Conductive Scaffold Research Articles

Porous nitrogen-doped graphene nanofibers comprising metal organic framework-derived hollow and ultrafine layered double metal oxide nanocrystals as high-performance anodes for lithium-ion batteries

The growth of unique nanostructures with multicomponent systems is a renowned strategy for developing advanced materials for various energy storage applications. Herein, we utilize a facile approach to synthesize multicomponent high-performance nanofibers as anodes that comprises hierarchically porous and self-supporting N-doped reduced graphene oxide (N-doped rGO) matrix grafted with metal-organic framework (MOF)-derived hollow and ultrafine layered double metal (Ni and Co) oxide (LDO) nanocrystals [P-(Ni, Co)O/rGO NFs]. The porous and highly conductive N-doped rGO scaffold not only provides structural integrity but also offers short Li-ion diffusion pathways along with enormous conductive channels for rapid charge transfer during cycling. The hollow and ultrafine LDO nanocrystals also provide sufficient space for rapid reaction sites and to absorb the severe volume stress generated during repeated charge-discharge cycles owing to their rich oxidation states. The Li-cell utilizing the P-(Ni, Co)O/rGO NFs as anodes exhibits overall enhanced electrochemical performance with prolonged cycling stability (907 mA h g−1 at the end of 500th cycle) and a satisfactory high-rate capability (519 mA h g−1 at 5.0 A g−1).

Nanosheet-Assembled MnO2-Integrated Electrode Based on the Low-Temperature and Green Chemical Route

The development of superior electrochemical energy-storage devices designed through a facile, cost-efficient, and green synthesis technique is the key to addressing the intermittent nature of renewable energy sources such as solar and wind energy. In our present work, we design a simple, surfactant-free, and low-temperature chemical strategy to prepare novel integrated, MnO2 composite electrodes with two-dimensional (2D) nanosheet film directly supported on three-dimensional (3D) conductive nickel foam. Benefiting from the specific 2D nanosheet architecture to provide a large interfacial contact area and highly conductive metal scaffolds to facilitate fast electron transfer, the novel nanosheet-assembled MnO2-integrated electrodes exhibit higher specific capacitance of 446 F g−1 at the current density of 1 A g−1 compared with nanostructured MnO2 and commercial MnO2 powder electrodes. More importantly, the as-synthesized devices are able to achieve an outstanding cycling performance of 95% retention after 3000 cycles. The present work, which is based on the low-temperature chemical route to deposit active materials on the conductive substrate, provides new insights into designing a binder-free supercapacitor system to improve the specific capacitance, cycling, and rate performance as next-generation, energy-storage devices.

Tunable surface pseudocapacitance assisted fast and flexible lithium storage of graphene wrapped NiO nano-arrays on nitrogen-doped carbon foams

Advanced materials incorporating battery-like high capacity and capacitor-like high rate capability hold promise for achieving both high energy and power density lithium ion batteries (LIBs). However, capacitive behavior for high capacity NiO anode has seldom been reported because the surface or near-surface fast faradic surface redox reactions highly depends on specific structure design. Herein, a flexible electrode that graphene wrapped NiO nanosheet arrays anchor on three-dimensional porous nitrogen-doped carbon foam (rGO@NiONCF) is fabricated. The rGO@NiONCF composite possesses a unique sandwich structure with 3D porous NCF as the inner conductive scaffold, ultrathin NiO nanosheet arrays as a middle layer, and rGO as the outer conductive buffer layer. The elaborated structure design endows rGO@NiONCF with enhanced electronic conductivity, sufficient electrolyte infiltration and restricted volume variation. As a result, the rGO@NiONCF electrode delivers high reversible capacity (1583 mAh g−1 at 0.1 A g−1) and superior cycling stability (maintains 607 mA h g−1 at 1 A g−1 after 500 cycles). Moreover, the enhanced surface capacitance adroitly facilitates an impressive fast charge and slow discharge performance. These results reveal that rational material design to encourage pseudocapacitance effect is a valuable roadmap for NiO-based battery towards more practical applications.

