Linna Zhou

Live cells in tissue are plastic, phenotypically dynamic, and modify their function in response to genetic and environmental perturbations. To unleash the power of live-cell imaging to identify phenotype-genotype-function coupling over time, we report the development of a standardized Shape-Appearance-Motion (SAM) “phenome” and SAM-Phenotype-Observation-Tool (SPOT), that act as an image-“transcriptome” and image-“transcriptome analyzer” respectively, and provide an unbiased and comprehensive description of morpho-dynamic phenotypes without prior knowledge. We apply SAM-SPOT to our simulated organoids database with known ground-truth and >1.6 million mouse and human organoid instances with defined genetic and chemical perturbations. SAM-SPOT can effectively and robustly characterize 3D morpho-dynamics from 2D projection videos. Combined with single-cell RNA sequencing, SAM-SPOT reveals that altered WNT signaling, but not mutant RAS or p53, predisposes intestinal organoids to irregular morphogenesis. SAM-SPOT advances biomedical discovery by empowering live-cell imaging to identify phenotype-genotype-function relationships through large-scale and cost-effective label-free live-cell imaging.

Regenerative medicine offers a promising approach to treat brain injuries, yet challenges persist in promoting neuronal survival and integration. Recent studies demonstrate that human cells implanted into rodent brains can exhibit plasticity, integrate into neural circuits and alleviate functional deficits. However, integration is often poor, with inadequate vascularization, and insufficient support cells such as astrocytes. Astrocytes play a crucial role in neuronal development and recovery by releasing growth factors, facilitating synaptogenesis, and promoting blood vessel formation. This study investigated human neuronal progenitor cells cultured alone or cultured with mouse astrocytes and formed into 3D constructs using microfluidics. Co‐cultures exhibited enhanced neuronal maturation, viability, and density. Following implantation into mouse brains, co‐cultures reduced lesion size, increased axonal growth, and improved astrocyte coupling to blood vessels within the graft. Additionally, we show that NPCs and co‐cultures increased astrocyte size in implants. Deconvolved high‐resolution microscopy identified synapses and optogenetics showed functional connections between the host and implants. These findings underscore the essential role of astrocytes in enhancing neuronal tissue integration and advancing brain injury treatments.

The poor survival of ovarian cancer patients is linked to their high likelihood of relapse. In spite of full apparent macroscopic clearance, tumor recurrences arise from cells that are resistant to primary chemotherapy in the form of minimal residual disease (MRD). MRD exhibits distinct molecular drivers from bulk cancer and therefore necessitates alternative therapeutic strategies. However, there is a lack of 3D models that faithfully recapitulate MRD ex vivo for therapy development. This study constructs microfluidics‐based 3D microtumors to generate a clinically‐relevant model for ovarian cancer MRD. The microtumors recapitulate the non‐genetic heterogeneity of ovarian cancer, capturing the “Oxford Classic” five molecular signatures. Gene expression in the 3D microtumors aligns closely with MRD from ovarian cancer patients and features the upregulation of fatty acid metabolism genes. Finally, the MRD 3D microtumors respond to the approved fatty acid oxidation inhibitor, perhexiline, demonstrating their utility in drug discovery. This system might be used as a drug‐testing platform for the discovery of novel MRD‐specific therapies in ovarian cancer.

Advances in the development of tiny devices with sizes below a few cubic millimeters require a corresponding decrease in the volume of driving power sources. To be minimally invasive, prospective power sources in biomedical devices must be fabricated from soft materials. Previous endeavors with droplet-based devices have produced promising miniature power sources; however, a droplet-based rechargeable battery has remained out of reach. Here we report a microscale soft flexible lithium-ion droplet battery (LiDB) based on the lipid-supported assembly of droplets constructed from a biocompatible silk hydrogel. Capabilities such as triggerable activation, biocompatibility and biodegradability and high capacity are demonstrated. We have used the LiDB to power the electrophoretic translocation of charged molecules between synthetic cells and to mediate the defibrillation and pacing of ex vivo mouse hearts. By the inclusion of magnetic particles to enable propulsion, the LiDB can function as a mobile energy courier. Our tiny versatile battery will thereby enable a variety of biomedical applications.

