Organoids by design

Enhancing organoid technology with carbon-based nanomaterial biosensors: Advancements, challenges, and future directions

Various carbon-based nanomaterials (CBNs) have been utilized to develop nano- and microscale biosensors that enable real-time and continuous monitoring of biochemical and biophysical changes in living biological systems. The integration of CBN-based biosensors into organoids has recently provided valuable insights into organoid development, disease modeling, and drug responses, enhancing their functionality and expanding their applications in diverse biomedical fields. These biosensors have been particularly transformative in studying neurological disorders, cardiovascular diseases, cancer progression, and liver toxicity, where precise, non-invasive monitoring is crucial for understanding pathophysiological mechanisms and assessing therapeutic efficacy. This review introduces intra- and extracellular biosensors incorporating CBNs such as graphene, carbon nanotubes (CNTs), graphene oxide (GO), reduced graphene oxide (rGO), carbon dots (CDs), and fullerenes. Additionally, it discusses strategies for improving the biocompatibility of CBN-based biosensors and minimizing their potential toxicity to ensure long-term organoid viability. Key challenges such as biosensor integration, data accuracy, and functional compatibility with specific organoid models are also addressed. Furthermore, this review highlights how CBN-based biosensors enhance the precision and relevance of organoid models in biomedical research, particularly in organ-specific applications such as brain-on-a-chip systems for neurodegenerative disease studies, liver-on-a-chip platforms for hepatotoxicity screening, and cardiac organoids for assessing cardiotoxicity in drug development. Finally, it explores how biosensing technologies could revolutionize personalized medicine by enabling high throughput drug screening, patient-specific disease modeling, and integrated sensing platforms for early diagnostics. By capturing current advancements and future directions, this review underscores the transformative potential of carbon-based nanotechnology in organoid research and its broader impact on medical science.

Cartilage repair: unleashing PRP's potential in organoid models

Platelet-rich plasma (PRP) has emerged as a promising biological therapy in regenerative medicine due to its high concentration of growth factors and cytokines, which promote tissue healing and regeneration. In recent years, its application in cartilage tissue engineering has garnered significant attention. This study explores the synergistic interaction between PRP and cartilage organoids, a novel three-dimensional in vitro culture system that closely mimics the structural and functional properties of native cartilage. Cartilage organoids serve as a physiologically relevant model for studying cartilage development, disease progression, and regeneration. By integrating PRP with cartilage organoids, this review aims to enhance chondrogenesis, extracellular matrix synthesis, and cellular proliferation within the organoids. Emerging evidence suggests that PRP supplementation significantly improves chondrocyte viability, growth, and differentiation in cartilage organoids, thereby accelerating their maturation. This combination holds great potential for advancing cartilage repair strategies, providing a robust platform for preclinical studies, and paving the way for innovative therapeutic approaches for cartilage-related injuries and degenerative diseases. These key aspects-chondrogenesis, matrix synthesis, and cellular proliferation-were specifically selected due to their fundamental roles in cartilage tissue engineering and regeneration. Chondrogenesis is crucial for chondrocyte differentiation and maintenance, matrix synthesis ensures the structural integrity and functional properties of regenerated cartilage, and cellular proliferation supports tissue viability and repair. Addressing these factors is essential, as current cartilage regeneration strategies often suffer from limited long-term efficacy and inadequate extracellular matrix production. By elucidating the synergistic effects of PRP and cartilage organoids in these areas, this study seeks to bridge existing knowledge gaps and provide valuable insights for improving regenerative approaches in clinical applications, particularly for osteoarthritis and cartilage defects.

Musculoskeletal organoids: An emerging toolkit for establishing personalized models of musculoskeletal disorders and developing regenerative therapies

Musculoskeletal (MSK) conditions are the primary cause of physical disability globally. These disorders are physically and mentally debilitating and severely impact the patients' quality of life. As the median age of the world's population increases, there has been an intensifying urgency of developing efficacious therapies for various orthopaedic conditions. Furthermore, the highly heterogeneous nature of MSK conditions calls for a personalized approach to studying disease mechanisms and developing regenerative treatments. Organoids have emerged as an advanced approach to generating functional tissue/organ mimics in vitro, which hold promise in MSK regeneration, disease modeling, and therapeutic development. Herein, we review the preparation, characterization, and application of various MSK organoids. We highlight the potential of patient-specific organoids in the development of personalized medicine and discuss the challenges and opportunities in the future development of MSK organoids. STATEMENT OF SIGNIFICANCE: Despite decades of research, translation of MSK research into clinical applications remains limited, partially attributed to our inadequate understanding of disease mechanisms. To advance therapeutic development, there are critical needs for MSK disease models with higher clinical relevance and predictive power. Additionally, engineered constructs that closely mimic the structural and functional features of native MSK tissues are highly desirable. MSK organoids have emerged as a promising approach to meet the above requirements. To unleash the full potential of MSK organoids necessitates a comprehensive understanding of their categories, construction, development, functions, applications, and challenges. This review aims to fulfill this crucial need, aiming to accelerate the clinical translation of MSK organoid platforms to benefit millions of patients afflicted with MSK conditions.

Self-assembled organoid-tissue modules for scalable organoid engineering: Application to chondrogenic regeneration

Tissue engineering has made significant strides in creating biomimetic grafts for the repair and regeneration of damaged tissues; however, the scalability of engineered tissue constructs remains a major technical hurdle. This study introduces a method for generating organoid-tissue modules (Organoid-TMs) through scaffold-free self-assembly of microblocks (MiBs) derived from adipose-derived mesenchymal stem cells (ADMSCs). The key parameters influencing Organoid-TM formation were identified as the density of MiBs and the controlled mixing ratio of large and small MiBs. The resulting Organoid-TM exhibited a distinctive cup-shaped morphology, a millimeter-scale structure with enhanced nutrient and oxygen diffusion compared to conventional spherical aggregates. Despite their larger size, Organoid-TMs maintained ADMSC stemness and differentiation potential, while stemness and differentiation were halted during fabrication. Organoid-TMs receiving chondrogenic cues during fabrication were transplanted into cartilage defect sites in animal models, demonstrating cartilage regeneration efficacy in a scaffold-independent and xeno-free manner. This fabrication method represents a highly reproducible and consistent process for developing spheroids or organoids, offering a robust platform for regenerative medicine applications. Specifically, Organoid-TMs provide a foundational framework for therapeutic strategies targeting cartilage defects and osteoarthritis, paving the way for advancements in tissue-engineered therapeutics. STATEMENT OF SIGNIFICANCE: This study introduces a distinct approach in tissue engineering, utilizing self-assembled Organoid-Tissue Modules (Organoid-TMs) to address persistent challenges in scalable organoid production and cartilage regeneration. By leveraging adipose-derived mesenchymal stem cells (ADMSCs) and carefully optimizing the size, ratio, and spatial organization of microblocks (MiBs), we successfully generated millimeter-scale Organoid-TMs. The distinctive cup-shaped architecture of these Organoid-TMs enhances oxygen and nutrient diffusion, effectively overcoming limitations such as core necrosis typically encountered in large-scale organoid culture. This system demonstrated substantial regenerative potential, particularly in chondrogenic differentiation and cartilage repair in both rabbit and pig models, without the use of artificial scaffolds or xenogenic materials.