Conductive poly(ε‐caprolactone)/polylactic acid scaffolds for tissue engineering applications: Synergy effect of zirconium nanoparticles and polypyrrole

AbstractBiocompatible and electrically conductive porous scaffolds with a desirable hydrophilicity and degradation rate and suitable mechanical performance are highly favorable for tissue engineering and regenerative medicine applications. In this study, we fabricated three‐dimensional (3D) porous bioscaffolds from poly(ε‐caprolactone) and polylactic acid containing different concentrations of zirconia nanoparticles (n‐ZrO2) through freeze‐drying technique. Afterward, the surface of the scaffolds was coated with an electrically conductive layer through in situ polymerization of polypyrrole (PPy) on the samples. Bioscaffolds exhibited a favorable range of mechanical properties and electrical conductivity, meeting the required mechanical performances and conductivity for a broad range of tissue engineering applications. Coating PPy on the scaffolds resulted in significantly higher hydrophilicity and faster biodegradation rate, as well as a noticeable enhancement on the in vitro cell attachment, proliferation, and viability. Our findings indicated that the simultaneous presence of n‐ZrO2 and PPy in the system presents a noticeable synergistic effect in overall properties and introduces the fabricated 3D porous scaffolds as promising candidates for tissue engineering and regenerative medicine applications.

Carbon-based electrically conductive materials for bone repair and regeneration

Electrically conductive bone scaffolds composed of carbon-based conductive materials are proposed as promising biomaterials for bone tissue engineering solutions.

Conductive Scaffolds for Bone Tissue Engineering: Current State and Future Outlook.

Bone tissue engineering strategies attempt to regenerate bone tissue lost due to injury or disease. Three-dimensional (3D) scaffolds maintain structural integrity and provide support, while improving tissue regeneration through amplified cellular responses between implanted materials and native tissues. Through this, scaffolds that show great osteoinductive abilities as well as desirable mechanical properties have been studied. Recently, scaffolding for engineered bone-like tissues have evolved with the use of conductive materials for increased scaffold bioactivity. These materials make use of several characteristics that have been shown to be useful in tissue engineering applications and combine them in the hope of improved cellular responses through stimulation (i.e., mechanical or electrical). With the addition of conductive materials, these bioactive synthetic bone substitutes could result in improved regeneration outcomes by reducing current factors limiting the effectiveness of existing scaffolding materials. This review seeks to overview the challenges associated with the current state of bone tissue engineering, the need to produce new grafting substitutes, and the promising future that conductive materials present towards alleviating the issues associated with bone repair and regeneration.

Hierarchical ultrathin NiFe-borate layered double hydroxide nanosheets encapsulated into biomass-derived nitrogen-doped carbon for efficient electrocatalytic oxygen evolution

Exploring highly efficient, cost-effective, and stable electrocatalysts toward oxygen evaluation reaction (OER) is of great significance for hydrogen generation. Herein, in situ growth of NiFe-borate layered double hydroxide (NiFe-BLDH) nanosheets on waste biomass-derived nitrogen-doped carbon (NC) with hierarchical architecture under microwave hydrothermal conditions is reported. The as-synthesized NiFe-borate layered double hydroxide/nitrogen-doped carbon (NiFe-BLDH/NC) exhibits outstanding OER activity, showing an extremely low overpotential of 243 mV at the current density of 10 mA cm−2 and a relatively small Tafel slope of 42.7 mV dec−1, which are superior to the commercial RuO2 and many previously reported NiFe-LDH-based OER electrocatalysts. Additionally, the catalyst also shows remarkable stability with unobvious decrease of current density over a period of 24 h. These excellent catalytic performances could be attributable to the synergistic effects between the conductive NC scaffold and NiFe-BLDH with excellent hydrophilicity caused by the intercalated borate anions, which provide many advantages, such as large surface area, abundant active sites, fast charge and mass transport pathways. This work provides new insights into the design and facile preparation green and efficient electrocatalysts

Promoting ethylene production over a wide potential window on Cu crystallites induced and stabilized via current shock and charge delocalization

Electrochemical CO2 reduction (CO2RR) in a product-orientated and energy-efficient manner relies on rational catalyst design guided by mechanistic understandings. In this study, the effect of conducting support on the CO2RR behaviors of semi-conductive metal-organic framework (MOF) — Cu3(HITP)2 are carefully investigated. Compared to the stand-alone MOF, adding Ketjen Black greatly promotes C2H4 production with a stabilized Faradaic efficiency between 60-70% in a wide potential range and prolonged period. Multicrystalline Cu nano-crystallites in the reconstructed MOF are induced and stabilized by the conducting support via current shock and charge delocalization, which is analogous to the mechanism of dendrite prevention through conductive scaffolds in metal ion batteries. Density functional theory calculations elucidate that the contained multi-facets and rich grain boundaries promote C–C coupling while suppressing HER. This study underlines the key role of substrate-catalyst interaction, and the regulation of Cu crystalline states via conditioning the charge transport, in steering the CO2RR pathway.

