Combination of FTIR spectroscopy with fiber optics provides a powerful diagnostic tool for diagnosing of human diseases, including osteoarthritis. To detect cartilage degradation, an arthroscopic probe based on polycrystalline fibers was developed and evaluated on equine cartilage specimen. The hook shape allows reaching a significant portion of the articular surface; the flat tip ensures avoidance of tissue destruction. Efficient QCL-coupling and stable transmission of PIR fibers under bending allows the assembling of effective thin arthroscopy probes and customized multispectral systems for medical diagnostic applications. The presented work was performed within the MIRACLE project (Grant Agreement No 780598, Horizon 2020).
Optical spectroscopy offers unique opportunities for a label-free investigation of tissues at the molecular level to identify the variety of diseases. To transfer spectroscopic analysis from the scientific laboratories to clinical environment, fiber optic probes are required as optical bridges between the equipment and tissue.
We developed single and combined fiber optic probes for the following set of spectroscopy methods: Mid IR-absorption, Raman scattering, Diffuse NIR-reflection, and auto-fluorescence. We benchmarked these methods and selected the optimal one (or their combination), that differentiate between healthy and malignant tissue, based on optical spectra. We tested cancer-normal tissue pairs of human body such as colon, kidney, brain as well as cartilages with and without injuries. Equines cartilage samples with and without osteoarthritis were tested as well. Obtained spectral data were evaluated by multivariate discrimination analysis to enable clear separation of malignant and normal tissues. Data fusion was revealed a synergic effect resulted in increasing of sensitivity, specificity and accuracy (up to 98% for kidney cancer).
Microfabricated diamond waveguides, between 5 and 20 μm thick, manufactured by chemical vapor deposition of diamond, followed by standard lithographic techniques and inductively coupled plasma etching of diamond, are used as bio-chemical sensors in the mid infrared domain: 5-11 μm. Infrared light, emitted from a broadly tunable quantum cascade laser with a wavelength resolution smaller than 20 nm, is coupled through the diamond waveguides for attenuated total reflection spectroscopy. The expected advantages of these waveguides are a high sensitivity due to the high number of internal reflections along the propagation direction, a high transmittance in the mid-IR domain, the bio-compatibility of diamond and the possibility of functionalizing the surface layer. The sensor will be used for analyzing different forms of proteins such as α-synuclein which is relevant in understanding the mechanism behind Parkinson's disease. The fabrication process of the waveguide, its characteristics and several geometries are introduced. The optical setup of the biosensor is described and our first measurements on two analytes to demonstrate the principle of the sensing method will be presented. Future use of this sensor includes the functionalization of the diamond waveguide sensor surface to be able to fish out alpha-synuclein from cerebrospinal fluid.
Plasmonic gold nanostars (NSts) demonstrate an enhanced electric field in their surrounding due to large number of ‘hot spots’ on their surface resulting in a unique ability to confine light within a nanometric volume. We are demonstrating beneficial properties of NSts as signal enhancers for tissue and cell imaging using optical coherence tomography (OCT), microscopy, surface-enhanced vibration spectroscopy (SEVS), including surface-enhanced Raman scattering (SERS), and surface-enhanced infrared absorption spectroscopy (SEIRAS) with an attenuated total reflectance (ATR) and infrared reflection-absorption spectroscopy (IRRAS) configurations.
Scattering ability of gold NSts with various sizes was investigated by OCT capillary imaging and light and confocal microscopy in vitro. The variation of NSts sizes allows one to shift plasmon resonance up to 1300 nm. The most intensive scattering signals were found from the largest NSts.
NSts were applied in SEVS scenarios using plasmonic chip-based systems containing self-assembled NSts on a silicon substrate both by evaporation and subsequent immobilization mediated by a gold layer and modified-dimercapto polyethylene glycol. The plasmonic substrates are able to concomitantly enhance Raman and mid-infrared signals. SERS and SEIRAS properties of such substrates were demonstrated. For SERS, by using crystal violet as a model analyte. The IR absorbance of analyte molecules placed on NSt-film deposited on a Si ATR crystal was up to 10 times higher for thioglycolic acid and 2 times higher for bovine serum albumin compared to a bare Si waveguide. For the best of our knowledge, this is the first attempt to use NSt-based substrate for SEIRAS studies.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.