Catalytic polymer self-cleavage for CO generation before combustion empowers materials with fire safety.

Polymeric materials, rich in carbon, hydrogen, and oxygen elements, present substantial fire hazards to both human life and property due to their intrinsic flammability. Overcoming this challenge in the absence of any flame-retardant elements is a daunting task. Herein, we introduce an innovative strategy employing catalytic polymer auto-pyrolysis before combustion to proactively release CO, akin to possessing responsive CO fire extinguishing mechanisms.

3D Bioprinting of Human Neural Tissues with Functional Connectivity.

Probing how the human neural networks operate is hindered by the lack of reliable human neural tissues amenable for dynamic functional assessment of neural circuits. We developed a 3D bioprinting platform to assemble tissues with defined human neural cell types in a desired dimension using a commercial bioprinter. The printed neuronal progenitors differentiate to neurons and form functional neural circuits in and between tissue layers with specificity within weeks, evidenced by the cortical-to-striatal projection, spontaneous synaptic currents and synaptic response to neuronal excitation.

3D bioprinting of human neural tissues with functional connectivity.

Probing how human neural networks operate is hindered by the lack of reliable human neural tissues amenable to the dynamic functional assessment of neural circuits. We developed a 3D bioprinting platform to assemble tissues with defined human neural cell types in a desired dimension using a commercial bioprinter. The printed neuronal progenitors differentiate into neurons and form functional neural circuits within and between tissue layers with specificity within weeks, evidenced by the cortical-to-striatal projection, spontaneous synaptic currents, and synaptic response to neuronal excitation.

Generation of locus coeruleus norepinephrine neurons from human pluripotent stem cells.

Central norepinephrine (NE) neurons, located mainly in the locus coeruleus (LC), are implicated in diverse psychiatric and neurodegenerative diseases and are an emerging target for drug discovery. To facilitate their study, we developed a method to generate 40-60% human LC-NE neurons from human pluripotent stem cells. The approach depends on our identification of ACTIVIN A in regulating LC-NE transcription factors in dorsal rhombomere 1 (r1) progenitors.

Neural lineage differentiation of human pluripotent stem cells: Advances in disease modeling.

Brain diseases affect 1 in 6 people worldwide. These diseases range from acute neurological conditions such as stroke to chronic neurodegenerative disorders such as Alzheimer's disease. Recent advancements in tissue-engineered brain disease models have overcome many of the different shortcomings associated with the various animal models, tissue culture models, and epidemiologic patient data that are commonly used to study brain disease.

Generation of Cerebral Cortical Neurons from Human Pluripotent Stem Cells in 3D Culture.

Human forebrain cortical neurons are essential for fundamental functions like memory and consciousness. Generation of cortical neurons from human pluripotent stem cells provides a great source for creating models specific to cortical neuron diseases and for developing therapeutics. This chapter describes a detailed and robust method for generating human mature cortical neurons from stem cells in 3D suspension culture.

Studying Heterotypic Cell⁻Cell Interactions in the Human Brain Using Pluripotent Stem Cell Models for Neurodegeneration.

Human cerebral organoids derived from induced pluripotent stem cells (iPSCs) provide novel tools for recapitulating the cytoarchitecture of the human brain and for studying biological mechanisms of neurological disorders. However, the heterotypic interactions of neurovascular units, composed of neurons, pericytes (i.e.

The Use of Pluripotent Stem Cell-Derived Organoids to Study Extracellular Matrix Development during Neural Degeneration.

The mechanism that causes the Alzheimer's disease (AD) pathologies, including amyloid plaque, neurofibrillary tangles, and neuron death, is not well understood due to the lack of robust study models for human brain. Three-dimensional organoid systems based on human pluripotent stem cells (hPSCs) have shown a promising potential to model neurodegenerative diseases, including AD. These systems, in combination with engineering tools, allow in vitro generation of brain-like tissues that recapitulate complex cell-cell and cell-extracellular matrix (ECM) interactions.

Cell population balance of cardiovascular spheroids derived from human induced pluripotent stem cells.

Stem cell-derived cardiomyocytes and vascular cells can be used for a variety of applications such as studying human heart development and modelling human disease in culture. In particular, protocols based on modulation of Wnt signaling were able to produce high quality of cardiomyocytes or vascular cells from human pluripotent stem cells (hPSCs). However, the mechanism behind the development of 3D cardiovascular spheroids into either vascular or cardiac cells has not been well explored.

