Biology subjects

Gentsch, G. J.

Publications and source records attributed to Gentsch, G. J..

3 recordsLinked to original sources

bioRxiv2026

UV photogrammetry for transparent and composite surfaces

Transparent and composite surfaces pose a fundamental challenge for stereo photogrammetry: optically smooth glass produces no detectable surface features under visible illumination, making three-dimensional reconstruction impossible without surface preparation. This excludes optical components such as lenses and cover glasses, composite assemblies, and semi-translucent biological specimens from non-contact geometric measurement. Here we show that coherent speckle illumination at 266 nm overcomes this limitation by exploiting wavelength-dependent scatter enhancement, generating sufficient backscattered signal on surfaces that are entirely invisible under visible illumination. We developed a multispectral stereo system and evaluated three illumination modalities under identical acquisition conditions. On transparent glass, both visible modalities produce complete reconstruction failure, recovering only non-transparent holder structures. Ultraviolet speckle illumination at 266 nm enables dense reconstruction of the same surfaces. We demonstrate recovery of an uncoated plano-convex lens with a fitted radius of 30.946 mm and point-cloud standard deviation of 106.5 {micro}m, defect detection on a transparent cover glass without surface preparation, and reconstruction of a semi-translucent biological specimen. On metrology-grade reference objects, ultraviolet speckle achieves a standard deviation of 116 {micro}m and completeness exceeding 93%, approaching the performance of optimised visible structured illumination. These results establish ultraviolet speckle photogrammetry as an enabling approach of optical metrology to otherwise uncooperative surfaces, with relevance to optical manufacturing inspection and biological surface analysis.

biophysics↗

bioRxiv2025

NanTex enables computational multiplexing and phenotyping of organelles across super-resolution modalities

Super-resolution microscopy (SRM) enables nanoscale visualization of cellular organelles but remains constrained by spectral overlap, labeling requirements, and temporal offsets in multicolor imaging. We present NanTex, a deep learning framework that introduces nanotexture as a universal descriptor of subcellular organization and achieves probabilistic demixing of multiple organelles from single-channel SRM images. Unlike segmentation methods that enforce exclusivity, NanTex preserves overlapping morphologies, enabling faithful reconstruction even in crowded regions. Trained on small curated datasets with augmentation, NanTex generalized across SMLM, MINFLUX, STED, SIM, and live-cell Airyscan, with modality-specific retraining where necessary. Demonstrated on cytoskeletal, endomembrane, and metabolic organelles, NanTex achieved high-fidelity reconstructions and extended uniquely to live-cell imaging, where it eliminated temporal misalignment and enabled quantitative tracking of vesicle-like ER subdomains. Notably, NanTex enables quantitative dynamic readouts directly from single-channel live-cell data, revealing and tracking hidden subdomains in real time without the need for additional labels. Beyond multiplexing, NanTex supported computational phenotyping by distinguishing structurally distinct yet molecularly identical populations, exemplified by nocodazole-induced microtubule depolymerization and its glyoxal-mediated modulation. Together, these results establish nanotexture as a paradigm-shifting descriptor for organelle identity and position NanTex as a modality-agnostic, label-efficient, and live-cell-ready strategy for quantitative nanoscale biology. Significance StatementNanTex reframes multiplexing as texture-based demixing, introducing nanotexture as a universal fingerprint of organelle identity. By enabling quantitative, label-efficient reconstructions across SRM modalities and live-cell phenotyping, including vesicle tracking from single-channel data, NanTex opens a path to studying organelle remodeling and disease progression with unprecedented fidelity across SRM modalities.

biophysics↗

bioRxiv2025

Applying telecentric stereo 3D-measurement to small Lepidopterans - bridging the macro and the microscale with isotropic micrometer resolution

We present a straightforward, application-driven telecentric stereo 3D-measurement system for high-precision measurements, designed for applications ranging from industrial quality control to biological research including scanning of Lepidoptera moths. Utilizing a dual-camera setup with telecentric lenses and structured illumination, our system achieves lateral resolution of 8.0 m and axial resolution of 4.46 m in a measurement volume of 11 mm x 11 mm x 6 mm. We address challenges typically encountered when using standard libraries like OpenCV, e.g. in extrinsic parameter estimation using a dedicated calibration method that corrects for a potential model mismatch due to telecentricity. Our approach adapts existing methods, such as telecentric stereo vision and structured illumination, into an optimized, user-friendly system tailored for life science research, enabling detailed 3D reconstructions of scattering objects, such as small moths, with isotropic micrometer accuracy. This work presents an application-driven approach for biological 3D metrology by integrating existing technologies (telecentric stereo vision, structured illumination) into a specialized imaging platform suitable for non-invasive morphological studies. Unlike conventional CT or microscopic approaches, our method provides a balance of precision, scalability, and practical usability for non-expert users with the aim to study developmental changes in species under varying environmental conditions, while also methodically bridging the gap between macroscopic and microscopic resolution in biological imaging.

biophysics↗