Name: Bidirectional Electrical and Optoelectronic Interfaces in Healthy and Ischemic Ex Vivo Rat Hearts (Video) | JoVE Journal
Uploaded: 2025-07-18T13:20:00.000+00:00
Duration: 8 min 33 s
Description: Discover bidirectional electrical and optoelectronic interfaces in ex vivo rat hearts using nanoporous carbon electrodes and optical stimulation. This protocol enables precise cardiac pacing, recording, and ischemia reperfusion modeling for bioelectronics research.

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This study was financially supported by the National Institute of Health through grant 1R56EB034289-01 and 1R01EB036091-01, and the US Army Research Office through grant W911NF-24-1-0053. P. L. is grateful for the support bestowed by the Grier Prize in Biophysical Sciences Innovation.

<ol><li>Sunwoo, S. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Soft+bioelectronics+for+the+management+of+cardiovascular+diseases%5BTitle%5D)+AND+%22Nat+Rev+Bioeng%22%5BJournal%5D)">Soft bioelectronics for the management of cardiovascular diseases.</a> Nat Rev Bioeng. 2 (1), 8-24 (2024).</li>
<li>Choi, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Adhesive+bioelectronics+for+sutureless+epicardial+interfacing%5BTitle%5D)+AND+%22Nat+Elect%22%5BJournal%5D)">Adhesive bioelectronics for sutureless epicardial interfacing.</a> Nat Elect. 6 (10), 779-789 (2023).</li>
<li>Choi, Y. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Fully+implantable+and+bioresorbable+cardiac+pacemakers+without+leads+or+batteries%5BTitle%5D)+AND+%22Nat+Biotech%22%5BJournal%5D)">Fully implantable and bioresorbable cardiac pacemakers without leads or batteries.</a> Nat Biotech. 39 (10), 1228-1238 (2021).</li>
<li>Cingolani, E., Goldhaber, J. I., Marbán, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Next-generation+pacemakers%3A+from+small+devices+to+biological+pacemakers%5BTitle%5D)+AND+%22Nat+Rev+Cardiol%22%5BJournal%5D)">Next-generation pacemakers: from small devices to biological pacemakers.</a> Nat Rev Cardiol. 15 (3), 139-150 (2018).</li>
<li>Sala, L., Ward-van Oostwaard, D., Tertoolen, L. G. J., Mummery, C. L., Bellin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Electrophysiological+Analysis+of+human+Pluripotent+Stem+Cell-derived+Cardiomyocytes+%28hPSC-CMs%29+Using+Multi-electrode+Arrays+%28MEAs%29%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Electrophysiological Analysis of human Pluripotent Stem Cell-derived Cardiomyocytes (hPSC-CMs) Using Multi-electrode Arrays (MEAs).</a> J Vis Exp. (123), e55587(2017).</li>
<li>Fiegle, D. J., Volk, T., Seidel, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Isolation+of+Human+Ventricular+Cardiomyocytes+from+Vibratome-Cut+Myocardial+Slices%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Isolation of Human Ventricular Cardiomyocytes from Vibratome-Cut Myocardial Slices.</a> J Vis Exp. (159), e61167(2020).</li>
<li>Alam, P., Maliken, B. D., Ivey, M. J., Jones, S. M., Kanisicak, O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Isolation%2C+Transfection%2C+and+Long-Term+Culture+of+Adult+Mouse+and+Rat+Cardiomyocytes%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Isolation, Transfection, and Long-Term Culture of Adult Mouse and Rat Cardiomyocytes.</a> J Vis Exp. (164), e61073(2020).</li>
<li>Nippert, F., Schreckenberg, R., Schlüter, K. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Isolation+and+Cultivation+of+Adult+Rat+Cardiomyocytes%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Isolation and Cultivation of Adult Rat Cardiomyocytes.</a> J Vis Exp. (128), e56634(2017).</li>
<li>Trayanova, N. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Whole-Heart+Modeling%3A+Applications+to+Cardiac+Electrophysiology+and+Electromechanics%5BTitle%5D)+AND+%22Circ+Res%22%5BJournal%5D)">Whole-Heart Modeling: Applications to Cardiac Electrophysiology and Electromechanics.</a> Circ Res. 108 (1), 113-128 (2011).</li>
<li>Yin, R. T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Open+thoracic+surgical+implantation+of+cardiac+pacemakers+in+rats%5BTitle%5D)+AND+%22Nat+Protoc%22%5BJournal%5D)">Open thoracic surgical implantation of cardiac pacemakers in rats.</a> Nat Protoc. 18 (2), 374-395 (2023).</li>
<li>Wu, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Modifications+of+the+Langendorff+Method+for+Simultaneous+Isolation+of+Atrial+and+Ventricular+Myocytes+from+Adult+Mice%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Modifications of the Langendorff Method for Simultaneous Isolation of Atrial and Ventricular Myocytes from Adult Mice.</a> J Vis Exp. (171), e62514(2021).</li>
<li>Pendexter, C. A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Modified+Langendorff+Perfusion+for+Extended+Perfusion+Times+of+Rodent+Cardiac+Grafts%5BTitle%5D)+AND+%22J+Vis+Exp%22%5BJournal%5D)">Modified Langendorff Perfusion for Extended Perfusion Times of Rodent Cardiac Grafts.</a> J Vis Exp. (208), e66815(2024).</li>
<li>Kałużna, E., Nadel, A., Zimna, A., Rozwadowska, N., Kolanowski, T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Modeling+the+human+heart+ex+vivo-current+possibilities+and+strive+for+future+applications%5BTitle%5D)+AND+%22J+Tissue+Eng+Regenerat+Med%22%5BJournal%5D)">Modeling the human heart ex vivo-current possibilities and strive for future applications.</a> J Tissue Eng Regenerat Med. 16 (10), 853-874 (2022).</li>
<li>Jiang, Y. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Topological+supramolecular+network+enabled+high-conductivity%2C+stretchable+organic+bioelectronics%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Topological supramolecular network enabled high-conductivity, stretchable organic bioelectronics.</a> Science. 375 (6587), 1411-1417 (2022).</li>