Boosting Alkaline Hydrogen and Oxygen Evolution Kinetic Process of Tungsten Disulfide-Based Heterostructures by Multi-Site Engineering.

Alkaline water electrolysis is an advanced technology for scalable H2 production using surplus electricity from intermittent energy sources, but it remains challenging for non-noble electrocatalysts to split water into hydrogen and oxygen efficiently, especially for tungsten disulfide (WS2 )-based catalysts. Density functional theory calculations in combination with experimental study are used to establish a multi-site engineering strategy for developing robust WS2 -based hybrid electrocatalyst on mesoporous bimetallic nitride (Ni3 FeN) nanoarrays for bifunctional water splitting. This ingenious design endows the catalyst with numerous edge sites chemically bonded with the conductive scaffold, which are favorable for water dissociation and hydrogen adsorption. Benefiting from the synergistic advantages, the N-WS2 /Ni3 FeN hybrid exhibits exceptional bifunctional properties for hydrogen and oxygen evolution reactions (HER and OER) in base with excellent large-current durability, requiring 84 mV to afford 10mAcm-2 for HER, and 240mV at 100mAcm-2 for OER, respectively. Assembling the catalytic materials as both the anode and cathode to construct an electrolyzer, it is actualized very good activities for overall water splitting with only 1.5 V to deliver 10 mAcm-2 , outperforming the IrO2 (+) //Pt(-) coupled electrodes and many non-noble bifunctional electrocatalysts thus far. This work provides a promising avenue for designing WS2 -based heterogeneous electrocatalysts for water electrolysis.

Highly Reversible Zn Electrodeposition Enabled by an Artificial 3D Defect-Rich Conductive Scaffold.

Rechargeable Zn metal batteries are attracting intensive attention due to the high capacity and safety of metallic Zn. However, their developments are strongly restricted by the poor reversibility and low areal capacity of anodes, especially at high rates. To achieve homogeneous and rapid Zn deposition is a way to solve these issues intrinsically. Here, we design a three-dimensional (3D) defect-rich conductive scaffold as an ideal substrate for Zn electrodeposition, which is built up of vertically aligned porous vanadium trioxide nanosheet skeleton supporting defective networks to provide fast electron- and ion-transfer paths. The abundant defects act as the energetically favorable nucleation sites inducing the in situ uniform growth of hierarchical Zn nanosheets on the substrate. The as-electrodeposited 3D Zn anodes achieve exceptionally reversible Zn plating/stripping over 5000 h at both moderate and high current densities (6 and 20 mA cm-2). The 100 A h cm-2 cumulative capacities at 80% depth of discharge are impressive and magnitude of orders greater than the reported Zn anodes so far. The unique 3D defective structure can be well maintained in thousands of cycles, which ensures a remarkably high Coulombic efficiency of 99.99956%. A full cell assembled with the ZnHCF cathode demonstrates a high-capacity retention of 91.2% at 2 A g-1 after 20,000 cycles, over 10 times that of a Zn plate anode. This work provides an eligible anode for advanced rechargeable Zn metal batteries.

Host/Guest Nanostructured Photoanodes Integrated with Targeted Enhancement Strategies for Photoelectrochemical Water Splitting.

Photoelectrochemical (PEC) hydrogen production from water splitting is a green technology that can solve the environmental and energy problems through converting solar energy into renewable hydrogen fuel. The construction of host/guest architecture in semiconductor photoanodes has proven to be an effective strategy to improve solar‐to‐fuel conversion efficiency dramatically. In host/guest photoanodes, the absorber layer is deposited onto a high‐surface‐area electron collector, resulting in a significant enhancements in light‐harvesting as well as charge collection and separation efficiency. The present review aims to summarize and highlight recent state‐of‐the‐art progresses in the architecture designing of host/guest photoanodes with integrated enhancement strategies, including i) light trapping effect; ii) optimization of conductive host scaffolds; iii) hierarchical structure engineering. The challenges and prospects for the future development of host/guest nanostructured photoanodes are also presented.

