3 research outputs found
Force-Bioreactor for Assessing Pharmacological Therapies for Mechanobiological Targets
Tissue fibrosis is a major health issue that impacts millions of people and is costly to treat. However, few effective anti-fibrotic treatments are available. Due to their central role in fibrotic tissue deposition, fibroblasts and myofibroblasts are the target of many therapeutic strategies centered primarily on either inducing apoptosis or blocking mechanical or biochemical stimulation that leads to excessive collagen production. Part of the development of these drugs for clinical use involves in vitro prescreening. 2D screens, however, are not ideal for discovering mechanobiologically significant compounds that impact functions like force generation and other cell activities related to tissue remodeling that are highly dependent on the conditions of the microenvironment. Thus, higher fidelity models are needed to better simulate in vivo conditions and relate drug activity to quantifiable functional outcomes. To provide guidance on effective drug dosing strategies for mechanoresponsive drugs, we describe a custom force-bioreactor that uses a fibroblast-seeded fibrin gels as a relatively simple mimic of the provisional matrix of a healing wound. As cells generate traction forces, the volume of the gel reduces, and a calibrated and embedded Nitinol wire deflects in proportion to the generated forces over the course of 6Â days while overhead images of the gel are acquired hourly. This system is a useful in vitro tool for quantifying myofibroblast dose-dependent responses to candidate biomolecules, such as blebbistatin. Administration of 50Â ÎĽM blebbistatin reliably reduced fibroblast force generation approximately 40% and lasted at least 40Â h, which in turn resulted in qualitatively less collagen production as determined via fluorescent labeling of collagen
Development and Evaluation of a Nanometer-Scale Hemocompatible and Antithrombotic Coating Technology Platform for Commercial Intracranial Stents and Flow Diverters
An intracranial aneurysm is a local
dilation of an artery in the
cerebral circulation and can be endovascularly treated with two types
of medical devices known as intracranial stents or flow diverters–both
are metallic devices that help redirect blood from the diseased arterial
segment; yet the placement of intracranial devices in the cerebral
circulation mandates the adjunctive administration of dual antiplatelet
pharmaceuticals to the patient to minimize thromboembolic events,
despite being associated with increased patient risk. We present a
new multilayer, nanometer-scale coating technology platform suitable
for commercial intracranial flow diverters to minimize the use of
dual antiplatelet therapy in the elective setting and expand the use
of intracranial devices in the acute setting of ruptured intracranial
aneurysms. A combination of qualitative and quantitative characterization
techniques including scanning electron microscopy, ellipsometry, confocal
microscopy, X-ray photoelectron spectroscopy, and focused ion beam
milling coupled with scanning electron microscopy were used to assess
the composition, uniformity, and thickness of each coating layer on
commercially available flow diverting devices. Overall, the coating
was found to be relatively uniform, less than 50 nm thick, and conformal
to device microwires. X-ray photoelectron spectroscopy data further
indicates the developed nanoscale coating technology can be modified
for use as a platform for the attachment of human recombinant thrombomodulin,
a naturally occurring glycoprotein with antithrombotic functionality.
The in vitro thrombin generation capacity of commercial intracranial
flow diverters coated with the technology was assessed using the calibrated
automated thrombogram assay; further, platelet and fibrin deposition
on coated commercial flow diverters was assessed ex vivo via a primate
arteriovenous shunt model. The in vitro and ex vivo test results suggest
potential hemocompatible and antithrombotic properties