<li>Driscoll, N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((MXene-infused+bioelectronic+interfaces+for+multiscale+electrophysiology+and+stimulation%5BTitle%5D)+AND+%22Sci+Transl+Med%22%5BJournal%5D)">MXene-infused bioelectronic interfaces for multiscale electrophysiology and stimulation.</a> Sci Transl Med. 13 (612), eabf8629(2021).</li>
<li>Gablech, I., Głowacki, E. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((State-of-the-Art+Electronic+Materials+for+Thin+Films+in+Bioelectronics%5BTitle%5D)+AND+%22Adv+Elect+Mater%22%5BJournal%5D)">State-of-the-Art Electronic Materials for Thin Films in Bioelectronics.</a> Adv Elect Mater. 9 (8), 2300258(2023).</li>
<li>Cho, Y. H., Park, Y., Kim, S., Park, J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((3D+Electrodes+for+Bioelectronics%5BTitle%5D)+AND+%22Adv+Mater%22%5BJournal%5D)">3D Electrodes for Bioelectronics.</a> Adv Mater. 33 (47), 2005805(2021).</li>
<li>Chen, Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((bioresorbable%2C+transparent+microelectrode+arrays+for+multimodal+spatiotemporal+mapping+and+modulation+of+cardiac+physiology%5BTitle%5D)+AND+%22Sci+Adv%22%5BJournal%5D)">bioresorbable, transparent microelectrode arrays for multimodal spatiotemporal mapping and modulation of cardiac physiology.</a> Sci Adv. 9 (27), eadi0757(2023).</li>
<li>Jiang, Y. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Rational+design+of+silicon+structures+for+optically+controlled+multiscale+biointerfaces%5BTitle%5D)+AND+%22Nat+Biomed+Eng%22%5BJournal%5D)">Rational design of silicon structures for optically controlled multiscale biointerfaces.</a> Nat Biomed Eng. 2 (7), 508-521 (2018).</li>
<li>Prominski, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Porosity-based+heterojunctions+enable+leadless+optoelectronic+modulation+of+tissues%5BTitle%5D)+AND+%22Nat+Mater%22%5BJournal%5D)">Porosity-based heterojunctions enable leadless optoelectronic modulation of tissues.</a> Nat Mater. 21 (6), 647-655 (2022).</li>
<li>Huang, Y. X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Bioresorbable+thin-film+silicon+diodes+for+the+optoelectronic+excitation+and+inhibition+of+neural+activities%5BTitle%5D)+AND+%22Nat+Biomed+Eng%22%5BJournal%5D)">Bioresorbable thin-film silicon diodes for the optoelectronic excitation and inhibition of neural activities.</a> Nat Biomed Eng. 7 (4), 486-498 (2023).</li>
<li>Balamur, R., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Capacitive+and+Efficient+Near-Infrared+Stimulation+of+Neurons+via+an+Ultrathin+AgBiS2+Nanocrystal+Layer%5BTitle%5D)+AND+%22ACS+Appl+Mater+Inter%22%5BJournal%5D)">Capacitive and Efficient Near-Infrared Stimulation of Neurons via an Ultrathin AgBiS2 Nanocrystal Layer.</a> ACS Appl Mater Inter. 16 (23), 29610-29620 (2024).</li>
<li>Karatum, O., Kaleli, H. N., Eren, G. O., Sahin, A., Nizamoglu, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Electrical+Stimulation+of+Neurons+with+Quantum+Dots+via+Near-Infrared+Light%5BTitle%5D)+AND+%22ACS+Nano%22%5BJournal%5D)">Electrical Stimulation of Neurons with Quantum Dots via Near-Infrared Light.</a> ACS Nano. 16 (5), 8233-8243 (2022).</li>
<li>Han, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Photovoltaic+neurointerface+based+on+aluminum+antimonide+nanocrystals%5BTitle%5D)+AND+%22Comm+Mater%22%5BJournal%5D)">Photovoltaic neurointerface based on aluminum antimonide nanocrystals.</a> Comm Mater. 2 (1), (2021).</li>
<li>Ejneby, M. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Chronic+electrical+stimulation+of+peripheral+nerves+via+deep-red+light+transduced+by+an+implanted+organic+photocapacitor%5BTitle%5D)+AND+%22Nat+Biomed+Eng%22%5BJournal%5D)">Chronic electrical stimulation of peripheral nerves via deep-red light transduced by an implanted organic photocapacitor.</a> Nat Biomed Eng. 6 (6), 741-753 (2022).</li>
<li>Li, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Monolithic+silicon+for+high+spatiotemporal+translational+photostimulation%5BTitle%5D)+AND+%22Nature%22%5BJournal%5D)">Monolithic silicon for high spatiotemporal translational photostimulation.</a> Nature. 626 (8001), 990-998 (2024).</li>
<li>Yang, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+bioinspired+permeable+junction+approach+for+sustainable+device+microfabrication%5BTitle%5D)+AND+%22Nat+Sustain%22%5BJournal%5D)">A bioinspired permeable junction approach for sustainable device microfabrication.</a> Nat Sustain. 7 (9), 1190-1203 (2024).</li>
<li>Shi, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Monolithic-to-focal+evolving+biointerfaces+in+tissue+regeneration+and+bioelectronics%5BTitle%5D)+AND+%22Nat+Chem+Eng%22%5BJournal%5D)">Monolithic-to-focal evolving biointerfaces in tissue regeneration and bioelectronics.</a> Nat Chem Eng. 1 (1), 73-86 (2024).</li>
<li>Shi, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Active+biointegrated+living+electronics+for+managing+inflammation%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">Active biointegrated living electronics for managing inflammation.</a> Science. 384 (6699), 1023-1030 (2024).</li>
<li>Zhang, L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Marangoni+Effect-Driven+Motion+of+Miniature+Robots+and+Generation+of+Electricity+on+Water%5BTitle%5D)+AND+%22Langmuir%22%5BJournal%5D)">Marangoni Effect-Driven Motion of Miniature Robots and Generation of Electricity on Water.</a> Langmuir. 33 (44), 12609-12615 (2017).</li>
<li>Cogan, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Neural+Stimulation+and+Recording+Electrodes%5BTitle%5D)+AND+%22Ann+Rev+Biomed+Eng%22%5BJournal%5D)">Neural Stimulation and Recording Electrodes.</a> Ann Rev Biomed Eng. 10 (1), 275-309 (2008).</li>