Editorial: From Passive to Active Regeneration: The New Gold Standard in Bone and Soft Tissue Grafting

Editorial: From Passive to Active Regeneration: The New Gold Standard in Bone and Soft Tissue Grafting

Conductive Polymeric-Based Electroactive Scaffolds for Tissue Engineering Applications: Current Progress and Challenges from Biomaterials and Manufacturing Perspectives.

The practice of combining external stimulation therapy alongside stimuli-responsive bio-scaffolds has shown massive potential for tissue engineering applications. One promising example is the combination of electrical stimulation (ES) and electroactive scaffolds because ES could enhance cell adhesion and proliferation as well as modulating cellular specialization. Even though electroactive scaffolds have the potential to revolutionize the field of tissue engineering due to their ability to distribute ES directly to the target tissues, the development of effective electroactive scaffolds with specific properties remains a major issue in their practical uses. Conductive polymers (CPs) offer ease of modification that allows for tailoring the scaffold’s various properties, making them an attractive option for conductive component in electroactive scaffolds. This review provides an up-to-date narrative of the progress of CPs-based electroactive scaffolds and the challenge of their use in various tissue engineering applications from biomaterials perspectives. The general issues with CP-based scaffolds relevant to its application as electroactive scaffolds were discussed, followed by a more specific discussion in their applications for specific tissues, including bone, nerve, skin, skeletal muscle and cardiac muscle scaffolds. Furthermore, this review also highlighted the importance of the manufacturing process relative to the scaffold’s performance, with particular emphasis on additive manufacturing, and various strategies to overcome the CPs’ limitations in the development of electroactive scaffolds.

Decoration of Graphenated Carbon Nanotube Electrodes with Platinum Nanoparticles via Atomic Layer Deposition

Platinum electrodes are commonly used in devices such as fuel cells, neurostimulators, and sensors. Device performance can be improved by increasing the electrochemically active surface area of the platinum, which increases the charge storage capacitance, oxygen reduction reaction (ORR) rates, and catalytic activity. Therefore, there is significant motivation to fabricate platinum 3D structures, but it is challenging to accomplish successfully. In this study, graphenated carbon nanotubes (gCNTs), a type of carbon nanotube with leaf-like graphene foliates, were decorated with platinum nanoparticles to fabricate a 3D structure with increased Pt surface area. The carbon nanotubes act as a conductive scaffold and the foliates provide increased surface area and highly reactive edge sites.The development of gCNTs was accomplished by systematically adjusting growth parameters in a microwave plasma enhanced chemical vapor deposition system. The primary growth parameters were growth temperature, growth time, process gas composition (methane flow rate vs ammonia flow rate), and microwave power. gCNTs were characterized to obtain the best relevant electrochemical properties, i.e., impedance, voltage window, stability, and charge storage capacity. Compared to platinum, typical gCNT electrodes had lower impedance at 100 Hz at 230 Ω vs 375 Ω for Pt. The electrochemical properties of the gCNTs were compared to scanning electron microscope images (Fig. 1) and it was found that a medium foliate density (3.0 CH4: 1 NH3) had the best electrochemical properties.Next, the gCNTs electrodes can be further enhanced by decoration with nanoparticles of platinum via atomic layer deposition (ALD). Atomic layer deposition alternates two reagents so that the first adsorbs on the surface in a monolayer and the second reacts with the monolayer. The most reactive sides tend to nucleate first, so that at low deposition density, particles preferentially deposit at the edges of the graphene foliates. A major advantage of ALD is that it produces much more monodispersed nanoparticles, which yields more uniform properties. The combined electrodes will have the larger electrochemical surface area of gCNTs and the catalytic and charge storage properties of platinum electrodes. Electrochemical properties of Pt-gCNTs will be compared to gCNTs and planar Pt electrodes. Figure 1

Carbon Fiber-Paper Supported Carbon Nanofoams As Device-Ready Electrode Architectures for Sodium-Ion Batteries

