Study of rotational dynamics of receptor-targeted contrast agents in cancerous and normal prostate tissues using time-resolved picosecond emission spectroscopy

Optical Biopsy XIII: Toward Real-Time Spectroscopic Imaging and Diagnosis

2015

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Optical spectroscopy has been considered a promising method for cancer detection for past thirty years because of its advantages over the conventional diagnostic methods of no tissue removal, minimal invasiveness, rapid diagnoses, less time consumption and reproducibility since the first use in 1984. It offers a new armamentarium. Human tissue is mainly composed of extracellular matrix of collagen fiber, proteins, fat, water, and epithelial cells with key molecules in different structures. Tissues contain a number of key fingerprint native endogenous fluorophore molecules, such as tryptophan, collagen, elastin, reduced nicotinamide adenine dinucleotide (NADH), flavin adenine dinucleotide (FAD) and porphyrins. It is well known that abnormalities in metabolic activity precede the onset of a lot of main diseases: carcinoma, diabetes mellitus, atherosclerosis, Alzheimer, and Parkinson's disease, etc. Optical spectroscopy may help in detecting various disorders. Conceivably the biochemical or morphologic changes that cause the spectra variations would appear earlier than the histological aberration. Therefore, "optical biopsy" holds a great promise as clinical tool for diagnosing early stage of carcinomas and other deceases by combining with available photonic technology (e.g. optical fibers, photon detectors, spectrographs spectroscopic ratiometer, fiber-optic endomicroscope and nasopharyngoscope) for in vivo use. This paper focuses on various methods available to detect spectroscopic changes in tissues, for example to distinguish cancerous prostate tissues and/or cells from normal prostate tissues and/or cells. The methods to be described are fluorescence, stokes shift, scattering, Raman, and time-resolved spectroscopy will be reviewed. The underlying physical and biological basis for these optical approaches will be discussed with examples. The idea is to present some of the salient works to show the usefulness and methods of Optical Biopsy for cancer detection and show new directions.

Section: Elastic Scattering Spectroscopy (Ess)mentioning

confidence: 99%

Section: Elastic Scattering Spectroscopy (Ess)mentioning

confidence: 99%

Optical biopsy - a new armamentarium to detect disease using light

Optical Biopsy XIII: Toward Real-Time Spectroscopic Imaging and Diagnosis

2015

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“…Alfano's group studied the whole temporal profiles of donor and acceptor dyes in solution from the time-resolved fluorescence spectra measured with a streak camera and extracted rise time τ rise , which measures the non-radiative relaxation from the photo-excited state S * 1 to the emitting state S 1 and is ultrashort in time domain of tens picosecond range [48][49][50]. This key step finalizes the model of ultrafast fluorescence polarization dynamics and anisotropy in picosecond range [48][49][50]. In mixed dyes, Förster resonance energy transfer (FRET) occurs between donors and acceptor molecules [48].…”

Section: Introductionmentioning

confidence: 99%

Time-resolved fluorescence polarization spectroscopy of visible and near infrared dyes in picosecond dynamics

2015

SPIE Proceedings

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Near-infrared (NIR) dyes absorb and emit light within the range from 700 to 900 nm have several benefits in biological studies for one-and/or two-photon excitation for deeper penetration of tissues. These molecules undergo vibrational and rotational motion in the relaxation of the excited electronic states. Due to the less ideal anisotropy behavior of NIR dyes stemming from the fluorophores elongated structures and short fluorescence lifetime in picosecond range, no significant efforts have been made to recognize the theory of these dyes in time-resolved polarization dynamics. In this study, the depolarization of the fluorescence due to emission from rotational deactivation in solution will be measured with the excitation of a linearly polarized femtosecond laser pulse and a streak camera. The theory, experiment and application of the ultrafast fluorescence polarization dynamics and anisotropy are illustrated with examples of two of the most important medical based dyes. One is NIR dye, namely Indocyanine Green (ICG). ICG dye is compared with Fluorescein which is in visible range with much longer lifetime to study the salient property of the time-resolved polarization spectroscopy in picosecond range. A set of first-order linear differential equations was developed to model fluorescence polarization dynamics of NIR dye in picosecond range. Using this model, the important parameters of ultrafast polarization spectroscopy were identified: risetime, initial time, fluorescence lifetime, and rotation times.

“…These methods include microscopy, ATP (adenosine triphosphate) bioluminescence, and techniques based on immunological or nucleic acid-based procedures [17], using native fluorescence [18][19][20][21][22][23], optical molecule-labeling [24][25][26][27][28][29][30] and optical microscopic [31,32] techniques in the medical spectroscopy and imaging [33][34][35][36][37][38][39][40]. These techniques are time-consuming [41,42], expensive and labor-intensive [43,44], give retrospective information [45], and require long term trained professionals [46].…”

Section: Introductionmentioning

confidence: 99%

Spoilage of foods monitored by native fluorescence spectroscopy with selective excitation wavelength

Wang

2015

SPIE Proceedings

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The modern food processing and storage environments require the real-time monitoring and rapid microbiological testing. Optical spectroscopy with selective excitation wavelengths can be the basis of a novel, rapid, reagent less, noncontact and non-destructive technique for monitoring the food spoilage. The native fluorescence spectra of muscle foods stored at 2-4 o C (in refrigerator) and 20-24 o C (in room temperature) were measured as a function of time with a selective excitation wavelength of 340nm. The contributions of the principal molecular components to the native fluorescence spectra of meat were measured spectra of each fluorophore: collagen, reduced nicotinamide adenine dinucleotide (NADH), and flavin. The responsible components were extracted using a method namely Multivariate Curve Resolution with Alternating Least-Squares (MCR-ALS). The native fluorescence combined with MCR-ALS can be used directly on the surface of meat to produce biochemically interpretable "fingerprints", which reflects the microbial spoilage of foods involved with the metabolic processes. The results show that with time elapse, the emission from NADH in meat stored at 24 o C increases much faster than that at 4 o C. This is because multiplying of microorganisms and catabolism are accompanied by the generation of NADH. This study presents changes of relative content of NADH may be used as criterion for detection of spoilage degree of meat using native fluorescence spectroscopy.