Biology subjects

Bischof, T. S.

Publications and source records attributed to Bischof, T. S..

3 recordsLinked to original sources

bioRxiv2023

Shortwave infrared (SWIR) fluorescence imaging of peripheral organs in awake and freely moving mice

Extracting biological information from awake and unrestrained mice is imperative to in vivo basic and pre-clinical research. Accordingly, imaging methods which preclude invasiveness, anesthesia, and/or physical restraint enable more physiologically relevant biological data extraction by eliminating these extrinsic confounders. In this article we discuss the recent development of shortwave infrared (SWIR) fluorescent imaging to visualize peripheral organs in freely-behaving mice, as well as propose potential applications of this imaging modality in the neurosciences.

bioengineering↗

bioRxiv2022

Development of a shortwave infrared (SWIR) sinuscope for the detection of cerebrospinal fluid (CSF) leaks

SignificanceCSF rhinorrhea (leakage of brain fluid from the nose) can be difficult to identify and currently requires invasive procedures such as intrathecal fluorescein which requires a lumbar drain placement. Fluorescein is also known to have rare but significant side effects including seizures and death. As the number of endonasal skull base cases increase, the number of CSF leaks have also increased for which an alternative diagnostic method would be highly advantageous to patients. AimTo develop an instrument to identify CSF leaks based on water absorption in the SWIR without the need of intrathecal contrast agents. This device needed to be adapted to the anatomy of the human nasal cavity while maintaining low weight and ergonomic characteristics of current surgical instruments. ApproachAbsorption spectra of CSF and artificial CSF were obtained to characterize the absorption peaks that could be targeted with SWIR light. Different illumination systems were tested and refined prior to adapting them into a portable endoscope for testing in 3D printed models and cadavers for feasibility. ResultsWe identified CSF to have an identical absorption profile as water. In our testing, a narrow band laser source at 1480nm proved superior to using a broad 1450 nm LED. Using a SWIR enabling endoscope set up, we tested the ability to detect artificial CSF in a cadaver model. ConclusionsAn endoscopic system based on SWIR narrow band imaging can provide an alternative in the future to invasive methods of CSF leak detection.

bioengineering↗

bioRxiv2022

Shortwave-Infrared Line-Scan Confocal Microscope for Deep Tissue Imaging in Intact Organs

Imaging at wavelengths beyond the visible spectrum enables imaging depths of hundreds of microns in intact tissue, making this attractive for volumetric imaging applications. The development of fluorophores with photoemission beyond 1000nm provide the opportunity to develop novel fluorescence microscopes sensitive to those wavelengths. Here, we present a shortwave-infrared line-scan confocal microscope that is capable of deep imaging of biological specimens, as demonstrated by visualization of labelled glomeruli in a fixed uncleared kidney at depths beyond 400 m. We also show imaging of brain vasculature labelled with the near-infrared organic dye indocyanine green, the shortwave-infrared organic dye Chrom7, and rare earth-doped nanoparticles, thus encompassing the entire spectrum detectable by a typical shortwave-infrared sensitive InGaAs detector.

bioengineering↗