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Spatiotemporal imaging of development, disease and regeneration using advanced light-based techniques

Gvazava, Nika LU (2026) In Lund University, Faculty of Medicine Doctoral Dissertation Series 2026:115(2026:115).
Abstract
Biological tissues are complex, dynamic and inherently three-dimensional systems whose physiological and anatomical organization is shaped by their native structural and molecular context. Recent advances in three-dimensional and label-free imaging are transforming our ability to interrogate complex biological specimens across molecular, cellular, and organ scales. However, many conventional imaging workflows can disrupt native tissue architecture and obscure transient or physiologically relevant molecular states.

In this thesis, we first explored novel optical photothermal infrared spectroscopy (OPTIR) as a label-free chemical imaging platform for the analysis of biological specimens under native conditions. We found that O-PTIR... (More)
Biological tissues are complex, dynamic and inherently three-dimensional systems whose physiological and anatomical organization is shaped by their native structural and molecular context. Recent advances in three-dimensional and label-free imaging are transforming our ability to interrogate complex biological specimens across molecular, cellular, and organ scales. However, many conventional imaging workflows can disrupt native tissue architecture and obscure transient or physiologically relevant molecular states.

In this thesis, we first explored novel optical photothermal infrared spectroscopy (OPTIR) as a label-free chemical imaging platform for the analysis of biological specimens under native conditions. We found that O-PTIR enables submicrometer infrared spectroscopic imaging of freshly isolated, fully hydrated biopsies from diverse organs which can be chemically analyzed while preserving their native state. We further found that O-PTIR can distinguish between healthy and amyloid plaque regions in fully hydrated brain slices from APP/PS1 mice. Moreover, O-PTIR enabled molecular imaging of living small vertebrate organisms without compromising their subsequent development, highlighting its potential for non-destructive, in situ chemical imaging of living biological systems.

Further in this thesis, to address key limitations of solvent-based tissue clearing techniques, we developed PROTEUS, a novel solvent-based forward and reverse optical clearing methodology which enables transitioning whole organs in and out of light sheet fluorescence microscopy (LSFM) refractive index matching solutions to enable their use with other standard and state of the art imaging modalities. We demonstrate that PROTEUS preserves endogenous fluorescent proteins, known to be challenging with organic solvent-based clearing, as well as other diverse fluorescent molecular probes.

This is exemplified in murine brains, transplanted blood vessels and developing murine and chick embryos. Together, the work presented in this thesis advances two complementary strategies for interrogating biological systems in their native three-dimensional context. O-PTIR provides label-free, submicrometer chemical imaging of hydrated living tissues and organisms, while PROTEUS enables reversible optical clearing of intact organs and embryos for three-dimensional fluorescence imaging followed by downstream multimodal analysis. Collectively, these approaches expand the capacity to extract structural, spatial and chemical information from complex biological specimens and provide a foundation for more integrated and physiologically relevant analysis of tissues in development, homeostasis and disease. (Less)
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author
supervisor
opponent
  • Associate Professor Dean, Charlotte H., Imperial Collage London
organization
publishing date
type
Thesis
publication status
published
subject
keywords
O-PTIR, Precision-Cut Lung Slices, Tissue clearing, Alzeimer's disease, Light-sheet Flourescence Microscopy, Idiopathic pulmonary fibrosis
in
Lund University, Faculty of Medicine Doctoral Dissertation Series
volume
2026:115
issue
2026:115
pages
162 pages
publisher
Lund University, Faculty of Medicine
defense location
Segerfalksalen, BMC A10, Sölvegatan 17 i Lund
defense date
2026-09-17 09:00:00
ISSN
1652-8220
ISBN
978-91-8021-913-6
language
English
LU publication?
yes
id
fdde370a-b13e-4e3c-8436-4a5919573db5
date added to LUP
2026-08-24 18:49:42
date last changed
2026-08-27 07:23:58
@phdthesis{fdde370a-b13e-4e3c-8436-4a5919573db5,
  abstract     = {{Biological tissues are complex, dynamic and inherently three-dimensional systems whose physiological and anatomical organization is shaped by their native structural and molecular context. Recent advances in three-dimensional and label-free imaging are transforming our ability to interrogate complex biological specimens across molecular, cellular, and organ scales. However, many conventional imaging workflows can disrupt native tissue architecture and obscure transient or physiologically relevant molecular states.<br/><br/>In this thesis, we first explored novel optical photothermal infrared spectroscopy (OPTIR) as a label-free chemical imaging platform for the analysis of biological specimens under native conditions. We found that O-PTIR enables submicrometer infrared spectroscopic imaging of freshly isolated, fully hydrated biopsies from diverse organs which can be chemically analyzed while preserving their native state. We further found that O-PTIR can distinguish between healthy and amyloid plaque regions in fully hydrated brain slices from APP/PS1 mice. Moreover, O-PTIR enabled molecular imaging of living small vertebrate organisms without compromising their subsequent development, highlighting its potential for non-destructive, in situ chemical imaging of living biological systems.<br/><br/>Further in this thesis, to address key limitations of solvent-based tissue clearing techniques, we developed PROTEUS, a novel solvent-based forward and reverse optical clearing methodology which enables transitioning whole organs in and out of light sheet fluorescence microscopy (LSFM) refractive index matching solutions to enable their use with other standard and state of the art imaging modalities. We demonstrate that PROTEUS preserves endogenous fluorescent proteins, known to be challenging with organic solvent-based clearing, as well as other diverse fluorescent molecular probes.<br/><br/>This is exemplified in murine brains, transplanted blood vessels and developing murine and chick embryos. Together, the work presented in this thesis advances two complementary strategies for interrogating biological systems in their native three-dimensional context. O-PTIR provides label-free, submicrometer chemical imaging of hydrated living tissues and organisms, while PROTEUS enables reversible optical clearing of intact organs and embryos for three-dimensional fluorescence imaging followed by downstream multimodal analysis. Collectively, these approaches expand the capacity to extract structural, spatial and chemical information from complex biological specimens and provide a foundation for more integrated and physiologically relevant analysis of tissues in development, homeostasis and disease.}},
  author       = {{Gvazava, Nika}},
  isbn         = {{978-91-8021-913-6}},
  issn         = {{1652-8220}},
  keywords     = {{O-PTIR; Precision-Cut Lung Slices; Tissue clearing; Alzeimer's disease; Light-sheet Flourescence Microscopy; Idiopathic pulmonary fibrosis}},
  language     = {{eng}},
  number       = {{2026:115}},
  publisher    = {{Lund University, Faculty of Medicine}},
  school       = {{Lund University}},
  series       = {{Lund University, Faculty of Medicine Doctoral Dissertation Series}},
  title        = {{Spatiotemporal imaging of development, disease and regeneration using advanced light-based techniques}},
  url          = {{https://lup.lub.lu.se/search/files/259189358/Nika_Gvazava_-_WEBB.pdf}},
  volume       = {{2026:115}},
  year         = {{2026}},
}