Combined spatial frequency spectroscopy analysis with visible resonance Raman for optical biopsy of human brain metastases of lung cancers

Abstract

The purpose of this study is to examine optical spatial frequency spectroscopy analysis (SFSA) combined with visible resonance Raman (VRR) spectroscopic method, for the first time, to discriminate human brain metastases of lung cancers adenocarcinoma (ADC) and squamous cell carcinoma (SCC) from normal tissues. A total of 31 label-free micrographic images of three types of brain tissues were obtained using a confocal micro-Raman spectroscopic system. VRR spectra of the corresponding samples were synchronously collected using excitation wavelength of 532[Formula: see text]nm from the same sites of the tissues. Using SFSA method, the difference in the randomness of spatial frequency structures in the micrograph images was analyzed using Gaussian function fitting. The standard deviations, [Formula: see text] calculated from the spatial frequencies of the micrograph images were then analyzed using support vector machine (SVM) classifier. The key VRR biomolecular fingerprints of carotenoids, tryptophan, amide II, lipids and proteins (methylene/methyl groups) were also analyzed using SVM classifier. All three types of brain tissues were identified with high accuracy in the two approaches with high correlation. The results show that SFSA–VRR can potentially be a dual-modal method to provide new criteria for identifying the three types of human brain tissues, which are on-site, real-time and label-free and may improve the accuracy of brain biopsy.

A Handheld Visible Resonance Raman Analyzer Used in Intraoperative Detection of Human Glioma

“…We observed that Raman peaks due to carotenoids, proteins, and lipids from the margin tissues were different from those in the tumor tissues. Similar Raman spectral changes were also observed in skin, breast, and heart tissue in our previous studies [ 26 , 34 , 40 , 41 , 45 , 46 , 47 ].…”

“…Raman spectral changes can reveal the metabolic processes of brain tissue [ 24 , 25 , 30 ] and can potentially be used for margin assessment, even during surgery [ 24 , 30 , 31 , 32 , 33 , 34 , 35 ]. Raman spectroscopy techniques have been used to study human bladder cancer, esophageal cancer, gastrointestinal cancer, cervical cancer, skin melanoma lesions, lung cancer, breast cancer, and brain tumors, not only ex vivo but also in vivo [ 15 , 16 , 19 , 20 , 21 , 22 , 22 , 23 , 26 , 27 , 28 , 31 , 33 , 36 , 37 , 38 , 39 , 40 ]. Besides solid tumors, Raman spectroscopy has also been used to detect vulnerable atherosclerotic plaques, atherosclerotic abdominal aortic tissues, and nerve tissues, and even the cerebrospinal fluid and serum of patients [ 41 , 42 , 43 , 44 ].…”

“…We have developed a novel optical spectroscopic technique based on visible resonance Raman (VRR) spectroscopy that can probe the specific molecular vibration bonds in a tissue and provide information to make an optical pathology diagnosis. This new optical biopsy technique using 532 nm wavelength excitation has been used for the investigation and diagnosis of human lesions since 2011 and has shown unique advantages [ 26 , 34 , 40 , 41 , 45 , 46 , 47 ]. Besides the existing advantages of conventional spontaneous Raman (SR), near-infrared Raman (NIR), and ultraviolet resonance Raman (UVRR) methods, VRR has additional advantages over other Raman techniques [ 48 ].…”

Raman Ink for Steganography

“…Obviously, conventional fluorescent molecules cannot meet these criteria. In contrast, surface‐enhanced Raman scattering (SERS) nanotags can produce strong and unique fingerprint Raman signals under laser excitation, [ 10–13 ] leading to distinct spectral features from the background of regular ink. Compared with fluorophores that are commonly applied in security ink, [ 5,6,14,15 ] SERS nanotags show a much better stability as well as a greater multiplexing capability due to the narrower spectral linewidth, [ 16 ] allowing multiplexed steganography.…”

Direct Imaging of Integrated Circuits in CPU with 60 nm Super-Resolution Optical Microscope

“…Furthermore, the super-resolution optical microscopes have achieved incredible success in revealing nanoarchitectures in single cells. − However, the human-made semiconductor nanostructures in IC chips have hardly been imaged or characterized by super-resolution optical microscopes because of their inapplicability for fluorescence labeling. Label-free and far-field optical super-resolution nanoscopy was thought to provide tremendous opportunities for direct and easy IC visualization and inspection, and it has also been theoretically and experimentally pursued by various methods in Raman, , coherent anti-Stokes Raman scattering (CARS), − stimulated Raman scattering (SRS), − and pump–probe (PP) − microscopes. Pump–probe microscopes have demonstrated super-resolution imaging of graphene by applying excessive laser power or higher photon energy in the donut beam to saturate the signal therein. , Although the pump–probe signal was also observed in copper, the saturation is not applicable to copper wires in ICs.…”