Enzyme‐enabled biobatteries are promising green options to power the next‐generation of bioelectronics and implantable medical devices. However, existing power sources based on enzymatic biofuel chemistry exhibit limited scale‐down feasibility due to the solid and bulky battery structures. Therefore, miniature and soft alternatives are needed for integration with implants and tissues. Here, a biobattery built from nanolitre droplets, fuelled by the enzyme‐enabled oxidation of reduced nicotinamide adenine dinucleotide, generates electrical outputs and powers ion fluxes in droplet networks. Optimization of the droplet biobattery components ensures a stable output current of ~13,000 pA for over 24 h, representing a more than 600‐fold increase in output over previous approaches, including light‐driven processes. The enzyme‐enabled droplet biobattery opens new avenues in bioelectronics and bioiontronics, exemplified by tasks such as the ability to drive chemical signal transmission in integrated synthetic tissues.

Enzyme‐enabled biobatteries are promising green options to power the next‐generation of bioelectronics and implantable medical devices. However, existing power sources based on enzymatic biofuel chemistry exhibit limited scale‐down feasibility due to the solid and bulky battery structures. Therefore, miniature and soft alternatives are needed for integration with implants and tissues. Here, a biobattery built from nanolitre droplets, fuelled by the enzyme‐enabled oxidation of reduced nicotinamide adenine dinucleotide, generates electrical outputs and powers ion fluxes in droplet networks. Optimization of the droplet biobattery components ensures a stable output current of ~13,000 pA for over 24 h, representing a more than 600‐fold increase in output over previous approaches, including light‐driven processes. The enzyme‐enabled droplet biobattery opens new avenues in bioelectronics and bioiontronics, exemplified by tasks such as the ability to drive chemical signal transmission in integrated synthetic tissues.

Human mutations in neuropeptide Y (NPY) have been linked to high body mass index but not altered dietary patterns¹. Here we uncover the mechanism by which NPY in sympathetic neurons^2,3 protects from obesity. Imaging of cleared mouse brown and white adipose tissue (BAT and WAT, respectively) established that NPY⁺ sympathetic axons are a smaller subset that mostly maps to the perivasculature; analysis of single-cell RNA sequencing datasets identified mural cells as the main NPY-responsive cells in adipose tissues. We show that NPY sustains the proliferation of mural cells, which are a source of thermogenic adipocytes in both BAT and WAT^4–6. We found that diet-induced obesity leads to neuropathy of NPY⁺ axons and concomitant depletion of mural cells. This defect was replicated in mice with NPY abrogated from sympathetic neurons. The loss of NPY in sympathetic neurons whitened interscapular BAT, reducing its thermogenic ability and decreasing energy expenditure before the onset of obesity. It also caused adult-onset obesity of mice fed on a regular chow diet and rendered them more susceptible to diet-induced obesity without increasing food consumption. Our results indicate that, relative to central NPY, peripheral NPY produced by sympathetic nerves has the opposite effect on body weight by sustaining energy expenditure independently of food intake.

Engineering human tissue with diverse cell types and architectures remains challenging. The cerebral cortex, which has a layered cellular architecture composed of layer-specific neurons organised into vertical columns, delivers higher cognition through intricately wired neural circuits. However, current tissue engineering approaches cannot produce such structures. Here, we use a droplet printing technique to fabricate tissues comprising simplified cerebral cortical columns. Human induced pluripotent stem cells are differentiated into upper- and deep-layer neural progenitors, which are then printed to form cerebral cortical tissues with a two-layer organization. The tissues show layer-specific biomarker expression and develop a structurally integrated network of processes. Implantation of the printed cortical tissues into ex vivo mouse brain explants results in substantial structural implant-host integration across the tissue boundaries as demonstrated by the projection of processes and the migration of neurons, and leads to the appearance of correlated Ca²⁺ oscillations across the interface. The presented approach might be used for the evaluation of drugs and nutrients that promote tissue integration. Importantly, our methodology offers a technical reservoir for future personalized implantation treatments that use 3D tissues derived from a patient’s own induced pluripotent stem cells.