capable of reflecting the systemic health condition of human, showing promising potential as an effect medium for disease monitoring. Compared with the serum samples, the collection and processing of saliva is safer, more convenient and noninvasive. Thus, saliva test is becoming the hotspot issues of the noninvasive cancer research field. This review highlights and analyzes current application progress within the field of SERS saliva test in cancer detection. Meanwhile, the primary research results of SERS saliva for the noninvasive differentiation of nasopharyngeal cancer, normal and rhinitis obtained by our group are shown.

Study on nasopharyngeal cancer tissue using surface-enhanced Raman spectroscopy

Surface-enhanced Raman spectroscopy (SERS) can provide detailed molecular structure and composition information, and has demonstrated great potential in biomedical filed. This spectroscopy technology has become one of the most important optical techniques in the early diagnosis of cancer. Nasopharyngeal cancer (NPC) is a malignant neoplasm arising in the nasopharyngeal epithelial lining, which has relatively high incidence and death rate in Southeast Asia and southern China. This paper reviews the current progress of SERS in the field of cancer diagnostics, including gastric cancer, colorectal cancer, cervical cancer and nasopharyngeal cancer. In addition to above researches, we recently develop a novel NPC detection method based on tissue section using SERS, and obtain primary results. The proposed method has promising potential for the detection of nasopharyngeal carcinoma.

Diffuse reflectance spectroscopy study of in vitro tissue for nasopharyngeal carcinoma diagnosis

Diffuse reflectance spectroscopy is a non-contact, non-invasive, and low-cost optical technique that provides real-time feedback about the absorptive characteristics and the microstructure properties of biological tissue. This optical technique shows the potential for monitoring metabolic status associated with malignancy transformation. Nasopharyngeal carcinoma (NPC) is the third most frequently diagnosed cancer associated with virus and is the most common male malignancy with a characteristic regional and racial distribution worldwide. This paper investigates the current screening state of nasopharyngeal malignancies and also provides an overview on the applications of diffuse reflectance spectroscopy in the cancer detection. Furthermore, the latest research relevant to the diagnosis of NPC in vitro tissue using diffuse reflectance spectroscopy is introduced. The results of diffuse reflectance spectroscopy are summarized, showing a significant experimental and clinical value for further NPC detection in vivo in the future.

Comparative analysis of diagnostic efficiency of confocal micro-Raman spectroscopy and surface-enhanced Raman spectroscopy for nasopharyngeal carcinoma detection based on tissue smears method

Raman spectroscopy is a practice tool for tissue detection. This work demonstrated that confocal micro-Raman spectroscopy (CMRS) and surface-enhanced Raman spectroscopy (SERS) have promising exploratory potential for the detection of nasopharyngeal carcinoma (NPC) based on nasopharyngeal swab smear.