Carbon nanofoam papers (CNFPs) in which resorcinol–formaldehyde-derived carbon nanofoam domains span the voids of commercial carbon fiber paper [1] show effective performance and function as device-ready electrodes for diverse energy-storage configurations. We recently demonstrated that CNFPs are promising anode candidates for nonaqueous Na-ion batteries, delivering specific capacity >200 mAh g–1 at a 1C rate and >150 mAh g–1 at 10C in half-cell tests [2]. Fast and reversible Na-ion storage is supported by an architected combination of the disordered nature of the hard carbon that comprises the solid-state CNF domains and the through-connected porosity of the nanofoam. For fundamental characterization of the charge-storage process, we use in situ optical imaging of CNFP electrodes to monitor color changes that correlate with various stages of Na-ion storage. These CNFPs can also be used as porous, conductive scaffolds for the inclusion of complementary charge-storing phases such as Na3V2(PO4)3, permitting the construction of full-cell Na-ion devices. Our results demonstrate the utility of CNFPs to construct next-generation Na-ion batteries with technologically relevant form factors and performance metrics.[1] J.C. Lytle, J.M. Wallace, M.B. Sassin, A.J. Barrow, J.W. Long, J.L. Dysart, C.H. Renninger, M.P. Saunders, N.L. Brandell, and D.R. Rolison, Energy Environ. Sci., 4 (2011) 1913–1925.[2] R.H. DeBlock, J.S. Ko, M.B. Sassin, A.N. Hoffmaster, B.S. Dunn, D.R. Rolison, and J.W. Long, Energy Storage Mater., 21 (2019) 581–486.

Asymmetric separator integrated with ferroelectric-BaTiO3 and mesoporous-CNT for the reutilization of soluble polysulfide in lithium-sulfur batteries

In this study we report the use of a hybrid separator coated with mesoporous multi-walled carbon nanotubes (MWCNTs) and ferroelectric BaTiO3 (BTO) as a “conductive scaffold” and polysulfide barrier for high-performance lithium-sulfur batteries. The effectiveness of the hybrid separator was verified by using a high sulfur cathode (70%). The modified separator effectively limited the migration of lithium polysulfides, improved the integrity of the sulfur cathode, and provided a conductive channel for ion and electron transport. As a result, the cell utilizing the separator coated with MWCNT and BTO (AHT-MWCNT–BTO) exhibited excellent electrochemical performance and rate kinetics, delivering a high initial discharge capacity of 1388.6 mAh g−1 at 0.1 C-rate, corresponding to 83% sulfur utilization in the electrode. Additionally, the cycling performance revealed a 77% capacity retention of the initial value after 100 repeated cycles at 0.5 C-rate. Furthermore, even at a high current density of 2.0 C, the cell with the AHT-MWCNT–BTO-coated separator delivered a discharge capacity of 422.8 mAh g−1 after 350 cycles, besides significantly increasing the sulfur utilization and effectively improving the electrochemical conversion of trapped polysulfides. These results reveal the exceptional potential of AHT-MWCNT–BTO-coated separators in the development of next generation high-performance lithium–sulfur batteries.

Advocating Electrically Conductive Scaffolds with Low Immunogenicity for Biomedical Applications: A Review.

Scaffolds support and promote the formation of new functional tissues through cellular interactions with living cells. Various types of scaffolds have found their way into biomedical science, particularly in tissue engineering. Scaffolds with a superior tissue regenerative capacity must be biocompatible and biodegradable, and must possess excellent functionality and bioactivity. The different polymers that are used in fabricating scaffolds can influence these parameters. Polysaccharide-based polymers, such as collagen and chitosan, exhibit exceptional biocompatibility and biodegradability, while the degradability of synthetic polymers can be improved using chemical modifications. However, these modifications require multiple steps of chemical reactions to be carried out, which could potentially compromise the end product’s biosafety. At present, conducting polymers, such as poly(3,4-ethylenedioxythiophene) poly(4-styrenesulfonate) (PEDOT: PSS), polyaniline, and polypyrrole, are often incorporated into matrix scaffolds to produce electrically conductive scaffold composites. However, this will reduce the biodegradability rate of scaffolds and, therefore, agitate their biocompatibility. This article discusses the current trends in fabricating electrically conductive scaffolds, and provides some insight regarding how their immunogenicity performance can be interlinked with their physical and biodegradability properties.