<li>Nussinovitch, U., Gepstein, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Optogenetics+for+in+vivo+cardiac+pacing+and+resynchronization+therapies%5BTitle%5D)+AND+%22Nat+Biotechnol%22%5BJournal%5D)">Optogenetics for in vivo cardiac pacing and resynchronization therapies.</a> Nat Biotechnol. 33 (7), 750-754 (2015).</li>
<li>Hsueh, B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Cardiogenic+control+of+affective+behavioural+state%5BTitle%5D)+AND+%22Nature%22%5BJournal%5D)">Cardiogenic control of affective behavioural state.</a> Nature. 615 (7951), 292-299 (2023).</li>
<li>Tian, B. Z., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Macroporous+nanowire+nanoelectronic+scaffolds+for+synthetic+tissues%5BTitle%5D)+AND+%22Nat+Mater%22%5BJournal%5D)">Macroporous nanowire nanoelectronic scaffolds for synthetic tissues.</a> Nat Mater. 11 (11), 986-994 (2012).</li>
<li>Fang, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Micelle-enabled+self-assembly+of+porous+and+monolithic+carbon+membranes+for+bioelectronic+interfaces%5BTitle%5D)+AND+%22Nat+Nanotechnol%22%5BJournal%5D)">Micelle-enabled self-assembly of porous and monolithic carbon membranes for bioelectronic interfaces.</a> Nat Nanotechnol. 16 (2), 206-213 (2021).</li>
<li>Kay, G. N., Shepard, R. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Stimulation+and+Excitation+of+Cardiac+Tissues%5BTitle%5D)+AND+%22Clin+Cardiac+Pacing+Defibrillat+Resynchronizat+Ther%22%5BJournal%5D)">Stimulation and Excitation of Cardiac Tissues.</a> Clin Cardiac Pacing Defibrillat Resynchronizat Ther. , 61-113 (2017).</li>
<li>Zhang, J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Gold-modified+nanoporous+silicon+for+photoelectrochemical+regulation+of+intracellular+condensates%5BTitle%5D)+AND+%22Nat+Nanotechnol%22%5BJournal%5D)">Gold-modified nanoporous silicon for photoelectrochemical regulation of intracellular condensates.</a> Nat Nanotechnol. , (2025).</li>
<li>Li, P., Kim, S., Tian, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Beyond+25+years+of+biomedical+innovation+in+nano-bioelectronics%5BTitle%5D)+AND+%22Device%22%5BJournal%5D)">Beyond 25 years of biomedical innovation in nano-bioelectronics.</a> Device. 2 (7), 100401(2024).</li>
<li>Yang, C., Cheng, Z., Li, P., Tian, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Exploring+Present+and+Future+Directions+in+Nano-Enhanced+Optoelectronic+Neuromodulation%5BTitle%5D)+AND+%22Acc+Chem+Res%22%5BJournal%5D)">Exploring Present and Future Directions in Nano-Enhanced Optoelectronic Neuromodulation.</a> Acc Chem Res. 57 (9), 1398-1410 (2024).</li>
<li>Prominski, A., Li, P., Miao, B. A., Tian, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanoenabled+Bioelectrical+Modulation%5BTitle%5D)+AND+%22Acc+Mater+Res%22%5BJournal%5D)">Nanoenabled Bioelectrical Modulation.</a> Acc Mater Res. 2 (10), 895-906 (2021).</li>
<li>Li, P., Kim, S., Tian, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Nanoenabled+Trainable+Systems%3A+From+Biointerfaces+to+Biomimetics%5BTitle%5D)+AND+%22ACS+Nano%22%5BJournal%5D)">Nanoenabled Trainable Systems: From Biointerfaces to Biomimetics.</a> ACS Nano. 16 (12), 19651-19664 (2022).</li>
<li>Majmudar, A., Kim, S., Li, P., Tian, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Perspectives+on+non-genetic+optoelectronic+modulation+biointerfaces+for+advancing+healthcare%5BTitle%5D)+AND+%22Med-X%22%5BJournal%5D)">Perspectives on non-genetic optoelectronic modulation biointerfaces for advancing healthcare.</a> Med-X. 2 (1), 18(2024).</li>
<li>Hwang, S. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+Physically+Transient+Form+of+Silicon+Electronics%5BTitle%5D)+AND+%22Science%22%5BJournal%5D)">A Physically Transient Form of Silicon Electronics.</a> Science. 337 (6102), 1640-1644 (2012).</li>
<li>Yu, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Enhanced+photoelectrochemical+efficiency+and+stability+using+a+conformal+TiO2+film+on+a+black+silicon+photoanode%5BTitle%5D)+AND+%22Nat+Ener%22%5BJournal%5D)">Enhanced photoelectrochemical efficiency and stability using a conformal TiO2 film on a black silicon photoanode.</a> Nat Ener. 2 (6), 17045(2017).</li>
<li>Kosta, S., Dauby, P. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Frank-Starling+mechanism%2C+fluid+responsiveness%2C+and+length-dependent+activation%3A+Unravelling+the+multiscale+behaviors+with+an+in+silico+analysis%5BTitle%5D)+AND+%22PLoS+Computat+Bio%22%5BJournal%5D)">Frank-Starling mechanism, fluid responsiveness, and length-dependent activation: Unravelling the multiscale behaviors with an in silico analysis.</a> PLoS Computat Bio. 17 (10), e1009469(2021).</li>
<li>Silverman, D. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Heart+Rate-Induced+Myocardial+Ca2%2B+Retention+and+Left+Ventricular+Volume+Loss+in+Patients+With+Heart+Failure+With+Preserved+Ejection+Fraction%5BTitle%5D)+AND+%22J+Am+Heart+Assoc%22%5BJournal%5D)">Heart Rate-Induced Myocardial Ca2+ Retention and Left Ventricular Volume Loss in Patients With Heart Failure With Preserved Ejection Fraction.</a> J Am Heart Assoc. 9 (17), e017215(2020).</li>
<li>Zeng, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Printing+thermoelectric+inks+toward+next-generation+energy+and+thermal+devices%5BTitle%5D)+AND+%22Chem+Soc+Rev%22%5BJournal%5D)">Printing thermoelectric inks toward next-generation energy and thermal devices.</a> Chem Soc Rev. 51 (2), 485-512 (2022).</li>
<li>Rastogi, S. K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Remote+nongenetic+optical+modulation+of+neuronal+activity+using+fuzzy+graphene%5BTitle%5D)+AND+%22Proc+Natl+Acad+Sci%22%5BJournal%5D)">Remote nongenetic optical modulation of neuronal activity using fuzzy graphene.</a> Proc Natl Acad Sci. 117 (24), 13339-13349 (2020).</li>
</ol>