3D Bioprinting Models for Glioblastoma: From Scaffold Design to Therapeutic Application

Conventional in vitro models fail to accurately mimic the tumor in vivo characteristics, being appointed as one of the causes of clinical attrition rate. Recent advances in 3D culture techniques, replicating essential physical and biochemical cues such as cell-cell and cell-extracellular matrix interactions, have led to the development of more realistic tumor models. Bioprinting has emerged to advance the creation of 3D in vitro models, providing enhanced flexibility, scalability, and reproducibility. This is crucial for the development of more effective drug treatments, and glioblastoma (GBM) is no exception. GBM, the most common and deadly brain cancer, remains a major challenge, with a median survival of only 15 months post-diagnosis. This review highlights the key components needed for 3D bioprinted GBM models. It encompasses an analysis of natural and synthetic biomaterials, along with crosslinking methods to improve structural integrity. Also, it critically evaluates current 3D bioprinted GBM models and their integration into GBM-on-a-chip platforms, which hold noteworthy potential for drug screening and personalized therapies. A versatile development framework grounded on Quality-by-Design principles is proposed to guide the design of bioprinting models. Future perspectives, including 4D bioprinting and machine learning approaches, are discussed, along with the current gaps to advance the field further.

Engineering neuronal networks in granular microgels to innervate bioprinted cancer organoids on-a-chip

Organoid models are invaluable for studying organ processes in vitro, offering an unprecedented ability to replicate organ function. Despite recent advancements that have increased their cellular complexity, organoids generally lack key specialized cell types, such as neurons, limiting their ability to fully model organ function and dysfunction. Innervating organoids remains a significant challenge due to the asynchronous biological cues governing neural and organ development. Here, we present a versatile organ-on-a-chip platform designed to innervate organoids across diverse tissue types. Our strategy enables the development of innervated granular hydrogel tissue constructs, followed by the sequential addition of organoids. The microfluidic device features an open tissue chamber, which can be easily manipulated using standard pipetting or advanced bioprinting techniques. Engineered to accommodate microgels of any material larger than 50 μm, the chamber provides flexibility for constructing customizable hydrogel environments. Organoids and other particles can be precisely introduced into the device at any stage using aspiration-assisted bioprinting. To validate this platform, we demonstrate the successful growth of primary mouse superior cervical ganglia (mSCG) neurons and the platform's effectiveness in innervating prostate cancer spheroids and patient-derived renal cell carcinoma organoids. This platform offers a robust and adaptable tool for generating complex innervated organoids, paving the way for more accurate in vitro models of organ development, function, and disease.

Nanocomposite Hydrogels and Micro/Nanostructures for Printing Organoids

Organoids are 3D artificial miniature organs composed of a cluster of self-renewing and self-organizing cells in vitro, which mimic the functions of real organs. Nanotechnologies, including the preparation of nanomaterials and the fabrication of micro/nanostructures, have been proven to promote cell proliferation, guide cell differentiation, and regulate cell self-organization, showing great promise in engineering organoids. In this Perspective, different types of nanocomposite hydrogels for organoid culture are summarized, the effects of micro/nanostructures on organoid growth and development are discussed, and 3D bioprinting technologies for constructing organoid models are introduced.

Development and Applications of Organoids in Gynecological Diseases

Organoids are rapidly self-organizing 3D in vitro cultures derived from pluripotent stem cells (PSCs) or adult stem cells (ASCs) that possess disease-like characteristics with high success rates. Due to their ability to retain tissue structure, biological phenotypes, and genetic information, they have been utilized as a novel in vitro model for disease research. In recent years, scientists have established self-organizing 3D organoids for human endometrium, fallopian tubes, ovaries, and cervix by culturing stem cells with cytokines in 3D scaffolds. The integration of organoids with animal models, organ-on-a-chip systems, and 3D printing technologies offers a novel preclinical model for exploring disease mechanisms and developing treatments. This review elaborate on the recent research progress of stem cells-formed organoids in the field of gynecology from the aspects of constructing gynecological disease organoids, drug screening and new drug development, simulation modeling, allogeneic transplantation, regenerative medicine and personalized treatment."

4D Biofabrication of Magnetically Augmented Callus Assembloid Implants Enables Rapid Endochondral Ossification via Activation of Mechanosensitive Pathways

The use of magnetic-driven strategies for non-contact manipulation of engineered living modules opens up new possibilities for tissue engineering. The integration of magnetic nanoparticles (MNPs) with cartilaginous microtissues enables model-driven 4D bottom-up biofabrication of remotely actuated assembloids, providing unique properties to mechanoresponsive tissues, particularly skeletal constructs. However, for clinical use, the long-term effects of magnetic stimulation on phenotype and in vivo functionality need further exploration. Magnetic-driven biofabrication includes both rapid processes, such as guided microtissue assembly, and slower biological processes, like extracellular matrix secretion. This work explores the interplay between magnetic fields and MNP-loaded cartilaginous microtissues through mathematical modeling and experimental approaches, investigating long-term stimulation effects on ECM maturation and chondrogenic hypertrophy. Transcriptomic analysis reveal that magnetic stimulation activated mechanosensitive pathways and catabolic processes, driving accelerated cartilage-to-bone transitions via endochondral ossification, outcomes not observed in non-stimulated controls. This study paves the way for pre-programmed, remotely actuated skeletal assembloids with superior bone-forming capacity for regenerating challenging bone fractures.

Dynamic GelMA/DNA Dual-Network Hydrogels Promote Woven Bone Organoid Formation and Enhance Bone Regeneration

Bone organoids, in vitro models mimicking native bone structure and function, rely on 3D stem cell culture for self-organization, differentiation, ECM secretion, and biomineralization, ultimately forming mineralized collagen hierarchies. However, their development is often limited by the lack of suitable matrices with optimal mechanical properties for sustained cell growth and differentiation. To address this, a dynamic DNA/Gelatin methacryloyl (GelMA) hydrogel (CGDE) is developed to recapitulate key biochemical and mechanical features of the bone ECM, providing a supportive microenvironment for bone organoid formation. This dual-network hydrogel is engineered through hydrogen bonding between DNA and GelMA, combined with GelMA network crosslinking, resulting in appropriate mechanical strength and enhanced viscoelasticity. During a 21-day 3D culture, the CGDE hydrogel facilitates cellular migration and self-organization, promoting woven bone organoid (WBO) formation via intramembranous ossification. These WBOs exhibit spatiotemporal architectures supporting dynamic mineralization and tissue remodeling. In vivo studies demonstrate that CGDE-derived WBOs exhibit self-adaptive properties, enabling rapid osseointegration within 4 weeks. This work highlights the CGDE hydrogel as a robust and scalable platform for bone organoid development, offering new insights into bone biology and innovative strategies for bone tissue regeneration.

