Combined Optical Coherence and Fluorescence Microscopy to assess dynamics and specificity of pancreatic beta-cell tracers.

By | May 17, 2020

The identification of a beta-cell tracer is a serious quest in diabetes analysis. However, since MRI, PET and SPECT can’t resolve particular person islets, optical methods are required to assess the specificity of these tracers.

We suggest to mix Optical Coherence Microscopy (OCM) with fluorescence detection in a single optical platform to facilitate these preliminary screening steps from cell tradition up to residing rodents.

OCM can picture islets and vascularization with none labeling. Thereby, it alleviates the necessity of each genetically modified mice to detect islets and injection of exterior dye to reveal vascularization.

We characterised Cy5.5-exendin-3, an agonist of glucagon-like peptide 1 receptor (GLP1R), for which different imaging modalities have been used and can function a reference.

Cultured cells transfected with GLP1R and incubated with Cy5.5-exendin-Three present full tracer internalization. We decided {that a} dose of 1 μg of Cy5.5-exendin-Three is adequate to optically detect in vivo the tracer in islets with a excessive specificity.

In a subsequent step, time-lapse OCM imaging was used to monitor the fast and particular tracer accumulation in murine islets and its persistence over hours. This optical platform represents a flexible toolbox for choosing beta-cell particular markers for diabetes analysis and future medical prognosis.

Miniature probe integrating optical-resolution photoacoustic microscopy, optical coherence tomography, and ultrasound imaging: proof-of-concept.

In this Letter, we current a novel tri-modal miniature side-view probe, via which optical-resolution photoacoustic microscopy (OR-PAM), optical coherence tomography (OCT), and pulse-echo ultrasound (US) pictures may be coaxially acquired and displayed concurrently.

The probe consists of a typical optical path for OR-PAM (gentle supply) and OCT (gentle supply/detection), and a 40-MHz unfocused ultrasound transducer for OR-PAM (photoacoustic detection) and US (ultrasound transmission/receiving) with an total diameter of 2 mm.

Combining OR-PAM, OCT, and US would supply complementary info together with optical absorption (OR-PAM), optical back-scattering (OCT), and deep tissue constructions (US) about organic tissue.

Based on an built-in imaging system consisting of OR-PAM, time-domain OCT, and US, phantom pictures and in vivo pictures of rat ear had been acquired to exhibit the capabilities of the built-in tri-modality imaging probe. The probe yields a lateral decision of 13.6 μm for OR-PAM and OCT, and an axial decision of 43 μm for OR-PAM and US. Currently, for a scanning space of 1 ×1 mm, it took ∼25 min to purchase knowledge for tri-modal volumetric imaging.