Biomechanics & Medical Devices

Eukaryotic parasites have evolved striking biomechanical and morphogenetic abilities that (1) enable successful infection of billions of human bodies and (2) present an exciting frontier for mechanobiology. My work focuses on key mechanical processes in the lives of parasites: motility, penetration of host tissue, and organismal shape change. This talk will focus on gliding motility, the unique form of cell locomotion used during host infection by unicellular apicomplexan parasites like Toxoplasma gondii and the Plasmodium species that cause malaria.

In the first part of my talk, I will present our ongoing efforts to enhance T cell migration within tumors. While significant advances have been made in understanding the amoeboid-mesenchymal migratory balance, the mechanical processes by which T cells navigate tumor environments and the factors that determine their migration capabilities are still not well understood. To investigate this, we have developed a biophysical model of T cell migration that sheds light on the physical principles and molecular components modulating their movement [1].

While pathogenic microbes are associated with poor health outcomes in orthopaedic surgery, recent findings have suggested that commensal gut microbes may be beneficial in promoting bone health. Novel biomaterial strategies to combat pathogenic microbes in periprosthetic joint infection will first be presented. To locally treat orthopaedic infections, antibiotics are incorporated into poly(methyl methacrylate) (PMMA) bone cement. However, this strategy results in insufficient elution of drug to treat chronic infections and few antibiotics are compatible.

Fibrous elastic networks occur ubiquitously in biological materials ranging from the subcellular cytoskeleton to the extracellular matrix. Due to their disordered structure and the propensity of slender fibers to bend and buckle,  these biomaterials exhibit unique mechanical properties such as elastic nonlinearity and rigidity transitions, and long-range but heterogeneous force transmission. These  properties emerge from the collective response of individual fibers to external stress as well as to intrinsic active stresses created by contractile cells.

Eukaryotic cells contain a variety of complex architectures that modulate the transport, distribution, and delivery of molecular components.

            Dr. Jahed is an assistant professor of Nanoengineering, and an affiliate professor of Bioengineering at the University of California San Diego.

Mechanotransduction – the process of converting mechanical forces into immediate biochemical changes or distal changes in cell fate – is now an appreciated facet of biology.

In the dynamic environments of tissues, mechanical forces play a crucial role in shaping cell behavior and function. Our research aims to decode and control the mechanisms by which cells perceive, store, and respond to these mechanical cues, a process known as mechanotransduction. By integrating experiment with multiscale computational modeling, we are developing a predictive understanding of how cells and their surrounding extracellular matrix interact and adapt recursively to mechanical stimuli.

            Biogenic composite materials such as bone exhibit a combination of properties exceeding that of their constituents, a feat generally credited to their hierarchal structure, down to the nanoscale. Bone is complex tissue with nanoscale mineralized collagen fibrils as mechanical building blocks. Because of the inherent nanometer scale, we have a limited knowledge of time-dependent and small-scale bone response to physiological loading.

            Inflammation and fibrosis are conserved phases of wound healing in the heart, skin, and other organs. Yet therapeutic attempts at manipulating inflammation and fibrosis have had limited success. In this talk, I will present our computational and experimental systems biology research on cardiac inflammation and fibrosis.