Fast Generation of Functional Subtype Astrocytes from Human Pluripotent Stem Cells.

Differentiation of astrocytes from human pluripotent stem cells (hPSCs) is a tedious and variable process. This hampers the study of hPSC-generated astrocytes in disease processes and drug development. By using CRISPR/Cas9-mediated inducible expression of NFIA or NFIA plus SOX9 in hPSCs, we developed a method to efficiently generate astrocytes in 4-7 weeks.

Modeling Neurodegenerative Microenvironment Using Cortical Organoids Derived from Human Stem Cells.

Alzheimer's disease (AD) is one of the most common neurodegenerative disorders and causes cognitive impairment and memory deficits of the patients. The mechanism of AD is not well known, due to lack of human brain models. Recently, mini-brain tissues called organoids have been derived from human induced pluripotent stem cells (hiPSCs) for modeling human brain development and neurological diseases.

Derivation of Cortical Spheroids from Human Induced Pluripotent Stem Cells in a Suspension Bioreactor.

Human induced pluripotent stem cells (hiPSCs) emerge as a promising source to construct human brain-like tissues, spheroids, or organoids in vitro for disease modeling and drug screening. A suspension bioreactor can be used to generate large size of brain organoids from hiPSCs through enhanced diffusion, but the influence of a dynamic bioreactor culture environment on neural tissue patterning from hiPSCs has not been well understood. The objective of this study is to assess the influence of a suspension bioreactor culture on cortical spheroid (i.

Pluripotent stem cell expansion and neural differentiation in 3-D scaffolds of tunable Poisson's ratio.

Unlabelled: Biophysical properties of the scaffolds such as the elastic modulus, have been recently shown to impact stem cell lineage commitment. On the other hand, the contribution of the Poisson's ratio, another important biophysical property, to the stem cell fate decision, has not been studied. Scaffolds with tunable Poisson's ratio (ν) (termed as auxetic scaffolds when Poisson's ratio is zero or negative) are anticipated to provide a spectrum of unique biophysical 3-D microenvironments to influence stem cell fate.

Catalase-Laden Microdevices for Cell-Mediated Enzyme Delivery.

Enzymes have been used to treat various human diseases and traumas. However, the therapeutic utility of free enzymes is impeded by their short circulation time, lack of targeting ability, immunogenicity, and inability to cross biological barriers. Cell-mediated drug delivery approach offers the unique capability to overcome these limitations, but the traditional cell-mediated enzyme delivery techniques suffer from drawbacks such as risk of intracellular degradation of and low loading capacity for the payload enzyme.

Neural patterning of human induced pluripotent stem cells in 3-D cultures for studying biomolecule-directed differential cellular responses.

Introduction: Appropriate neural patterning of human induced pluripotent stem cells (hiPSCs) is critical to generate specific neural cells/tissues and even mini-brains that are physiologically relevant to model neurological diseases. However, the capacity of signaling factors that regulate 3-D neural tissue patterning in vitro and differential responses of the resulting neural populations to various biomolecules have not yet been fully understood.

Methods: By tuning neural patterning of hiPSCs with small molecules targeting sonic hedgehog (SHH) signaling, this study generated different 3-D neuronal cultures that were mainly comprised of either cortical glutamatergic neurons or motor neurons.

Generation of Neural Progenitor Spheres from Human Pluripotent Stem Cells in a Suspension Bioreactor.

Conventional two-dimensional (2-D) culture systems cannot provide large numbers of human pluripotent stem cells (hPSCs) and their derivatives that are demanded for commercial and clinical applications in in vitro drug screening, disease modeling, and potentially cell therapy. The technologies that support three-dimensional (3-D) suspension culture, such as a stirred bioreactor, are generally considered as promising approaches to produce the required cells. Recently, suspension bioreactors have also been used to generate mini-brain-like structure from hPSCs for disease modeling, showing the important role of bioreactor in stem cell culture.

Crosslinking of extracellular matrix scaffolds derived from pluripotent stem cell aggregates modulates neural differentiation.

Unlabelled: At various developmental stages, pluripotent stem cells (PSCs) and their progeny secrete a large amount of extracellular matrices (ECMs) which could interact with regulatory growth factors to modulate stem cell lineage commitment. ECMs derived from PSC can be used as unique scaffolds that provide broad signaling capacities to mediate cellular differentiation. However, the rapid degradation of ECMs can impact their applications as the scaffolds for in vitro cell expansion and in vivo transplantation.

Differential effects of acellular embryonic matrices on pluripotent stem cell expansion and neural differentiation.