P.L. and B. T. filed a patent on the nanoporous silicon device fabrication and application. P.L., C. Y. and B. T. filed a patent on the nanoporous carbon device fabrication and application. P. L. and B.T. filed a patent on the flexible microelectron array fabrication and application.

This protocol introduced the ex vivo rat heart platform (Figure 1A) and the I/R model to offer quick and convenient organ-level electrophysiology studies to accompany the fast-growing research efforts and demands in bioelectronics38. It detailed the fabrication and validation of three device systems, namely nanoporous silicon, flexible multielectrode arrays, and nanoporous carbon (Figures 1B-D), as the benchmark for bidirectional electrophysiological interrogations. Nanoporous silicon enables low-intensity, capacitive, and high spatiotemporal pacing, flexible multielectrode arrays enable multichannel recording and mapping of epicardial activities, and nanoporous carbon leads to low-voltage stimulation and high SNR recording when combined with MEAs27.
Optical pacing has been previously demonstrated using optogenetics, a method that requires genetic modification to express light-sensitive ion channels in target tissues33. While effective, optogenetics introduces significant complexity due to the need for viral vectors or transgenic approaches, raising safety, ethical, and regulatory concerns, particularly for clinical applications. In contrast, semiconductor-based, nongenetic biostimulation offers a simpler and more translationally viable alternative39,40,40,42. Materials like silicon and other organic semiconductors enable direct optoelectronic modulation of tissues without genetic alteration, leveraging capacitive photocurrents for biosafe and charge-balanced stimulation. This approach achieves comparable or even superior performance to optogenetics in terms of pacing intensity, operating well below laser safety thresholds to minimize tissue damage31,32 (Figure 8). The nongenetic nature of semiconductor-based biostimulation eliminates the barriers associated with genetic modification, paving the way for broader adoption in clinical settings and diverse applications in tissue engineering and bioelectronic medicine. However, the devices need to be carefully designed to integrate with the tissue, where biocompatibility needs to be carefully considered, as well as the place of interfacing for efficient stimulation and recording (Figure 8A-B). In addition, the presence of material on the tissue surface may impede the possibility of real-time imaging, unless a device can be engineered to be transparent to the excitation-emission window of certain imaging agents.
Nanoporous silicon stands out among semiconductor photostimulators as it does not require an artificial return electrode, unlike previously reported materials26. This unique property arises from its ability to form spatially resolved cathode and anode regions based on the light spot size and location. The illuminated surface serves as the cathodic injection site, while the surrounding peripheral regions facilitate anodic current return. This mechanism enables multisite stimulation on monolithic, pixel-less membranes, allowing for precise and localized stimulation. Notably, localized light stimulation, rather than global illumination, is critical for creating efficient bipolar stimulation profiles. Additionally, the device size significantly impacts performance; larger devices generate higher currents under the same stimulation conditions, further enhancing their functional versatility.
The failure of optical pacing can result from various factors, even in healthy biological models, primarily related to device integrity and biointerface coupling. First, thorough photocurrent characterization is critical before heart stimulation. Lower-than-expected photocurrents may arise from material degradation43 oxide passivation after prolonged storage, over-etching during the stain-etching process, device fractures during handling or transferring, or incorrect device orientation during interfacing. To mitigate mechanical damage, PDMS was used as a soft substrate for accommodating the nanoporous silicon membranes, providing protection against potential damage from direct handling with tweezers. Second, establishing a seamless interface with the epicardium, which is perfused with biofluids in this setup, is essential. A thick biofluid layer can impede proper attachment and compromise pacing efficacy. To enhance biointerface coupling, bioadhesives42,43 or suturing can be employed to stabilize the connection and ensure reliable stimulation. Notably, the nanoporous silicon used in our study is biodegradable, supporting temporary pacing applications but degrading in performance within 1-2 days under physiological conditions. For longer-term stability, surface passivation44 or the use of more durable semiconductor materials should be considered.
During ex vivo pacing, the gradual LVP increase (Figure 8E) at higher frequencies (e.g., 4 Hz) likely results from enhanced myocardial contractility, calcium accumulation, and the Frank-Starling mechanism45. Elevated pacing rates improve intracellular calcium cycling and ventricular filling dynamics, increasing preload and contraction strength46. While this may raise myocardial oxygen demand and arrhythmia risk, these effects can be mitigated by sufficient pre-oxygenation, close ECG monitoring, and controlled pacing parameters. In our experiments, no significant adverse effects were observed.
In multielectrode recording, specifying the electrode locations on the heart and their relative positions to the pacing electrode is crucial for meaningful analysis. It is essential to eliminate crosstalk between electrodes to ensure the capture of distinct waveforms and temporally resolved patterns. Flexible electrode arrays typically establish a good interface with the epicardium; however, adhesion can be further enhanced using ionically conductive adhesive coatings, such as thin hydrogel layers28,43 to improve stability and signal quality.
Nanostructured graphene/carbon materials, with large surface areas for charge storage and injection, can improve bioelectronic device performance by reducing impedance at electrode-saline junctions and increasing charge injection capabilities35. Current methods for patterning graphene materials onto flexible electrodes (e.g., Au) include electrodeposition, spin coating, and screen printing47. However, these methods are typically associated with complex fabrication processes, limited patterning capabilities, and reduced performance due to the dead volume of binders. A laser synthesis method was utilized to generate nanostructured carbon patterns onto cellulose substrate and then transfer them onto other soft films to create a compliant biointerface, which presents a facile and effective way for bioelectronics fabrication. The combination of patterned carbon coatings with small geometric sizes down to the single-cell level, which would increase the localized electrical field, and highly porous structures of carbon membrane to decrease resistance at the electrode-tissue interface, will synergistically achieve efficient biological stimulation and recording in the future48.
While it is a convenient disease model, the Langendorff ex vivo I/R model lacks systemic interactions, isolating the heart from neurohormonal and immune responses, and relies on artificial perfusion with buffers, which can alter physiological conditions such as oxygen delivery and endothelial function. Its limited viability confines studies to acute events. Nonetheless, the model offers a highly controlled environment with precise parameter adjustments and good reproducibility. It also enables real-time cardiac function measurement, making it a valuable tool for exploring novel therapeutic strategies for ischemic heart disease. For instance, electroceutical devices could be envisioned to precondition the heart, training it to endure severe reactive oxygen species (ROS) environments, or to mitigate ROS levels for enhanced recovery. The efficacy of such treatments could be evaluated through metrics like heartbeat patterns, ECG waveforms, and conduction velocity. Furthermore, a multisite stimulation platform could provide spatial information about myocardial infarction, enabling a more detailed assessment of the affected regions. This approach could also demonstrate improved stimulation thresholds, correlated with the severity of the infarction, offering a comprehensive framework for therapeutic evaluation and optimization.
While the protocol highlighted the use of the three devices in bidirectional ex vivo heart models, their applicability extends far beyond cardiac tissues. These devices can be readily adapted for use with other electrically excitable tissues or organs, such as neural tissues, skeletal muscles, and gastrointestinal systems, where precise electrical modulation is critical, making them versatile tools for both research and translational applications in bioelectronic medicine.

