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Schutt, C. E.

Publications and source records attributed to Schutt, C. E..

2 recordsLinked to original sources

A Linkable, Polycarbonate Gut Microbiome-Distal Tumor Chip Platform for Interrogating Cancer Promoting Mechanisms

Gut microbiome composition has been tied to diseases ranging from arthritis to cancer to depression. However, mechanisms of action are poorly understood, limiting development of relevant therapeutics. Organ-on-chip platforms, which model minimal functional units of tissues and can tightly control communication between them, are ideal platforms to study these relationships. Many gut microbiome models have been published to date but devices are typically fabricated using oxygen permeable PDMS, requiring interventions to support anaerobic bacteria. To address this challenge, a novel platform was developed where the chips were fabricated entirely from gas-impermeable polycarbonate without tapes or gaskets. These chips replicated polarized villus-like structures of the native tissue. Further, they enabled co-cultures of commensal anaerobic bacteria Blautia coccoides on the surface of gut epithelia for two days within a standard incubator. Another complication of PDMS devices is high ad-/absorption, limiting applications in high-resolution microscopy and biomolecule interaction studies. For future communication studies between gut microbiota and distal tumors, an additional polycarbonate chip design was developed to support hydrogel-embedded tissue culture. These chips enable high-resolution microscopy with all relevant processing done on-chip. Designed for facile linking, this platform will make a variety of mechanistic studies possible.

bioengineering↗

Muscle contraction as a Markov Process - II: x-ray interference data (M3 & M6 reflections) imply myosin cross-bridge motions are controlled by structural transitions along actin filaments.

The unit underlying the construction and functioning of muscle fibers is the sarcomere. Tension develops in fibers as thousands of sarcomeres arranged in series contract in unison. Shortening is due to the sliding of actin thin filaments along antiparallel arrays of myosin thick filaments. Remarkably, myosin catalytic heads situated across the center M-line of a sarcomere are separated by a distance that is a half integral of the 14.5 nm spacing between successive layers of myosin heads on the thick filaments. This results in the splitting of the 14.5 nm meridional reflection in X-ray diffraction patterns of muscle fibers. Following a quick drop in tension, changes in the relative intensities of the split meridional peaks provide a sensitive measure of myosin head movements. We use published data obtained with the x-ray interference method to validate a theory of muscle contraction in which cooperative structural transitions along force-generating actin filaments regulate the binding of myosin heads. The probability that an actin-bound myosin head will detach is represented here by a statistical function that yields a length-tension curve consistent with classical descriptions of the recovery of contracting muscle fibers subjected to millisecond drops in tension.

biophysics↗