A microfluidic platform for anterior-posterior human endoderm patterning via countervailing morphogen gradients in vitro

Understanding how morphogen gradients spatially pattern tissues is a fundamental question in developmental biology but can be difficult to directly address using conventional approaches. Here, we expose hPSC-derived endoderm cells to countervailing gradients of anteriorizing and posteriorizing signals using a widely available microfluidic device. This approach yielded spatially patterned cultures comprising anterior foregut (precursor to the thyroid, esophagus, and lungs) and mid/hindgut (precursor to the intestines) cells, whose identities were confirmed using single-cell RNA sequencing (scRNA-seq). By exposing stem cells to externally applied signaling gradients, this widely accessible microfluidic platform should accelerate the production of spatially patterned tissues, complementing internally self-organizing organoids. Applying artificial morphogen gradients in vitro may also illuminate how developing tissues interpret signaling gradients in systems that are not readily accessible for in vivo studies.

Organoids-on-a-chip: microfluidic technology enables culture of organoids with enhanced tissue function and potential for disease modeling

Organoids are stem-cell derived tissue structures mimicking specific structural and functional characteristics of human organs. Despite significant advancements in the field over the last decade, challenges like limited long-term functional culture and lack of maturation are hampering the implementation of organoids in biomedical research. Culture of organoids in microfluidic chips is being used to tackle these challenges through dynamic and precise control over the organoid microenvironment. This review highlights the significant breakthroughs that have been made in the innovative field of "organoids-on-chip," demonstrating how these have contributed to advancing organoid models. We focus on the incorporation of organoids representative for various tissues into chips and discuss the latest findings in multi-organoids-on-chip approaches. Additionally, we examine current limitations and challenges of the field towards the development of reproducible organoids-on-chip systems. Finally, we discuss the potential of organoids-on-chip technology for both in vitro and in vivo applications.

Hepatobiliary organoid research: the progress and applications

Organoid culture has emerged as a forefront technology in the life sciences field. As "in vitro micro-organs", organoids can faithfully recapitulate the organogenesis process, and conserve the key structure, physiological function and pathological state of the original tissue or organ. Consequently, it is widely used in basic and clinical studies, becoming important preclinical models for studying diseases and developing therapies. Here, we introduced the definition and advantages of organoids and described the development and advances in hepatobiliary organoids research. We focus on applying hepatobiliary organoids in benign and malignant diseases of the liver and biliary tract, drug research, and regenerative medicine to provide valuable reference information for the application of hepatobiliary organoids. Despite advances in research and treatment, hepatobiliary diseases including carcinoma, viral hepatitis, fatty liver and bile duct defects have still been conundrums of the hepatobiliary field. It is necessary and crucial to study disease mechanisms, establish efficient and accurate research models and find effective treatment strategies. The organoid culture technology shed new light on solving these issues. However, the technology is not yet mature, and many hurdles still exist that need to be overcome. The combination with new technologies such as CRISPR-HOT, organ-on-a-chip may inject new vitality into future development.

Simple-Flow: A 3D-Printed Multiwell Flow Plate to Coculture Primary Human Lung Cells at the Air-Liquid Interface

Immortalized epithelial cell lines and animal models have been used in fundamental and preclinical research to study pulmonary diseases. However valuable, though, these models incompletely recapitulate the in vivo human lung, which leads to low predictive outcomes in potential respiratory treatments. Advanced technology and cell culture techniques stimulate the development of improved models that more closely mimic the physiology of the human lung. Nonetheless, most of these models are technically demanding and have a low throughput and reproducibility. Here, we describe a robust fluidic device consisting of a biocompatible and customizable 3D-printed cell culture plate, the Simple-Flow, which has medium throughput, is simple to manufacture, and is easy to set up. As a proof of principle, human primary bronchial epithelial cells (hPBECs) and human pulmonary microvascular endothelial cells (hMVECs) were cocultured on the apical and basolateral sides of the inset membranes, respectively. While hPBECs were cultured at the air-liquid interface to induce mucociliary differentiation, hMVECs were exposed to flow medium for up to 2 weeks. We show the versatility of 3D-printing technology in designing in vitro models for cell culturing applications, such as pediatric lung diseases or other pulmonary disorders.

Modeling the Effect of Cannabinoid Exposure During Human Neurodevelopment Using Bidimensional and Tridimensional Cultures

Our knowledge about the consumption of cannabinoids during pregnancy lacks consistent evidence to determine whether it compromises neurodevelopment. Addressing this task is challenging and complex since pregnant women display multiple confounding factors that make it difficult to identify the real effect of cannabinoids' consumption. Recent studies shed light on this issue by using pluripotent stem cells of human origin, which can recapitulate human neurodevelopment. These revolutionary platforms allow studying how exogenous cannabinoids could alter human neurodevelopment without ethical concerns and confounding factors. Here, we review the information to date on the clinical studies about the impact of exogenous cannabinoid consumption on human brain development and how exogenous cannabinoids alter nervous system development in humans using cultured pluripotent stem cells as 2D and 3D platforms to recapitulate brain development.

In toto biological framework: Modeling interconnectedness during human development

Recent advancements in pluripotent stem cell and synthetic tissue technology have brought significant breakthroughs in studying early embryonic development, particularly within the first trimester of development in humans. However, during fetal stage development, investigating further biological events represents a major challenge, partly due to the evolving complexity and continued interaction across multiple organ systems. To bridge this gap, we propose an "in toto" biological framework that leverages a triad of technologies: synthetic tissues, intravital microscopy, and computer vision to capture in vivo cellular morphodynamics, conceptualized as single-cell choreography. This perspective will discuss the inherent challenges in capturing such complexities and explore engineering technologies to delve into the less-explored phase of human development. We also propose reframing the organ-centric to a system-centric paradigm, as such a framework broadens the value of the in vivo-embedded synthetic-tissue-based approach for interrogating the multifaceted interplay of human developmental processes during this crucial stage.

Deciphering the interplay between biology and physics with a finite element method-implemented vertex organoid model: A tool for the mechanical analysis of cell behavior on a spherical organoid shell

Understanding the interplay between biology and mechanics in tissue architecture is challenging, particularly in terms of 3D tissue organization. Addressing this challenge requires a biological model enabling observations at multiple levels from cell to tissue, as well as theoretical and computational approaches enabling the generation of a synthetic model that is relevant to the biological model and allowing for investigation of the mechanical stresses experienced by the tissue. Using a monolayer human colon epithelium organoid as a biological model, freely available tools (Fiji, Cellpose, Napari, Morphonet, or Tyssue library), and the commercially available Abaqus FEM solver, we combined vertex and FEM approaches to generate a comprehensive viscoelastic finite element model of the human colon organoid and demonstrated its flexibility. We imaged human colon organoid development for 120 hours, following the evolution of the organoids from an immature to a mature morphology. According to the extracted architectural/geometric parameters of human colon organoids at various stages of tissue architecture establishment, we generated organoid active vertex models. However, this approach did not consider the mechanical aspects involved in the organoids' morphological evolution. Therefore, we applied a finite element method considering mechanical loads mimicking osmotic pressure, external solicitation, or active contraction in the vertex model by using the Abaqus FEM solver. Integration of finite element analysis (FEA) into the vertex model achieved a better fit with the biological model. Therefore, the FEM model provides a basis for depicting cell shape, tissue deformation, and cellular-level strain due to imposed stresses. In conclusion, we demonstrated that a combination of vertex and FEM approaches, combining geometrical and mechanical parameters, improves modeling of alterations in organoid morphology over time and enables better assessment of the mechanical cues involved in establishing the architecture of the human colon epithelium.