The field of cardiac bioelectronics is advancing rapidly, driven by the need to develop materials and devices that enable precise and efficient bidirectional communications with the heart1,2,3,4. Electrophysiological studies play a pivotal role in this endeavor, providing critical insights into how materials interact with cardiac biointerfaces through modulation and sensing. While in vitro models, such as cultured HL-1 cell lines and primary cardiomyocytes from rodents, offer a controlled environment for initial assessments5,6,7,8, their simplicity often fails to replicate the complex, dynamic conditions of a living heart. These models lack the heart&#39;s 3D architecture, crucial for coordinated electrical conduction and mechanical force generation, and cannot mimic rhythmic contraction-relaxation cycles or perfusion dynamics critical for oxygen and nutrient delivery9. Conversely, in vivo models provide the most physiologically relevant insights but come with significant ethical, administrative, and technical challenges, including the need for extensive training, sophisticated surgical setups, and compliance with stringent regulatory frameworks10.
To bridge this gap, ex vivo heart models, such as the Langendorff-perfused adult rat heart, offer a compelling alternative to scientific research11,12. These models combine the physiological relevance of in vivo systems with the controllability and accessibility of in vitro setups. By isolating the heart and maintaining it in a functional state, the Langendorff apparatus enables researchers to conduct high-fidelity studies on cardiac electrophysiology under precisely controlled conditions. The absence of systemic variables such as neural inputs and circulating hormones simplifies the interpretation of results while preserving key aspects of cardiac physiology. Additionally, ex vivo models mitigate many ethical concerns and reduce resource burdens, making them a versatile and practical platform for translational research13.
In addition to its translational potential, this protocol sets a benchmark for material performance evaluation. By incorporating representative material strategies, such as optoelectronic platforms for wireless photostimulation and electronic systems for wired stimulation and recording, it establishes a reproducible framework for comparative studies. This standardization not only facilitates innovation but also enhances the reproducibility and reliability of findings across research groups. In the past, many high-performance photoelectrodes and electrodes have shown great promise for bioelectrical studies, such as PEDOT: PSS14, MXene15, iridium oxides16, platinum17, molybdenum18, silicon19,20,21, quantum dots22,23,24, and organic semiconductors25. Here, this protocol presents representative and state-of-the-art materials, including nanoporous silicon26, nanoporous carbon27, and flexible mesh-like gold multielectrode arrays (MEAs)28,29, integrating into the protocol to demonstrate their capabilities in bidirectional cardiac interfaces. These materials enable low-intensity suprathreshold stimulation, high spatiotemporal resolution, and high SNR recordings, showcasing their potential for advancing cardiac bioelectronics. Moreover, the inclusion of a myocardial infarction model induced by I/R injury provides a robust framework for disease-relevant studies and therapeutic explorations.
This work presents detailed methods for fabricating and applying advanced materials for leadless photostimulation and electrical stimulation and sensing with ex vivo rat hearts (Figure 1A). Nanoporous silicon membranes were fabricated through photolithography patterning, reactive ion etching (RIE), and buffered hydrofluoric acid (HF) release from silicon-on-insulator (SOI) wafers with a 5 &#181;m device layer, followed by stain-etching and transfer to soft Polydimethylsiloxane (PDMS) membranes26. For electrical stimulation and recording, nanoporous carbon was developed by laser ablation of salt-incubated cellulose substrates, followed by water-phase transfer and heat lamination, offering improved charge storage and injection capabilities compared to traditional gold electrodes27. Additionally, flexible MEAs were fabricated on polyimide-coated Si wafers using photolithography, e-beam metallization, etching, encapsulation, and release processes to enable spatially resolved epicardial recording and mapping28,29.
Beyond fabrication, the protocol provides a step-by-step protocol for adult rat heart isolation, perfusion, monitoring, and interfacing with optical and electrical devices. The devices were tested on isolated hearts, demonstrating representative results in pacing and recording for electrophysiological evaluation. This protocol also introduces a method for creating a myocardial infarction model through I/R, validated by physiological recordings, staining, and morphological evaluations. This comprehensive methodology establishes a reproducible framework for evaluating materials and devices in cardiac biointerfaces. Figure 1B-D outlines the workflows of materials fabrication for&#160;evaluation in this ex vivo cardiac model. Figure 2A-C demonstrates the expected results in pictures of the as-fabricated devices.

