A5052909220- Neuroscience and Neural Engineering
- Pluripotent Stem Cells Research
- Cardiac electrophysiology and arrhythmias
- Congenital heart defects research
- Tissue Engineering and Regenerative Medicine
- Cardiomyopathy and Myosin Studies
- Cardiac pacing and defibrillation studies
- Ion channel regulation and function
- CRISPR and Genetic Engineering
- 3D Printing in Biomedical Research
- Viral Infections and Immunology Research
- CCD and CMOS Imaging Sensors
- Microfluidic and Bio-sensing Technologies
- Mitochondrial Function and Pathology
- Advanced Memory and Neural Computing
- Cardiac Arrhythmias and Treatments
- ECG Monitoring and Analysis
- Electrochemical Analysis and Applications
- Electrospun Nanofibers in Biomedical Applications
- Cellular Mechanics and Interactions
- Cardiac Fibrosis and Remodeling
- Cardiac Ischemia and Reperfusion
- Cardiac Valve Diseases and Treatments
- Virus-based gene therapy research
- Analytical Chemistry and Sensors
Johns Hopkins University
2004-2025
Johns Hopkins Medicine
2006-2025
Johns Hopkins Children's Center
2022-2025
Emory University
2015-2024
Children's Healthcare of Atlanta
2016-2024
Georgia Institute of Technology
2016-2023
The Wallace H. Coulter Department of Biomedical Engineering
2016-2023
Emory and Henry College
2018-2019
AID Atlanta
2018
Cedars-Sinai Medical Center
2010-2016
Background— Ex vivo expansion of resident cardiac stem cells, followed by delivery to the heart, may favor regeneration and functional improvement. Methods Results— Percutaneous endomyocardial biopsy specimens grown in primary culture developed multicellular clusters known as cardiospheres, which were plated yield cardiosphere-derived cells (CDCs). CDCs from human comparable porcine samples examined vitro for biophysical cytochemical evidence cardiogenic differentiation. In addition,...
Background— Human embryonic stem cells (hESCs) derived from blastocysts can propagate indefinitely in culture while maintaining pluripotency, including the ability to differentiate into cardiomyocytes (CMs); therefore, hESCs may provide an unlimited source of human CMs for cell-based therapies. Although be ex vivo, it remains uncertain whether a functional syncytium formed between donor and recipient after engraftment. Methods Results— Using combination electrophysiological imaging...
TBX18 gene therapy reprogrammed cardiomyocytes to become pacemaker cells in a pig model of heart block.
Commercially available health monitors rely on rigid electronic housing coupled with aggressive adhesives and conductive gels, causing discomfort inducing skin damage. Also, research-level skin-wearable devices, while excelling in some aspects, fall short as concept-only presentations due to the fundamental challenges of active wireless communication integration a single device platform. Here, an all-in-one, wireless, stretchable hybrid electronics key capabilities for real-time...
When pluripotency factors are removed, embryonic stem cells (ESCs) undergo spontaneous differentiation, which, among other lineages, also gives rise to cardiac sublineages, including chamber cardiomyocytes and pacemaker cells. Such heterogeneity complicates the use of ESC-derived heart in therapeutic diagnostic applications. We sought direct ESCs differentiate specifically into by overexpressing a transcription factor critical for patterning native (the sinoatrial node). Overexpression SHOX2...
Efficient generation of cardiomyocytes from human pluripotent stem cells is critical for their regenerative applications. Microgravity and 3D culture can profoundly modulate cell proliferation survival. Here, we engineered microscale progenitor cardiac spheres exposed the to simulated microgravity using a random positioning machine 3 days during differentiation cardiomyocytes. This process resulted in production highly enriched (99% purity) with high viability (90%) expected functional...
The cardiac action potential (AP) is vital for understanding healthy and diseased biology drug safety testing. However, techniques high throughput AP measurements have been limited. Here, we introduce a novel technique reliably increasing the coupling of cardiomyocyte syncytium to planar multiwell microelectrode arrays, resulting in stable, label-free local extracellular (LEAP). We characterized reliability stability LEAP, its relationship field potential, efficacy quantifying morphology...
Abstract Cardiac differentiation of embryonic stem cells (ESCs) can give rise to de novo chamber cardiomyocytes and nodal pacemaker cells. Compared with our understanding direct toward atrial ventricular myocytes, the mechanisms for cell commitment are not well understood. Taking a cue from prominence canonical Wnt signaling during cardiac tissue development in chick embryos, we asked if modulations influence progenitors bifurcate either or Omitting an exogenous inhibitor, which is routinely...