The Promise and Challenges of Bioprinting in Tissue Engineering

Organ transplantation, biomimetic organ models, and the restoration of damaged or eviscerated tissues have been key goals in surgical and medical research since their inception [...].

An integrated microfluidic device for sorting of tumor organoids using image recognition

Tumor organoids present a challenge in drug screening due to their considerable heterogeneity in morphology and size. To address this issue, we proposed a portable microfluidic device that employs image processing algorithms for specific target organoid recognition and microvalve-controlled deflection for sorting and collection. This morphology-activated organoid sorting system offers numerous advantages, such as automated classification, portability, low cost, label-free sample preparation, and gentle handling of organoids. We conducted classification experiments using polystyrene beads, F9 tumoroids and patient-derived tumor organoids, achieving organoid separation efficiency exceeding 88%, purity surpassing 91%, viability exceeding 97% and classification throughput of 800 per hour, thereby meeting the demands of clinical organoid medicine.

Modeling development of breast cancer: from tumor microenvironment to preclinical applications

Breast cancer is a complex disease and its progression is related not only to tumor cells but also to its microenvironment, which can not be sufficiently reflected by the traditional monolayer cell culture manner. The novel human cancer models comprising tumor microenvironment (TME), such as tumor organoids and organs-on-a-chip, has been established in recent years to help elucidate the underlying mechanisms of tumorigenesis and promote the development of cancer therapies. In this review, we first discuss the current state of breast cancer and their treatment strategies, and elucidates the complex properties of TME of breast cancer in vivo. The culture models used in breast cancer research are then summarized with insights into recent development. Finally, we also conclude by discussing the current limitations and future directions of culture models in breast cancer research for providing a preclinical reference for the precise treatment of cancer patients.

Spatially defined microenvironment for engineering organoids

In the intricately defined spatial microenvironment, a single fertilized egg remarkably develops into a conserved and well-organized multicellular organism. This observation leads us to hypothesize that stem cells or other seed cell types have the potential to construct fully structured and functional tissues or organs, provided the spatial cues are appropriately configured. Current organoid technology, however, largely depends on spontaneous growth and self-organization, lacking systematic guided intervention. As a result, the structures replicated in vitro often emerge in a disordered and sparse manner during growth phases. Although existing organoids have made significant contributions in many aspects, such as advancing our understanding of development and pathogenesis, aiding personalized drug selection, as well as expediting drug development, their potential in creating large-scale implantable tissue or organ constructs, and constructing multicomponent microphysiological systems, together with functioning at metabolic levels remains underutilized. Recent discoveries have demonstrated that the spatial definition of growth factors not only induces directional growth and migration of organoids but also leads to the formation of assembloids with multiple regional identities. This opens new avenues for the innovative engineering of higher-order organoids. Concurrently, the spatial organization of other microenvironmental cues, such as physical stresses, mechanical loads, and material composition, has been minimally explored. This review delves into the burgeoning field of organoid engineering with a focus on potential spatial microenvironmental control. It offers insight into the molecular principles, expected outcomes, and potential applications, envisioning a future perspective in this domain.

Controlling Cell Interactions with DNA Directed Assembly

The creation of complex cellular environments is critical to mimicking tissue environments that will play a critical role in next-generation tissue engineering, stem cell programming, and therapeutic screening. To address this growing need, techniques capable of manipulating cell-cell and cell-material interactions are required that span single-cell to 3D tissue architectures. DNA programmed assembly and placement of cells present a powerful technique for the bottom-up synthesis of living microtissues for probing key questions in cell-cell and cell-material-driven behaviors through its refined control over placement and architecture. This review examines the current state of the art in the programming of cellular interactions with DNA and its applications spanning tissue model building, fundamental cellular biology, and cell manipulation for measurements across a host of applications.

The Assembly of Miniaturized Droplets toward Functional Architectures

Recent explorations of bioengineering have generated new concepts and strategies for the processing of soft and functional materials. Droplet assembly techniques can address problems in the construction of extremely soft architectures by expanding the manufacturing capabilities using droplets containing liquid or hydrogels including weak hydrogels. This Perspective sets out to provide a brief overview of this growing field, and discusses the challenges and opportunities ahead. The study highlights the recent key advances of materials and architectures from hitherto effective droplet-assembly technologies, as well as the applications in biomedical and bioengineering fields from artificial tissues to bioreactors. It is envisaged that these assembled architectures, as nature-inspired models, will stimulate the discovery of biomaterials and miniaturized platforms for interdisciplinary research in health, biotechnology, and sustainability.

Microfluidic Platform for Generating and Releasing Patient-Derived Cancer Organoids with Diverse Shapes: Insight into Shape-Dependent Tumor Growth

Multicellular spheroids and patient-derived organoids find many applications in fundamental research, drug discovery, and regenerative medicine. Advances in the understanding and recapitulation of organ functionality and disease development require the generation of complex organoid models, including organoids with diverse morphologies. Microfluidics-based cell culture platforms enable time-efficient confined organoid generation. However, the ability to form organoids with different shapes with a subsequent transfer from microfluidic devices to unconstrained environments for studies of morphology-dependent organoid growth is yet to be demonstrated. Here, a microfluidic platform is introduced that enables high-fidelity formation and addressable release of breast cancer organoids with diverse shapes. Using this platform, the impact of organoid morphology on their growth in unconstrained biomimetic hydrogel is explored. It is shown that proliferative cancer cells tend to localize in high positive curvature organoid regions, causing their faster growth, while the overall growth pattern of organoids with diverse shapes tends to reduce interfacial tension at the organoid-hydrogel interface. In addition to the formation of organoids with diverse morphologies, this platform can be integrated into multi-tissue micro-physiological systems.

Engineering next generation vascularized organoids

Organoids are self-organizing 3D cell culture models that are valuable for studying the mechanisms underlying both development and disease in multiple species, particularly, in humans. These 3D engineered tissues can mimic the structure and function of human organs in vitro. Methods to generate organoids have substantially improved to better resemble, in various ways, their in vivo counterpart. One of the major limitations in current organoid models is the lack of a functional vascular compartment. Here we discuss methodological approaches to generating perfusable blood vessel networks in organoid systems. Inclusion of perfused vascular compartments markedly enhances the physiological relevance of organoid systems and is a critical step in the establishment of next generation, higher-complexity in vitro systems for use in developmental, clinical, and drug-development settings.

