Selective Induction of Molecular Assembly to Tissue-Level Anisotropy on Peptide-Based Optoelectronic Cardiac Biointerfaces.

The conduction efficiency of ions in excitable tissues and of charged species in organic conjugated materials both benefit from having ordered domains and anisotropic pathways. In this study, a photocurrent-generating cardiac biointerface is presented, particularly for investigating the sensitivity of cardiomyocytes to geometrically comply to biomacromolecular cues differentially assembled on a conductive nanogrooved substrate. Through a polymeric surface-templated approach, photoconductive substrates with symmetric peptide-quaterthiophene (4T)-peptide units assembled as 1D nanostructures on nanoimprinted polyalkylthiophene (P3HT) surface are developed. The 4T-based peptides studied here can form 1D nanostructures on prepatterned polyalkylthiophene substrates, as directed by hydrogen bonding, aromatic interactions between 4T and P3HT, and physical confinement on the nanogrooves. It is observed that smaller 4T-peptide units that can achieve a higher degree of assembly order within the polymeric templates serve as a more efficient driver of cardiac cytoskeletal anisotropy than merely presenting aligned -RGD bioadhesive epitopes on a nanotopographic surface. These results unravel some insights on how cardiomyocytes perceive submicrometer dimensionality, local molecular order, and characteristics of surface cues in their immediate environment. Overall, the work offers a cardiac patterning platform that presents the possibility of a gene modification-free cardiac photostimulation approach while controlling the conduction directionality of the biotic and abiotic components.

Engineering Multi-Scale Organization for Biotic and Organic Abiotic Electroactive Systems.

Multi-scale organization of molecular and living components is one of the most critical parameters that regulate charge transport in electroactive systems-whether abiotic, biotic, or hybrid interfaces. In this article, an overview of the current state-of-the-art for controlling molecular order, nanoscale assembly, microstructure domains, and macroscale architectures of electroactive organic interfaces used for biomedical applications is provided. Discussed herein are the leading strategies and challenges to date for engineering the multi-scale organization of electroactive organic materials, including biomolecule-based materials, synthetic conjugated molecules, polymers, and their biohybrid analogs. Importantly, this review provides a unique discussion on how the dependence of conduction phenomena on structural organization is observed for electroactive organic materials, as well as for their living counterparts in electrogenic tissues and biotic-abiotic interfaces. Expansion of fabrication capabilities that enable higher resolution and throughput for the engineering of ordered, patterned, and architecture electroactive systems will significantly impact the future of bioelectronic technologies for medical devices, bioinspired harvesting platforms, and in vitro models of electroactive tissues. In summary, this article presents how ordering at multiple scales is important for modulating transport in both the electroactive organic, abiotic, and living components of bioelectronic systems.