<table><tbody><tr><td>16 Channel Headstage</td><td>Intan Technologies</td><td>C3334</td><td></td></tr><tr><td>2,3,5-Triphenyltetrazolium chloride</td><td>Sigma Aldrich</td><td>T8877-5G</td><td>triphenyltetrazolium chloride </td></tr><tr><td>2-Propanol (IPA) </td><td>Fischer Scientific</td><td>A451-4</td><td></td></tr><tr><td>635 nm Laser, 500 mW</td><td>Laserglow</td><td>NA</td><td></td></tr><tr><td>Acetone</td><td>Fischer Scientific</td><td>A18-4</td><td></td></tr><tr><td>Angstrom Evovac e-beam evaporator</td><td>Angstrom</td><td>NA</td><td></td></tr><tr><td>AZ 300MIF Developer</td><td>Microchemicals</td><td>18441123163</td><td>Developer</td></tr><tr><td>AZ nlof 2020 </td><td>Microchemicals</td><td>1A002020</td><td></td></tr><tr><td>AZ NMP </td><td>Microchemicals</td><td>NA</td><td>Photoresist remover</td></tr><tr><td>AZ40XT-11D </td><td>Microchemicals</td><td>1000300</td><td>Photoresist</td></tr><tr><td>Buffered HF</td><td>Thermo Scientific</td><td>AA44627K2</td><td></td></tr><tr><td>CaCl2.2H2O</td><td>Sigma Aldrich</td><td>(C3881)</td><td></td></tr><tr><td>CO&lt;sub&gt;2&lt;/sub&gt; laser </td><td>Universal Laser Systems</td><td>VLS 4.60</td><td></td></tr><tr><td>Conductive silver paint</td><td>PELCO</td><td>16062</td><td>Conductive adhesion between electrode and connecting Cu wire</td></tr><tr><td>Copper wire encapsulated 0.1 mm</td><td>Amazon</td><td>https://www.amazon.com/Enameled-Temperature-Resistance-Transformers-Inductors/dp/&lt;br/&gt; B09TNM51S5/ref=asc_df_B09&lt;br/&gt; TNM51S5?mcid=155de761ea4&lt;br/&gt; c389ea86d45ba61a83e8d&amp;amp;tag&lt;br/&gt; =hyprod-20&amp;amp;linkCode=df0&amp;amp;hvadid&lt;br/&gt; =693675076770&amp;amp;hvpos=&amp;amp;hvnetw&lt;br/&gt; =g&amp;amp;hvrand=664358781094905&lt;br/&gt; 4431&amp;amp;hvpone=&amp;amp;hvptwo=&amp;amp;hvqmt&lt;br/&gt; =&amp;amp;hvdev=c&amp;amp;hvdvcmdl=&amp;amp;hvlocint&lt;br/&gt; =&amp;amp;hvlocphy=9021716&amp;amp;hvtargid=&lt;br/&gt; pla-1878323158943&amp;amp;psc=1</td><td></td></tr><tr><td>Digidata 1550 digitizer</td><td>Molecular Devices</td><td>NA</td><td></td></tr><tr><td>Glucose</td><td>Sigma Aldrich</td><td>G7021</td><td></td></tr><tr><td>HBSS, no calcium, no magnesium, no phenol red</td><td>Thermo Scientific</td><td>14175095</td><td></td></tr><tr><td>Heidelberg MLA150 direct writer</td><td>Heidelberg</td><td>NA</td><td></td></tr><tr><td>heparin (1000 IU/kg)</td><td>Sagent Pharmaceuticals</td><td>1009655</td><td></td></tr><tr><td>HEPES</td><td>Sigma Aldrich</td><td>(H4034)</td><td></td></tr><tr><td>Hexane </td><td>Sigma Aldrich</td><td>52750-10ML</td><td>Solvent</td></tr><tr><td>HF</td><td>Fisher Scientific</td><td>A513-500</td><td>Tracemetal grade</td></tr><tr><td>HMDS Vapor Prime Oven</td><td>Yield Engineering Systems</td><td>NA</td><td></td></tr><tr><td>HNO3</td><td>Fisher Scientific</td><td>A509P500</td><td>Tracemetal grade</td></tr><tr><td>Hot laminator</td><td>Office Depot</td><td>L410-A</td><td>Multilayer encapsulation </td></tr><tr><td>Intan RHD systems</td><td>Intan Technologies</td><td>C3100</td><td></td></tr><tr><td>iWorx ECG</td><td>iWorx</td><td> IA-400D</td><td></td></tr><tr><td>iWorx LVD probe</td><td>iWorx</td><td>BP-100</td><td></td></tr><tr><td>iWorx preamplifier</td><td>iWorx</td><td>C-ISO-256</td><td></td></tr><tr><td>KCl</td><td>Sigma Aldrich</td><td>(P4504)</td><td></td></tr><tr><td>Latex Balloon (size 4)</td><td>Radnoti</td><td>170404</td><td></td></tr><tr><td>MgCl2.7H2O</td><td>Sigma Aldrich</td><td>(M9272)</td><td></td></tr><tr><td>NaCl</td><td>Sigma Aldrich</td><td>(S9625)</td><td></td></tr><tr><td>Nafion 117 containing solution</td><td>Sigma Aldrich</td><td>31175-20-9</td><td>Fixing reagent for nanoporous carbon pattern</td></tr><tr><td>NaH2PO4</td><td>Sigma Aldrich</td><td>(S0751)</td><td></td></tr><tr><td>NaOH</td><td>Sigma Aldrich</td><td>221465</td><td></td></tr><tr><td>PDMS</td><td>Fisher Scientific</td><td>NC9285739</td><td></td></tr><tr><td>Plasma-Therm inductively coupled plasma fluoride etcher</td><td>Plasma-Therm</td><td>NA</td><td></td></tr><tr><td>PMMA (495 A6) </td><td>Microchemicals</td><td>M130006 </td><td></td></tr><tr><td>poly (pyromellitic dianhydride-co-4,4&#039;-oxydianiline)</td><td>Sigma Aldrich</td><td>575801</td><td>PI precursor</td></tr><tr><td>Poly(ethylene-co-vinyl acetate)</td><td>Sigma Aldrich</td><td>437247-250G</td><td>Polymer for infiltration</td></tr><tr><td>Poly(vinyl alcohol)</td><td>Sigma Aldrich</td><td>341584-25G</td><td></td></tr><tr><td>Polyethylene terephthalate (PET)</td><td>Amazon</td><td>KS-6304-21-11</td><td>Type D Clear PET Sheet .0005&quot; Thick x 27&quot; Width x 10 Ft Length 1 pc</td></tr><tr><td>Potentiostat</td><td>BioLogic</td><td>SP-200</td><td>Electrical stimulation</td></tr><tr><td>resist oven</td><td> Despatch</td><td>LCC1-15-5</td><td></td></tr><tr><td>Scanning electron microscopy</td><td>Carl Zeiss</td><td>Merlin</td><td>Instrument for morphology characterization</td></tr><tr><td>silicon wafer </td><td>NOVA Electronic Materials</td><td>HS39626</td><td></td></tr><tr><td>Silicone adhesive</td><td>WPI</td><td>KWIK-SIL-S</td><td>Encapsulation</td></tr><tr><td>Sodium Borate</td><td>Sigma Aldrich</td><td>SX0355</td><td></td></tr><tr><td>SOI wafer</td><td>Ultrasil</td><td>3-10541</td><td>Type-Orient:P/B(100) DT:7+/-1um DR:&amp;#60;.005 Ohmcm HT:300+/-10um HR:1-30 Ohmcm Box:1um+/-5% UD-13998/UH-13962</td></tr><tr><td>SU-8 2002</td><td>Microchemicals</td><td>SU-8 2000 Series</td><td></td></tr><tr><td>SU-8 developer</td><td>Microchemicals</td><td>SU-8 2000 Series</td><td></td></tr><tr><td>Wet tissue adhesive</td><td>3M</td><td>1469SB</td><td></td></tr><tr><td>Whatman qualitative filter paper, Grade 1</td><td>Sigma Aldrich</td><td>WHA1001150</td><td>Substrate for carbon patterning</td></tr></tbody></table>