Bioprinting of Cells, Organoids and Organs-on-a-Chip Together with Hydrogels Improves Structural and Mechanical Cues

The 3D bioprinting technique has made enormous progress in tissue engineering, regenerative medicine and research into diseases such as cancer. Apart from individual cells, a collection of cells, such as organoids, can be printed in combination with various hydrogels. It can be hypothesized that 3D bioprinting will even become a promising tool for mechanobiological analyses of cells, organoids and their matrix environments in highly defined and precisely structured 3D environments, in which the mechanical properties of the cell environment can be individually adjusted. Mechanical obstacles or bead markers can be integrated into bioprinted samples to analyze mechanical deformations and forces within these bioprinted constructs, such as 3D organoids, and to perform biophysical analysis in complex 3D systems, which are still not standard techniques. The review highlights the advances of 3D and 4D printing technologies in integrating mechanobiological cues so that the next step will be a detailed analysis of key future biophysical research directions in organoid generation for the development of disease model systems, tissue regeneration and drug testing from a biophysical perspective. Finally, the review highlights the combination of bioprinted hydrogels, such as pure natural or synthetic hydrogels and mixtures, with organoids, organoid-cell co-cultures, organ-on-a-chip systems and organoid-organ-on-a chip combinations and introduces the use of assembloids to determine the mutual interactions of different cell types and cell-matrix interferences in specific biological and mechanical environments.

Standardization and quality assessment for human intestinal organoids

To enhance the practical application of intestinal organoids, it is imperative to establish standardized guidelines. This proposed standardization outlines a comprehensive framework to ensure consistency and reliability in the development, characterization, and application of intestinal organoids. The recommended guidelines encompass crucial parameters, including culture conditions, critical quality attributes, quality control measures, and functional assessments, aimed at fostering a standardized approach across diverse research initiatives. The implementation of these guidelines is anticipated to significantly contribute to the reproducibility and comparability of results in the burgeoning field of intestinal organoid research.

Bidirectional in-silico clearing approach for deep refractive-index tomography using a sparsely sampled transmission matrix

Optical diffraction tomography (ODT) enables the label-free volumetric imaging of biological specimens by mapping their three-dimensional refractive index (RI) distribution. However, the depth of imaging achievable is restricted due to spatially inhomogeneous RI distributions that induce multiple scattering. In this study, we introduce a novel ODT technique named bidirectional in-silico clearing RI tomography. This method incorporates both forward and reversed in-silico clearing. For the reversed in-silico clearing, we have integrated an ODT reconstruction framework with a transmission matrix approach, which enables RI reconstruction and wave backpropagation from the illumination side without necessitating modifications to the conventional ODT setup. Furthermore, the framework employs a sparsely sampled transmission matrix, significantly reducing the requisite number of measurements and computational expenses. Employing this proposed technique, we successfully imaged a spheroid with a thickness of 263 µm, corresponding to 11.4 scattering mean free paths. This method was successfully applied to various biological specimens, including liver and colon spheroids, demonstrating consistent imaging performance across samples with varied morphologies.

Compressible Hollow Microlasers in Organoids for High-Throughput and Real-Time Mechanical Screening

Mechanical stress within organoids is a pivotal indicator in disease modeling and pharmacokinetics, yet current tools lack the ability to rapidly and dynamically screen these mechanics. Here, we introduce biocompatible and compressible hollow microlasers that realize all-optical assessment of cellular stress within organoids. The laser spectroscopy yields identification of cellular deformation at the nanometer scale, corresponding to tens of pascals stress sensitivity. The compressibility enables the investigation of the isotropic component, which is the fundamental mechanics of multicellular models. By integrating with a microwell array, we demonstrate the high-throughput screening of mechanical cues in tumoroids, establishing a platform for mechano-responsive drug screening. Furthermore, we showcase the monitoring and mapping of dynamic contractile stress within human embryonic stem cell-derived cardiac organoids, revealing the internal mechanical inhomogeneity within a single organoid. This method eliminates time-consuming scanning and sample damage, providing insights into organoid mechanobiology.

Organoid as a promising tool for primary liver cancer research: a comprehensive review

Primary liver cancer (PLC) is one of the most common malignant gastrointestinal tumors worldwide. Limited by the shortage of liver transplantation donors and the heterogeneity of tumors, patients with liver cancer lack effective treatment options, which leads to rapid progression and metastasis. Currently, preclinical models of PLC fall short of clinical reality and are limited in their response to disease progression and the effectiveness of drug therapy. Organoids are in vitro three-dimensional cultured preclinical models with a high degree of heterogeneity that preserve the histomorphological and genomic features of primary tumors. Liver cancer organoids have been widely used for drug screening, new target discovery, and precision medicine; thus representing a promising tool to study PLC. Here, we summarize the progress of research on liver cancer organoids and their potential application as disease models. This review provides a comprehensive introduction to this emerging technology and offers new ideas for researchers to explore in the field of precision medicine.

Engineering Cell Instructive Microenvironments for In Vitro Replication of Functional Barrier Organs

Multicellular organisms exhibit synergistic effects among their components, giving rise to emergent properties crucial for their genesis and overall functionality and survival. Morphogenesis involves and relies upon intricate and biunivocal interactions among cells and their environment, that is, the extracellular matrix (ECM). Cells secrete their own ECM, which in turn, regulates their morphogenetic program by controlling time and space presentation of matricellular signals. The ECM, once considered passive, is now recognized as an informative space where both biochemical and biophysical signals are tightly orchestrated. Replicating this sophisticated and highly interconnected informative media in a synthetic scaffold for tissue engineering is unattainable with current technology and this limits the capability to engineer functional human organs in vitro and in vivo. This review explores current limitations to in vitro organ morphogenesis, emphasizing the interplay of gene regulatory networks, mechanical factors, and tissue microenvironment cues. In vitro efforts to replicate biological processes for barrier organs such as the lung and intestine, are examined. The importance of maintaining cells within their native microenvironmental context is highlighted to accurately replicate organ-specific properties. The review underscores the necessity for microphysiological systems that faithfully reproduce cell-native interactions, for advancing the understanding of developmental disorders and disease progression.

Designer cellular spheroids with DNA origami for drug screening

Current in vitro models struggle to balance the complexity of human diseases with suitability for large-scale drug tests. While 3D cultures simulate human tissues, they lack cellular intricacy, and integrating these models with high-throughput drug screening remains a challenge. Here, we introduce a method that uses self-assembling nucleic acid nanostructures decorated living cells, termed NACs, to create spheroids with a customizable 3D layout. To demonstrate its uniqueness, our method effectively creates designer 3D spheroids by combining parenchymal cells, stromal cells, and immune cells, leading to heightened physiological relevance and detailed modeling of complex chronic diseases and immune-stromal interactions. Our approach achieves a high level of biological fidelity while being standardized and straightforward to construct with the potential for large-scale drug discovery applications. By merging the precision of DNA nanotechnology with advanced cell culture techniques, we are streamlining human-centric models, striking a balance between complexity and standardization, to boost drug screening efficiency.

