Cell & tissue imaging core
Enteric nervous system imaging
The enteric nervous system controls secretion, absorption and motor behavior of the gastro-intestinal tract for which accurate communication (synaptic and paracrine) between the different enteric nervous system cell types is necessary. It also interacts with cells of the immune system, is influenced by gut microbiota and dietary factors and is implicated in the gut-brain axis and in (central) neurodegeneration.
Central to understanding it integrated function, is the measurement of cellular activity in their native and intact three-dimensional (3D) environment at high spatial resolution and with sufficient speed to understand the temporal relations between the components involved.
Two-photon excitation
Two-photon excitation microscopy allows us to structurally and functionally image the different layers of the enteric nervous system through the entire thickness of the gut wall
Photons are absorbed by a fluorophore in a single quantum event. Each of the photons carries half the energy to excite a molecule and has thus double the wavelength. Less energetic photons are less phototoxic.
Since the photons are red-shifted, less scatter occurs and we are able to penetrate deeper into tissues. The probability of 2-photon excitation is proportional to the photon flux and therefore it requires a sufficient concentration of photons in space and time. This means that there is virtually no out of focus absorption, strongly suppressing background signal.
Second harmonic imaging
We offer a unique setup to detect four non-descanned channels simultaneously with a single excitation wavelength
Second harmonic generation, also called frequency doubling, is a label-free, non-linear optical process in which two high intensity photons are scattered as one photon with double the frequency. Since no absorption of photons takes place, second harmonic photons are coherent, which can cause them to interfere constructively or destructively under certain conditions. For second harmonics to occur, the photons need to pass through a nonlinear material lacking inversion symmetry and with a sufficiently high hyper polarizability. Only certain biomolecules fulfil these requirements such as collagen, myosin and microtubules, allowing us to extract additional contextual structural information not only from the enteric nervous system but also other tissues.
The experts
The Cell and Tissue Imaging Core (CIC) is a KU Leuven core facility that brings together scientists from a wide range of disciplines who use microscopy techniques to answer biological and biomedical questions. The CIC provides access to cutting-edge optical technologies, integrates and improves the expertise in fluorescence imaging and offers experience related to live imaging. The CIC integrates live fluorescence imaging with 2 photon excitation microscopy and second harmonic generation to provide multiplexed, real-time structural and physiological information on the enteric nervous system and other samples such as cells, organelles, tissues, organs and animals.
