Poly(glycerol sebacate) (PGS) is promising for engineering flexible cardiac patches for myocardial infarction repair due to its unique elasticity. However, its insulating nature and complex thermal curing process hinder existing 3D printing techniques from producing patches that recapitulate the mechanical, electrical, and anatomical features of native myocardium. Here, a melt-based embedded printing strategy enabling direct, freeform fabrication of thermosetting PGS architectures with in situ thermal curing is proposed. The viscoelastic matrix enables high-fidelity extrusion of PGS prepolymer into microscale filaments while providing temporary support for in situ curing of PGS elastomeric architectures with seamless interface fusion and mechanical stability. This platform further allows direct printing of electro-conductive cardiac patches using carbon nanotube-incorporated PGS that mimic ventricular curvature and mechanical anisotropy. Compared to pure PGS controls, the electro-conductive patches enhance cardiomyocyte maturation in vitro, evidenced by improved sarcomere organization, calcium handling, and electrical synchronization. In vivo, these acellular patches improve mechanical integration with host myocardium, promote vascularization, reduce inflammation, and preserve cardiomyocyte survival, collectively maintaining ejection fraction and attenuating adverse remodeling. This work, therefore, establishes a generalizable manufacturing strategy for printing thermosetting elastomeric constructs with integrated conductivity as acellular, mechanically and electrically functional patches for structural cardiac repair.
Both the cellular- and population-level properties of involved neurons are essential for unveiling the learning and memory functions of the brain. To give equal attention to these two aspects, neural sensors based on microelectrode arrays (MEAs) have been in the limelight due to their noninvasive detection and regulation capabilities. Here, we fabricated a neural sensor using carboxylated graphene/3,4-ethylenedioxythiophene:polystyrenesulfonate (cGO/PEDOT:PSS), which is effective in sensing and monitoring neuronal electrophysiological activity in vitro for a long time. The cGO/PEDOT:PSS-modified microelectrodes exhibited a lower electrochemical impedance (7.26 ± 0.29 kΩ), higher charge storage capacity (7.53 ± 0.34 mC/cm2), and improved charge injection (3.11 ± 0.25 mC/cm2). In addition, their performance was maintained after 2 to 4 weeks of long-term cell culture and 50,000 stimulation pulses. During neural network training, the sensors were able to induce learning function in hippocampal neurons through precise electrical stimulation and simultaneously detect changes in neural activity at multiple levels. At the cellular level, not only were three kinds of transient responses to electrical stimulation sensed, but electrical stimulation was also found to affect inhibitory neurons more than excitatory neurons. As for the population level, changes in connectivity and firing synchrony were identified. The cGO/PEDOT:PSS-based neural sensor offers an excellent tool in brain function development and neurological disease treatment.Keywords:neural sensor;porous graphene;PEDOT;neurons;learning
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