In vitro throughput screening of anticancer drugs using patient-derived cell lines cultured on vascularized three-dimensional stromal tissues

The development of high-throughput anticancer drug screening methods using patient-derived cancer cell (PDC) lines that maintain their original characteristics in an in vitro three-dimensional (3D) culture system poses a significant challenge to achieving personalized cancer medicine. Because stromal tissue plays a critical role in the composition and maintenance of the cancer microenvironment, in vitro 3D-culture using reconstructed stromal tissues has attracted considerable attention. Here, a simple and unique in vitro 3D-culture method using heparin and collagen together with fibroblasts and endothelial cells to fabricate vascularized 3D-stromal tissues for in vitro culture of PDCs is reported. Whereas co-treatment with bevacizumab, a monoclonal antibody against vascular endothelial growth factor, and 5-fluorouracil significantly reduced the survival rate of 3D-cultured PDCs to 30%, separate addition of each drug did not induce comparable strong cytotoxicity, suggesting the possibility of evaluating the combined effect of anticancer drugs and angiogenesis inhibitors. Surprisingly, drug evaluation using eight PDC lines with the 3D-culture method resulted in a drug efficacy concordance rate of 75% with clinical outcomes. The model is expected to be applicable to in vitro throughput drug screening for the development of personalized cancer medicine. STATEMENT OF SIGNIFICANCE: To replicate the cancer microenvironment, we constructed a cancer-stromal tissue model in which cancer cells are placed above and inside stromal tissue with vascular network structures derived from vascular endothelial cells in fibroblast tissue using CAViTs method. Using this method, we were able to reproduce the invasion and metastasis processes of cancer cells observed in vivo. Using patient-derived cancer cells, we assessed the possibility of evaluating the combined effect with an angiogenesis inhibitor. Further, primary cancer cells also grew on the stromal tissues with the normal medium. These data suggest that the model may be useful for new in vitro drug screening and personalized cancer medicine.

Engineering programmable material-to-cell pathways via synthetic notch receptors to spatially control differentiation in multicellular constructs

Synthetic Notch (synNotch) receptors are genetically encoded, modular synthetic receptors that enable mammalian cells to detect environmental signals and respond by activating user-prescribed transcriptional programs. Although some materials have been modified to present synNotch ligands with coarse spatial control, applications in tissue engineering generally require extracellular matrix (ECM)-derived scaffolds and/or finer spatial positioning of multiple ligands. Thus, we develop here a suite of materials that activate synNotch receptors for generalizable engineering of material-to-cell signaling. We genetically and chemically fuse functional synNotch ligands to ECM proteins and ECM-derived materials. We also generate tissues with microscale precision over four distinct reporter phenotypes by culturing cells with two orthogonal synNotch programs on surfaces microcontact-printed with two synNotch ligands. Finally, we showcase applications in tissue engineering by co-transdifferentiating fibroblasts into skeletal muscle or endothelial cell precursors in user-defined micropatterns. These technologies provide avenues for spatially controlling cellular phenotypes in mammalian tissues.

The evolution of developmental biology through conceptual and technological revolutions

Developmental biology-the study of the processes by which cells, tissues, and organisms develop and change over time-has entered a new golden age. After the molecular genetics revolution in the 80s and 90s and the diversification of the field in the early 21st century, we have entered a phase when powerful technologies provide new approaches and open unexplored avenues. Progress in the field has been accelerated by advances in genomics, imaging, engineering, and computational biology and by emerging model systems ranging from tardigrades to organoids. We summarize how revolutionary technologies have led to remarkable progress in understanding animal development. We describe how classic questions in gene regulation, pattern formation, morphogenesis, organogenesis, and stem cell biology are being revisited. We discuss the connections of development with evolution, self-organization, metabolism, time, and ecology. We speculate how developmental biology might evolve in an era of synthetic biology, artificial intelligence, and human engineering.

Challenges of Spatially Resolved Metabolism in Cancer Research

Stable isotope-resolved metabolomics comprises a critical set of technologies that can be applied to a wide variety of systems, from isolated cells to whole organisms, to define metabolic pathway usage and responses to perturbations such as drugs or mutations, as well as providing the basis for flux analysis. As the diversity of stable isotope-enriched compounds is very high, and with newer approaches to multiplexing, the coverage of metabolism is now very extensive. However, as the complexity of the model increases, including more kinds of interacting cell types and interorgan communication, the analytical complexity also increases. Further, as studies move further into spatially resolved biology, new technical problems have to be overcome owing to the small number of analytes present in the confines of a single cell or cell compartment. Here, we review the overall goals and solutions made possible by stable isotope tracing and their applications to models of increasing complexity. Finally, we discuss progress and outstanding difficulties in high-resolution spatially resolved tracer-based metabolic studies.

Self-Organization of Sinusoidal Vessels in Pluripotent Stem Cell-derived Human Liver Bud Organoids

The induction of tissue-specific vessels in in vitro living tissue systems remains challenging. Here, we directly differentiated human pluripotent stem cells into CD32b+ putative liver sinusoidal progenitors (iLSEP) by dictating developmental pathways. By devising an inverted multilayered air-liquid interface (IMALI) culture, hepatic endoderm, septum mesenchyme, arterial and sinusoidal quadruple progenitors self-organized to generate and sustain hepatocyte-like cells neighbored by divergent endothelial subsets composed of CD32blowCD31high, LYVE1+STAB1+CD32bhighCD31lowTHBD-vWF-, and LYVE1-THBD+vWF+ cells. Wnt2 mediated sinusoidal-to-hepatic intercellular crosstalk potentiates hepatocyte differentiation and branched endothelial network formation. Intravital imaging revealed iLSEP developed fully patent human vessels with functional sinusoid-like features. Organoid-derived hepatocyte- and sinusoid-derived coagulation factors enabled correction of in vitro clotting time with Factor V, VIII, IX, and XI deficient patients' plasma and rescued the severe bleeding phenotype in hemophilia A mice upon transplantation. Advanced organoid vascularization technology allows for interrogating key insights governing organ-specific vessel development, paving the way for coagulation disorder therapeutics.

Advances in Organoid Technology: A Focus on Corneal Limbal Organoids

Organoid technology provides a versatile platform for simulating organogenesis, investigating disease pathogenesis, and exploring therapeutic interventions. Among various types of organoids that have been developed, corneal limbal organoids, the three-dimensional miniaturized corneas which are derived from either pluripotent stem cells or limbal epithelial stem cells, are particularly promising for clinical translation. This narrative review summarized the state-of-the-art in corneal limbal organoids research including the cultivation methods, clinical relevance and its limitations and challenges. The potential of corneal limbal organoids in mimicking corneal development, disease modelling, drug screening, and regenerative medicine was discussed. Technical improvements in cultivation techniques, imaging modalities, and gene editing tools are anticipated to overcome current limitations and further promote its clinical potential. Despite challenges and difficulties, the development of corneal limbal organoids opens a new era of regenerative medicine and provides a potential source of stem cell replacement therapies for challenging corneal diseases with the establishment of an in vitro corneal limbal organoid bank.