bidirectional electrical and optoelectronic interfaces in healthy and ischemic ex vivo rat hearts

Bidirectional Electrical and Optoelectronic Interfaces in Healthy and Ischemic Ex Vivo Rat Hearts

Electrophysiological studies are pivotal in exploring interactions between materials and cardiac biointerfaces. Recent advancements have introduced various novel conductor and semiconductor materials for bidirectional interfaces with cardiac models, facilitating low-intensity pacing alongside high spatiotemporal and high signal-to-noise ratio (SNR) recordings. The ex vivo rodent heart model serves as an effective platform for validating the functionalities of new materials and devices, bridging in vitro findings to translational insights while minimizing ethical and administrative concerns. In this protocol, we detail the isolation and ex vivo perfusion of adult rat hearts using a Langendorff apparatus, establishing precise bidirectional stimulation and recording with high-performance semiconductors and conductors, including nanoporous silicon, nanoporous carbon, and flexible mesh-like microelectrode arrays. Additionally, we present a myocardial infarction model induced by ischemia-reperfusion (I/R) injury, assessed through multichannel recording and mapping as well as infarct staining, enabling cardiac disease-relevant studies and potential therapeutic explorations. This methodology offers valuable insights into materials-bio interface research and the development of next-generation cardiac bioelectronics.

This protocol outlines advanced material fabrication and ex vivo rat heart methods for optical and electrical bidirectional biointerfacing, enabling precise cardiac stimulation, recording, and infarction modeling for bioelectronics research.

Electrophysiological studies are pivotal in exploring interactions between materials and cardiac biointerfaces. Recent advancements have introduced ...