Extracellular matrices (ECM) derived from pluripotent stem cells (PSCs) provide a unique tissue microenvironment that can direct cellular differentiation and tissue regeneration, and rejuvenate aged progenitor cells. The unlimited growth capacity of PSCs allows for the scalable generation of PSC-secreted ECMs. Therefore, the derivation and characterization of PSC-derived ECMs is of critical importance in drug screening, disease modeling and tissue regeneration.

Cryopreservation of embryonic stem cell-derived multicellular neural aggregates labeled with micron-sized particles of iron oxide for magnetic resonance imaging.

Magnetic resonance imaging (MRI) provides an effective approach to track labeled pluripotent stem cell (PSC)-derived neural progenitor cells (NPCs) for neurological disorder treatments after cell labeling with a contrast agent, such as an iron oxide derivative. Cryopreservation of pre-labeled neural cells, especially in three-dimensional (3D) structure, can provide a uniform cell population and preserve the stem cell niche for the subsequent applications. In this study, the effects of cryopreservation on PSC-derived multicellular NPC aggregates labeled with micron-sized particles of iron oxide (MPIO) were investigated.

Asymmetric biodegradable microdevices for cell-borne drug delivery.

Use of live cells as carriers for drug-laden particulate structures possesses unique advantages for drug delivery. In this work, we report on the development of a novel type of particulate structures called microdevices for cell-borne drug delivery. The microdevices were fabricated by soft lithography with a disklike shape.

Intracellular labeling of mouse embryonic stem cell-derived neural progenitor aggregates with micron-sized particles of iron oxide.

Background Aims: Pluripotent stem cell (PSC)-derived neural progenitor cells (NPCs) represent an unlimited source for the treatment of various neurological disorders. NPCs are usually derived from PSCs through the formation of embryoid body (EB), an aggregate structure mimicking embryonic development. This study investigated the effect of labeling multicellular EB-NPC aggregates with micron-sized particles of iron oxide (MPIO) for cell tracking using magnetic resonance imaging (MRI).

Facile functionalization and assembly of live cells with microcontact-printed polymeric biomaterials.

The functionalization and assembly of live cells with microfabricated polymeric biomaterials have attracted considerable interest in recent years, but the conventional methods suffer from high cost, high complexity, long processing time or inadequate capability. The present study reports on the development of a novel method for functionalizing and assembling live cells by integrating microcontact printing of polymeric biomaterials with a temperature-sensitive sacrificial layer prepared by spin-coating. This method has been used not only to functionalize live cells with microscopic polyelectrolyte and thermoplastic structures of various sizes and shapes, but also to assemble the cells into macroscopic stripes and sheets.

Labeling pluripotent stem cell-derived neural progenitors with iron oxide particles for magnetic resonance imaging.

Due to the unlimited proliferation capacity and the unique differentiation ability of pluripotent stem cells (PSCs), including both embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), large numbers of PSC-derived cell products are in demand for applications in drug screening, disease modeling, and especially cell therapy. In stem cell-based therapy, tracking transplanted cells with magnetic resonance imaging (MRI) has emerged as a powerful technique to reveal cell survival and distribution. This chapter illustrated the basic steps of labeling PSC-derived neural progenitors (NPs) with micron-sized particles of iron oxide (MPIO, 0.

The microenvironment of embryoid bodies modulated the commitment to neural lineage postcryopreservation.

Neural progenitor cells are usually derived from pluripotent stem cells (PSCs) through the formation of embryoid bodies (EBs), the three-dimensional (3D) aggregate-like structure mimicking embryonic development. Cryo-banking of EBs is a critical step for sample storage, process monitoring, and preservation of intermediate cell populations during the lengthy differentiation procedure of PSCs. However, the impact of microenvironment (including 3D cell organization and biochemical factors) of EBs on neural lineage commitment postcryopreservation has not been well understood.

Neural differentiation from pluripotent stem cells: The role of natural and synthetic extracellular matrix.

Neural cells differentiated from pluripotent stem cells (PSCs), including both embryonic stem cells and induced pluripotent stem cells, provide a powerful tool for drug screening, disease modeling and regenerative medicine. High-purity oligodendrocyte progenitor cells (OPCs) and neural progenitor cells (NPCs) have been derived from PSCs recently due to the advancements in understanding the developmental signaling pathways. Extracellular matrices (ECM) have been shown to play important roles in regulating the survival, proliferation, and differentiation of neural cells.