Engineering fibronectin-templated multi-component fibrillar extracellular matrices to modulate tissue-specific cell response

Cells assemble fibronectin, the major extracellular matrix (ECM) protein, into fibrillar matrices, which serve as 3D architectural scaffolds to provide, together with other ECM proteins tissue-specific environments. Although recent approaches enable to bioengineer 3D fibrillar fibronectin matrices in vitro, it remains elusive how fibronectin can be co-assembled with other ECM proteins into complex 3D fibrillar matrices that recapitulate tissue-specific compositions and cellular responses. Here, we introduce the engineering of fibrillar fibronectin-templated 3D matrices that can be complemented with other ECM proteins, including vitronectin, collagen, and laminin to resemble ECM architectures observed in vivo. For the co-assembly of different ECM proteins, we employed their innate fibrillogenic mechanisms including shear forces, pH-dependent electrostatic interactions, or specific binding domains. Through recapitulating various tissue-specific ECM compositions and morphologies, the large scale multi-composite 3D fibrillar ECM matrices can guide fibroblast adhesion, 3D fibroblast tissue formation, or tissue morphogenesis of epithelial cells. In other examples, we customize multi-composite 3D fibrillar matrices to support the growth of signal propagating neuronal networks and of human brain organoids. We envision that these 3D fibrillar ECM matrices can be tailored in scale and composition to modulate tissue-specific responses across various biological length scales and systems, and thus to advance manyfold studies of cell biological systems.

Parsing patterns: Emerging roles of tissue self-organization in health and disease

Patterned morphologies, such as segments, spirals, stripes, and spots, frequently emerge during embryogenesis through self-organized coordination between cells. Yet, complex patterns also emerge in adults, suggesting that the capacity for spontaneous self-organization is a ubiquitous property of biological tissues. We review current knowledge on the principles and mechanisms of self-organized patterning in embryonic tissues and explore how these principles and mechanisms apply to adult tissues that exhibit features of patterning. We discuss how and why spontaneous pattern generation is integral to homeostasis and healing of tissues, illustrating it with examples from regenerative biology. We examine how aberrant self-organization underlies diverse pathological states, including inflammatory skin disorders and tumors. Lastly, we posit that based on such blueprints, targeted engineering of pattern-driving molecular circuits can be leveraged for synthetic biology and the generation of organoids with intricate patterns.

Organoid models: the future companions of personalized drug development

High failure rates of the current drug development process are driving exemplary changes toward methodologies centered on human diseasein-vitromodeling. Organoids are self-organized tissue sub-units resembling their organ of origin and are widely acknowledged for their unique potential in recapitulating human physio-pathological mechanisms. They are transformative for human health by becoming the platform of choice to probe disease mechanisms and advance new therapies. Furthermore, the compounds' validation as therapeutics represents another point of the drug development pipeline where organoids may provide key understandings and help pharma organizations replace or reduce animal research. In this review, we focus on gastrointestinal organoid models, which are currently the most advanced organoid models in drug development. We focus on experimental validations of their value, and we propose avenues to enhance their use in drug discovery and development, as well as precision medicine and diagnostics.

Promoting Human Intestinal Organoid Formation and Stimulation Using Piezoelectric Nanofiber Matrices

Human organoid model systems have changed the landscape of developmental biology and basic science. They serve as a great tool for human specific interrogation. In order to advance our organoid technology, we aimed to test the compatibility of a piezoelectric material with organoid generation, because it will create a new platform with the potential for sensing and actuating organoids in physiologically relevant ways. We differentiated human pluripotent stem cells into spheroids following the traditional human intestinal organoid (HIO) protocol atop a piezoelectric nanofiber scaffold. We observed that exposure to the biocompatible piezoelectric nanofibers promoted spheroid morphology three days sooner than with the conventional methodology. At day 28 of culture, HIOs grown on the scaffold appeared similar. Both groups were readily transplantable and developed well-organized laminated structures. Graft sizes between groups were similar. Upon characterizing the tissue further, we found no detrimental effects of the piezoelectric nanofibers on intestinal patterning or maturation. Furthermore, to test the practical feasibility of the material, HIOs were also matured on the nanofiber scaffolds and treated with ultrasound, which lead to increased cellular proliferation which is critical for organoid development and tissue maintenance. This study establishes a proof of concept for integrating piezoelectric materials as a customizable platform for on-demand electrical stimulation of cells using remote ultrasonic waveforms in regenerative medicine.

Segmentation and Multi-Timepoint Tracking of 3D Cancer Organoids from Optical Coherence Tomography Images Using Deep Neural Networks

Recent years have ushered in a transformative era in in vitro modeling with the advent of organoids, three-dimensional structures derived from stem cells or patient tumor cells. Still, fully harnessing the potential of organoids requires advanced imaging technologies and analytical tools to quantitatively monitor organoid growth. Optical coherence tomography (OCT) is a promising imaging modality for organoid analysis due to its high-resolution, label-free, non-destructive, and real-time 3D imaging capabilities, but accurately identifying and quantifying organoids in OCT images remain challenging due to various factors. Here, we propose an automatic deep learning-based pipeline with convolutional neural networks that synergistically includes optimized preprocessing steps, the implementation of a state-of-the-art deep learning model, and ad-hoc postprocessing methods, showcasing good generalizability and tracking capabilities over an extended period of 13 days. The proposed tracking algorithm thoroughly documents organoid evolution, utilizing reference volumes, a dual branch analysis, key attribute evaluation, and probability scoring for match identification. The proposed comprehensive approach enables the accurate tracking of organoid growth and morphological changes over time, advancing organoid analysis and serving as a solid foundation for future studies for drug screening and tumor drug sensitivity detection based on organoids.

Generation of insulin-like growth factor 1 receptor-knockout pigs as a potential system for interspecies organogenesis

BACKGROUND

To overcome organ shortage during transplantation, interspecies organ generation via blastocyst complementation has been proposed, although not yet in evolutionarily distant species. To establish high levels of chimerism, low chimerism is required early in development, followed by high chimerism, to effectively complement the organ niche. Very few human cells are expected to contribute to chimerism in heterologous animals. Previous studies had demonstrated increased donor chimerism in both intra- and interspecies chimeras in rodents, using insulin-like growth factor 1 receptor (Igf1r) knockout (KO) mice; deletion of the Igf1r gene in the mouse host embryo created a cell-competitive niche. The current study aimed to generate IGF1R-KO pigs and evaluate whether they have the same phenotype as Igf1r-KO mice.

METHODS

To generate IGF1R-KO pigs, genome-editing molecules were injected into the cytoplasm of pig zygotes. The fetuses were evaluated at 104 days of gestation.