We developed an ex vivo heart model to evaluate optoelectronic and electronic materials for cardiac stimulation and sensing, bridging bench top innovation with translational bioelectronic applications. We bridge the gap between in vitro and in vivo by offering a controlled, non-genetic ex vivo heart model to evaluate both wired and wireless bioelectronic materials in real tissue. Our protocol enables fast reproducible testing of materials in whole beating hearts, combining physiological relevance with precise control, ideal for comparing stimulation and sensing performance across different devices.We explore therapeutic materials that modulate heart function and validate their efficiency in treating myocardial infarction using our ischemia reperfusion ex vivo model. To begin, confirm general anesthesia by pinching one of the paws of the anesthetized rat, and proceed only if no response is observed. Then, make a five centimeter incision just below the chest to open the ribcage.Using scissors, carefully cut through the diaphragm to expose the heart and lungs. Now, cut through the ribs on both sides to fully open the ribcage. Secure the opened ribcage at the sternum using a hemostat.Use a second hemostat to hold the vena cava from below the heart. Cut under the hemostat with bent blunt scissors as close to the bottom of the ribcage as possible to remove the heart. Transfer the heart immediately into a Petri dish filled with ice cold HBSS.Fill a cannula and a separate Petri dish completely with ice cold HBSS. Transfer the heart to the Petri dish, prefilled with the buffer for sectioning. Use tweezers or scissors to remove the lungs and other connective tissues attached to the heart.Then, press on the heart gently and trace the blood path to locate the aorta. If the aortic arch is preserved, cut under the first ascending artery. Cannulate the aorta carefully.Prime the Langendorff apparatus with preoxygenated working solution. Open the buffer flow and attach the cannula to the perfusion apparatus carefully, ensuring that no air bubbles enter the system. Observe the heart begins to contract once perfusion starts.Now, cut off part of the atria or atrial appendage using small scissors. Before inserting the balloon into the left ventricle, deflate it completely. Then, use the connected syringe to fill the balloon with water.Next, connect BP 100 pressure probes to the perfusion line and the water-filled balloons to monitor left ventricular pressure respectively. Amplify all signal outputs, including left ventricular pressure and ECG, using the IA-400D amplifier. Monitor the pressure of the HEPES Tyrode's buffer and adjust it to stay within the optimal range of 80 to 100 millimeters of mercury.Modify the volume of water in the balloon using the syringe to set the baseline left ventricular pressure to approximately 20 millimeters of mercury. Connect the electrocardiogram electrodes by grounding the cannula and placing the electrode wires at the sides, top, or apex of the heart based on user preference. Fill the heated chamber with HEPES Tyrode's buffer prewarmed to 37 degrees Celsius.Submerge the heart into the chamber and turn the stopcock to halt buffer flow, inducing global ischemia. After 30 minutes of ischemia, turn the stopcock to restore buffer flow and initiate reperfusion. Allow the heart to perfuse for 45 minutes before terminating the experiment for infarction staining.Verify the success of ischemia by observing a reduction in heart rate and irregular ECG signals. To establish bidirectional optoelectrical interfaces between devices and heart tissue, place a silicon optoelectronic membrane onto the desired stimulation site on the heart. Allow it to self-attach to the epicardium using capillary force.Connect the electrodes to the RHD recording system or a compatible electrophysiological platform. Then, position the flexible multi-electrode arrays on the ventricular surfaces of the isolated heart. Now, program the 635 nanometer laser source with the desired frequency and duty cycle using transistor-transistor logic signals.Focus the laser beam to a one millimeter spot and align it over the silicon membrane. Start the recording and stimulation protocol. Gradually increase the laser intensity until continuous override pacing of the heart is observed.To establish bidirectional electrode-based electrical interfaces between devices and heart tissue, connect the stimulation electrodes in a two-electrode configuration, placing a porous carbon working electrode on the left ventricular wall and a counter electrode on the right ventricular wall. Using a potentiostat, deliver square current waveforms, such as two milliampere with one millisecond pulse duration, until successful pacing of the heart is achieved. A nanoporous carbon-based platform for effective electrical modulation or sensing of cardiac systems was established.Upon four hertz stimulation at one milliampere. both gold and nanoporous carbon-coated gold electrodes achieved effective overdrive pacing, with higher electrocardiogram amplitudes observed in the nanoporous carbon group. Both electrodes demonstrated an exponential decrease in threshold current with increasing pulse duration.At a stimulation current of four milliamperes per square centimeter and one millisecond duration, the threshold voltage required for effective pacing was 1.32 volts for gold electrodes and 0.90 volts for nanoporous carbon-coated electrodes. A 16-channel nano porous carbon-grafted gold electrode significantly enhanced epicardial electrocardiogram signal detection, improving the signal-to-noise ratio by eightfold compared to standard gold electrodes. Successful induction of ischemia reperfusion infarction was validated post-experimentally by TTC staining, where infarcted hearts displayed distinct white regions representing myocardial damage.During real-time monitoring, ischemic hearts exhibited significantly reduced heart rate. Multi-electrode array mapping of ischemic hearts revealed decreased electrical conduction velocity across the epicardium, indicated by increased signal delay.

bidirectional-electrical-optoelectronic-interfaces-healthy-ischemic

Research

JoVE Journal

Bioengineering

This article describes a high temporal and spatial resolution technique to optically image action potential movement on the surface of Langendorff-perfused rat hearts using a potentiometric dye (di-8-ANEPPS).

Optical Mapping of Langendorff-perfused Rat Hearts

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Optical Mapping of Action Potentials and Calcium Transients in the Mouse Heart

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NADH Fluorescence Imaging of Isolated Biventricular Working Rabbit Hearts

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Electrophysiological Assessment of Murine Atria with High-Resolution Optical Mapping

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Optocardiography and Electrophysiology Studies of Ex Vivo Langendorff-perfused Hearts

This work reports a method for controlling the cardiac rhythm of intact murine hearts of transgenic channelrhodopsin-2 (ChR2) mice using local photostimulation with a micro-LED array and simultaneous optical mapping of epicardial membrane potential.

Advanced Cardiac Rhythm Management by Applying Optogenetic Multi-Site Photostimulation in Murine Hearts

This protocol introduces dual-dye optical mapping of mouse hearts obtained from wild-type and knock-in animals affected by catecholaminergic polymorphic ventricular tachycardia, including electrophysiological measurements of transmembrane voltage and intracellular Ca2+ transients with high temporal and spatial resolution.

Dual-Dye Optical Mapping of Hearts from RyR2R2474S Knock-In Mice of Catecholaminergic Polymorphic Ventricular Tachycardia

A 3D culture system for hematopoiesis is described using human cord blood and leukemic bone marrow cells. The method is based on the use of a porous synthetic polyurethane scaffold coated with extracellular matrix proteins. This scaffold is adaptable to accommodate a wide range of cells.

Ex vivo Mimicry of Normal and Abnormal Human Hematopoiesis

Discover bidirectional electrical and optoelectronic interfaces in ex vivo rat hearts using nanoporous carbon electrodes and optical stimulation. This protocol enables precise cardiac pacing, recording, and ischemia reperfusion modeling for bioelectronics research.

Bidirectional Electrical and Optoelectronic Interfaces in Healthy and Ischemic Ex Vivo Rat Hearts

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