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Biology subjects

Joy, M. S. H.

Publications and source records attributed to Joy, M. S. H..

3 recordsLinked to original sources

Biomechanical 3D tumor models on a micro-milled high-throughput force sensor array

The tumor microenvironment plays a critical role in drug resistance, with extracellular matrix (ECM) mechanics, cell-cell crosstalk, and transport barriers contributing to poor therapeutic outcomes. Traditional two-dimensional (2D) cultures fail to capture these features, and drug efficacy in 2D often does not translate to three-dimensional (3D) models or in vivo tumors. Here, we introduce a 3D tumor model integrated with a high- throughput biomechanical sensor array that enables simultaneous measurement of cellular forces, matrix remodeling, and molecular transport. Fabricated using a scalable and cost-effective micro-milling approach, the platform allows parallel generation of multiple tumor constructs within a single dish. Using patient-derived pancreatic ductal adenocarcinoma (PDA) cells and stromal fibroblasts, we show that responses to gemcitabine and all-trans retinoic acid (ATRA) in 3D differ markedly from 2D cultures, consistent with clinical observations. By integrating biochemical and biomechanical readouts, this technology provides a more physiologically relevant tumor model and a powerful tool for preclinical drug testing and personalized medicine.

cancer biology↗

Synapses without tension fail to fire in an in vitro network of hippocampal neurons.

Neurons in the brain communicate with each other at their synapses. It has long been understood that this communication occurs through biochemical processes. Here, we reveal a previously unrecognized paradigm wherein mechanical tension in neurons is essential for communication. Using in vitro rat hippocampal neurons, we find that (1) neurons become tout/tensed after forming synapses resulting in a contractile neural network, and (2) without this contractility, neurons fail to fire. To measure time evolution of network contractility in 3D (not 2D) extracellular matrix, we developed an ultra-sensitive force sensor with 1 nN resolution. We employed Multi-Electrode Array (MEA) and iGluSnFR, a glutamate sensor, to quantify neuronal firing at the network and at the single synapse scale, respectively. When neuron contractility is relaxed, both techniques show significantly reduced firing. Firing resumes when contractility is restored. Neural contractility may play a crucial role in memory, learning, cognition, and various neuropathologies.

neuroscience↗

A novel method for sensor-based quantification of single/multi-cellular traction dynamics and remodeling in 3D matrices

Cells in vivo generate mechanical forces (traction) on surrounding 3D extra cellular matrix (ECM) and cells. Such traction and biochemical cues may remodel the matrix, e.g. increase stiffness, which in turn influences cell functions and forces. This dynamic reciprocity mediates development and tumorigenesis. Currently, there is no method available to directly quantify single cell traction and matrix remodeling in 3D. Here, we introduce a method to fulfil this long-standing need. We developed a high-resolution microfabricated sensor which hosts a 3D cell-ECM tissue formed by self-assembly. It measures cell forces and tissue-stiffness and can apply mechanical stimulation to the tissue. We measured single and multicellular force dynamics of fibroblasts (3T3), human colon (FET) and lung (A549) cancer cells and cancer associated fibroblasts (CAF05) with 1 nN resolution. Single cells show significant force fluctuations in 3D. FET/CAF co-culture system, mimicking cancer tumor microenvironment, increased tissue stiffness by 3 times within 24 hours.

bioengineering↗