Antimicrobial PVDF nanofiber composites with the ZnO - vermiculite - chlorhexidine based nanoparticles and their tensile properties

The poly(vinylidene fluoride) (PVDF) nanofiber materials have attracted attention due to their enhanced and exceptional nanostructural characteristics. Electrospinning PVDF based nanofiber is one of the important new materials for the rapidly growing technology development such as nanofiber based conductive tissue engineering, scaffold materials, filters and medical textiles applications. At these areas the risk of microbial contamination is very high, hence in this study the PVDF nanofiber materials with antimicrobial zinc oxide (ZnO), zinc oxide/vermiculite (ZnO/V), zinc oxide/vermiculite-chlorhexidine (ZnO/V_CH) and vermiculite-chlorhexidine (V_CH) nanofillers were prepared by electrospinning, via one-step electrospinning process. The PVDF nanofiber diameters and their orientation were investigated using scanning electron microscope (SEM). The ZnO/V_CH and V/CH nanofillers with positive ζ - potential values were incorporated into PVDF nanofibers with an average diameter of 108 nm for PVDF_ZnO/V_CH and 100 nm for PVDF_V_CH samples. In contrast, ZnO and ZnO/V nanofillers with negative ζ - potential values reacted intensively with PVDF polymer. The slightly hydrophobe character was demonstrated by water contact angle from ∼100°. The chemical interactions were evaluated by the Fourier transform infrared spectroscopy (FTIR). The presence of the β-phase in the original PVDF and the small traces of the α-phase in PVDF_ZnO and PVDF_ZnO/V samples was confirmed. In the PVDF_ZnO/V_CH and PVDF_V/CH samples where the specific interaction of PVDF chains with CH a rapid decrease in the β-phase fraction was evaluated. The mechanical properties based on the Young's modulus (E) and tensile strength (Rm) values were evaluated from the tensile test curves. Antimicrobial activity (longer than 48 h) against S. aureus and E. coli for PVDF_ZnO/V_CH and PVDF_V/CH samples was obtained.

Facile template preparation of novel electroactive scaffold composed of polypyrrole-coated poly(glycerol-sebacate-urethane) for tissue engineering applications

• Porous poly(glycerol sebacate urethane)-based scaffolds prepared. • Loading of ZnO nanoparticles and in-situ polymerization of pyrrole in the scaffolds performed. • Electrical conductivity (4 ∼ 7 × 10 -2 S/cm) was obtained for pyrrole containing scaffolds. • ZnO particles could effectively suppress bacterial growth. • The scaffolds were elastic with full shape-retention ability under cyclic loading. Poly(glycerol-sebacate-urethane) (PGS-U) is an attractive candidate as a super-elastic and biocompatible scaffold for inserting nanoparticles and polymers with a straightforward synthesis. Herein, a series of PGS-U scaffolds with various crosslink densities was prepared for subsequent polypyrrole (PPy) polymerization. The in-situ polymerization of PPy was employed to deposit the PPy particles throughout the scaffolds, and the continuous electrically conductive pathways were built within the scaffolds. Moreover, due to their favorable mechanical and anti-bacterial properties, zinc oxide (ZnO) nanoparticles were embedded within the scaffold. The composition of the scaffolds was confirmed by different characterization techniques, including FTIR, FE-SEM, and EDX. Static and cyclic compression tests were conducted to evaluate the mechanical performance of scaffolds under dry and hydrated conditions. All scaffolds presented high structural stability and full shape recovery after releasing the load. They were thermally stable up to at least 200 °C. The addition of PPy boosted the electrical conductivity, and the inclusion of ZnO particles improved the surface hydrophilicity and anti-bacterial behavior of the scaffolds. Altogether, this study suggests the further developments of these nanocomposites as satisfactory electrically conductive scaffolds for tissue engineering applications.

Injectable and conductive cardiac patches repair infarcted myocardium in rats and minipigs.

Cardiac patches can help to restore the electrophysiological properties of the heart after myocardial infarction. However, scaffolds for the repair of heart muscle typically require surgical implantation or, if they are injectable, they are not electrically conductive or do not maintain their shape or function. Here, we report the performance, as demonstrated for the repair of infarcted heart muscle in rats and minipigs, of injectable and conductive scaffolds consisting of methacrylated elastin and gelatin, and carbon nanotubes that display shape-memory behaviour, a hierarchical porous structure and a negligible Poisson's ratio. In rats, the implantation of cell-free patches or patches seeded with rat cardiomyocytes onto the myocardium after ligation of the left anterior descending coronary artery led to functional repair after 4 weeks, as indicated by increases in fractional shortening and the ejection fraction, and by a decrease in the infarcted area. We also observed measures of functional recovery in minipigs with infarcted hearts after the delivery of cell-free patches or patches incorporating cardiomyocytes differentiated from human pluripotent stem cells.