RESULTS

IGF1R-KO pigs were generated successfully. Their phenotypes were almost identical to those of Igf1r-KO mice, including small lungs and enlarged endodermal organs in fetuses, and they were highly reproducible.

CONCLUSIONS

Pigs may allow the generation of organs using blastocyst complementation with developmentally-compatible xenogeneic pluripotent stem cells over a large evolutionary distance.

Synthetic human gonadal tissues for toxicology

The process of mammalian reproduction involves the development of fertile germ cells in the testis and ovary, supported by the surrounders. Fertilization leads to embryo development and ultimately the birth of offspring inheriting parental genome information. Any disruption in this process can result in disorders such as infertility and cancer. Chemical toxicity affecting the reproductive system and embryogenesis can impact birth rates, overall health, and fertility, highlighting the need for animal toxicity studies during drug development. However, the translation of animal data to human health remains challenging due to interspecies differences. In vitro culture systems offer a promising solution to bridge this gap, allowing the study of mammalian cells in an environment that mimics the physiology of the human body. Current advances on in vitro culture systems, such as organoids, enable the development of biomaterials that recapitulate the physiological state of reproductive organs. Application of these technologies to human gonadal cells would provide effective tools for drug screening and toxicity testing, and these models would be a powerful tool to study reproductive biology and pathology. This review focuses on the 2D/3D culture systems of human primary testicular and ovarian cells, highlighting the novel approaches for in vitro study of human reproductive toxicology, specifically in the context of testis and ovary.

Design of neural organoids engineered by mechanical forces

Neural organoids consist of three-dimensional tissue derived from pluripotent stem cells that could recapitulate key features of the human brain. During the past decade, organoid technology has evolved in the field of human brain science by increasing the quality and applicability of its products. Among them, a novel approach involving the design of neural organoids engineered by mechanical forces has emerged. This review describes previous approaches for the generation of neural organoids, the engineering of neural organoids by mechanical forces, and future challenges for the application of mechanical forces in the design of neural organoids.

Exploring tumor organoids for cancer treatment

As a life-threatening chronic disease, cancer is characterized by tumor heterogeneity. This heterogeneity is associated with factors that lead to treatment failure and poor prognosis, including drug resistance, relapse, and metastasis. Therefore, precision medicine urgently needs personalized tumor models that accurately reflect the tumor heterogeneity. Currently, tumor organoid technologies are used to generate in vitro 3D tissues, which have been shown to precisely recapitulate structure, tumor microenvironment, expression profiles, functions, molecular signatures, and genomic alterations in primary tumors. Tumor organoid models are important for identifying potential therapeutic targets, characterizing the effects of anticancer drugs, and exploring novel diagnostic and therapeutic options. In this review, we describe how tumor organoids can be cultured and summarize how researchers can use them as an excellent tool for exploring cancer therapies. In addition, we discuss tumor organoids that have been applied in cancer therapy research and highlight the potential of tumor organoids to guide preclinical research.

Generation of sarconoids from angiosarcoma patients as a systematic-based rational approach to treatment

Angiosarcoma is a rare subtype of malignant neoplasm originating from vascular or lymphatic endothelial cells; its low incidence has posed significant challenges for comprehensive investigations into its pathogenic mechanisms and the development of innovative treatment modalities through in vitro and in vivo models. Recent endeavors spearheaded by patient-partnered research initiatives have aimed to elucidate the intricacies of angiosarcomas by leveraging biological omics approaches, with the overarching objective of enhancing prognostic indicators and therapeutic options for this uncommon pathology. To bridge the gap between preclinical research and translational applications, we engineered angiosarcoma-derived organoids from surgically resected primary tumors, hereafter referred to as "sarconoids," as a proof-of-concept model. A novel protocol for the establishment of these sarconoids has been developed and validated. To ensure that the sarconoids faithfully recapitulate the heterogeneity and complexities of the patients' original tumors, including transcriptomic signatures, cell-type specificity, and morphological traits, exhaustive histological and transcriptomic analyses were conducted. Subsequently, we expanded the scope of our study to include an evaluation of a sarconoid-based drug screening platform; for this purpose, a drug library (AOD IX), supplied by the National Cancer Institute's Developmental Therapeutics Program, was screened using 96-well plates. Our findings suggest that sarconoids can be reliably generated from angiosarcoma patient-derived tissues and can serve as accurate models for evaluating therapeutic responses, thereby holding far-reaching implications for translational research and clinical applications aimed at advancing our understanding and treatment of angiosarcoma.

Boosting cartilage repair with silk fibroin-DNA hydrogel-based cartilage organoid precursor

Osteoarthritis (OA), a common degenerative disease, is characterized by high disability and imposes substantial economic impacts on individuals and society. Current clinical treatments remain inadequate for effectively managing OA. Organoids, miniature 3D tissue structures from directed differentiation of stem or progenitor cells, mimic native organ structures and functions. They are useful for drug testing and serve as active grafts for organ repair. However, organoid construction requires extracellular matrix-like 3D scaffolds for cellular growth. Hydrogel microspheres, with tunable physical and chemical properties, show promise in cartilage tissue engineering by replicating the natural microenvironment. Building on prior work on SF-DNA dual-network hydrogels for cartilage regeneration, we developed a novel RGD-SF-DNA hydrogel microsphere (RSD-MS) via a microfluidic system by integrating photopolymerization with self-assembly techniques and then modified with Pep-RGDfKA. The RSD-MSs exhibited uniform size, porous surface, and optimal swelling and degradation properties. In vitro studies demonstrated that RSD-MSs enhanced bone marrow mesenchymal stem cells (BMSCs) proliferation, adhesion, and chondrogenic differentiation. Transcriptomic analysis showed RSD-MSs induced chondrogenesis mainly through integrin-mediated adhesion pathways and glycosaminoglycan biosynthesis. Moreover, in vivo studies showed that seeding BMSCs onto RSD-MSs to create cartilage organoid precursors (COPs) significantly enhanced cartilage regeneration. In conclusion, RSD-MS was an ideal candidate for the construction and long-term cultivation of cartilage organoids, offering an innovative strategy and material choice for cartilage regeneration and tissue engineering.

Bioengineering toolkits for potentiating organoid therapeutics

Organoids are three-dimensional, multicellular constructs that recapitulate the structural and functional features of specific organs. Because of these characteristics, organoids have been widely applied in biomedical research in recent decades. Remarkable advancements in organoid technology have positioned them as promising candidates for regenerative medicine. However, current organoids still have limitations, such as the absence of internal vasculature, limited functionality, and a small size that is not commensurate with that of actual organs. These limitations hinder their survival and regenerative effects after transplantation. Another significant concern is the reliance on mouse tumor-derived matrix in organoid culture, which is unsuitable for clinical translation due to its tumor origin and safety issues. Therefore, our aim is to describe engineering strategies and alternative biocompatible materials that can facilitate the practical applications of organoids in regenerative medicine. Furthermore, we highlight meaningful progress in organoid transplantation, with a particular emphasis on the functional restoration of various organs.