Project Summary
In cardiovascular disease diagnosis, treatment, and monitoring, a plethora of deformable biointerface
devices are utilized. These devices are adept at gauging physiological metrics, administering bioelectrical
modulation, or dispensing therapeutics. Notwithstanding the advent of preclinical biotechnologies like
optogenetics and cell-based biological pacing, non-genetic electronic pacing persists as the predominant
therapeutic approach for cardiac rhythm anomalies. Recently, semiconductors have been identified as promising
instruments for non-genetic cardiovascular investigations. Our team is focusing on designing minimally invasive
photostimulation tools specifically tailored for cardiac pacing applications.
We recently published several photoelectrochemical methods for optically modulating cardiac activity in
cultured cells and adult rodent models ex vivo. Using these methods, we can achieve light-activated modulation
of cardiac tissue with a light intensity comparable to that used in optogenetics. In this current work, Tian, Hibino,
Jia and Aziz will work together to expand and strengthen our newest photostimulation system, porosity-based
silicon heterojunctions, for multi-site, leadless, nongenetic, and optoelectronic modulation of cardiac tissues.
Specifically, our team aims to design, fabricate, and evaluate a range of porosity-based heterojunctions
tailored for optical modulation of cardiac tissues. We will synthesize silicon membranes with non-
porous/nanoporous heterojunctions and three-dimensional surface topographies. To enhance the stability of
these heterojunctions and modulate their longevity under physiological conditions, we will employ atomic layer
deposition to passivate the silicon interfaces. We plan to modify the surface with metal or metal-oxide catalysts
to bolster signal transduction. To support the silicon heterojunctions, we will integrate soft matrices, including
polymers and hydrogels, enhancing both biocompatibility and signal transduction at biointerfaces. Concurrently,
we will produce biocompatible, stretchable optical fibers tailored for in vivo photostimulation. Our team is also
developing a catheter-analogous minimally invasive photostimulation tool. For multi-site optical pacing, we will
engineer and assess the requisite software, mechanical, electrical, and optical subsystems. We will validate the
performance metrics of our random access photostimulation tools, including accuracy, scanning velocity, and
power delivery, followed by ex vivo photostimulation trials. In vivo biocompatibility assessments will be conducted
in a rat model, while we will gauge heart pacing efficacy in acute and chronic scenarios using single-chamber,
dual-chamber, and multi-site stimulations in a pig model. We will test our hypothesis that deformable and
biocompatible heterojunction devices can be used for multi-site cardiac resynchronization therapy. The new
designs for semiconductor-based biointerfaces will allow for minimally-invasive, wireless, nongenetic, multiscale,
and random access photostimulation.
