Separation of endogenous fluorophores in normal and cancer cells

Li, Ye

doi:10.17077/etd.5lyxogsx

Cited by 5 publications

(3 citation statements)

References 135 publications

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“…1(f)) where and an additional maximum around 420 nm for healthy tissue fluorescence is distinguishable and could be attributed to collagen and its cross-links. For the maxima of NAD(P)H there is no prominent red spectral shift, the only difference between the spectra of cancerous and healthy fluorescence for this maxima is in the intensity, which is lower for cancerous tissues fluorescence and it was already observed [11,28,38].…”

Section: Resultsmentioning

confidence: 77%

Macro and micro spectroscopy parameters of cancerous and healthy gastrointestinal tissues

Genova

Borisova

Semyachkina-Glushkovskaya

et al. 2017

J-BPE

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New more sensitive diagnostic modalities, for either analysis of biopsy tissue samples or on site, in vivo microscopy tissue examination, emerge to aid the detection and accurate diagnosis of gastrointestinal cancer. One of the most intensively investigated techniques is the fluorescence spectroscopy approach. We present our investigation of the detailed macro and micro fluorescence characteristics of ex-vivo fresh and fixed tissue samples. The fluorescence spectra of unprocessed cancerous and healthy gastrointestinal (GIT) tissue, obtained with two approaches fluorescence and synchronous fluorescence spectroscopy were compared with microspectroscopy performed with laser scanning confocal fluorescence microscopy (LSCFM) system in Lambda-scan regime over fixed tissue samples. The evaluated optical macro-and micro-spectroscopy characteristics are presented and disscused in order to improve the current understanding of the origin of autofluorescence contrast between healthy and cancerous tissues and its application for improvement of the existing diagnostic modalities.

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Section: Resultsmentioning

confidence: 77%

Macro and micro spectroscopy parameters of cancerous and healthy gastrointestinal tissues

Genova

Borisova

Semyachkina-Glushkovskaya

et al. 2017

J-BPE

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“…Autofluorescence images (AFI) are used for polyp differentiation based on the analysis of the autofluorescence spectra, as changes are observed between adenomas and normal mucosa because of the biochemical and morphological tissue alterations during cancerous transformation (8,9) . In this manner, endogenous fluorophores and their role as intrinsic biomarkers offer an exceptionally powerful tool for characterizing, in real time, even subtle changes of interconnected morphological and metabolic properties of cells and tissues under physiological or altered conditions (10) .…”

Section: Introductionmentioning

confidence: 99%

Early Stages of Colorectal Cancer Characterization by Autofluorescence 3d Microscopy: A Preliminary Study

ERBES,

CASCO,

ADUR

2024

Arq. Gastroenterol.

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Background: Colorectal cancer is one of the most prevalent pathologies worldwide whose prognosis is linked to early detection. Colonoscopy is the gold standard for screening, and diagnosis is usually made histologically from biopsies. Aiming to reduce the inspection and diagnostic time as well as the biopsies and resources involved, other techniques are being promoted to conduct accurate in vivo colonoscopy assessments. Optical biopsy aims to detect normal and neoplastic tissues analysing the autofluorescence spectrum based on the changes in the distribution and concentration of autofluorescent molecules caused by colorectal cancer. Therefore, the autofluorescence contribution analysed by image processing techniques could be an approach to a faster characterization of the target tissue. Objective: Quantify intensity parameters through digital processing of two data sets of three-dimensional widefield autofluorescence microscopy images, acquired by fresh colon tissue samples from a colorectal cancer murine model. Additionally, analyse the autofluorescence data to provide a characterization over a volume of approximately 50 µm of the colon mucosa for each image, at second (2nd), fourth (4th) and eighth (8th) weeks after colorectal cancer induction. Methods: Development of a colorectal cancer murine model using azoxymethane/dextran sodium sulphate induction, and data sets acquisition of Z-stack images by widefield autofluorescence microscopy, from control and colorectal cancer induced animals. Pre-processing steps of intensity value adjustments followed by quantification and characterization procedures using image processing workflow automation by Fiji’s macros, and statistical data analysis. Results: The effectiveness of the colorectal cancer induction model was corroborated by a histological assessment to correlate and validate the link between histological and autofluorescence changes. The image digital processing methodology proposed was then performed on the three-dimensional images from control mice and from the 2nd, 4th, and 8th weeks after colorectal cancer chemical induction, for each data set. Statistical analyses found significant differences in the mean, standard deviation, and minimum parameters between control samples and those of the 2nd week after induction with respect to the 4th week of the first experimental study. This suggests that the characteristics of colorectal cancer can be detected after the 2nd week post-induction. Conclusion: The use of autofluorescence still exhibits levels of variability that prevent greater systematization of the data obtained during the progression of colorectal cancer. However, these preliminary outcomes could be considered an approach to the three-dimensional characterization of the autofluorescence of colorectal tissue, describing the autofluorescence features of samples coming from dysplasia to colorectal cancer.