Abstract Cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) possess tremendous potential for basic research and translational application. However, these structurally functionally resemble fetal cardiomyocytes, which is a major limitation of cells. Microgravity can significantly alter cell behavior function. Here we investigated the effect simulated microgravity on hiPSC-CM maturation. Following culture under in random positioning machine 7 days, 3D hiPSC-CMs had...
Cardiosphere-derived cells (CDCs) effect therapeutic regeneration after myocardial infarction (MI) both in animal models and humans. Here, we test the hypothesis that cell-cell contact plays a role mediating observed benefits of CDCs, above beyond conventional paracrine effects. Human CDCs or vehicle were injected into immunodeficient (SCID) mouse hearts during acute MI. CDC transplantation augmented proportion cycling (Ki67(+) ) cardiomyocytes improved ventricular function. CDC-conditioned...
Cardiac inward rectifier K+ currents (IK1) play an important role in maintaining resting membrane potential and contribute to late phase repolarization. Members of the Kir2.x channel family appear encode for IK1. The purpose this study was determine molecular composition cardiac IK1 rabbit ventricle. Western blots revealed that Kir2.1 Kir2.2, but not Kir2.3, are expressed Culturing myocytes resulted approximately 50% reduction density after 48 or 72 h culture which associated with 80%...
As an alternative to electronic pacemakers, we explored the feasibility of converting ventricular myocytes into pacemakers by somatic cell fusion. The idea is create chemically induced fusion between and syngeneic fibroblasts engineered express HCN1 pacemaker channels (HCN1-fibroblasts). HCN1-fibroblasts were fused with freshly isolated guinea pig using polyethylene-glycol 1500. In vivo myocyte-HCN1-fibroblast cells exhibited spontaneously oscillating action potentials; firing frequency...
This paper presents a fully integrated CMOS multimodality joint sensor/stimulator array with 1024 pixels for real-time holistic cellular characterization and drug screening. The proposed system consists of four pixel groups parallel signal-conditioning blocks. Every group contains 16 × pixels, each includes one 28 μm gold-plated electrode, 12 photodiodes, in-pixel circuits, within 58 footprint. Each supports realtime extracellular potential recording, optical detection, chargebalanced...
Calcium cycling figures prominently in excitation-contraction coupling and various signaling cascades involved the development of left ventricular hypertrophy. We hypothesized that genetic suppression L-type calcium channel accessory beta-subunit would modulate current suppress cardiac A short hairpin RNA template sequence capable mediating knockdown gene was incorporated into a lentiviral vector (PPT.CG.H1.beta(2)). Transduction myocytes vivo with active partially inhibited current. In...
The paper presents a 256-pixel CMOS sensor array with in-pixel dual electrochemical and impedance detection modalities for rapid, multi-dimensional characterization of exoelectrogens. IC has 16 parallel readout channels, allowing it to perform multiple measurements high throughput enable the chip handle different samples simultaneously. contains total 2 × 256 working electrodes size 44 μm 52 μm, along reference dimensions 56 399 32 counter 106 which together facilitate resolution screening...
The adenovirus-mediated somatic transfer of the embryonic T-box transcription factor 18 (TBX18) gene can convert chamber cardiomyocytes into induced pacemaker cells. However, translation therapeutic TBX18-induced cardiac pacing faces safety challenges. Here we show that myocardial expression synthetic TBX18 mRNA in animals generates de novo and limits innate inflammatory immune responses. In rats, intramyocardially injected remained localized, whereas direct injection an adenovirus carrying...
Volume regulatory Cl- channels are key regulators of ischemic preconditioning (IPC). Because efflux must be balanced by an cations to maintain cell membrane electroneutrality during volume regulation, we hypothesize that I(K1) may play a role in IPC. We subjected cultured cardiomyocytes 60-minute simulated ischemia (SI) followed reperfusion (SR) and assessed percent death using trypan blue staining. Ischemic (10-minute SI/10-minute SR) significantly (P<0.0001) reduced the nontransfected...
One key element of natural pacemakers is the pacemaker current encoded by hyperpolarization-activated nucleotide-gated channel (HCN) gene family. Although HCN transfer has been used to engineer biological pacemakers, this strategy may be confounded unpredictable consequences heteromultimerization with endogenous family members and limited flexibility regard frequency tuning engineered pacemaker.To circumvent these limitations, we converted a depolarization-activated potassium-selective...