Tissue-wide electrophysiology with single-cell and millisecond spatiotemporal resolution is critical for heart and brain studies. Issues arise, however, from the invasive, localized implantation of electronics that destroys well-connected cellular networks within matured organs. Here, we report the creation of cyborg organoids: the three-dimensional (3D) assembly of soft, stretchable mesh nanoelectronics across the entire organoid by the cell–cell attraction forces from 2D-to-3D tissue reconfiguration during organogenesis. We demonstrate that stretchable mesh nanoelectronics can migrate with and grow into the initial 2D cell layers to form the 3D organoid structure with minimal impact on tissue growth and differentiation. The intimate contact between the dispersed nanoelectronics and cells enables us to chronically and systematically observe the evolution, propagation, and synchronization of the bursting dynamics in human cardiac organoids through their entire organogenesis.

architecture, diversity, and electrophysiology of the human brain at early stages. [7,8] Brain organoids thus provide a reliable and easily accessible platform to study human brain development and neurodevelopmental diseases, [9][10][11][12] bridging the gap between animal research and human clinical study.However, long-term stable recording of single-cell electrophysiology in developing brain organoids is still a challenge. The recording technology not only needs to form minimally invasive and long-term stable electrical interfaces with individual neurons 3D distributed across brain organoids but also needs to accommodate the rapid volume change occurring during the organoid organogenesis and cortical expansion. Optical imaging coupled with fluorescence dyes [13] or calcium indicators [14] has been used to visualize the neuron activities in 3D. They, however, are limited by temporal resolution, penetration depth, and long-term signal stability. Electrical measurement techniques such as 2D multielectrode arrays (MEA) [15,16] and patch-clamp [17,18] have been applied to measure the functional development of brain organoids, but they can only capture the activities from the bottom surface of brain organoids [1,19,20] or assay one cell at a time with cell membrane disruption. The recent development of 3D bioelectronics enables 3D interfaces with brain organoids. [21][22][23][24][25][26][27] However, they either only contact organoids at the surface by flexible electronics, [21][22][23] where noncorrelated and 3D-distributed single-unit action potentials cannot be recorded, or penetrate organoids invasively by rigid probes, [25] which cannot further accommodate volume and morphological changes of brain organoids during development. It has also been shown that organoids can grow around a suspended array of electrodes, [26,27] but the electrodes cannot deform to adapt to the morphological changes of the organoid. To date, it is still a challenge to noninvasively probe neuron activity at single-cell, single-spike spatiotemporal resolution across the 3D volume of brain organoids, and over the time course of development. This constraint prevents further understanding of the functional development in brain organoids and standardizing culture conditions and protocols for brain organoid generation based on their electrical functions.Recently, we developed a cyborg organoid platform by integrating "tissue-like" stretchable mesh nanoelectronics with 2D stem cell sheets. Leveraging the 2D-to-3D reconfiguration Human induced pluripotent stem cell derived brain organoids have shown great potential for studies of human brain development and neurological disorders. However, quantifying the evolution of the electrical properties of brain organoids during development is currently limited by the measurement techniques, which cannot provide long-term stable 3D bioelectrical interfaces with developing brain organoids. Here, a cyborg brain organoid platform is reported, in which "tissue-like" stretchable mesh nanoelectronics are designed...

Quantifying RNAs in their spatial context is crucial to understanding gene expression and regulation in complex tissues. In situ transcriptomic methods generate spatially resolved RNA profiles in intact tissues. However, there is a lack of a unified computational framework for integrative analysis of in situ transcriptomic data. Here, we introduce an unsupervised and annotation-free framework, termed ClusterMap, which incorporates the physical location and gene identity of RNAs, formulates the task as a point pattern analysis problem, and identifies biologically meaningful structures by density peak clustering (DPC). Specifically, ClusterMap precisely clusters RNAs into subcellular structures, cell bodies, and tissue regions in both two- and three-dimensional space, and performs consistently on diverse tissue types, including mouse brain, placenta, gut, and human cardiac organoids. We demonstrate ClusterMap to be broadly applicable to various in situ transcriptomic measurements to uncover gene expression patterns, cell niche, and tissue organization principles from images with high-dimensional transcriptomic profiles.