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“…We also demonstrated that this methodology is amazingly robust, allowing one the flexibility to use different excitation wavelengths or solvents for CE versus fluorescence spectroscopy. The potential of this methodology for biological applications has been demonstrated by the work of my colleague Dr. Ye Li using mixtures of the universal endogenous fluorophores nicotinamide adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD)[101]. This opens the path for applying 2D hetero-correlation to cell extracts and tissue samples so that the identity of their hypothesized components could be confirmed.…”

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confidence: 99%

I. Hydrophobic nanoporous silica particles for biomedical applications. II. Novel approaches to two-dimensional correlation spectroscopy

Brumaru¹

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Many highly effective drugs display serious side-effects. To limit them, one can contain the drug in tiny containers, which are subsequently delivered toward targets inside the body. The entrapment of drug molecules prevents them from coming in contact with and thus causing damage to normal cells. Inherently, it is difficult to reach 100% efficiency of drug trapping and release when employing physical caps to seal the vehicles. Instead, we propose drug trapping inside the nanopores of hydrophobic silica particles by "hydrophobic trapping". This phenomenon is associated with the repulsive "force field" generated inside nanometer-sized hydrophobic channels that completely prevents aqueous solutions from entering the channels. We demonstrate the excellent trapping efficiency using C18-modified silica particles with 10 nm pores and the anticancer drug doxorubicin.The major challenge in using hydrophobic particles in biological applications is their tendency to cluster in aqueous media. To overcome it, we use surfactants as solubilization means. We have developed protocols that effectively solubilize the outer surface of the particles while preventing surfactant micelles from entering nanopores.Consequently, particles become well-dispersible in aqueous solutions, with the preloaded drug safely contained inside nanopores.Nanomaterials exhibit heterogeneity on their surfaces that impact their functional applications. Although techniques such as atomic force microscopy are great tools for studying nanomaterials with their excellent spatial resolution, they cannot probe the inner surface of porous structures. We have established a method of single-molecule ratiometric imaging that is currently the only technique able to provide the nanopolarity of adsorption sites located on the pore surface. We analyze the polarity distribution of adsorptions events for the solvatochromic probe Nile Red at the C18/acetonitrile interface and discover at least two different populations of adsorption sites. One of them corresponds to the polarity of surface silanol groups while the other sites have a polarity consistent with the environment inside the C18 organic layer. We also discover an additional adsorption mode situated at a polarity higher than exposed silanol surface that could presumably be linked to a different ionization state of the silanol groups.We are developing a method for resolving spectra of complex samples using twodimensional hetero-correlation spectroscopy by correlating the intensity fluctuations in optical spectra to those of completely separated peaks in analytical separations. We demonstrate this methodology for fluorescence spectra and electrophoregrams of mixtures anthracene-pyrene. All the individual vibronic features that overlap in mixtures are cleanly extracted in cross-sections of the two-dimensional asynchronous spectrum.Abstract Approved: ____________________________________ Thesis Supervisor ____________________________________

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Separation of endogenous fluorophores in normal and cancer cells

Cited by 5 publications

References 135 publications

Macro and micro spectroscopy parameters of cancerous and healthy gastrointestinal tissues

Macro and micro spectroscopy parameters of cancerous and healthy gastrointestinal tissues

Early Stages of Colorectal Cancer Characterization by Autofluorescence 3d Microscopy: A Preliminary Study

I. Hydrophobic nanoporous silica particles for biomedical applications. II. Novel approaches to two-dimensional correlation spectroscopy

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