Biology subjects

Vyas, K.

Publications and source records attributed to Vyas, K..

5 recordsLinked to original sources

bioRxiv2025

MOTUM: a system for Motion Online Tracking Under MRI

Attempts to implement realistic body-environment interactions during functional magnetic resonance imaging (fMRI) experiments have developed expensive, hardly reproducible, and task-specific setups. Here, we introduce MOTUM (Motion Online Tracking Under MRI), a novel system that combines real-time kinematic tracking with immersive virtual reality, enabling participants to perform naturalistic movements inside the scanner. As a proof-of-concept, we tested MOTUM during a reach-to-grasp task with and without visual feedback of ones hand (N = 7). The system achieved high-fidelity motion tracking, induced an intense immersive experience, evoked expected sensorimotor brain activations, and maintained high fMRI data quality. Standard fMRI control metrics were below the critical threshold in 99% of volumes, indicating that participants arm movements had minimal impact on head motion and data quality. While hand movements had little to no effect on brain activity, arm movements resulted in sparse spurious correlations that were easily controlled for. Critically, MOTUM allowed us to extract rich kinematic indices and link them directly to brain activity on a trial-by-trial basis. Parametric modulation analyses revealed that natural variations in movement dynamics significantly influenced neural responses in parietal, frontal, and occipital regions. In sum, MOTUM is a robust method to study motor control and beyond, enabling a new class of fMRI experiments that bridge ecological realism and experimental control, pushing current neuroimaging research towards real-life neuroscience.

neuroscience↗

bioRxiv2024

Engineering Human ARMMs as Therapeutic Non-Viral Vehicles for in vivo Delivery of Genome Editing Payloads

The ability to edit the human genome to treat previously incurable diseases or to modify previously undruggable targets has the potential to transform the lives of patients. However, delivery of genome editing machineries in vivo, and in a transient manner, continues to be a major challenge. We engineered human cell-derived ARRDC1-mediated microvesicles (ARMMs) as non-viral vehicles that mediate intracellular delivery of proteins, including DNA-modifying enzymes such as Cre recombinase and Cas9/guide RNA ribonucleoproteins (RNPs). ARMMs packaged multiple payloads per vesicle in our production system, yielding dose-dependent functional delivery of Cre or Cas9/gRNA RNP to a variety of cell types, including primary mouse and human cells. Oropharyngeal aspiration of ARMMs loaded with Cre led to biodistribution to alveolar macrophages (AMs), whereas intravenous administration predominantly to Kupffer cells (KCs), liver sinusoidal endothelial cells (LSECs), and splenocytes. Suprisingly, one administration of ARMMs loaded with Cas9 RNPs by oropharyngeal aspiration or intravenously resulted in efficient knockout of multiple genes in AMs or KCs, suggesting potential therapeutic utility. Through intravenous administration of ARMMs loaded with Cas9/NLRP3 gRNA we showed amelioration of drug-induced liver injury in a mouse model, supporting the use of ARMMs as human cell-derived therapeutic vehicles for genome editor delivery in vivo.

bioengineering↗

bioRxiv2024

Scalable Production and Purification of Engineered ARRDC1-Mediated Microvesicles in a HEK293 Suspension Cell System

The engineering of human ARRDC1-mediated microvesicles (ARMMs) as new non-viral vehicles for delivery of gene therapies overcomes challenges associated with current modalities. Hurdles such as generating sufficient material to meet demand and development of appropriate characterization assays, however, persist. Our study evaluated two scalable strategies to generate GFP-loaded ARMMs, transient transfection or stable cell line-based production. The upstream ARMMs production processes utilized a suspension HEK293-derived line, termed 5B8, from Lonza. Production was evaluated in shake flasks and bioreactors. Downstream ARMMs purification processes employed Tangential Flow Filtration (TFF) and Anion Exchange Chromatography (AEX). Analytical methods included single particle analysis, ELISA, and immunoblotting. Additionally, an in vivo study was conducted in mice to investigate the half-life and biodistribution of ARMMs administered intravenously. 5B8 cells yielded robust production of ARMMs after transient transfection with the ARMMs loading construct or using a stable cell line containing a transgene that encodes the ARMMs loading cassette, in shake flasks or a stirred tank bioreactor, respectively. Approximately 50% of all vesicles produced were payload-containing ARMMs. ARMMs were purified by ultracentrifugation (small scale) or a combination of TFF and AEX (large scale). Both purification methods produced comparable ARMMs. In vivo, ARMMs showed rapid biodistribution predominantly to the spleen and liver and, to a lesser extent, kidneys, and lungs. The successful scale-up of ARMMs production illustrates the potential of engineered extracellular vesicles (EVs). Furthermore, this study highlights the potential utility of ARMMs for in vivo delivery of therapeutic molecules.

bioengineering↗

bioRxiv2023

Fiberbots: Robotic fibers for high-precision minimally invasive surgery

Technologies that rely on the fundamental principle of thermal expansion have demonstrated high-precision, a growing demand in fields driven by miniaturization. However, scalable production of high aspect ratio devices that harness this capability while facilitating flexibility in design and functionality remains a challenge. We employed the high-throughput fiber thermal drawing technique to readily fabricate multimaterial fiberbots that can precisely and omnidirectionally move by asymmetric thermal expansion. These millimeter-scale fibers (< 2 mm) show excellent repeatability and linearity, negligible hysteresis, and can achieve micron-level resolution over four orders of magnitude motion range. By integrating these robotic fibers with medical devices that can perform cellular-level tissue imaging, diagnosis, and manipulation, we showcase their versatility through benchtop and preclinical animal studies and their overall potential impact on medicine, biomedical engineering, robotics, and beyond. One Sentence SummaryScalable manufacturing and integration of robotic fibers that deliver high-precision motion when heated.

bioengineering↗

bioRxiv2020

Widefield light sheet microscopy using an Airy beam combined with deep-learning super-resolution

Imaging across length scales and in depth has been an important pursuit of widefield optical imaging. This promises to reveal fine cellular detail within a widefield snapshot of a tissue sample. Current advances often sacrifice resolution through selective sub-sampling to provide a wide field of view in a reasonable time scale. We demonstrate a new avenue for recovering high-resolution images from sub-sampled data in light-sheet microscopy using deep-learning super-resolution. We combine this with the use of a widefield Airy beam to achieve high-resolution imaging over extended fields of view and depths. We characterise our method on fluorescent beads as test targets. We then demonstrate improvements in imaging amyloid plaques in a cleared brain from a mouse model of Alzheimers disease, and in excised healthy and cancerous colon and breast tissues. This development can be widely applied in all forms of light sheet microscopy to provide a two-fold increase in the dynamic range of the imaged length scale. It has the potential to provide further insight into neuroscience, developmental biology and histopathology.

biophysics↗