Tissue-wide electrophysiology with single-cell and millisecond spatiotemporal resolution is critical for heart and brain studies, yet issues arise from invasive, localized implantation of electronics that destructs the well-connected cellular networks within matured organs. Here, we report the creation of cyborg organoids: the three-dimensional (3D) assembly of soft, stretchable mesh nanoelectronics across the entire organoid by cell-cell attraction forces from 2D-to-3D tissue reconfiguration during organogenesis. We demonstrate that stretchable mesh nanoelectronics can grow into and migrate with the initial 2D cell layers to form the 3D structure with minimal interruptions to tissue growth and differentiation. The intimate contact of nanoelectronics to cells enables us to chronically and systematically observe the evolution, propagation and synchronization of the bursting dynamics in human cardiac organoids through their entire organogenesis.

Spatiotemporal regulation of the cellular transcriptome is crucial for proper protein expression and cellular function. However, the intricate subcellular dynamics of RNA remain obscured due to the limitations of existing transcriptomics methods. Here, we report TEMPOmap—a method that uncovers subcellular RNA profiles across time and space at the single-cell level. TEMPOmap integrates pulse-chase metabolic labeling with highly multiplexed three-dimensional in situ sequencing to simultaneously profile the age and location of individual RNA molecules. Using TEMPOmap, we constructed the subcellular RNA kinetic landscape in various human cells from transcription and translocation to degradation. Clustering analysis of RNA kinetic parameters across single cells revealed ‘kinetic gene clusters’ whose expression patterns were shaped by multistep kinetic sculpting. Importantly, these kinetic gene clusters are functionally segregated, suggesting that subcellular RNA kinetics are differentially regulated in a cell-state- and cell-type-dependent manner. Spatiotemporally resolved transcriptomics provides a gateway to uncovering new spatiotemporal gene regulation principles.

The cyborg brain organoid platform reported by Jia Liu and co-workers in article number 2106829 features "tissue-like" stretchable mesh nanoelectronics designed to match the mechanical properties of brain organoids and to be folded by the organogenetic process of progenitor or stem cells. Long-term stable, continuous recording is enabled and the emergence of single-cell action potentials from early-stage brain organoid development can be captured. A 3D reconstructed fluorescence image of cyborg brain organoid tissue is shown. The red represents neural stem cells, the green neurons, the blue cell nuclei, and the yellow soft nanoelectronic interconnects and sensors.

Clinical translation of stem cell therapies for heart disease requires electrical integration of transplanted cardiomyocytes. Generation of electrically matured human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) is critical for electrical integration. Here, we found that hiPSC-derived endothelial cells (hiPSC-ECs) promoted the expression of selected maturation markers in hiPSC-CMs. Using tissue-embedded stretchable mesh nanoelectronics, we achieved a long-term stable map of human three-dimensional (3D) cardiac microtissue electrical activity. The results revealed that hiPSC-ECs accelerated the electrical maturation of hiPSC-CMs in 3D cardiac microtissues. Machine learning–based pseudotime trajectory inference of cardiomyocyte electrical signals further revealed the electrical phenotypic transition path during development. Guided by the electrical recording data, single-cell RNA sequencing identified that hiPSC-ECs promoted cardiomyocyte subpopulations with a more mature phenotype, and multiple ligand-receptor interactions were up-regulated between hiPSC-ECs and hiPSC-CMs, revealing a coordinated multifactorial mechanism of hiPSC-CM electrical maturation. Collectively, these findings show that hiPSC-ECs drive hiPSC-CM electrical maturation via multiple intercellular pathways.

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