Translational organoid technology – the convergence of chemical, mechanical, and computational biology

Organoids of Musculoskeletal System for Disease Modeling, Drug Screening, and Regeneration

Musculoskeletal diseases have emerged as the leading cause of disability worldwide, with their prevalence increasing annually. In light of this escalating health challenge, organoids, an emerging technology in tissue engineering, offer promising solutions for disease modeling, drug screening, regeneration, and repair processes. The successful development of musculoskeletal organoids represents a significant breakthrough, providing a novel platform for studying musculoskeletal diseases and facilitating the discovery of new treatments. Moreover, organoids serve as valuable complements to traditional 2D culture methods and animal models, offering rich insights into musculoskeletal biology. This review provides an overview of organoid technology, outlining the construction processes of various musculoskeletal organoids and highlighting their similarities and differences. Furthermore, the challenges associated with organoid technology in musculoskeletal systems are discussed and insights into future perspectives are offered.

Integrating 3D Bioprinting and Organoids to Better Recapitulate the Complexity of Cellular Microenvironments for Tissue Engineering

Organoids, with their capacity to mimic the structures and functions of human organs, have gained significant attention for simulating human pathophysiology and have been extensively investigated in the recent past. Additionally, 3D bioprinting, as an emerging bio-additive manufacturing technology, offers the potential for constructing heterogeneous cellular microenvironments, thereby promoting advancements in organoid research. In this review, the latest developments in 3D bioprinting technologies aimed at enhancing organoid engineering are introduced. The commonly used bioprinting methods and materials for organoids, with a particular emphasis on the potential advantages of combining 3D bioprinting with organoids are summarized. These advantages include achieving high cell concentrations to form large cellular aggregates, precise deposition of building blocks to create organoids with complex structures and functions, and automation and high throughput to ensure reproducibility and standardization in organoid culture. Furthermore, this review provides an overview of relevant studies from recent years and discusses the current limitations and prospects for future development.

Droplet-engineered organoids recapitulate parental tissue transcriptome with inter-organoid homogeneity and inter-tumor cell heterogeneity

Organoids are expected to function as effective human organ models for precision cancer studies and drug development. Currently, primary tissue-derived organoids, termed non-engineered organoids (NEOs), are produced by manual pipetting or liquid handling that compromises organoid-organoid homogeneity and organoid-tissue consistency. Droplet-based microfluidics enables automated organoid production with high organoid-organoid homogeneity, organoid-tissue consistency, and a significantly improved production spectrum. It takes advantage of droplet-encapsulation of defined populations of cells and droplet-rendered microstructures that guide cell self-organization. Herein, we studied the droplet-engineered organoids (DEOs), derived from mouse liver tissues and human liver tumors, by using transcriptional analysis and cellular deconvolution on bulk RNA-seq data. The characteristics of DEOs are compared with the parental liver tissues (or tumors) and NEOs. The DEOs are proven higher reproducibility and consistency with the parental tissues, have a high production spectrum and shortened modeling time, and possess inter-organoid homogeneity and inter-tumor cell heterogeneity.

A Hierarchical Mechanotransduction System: From Macro to Micro

Mechanotransduction is a strictly regulated process whereby mechanical stimuli, including mechanical forces and properties, are sensed and translated into biochemical signals. Increasing data demonstrate that mechanotransduction is crucial for regulating macroscopic and microscopic dynamics and functionalities. However, the actions and mechanisms of mechanotransduction across multiple hierarchies, from molecules, subcellular structures, cells, tissues/organs, to the whole-body level, have not been yet comprehensively documented. Herein, the biological roles and operational mechanisms of mechanotransduction from macro to micro are revisited, with a focus on the orchestrations across diverse hierarchies. The implications, applications, and challenges of mechanotransduction in human diseases are also summarized and discussed. Together, this knowledge from a hierarchical perspective has the potential to refresh insights into mechanotransduction regulation and disease pathogenesis and therapy, and ultimately revolutionize the prevention, diagnosis, and treatment of human diseases.

A review on current brain organoid technologies from a biomedical engineering perspective

Brain organoids are 3D cytoarchitectures resembling the embryonic human brain. This review focuses on current advancements in biomedical engineering methods to develop organoids such as pluripotent stem cells assemblies, quickly aggregated floating culture, hydrogel suspension, microfluidic systems (both photolithography and 3D printing), and brain organoids-on-a-chip. These methods have the potential to create a large impact on neurological disorder studies by creating a model of the human brain investigating pathogenesis and drug screening for individual patients. 3D brain organoid cultures mimic not only features of patients' unknown drug reactions, but also early human brain development at cellular, structural, and functional levels. The challenge of current brain organoids lies in the formation of distinct cortical neuron layers, gyrification, and the establishment of complex neuronal circuitry, as they are critically specialized, developmental aspects. Furthermore, recent advances such as vascularization and genome engineering are in development to overcome the barrier of neuronal complexity. Future technology of brain organoids is needed to improve tissue cross-communication, body axis simulation, cell patterning signals, and spatial-temporal control of differentiation, as engineering methods discussed in this review are rapidly evolving.

In vitro high-content tissue models to address precision medicine challenges

The field of precision medicine allows for tailor-made treatments specific to a patient and thereby improve the efficiency and accuracy of disease prevention, diagnosis, and treatment and at the same time would reduce the cost, redundant treatment, and side effects of current treatments. Here, the combination of organ-on-a-chip and bioprinting into engineering high-content in vitro tissue models is envisioned to address some precision medicine challenges. This strategy could be employed to tackle the current coronavirus disease 2019 (COVID-19), which has made a significant impact and paradigm shift in our society. Nevertheless, despite that vaccines against COVID-19 have been successfully developed and vaccination programs are already being deployed worldwide, it will likely require some time before it is available to everyone. Furthermore, there are still some uncertainties and lack of a full understanding of the virus as demonstrated in the high number new mutations arising worldwide and reinfections of already vaccinated individuals. To this end, efficient diagnostic tools and treatments are still urgently needed. In this context, the convergence of bioprinting and organ-on-a-chip technologies, either used alone or in combination, could possibly function as a prominent tool in addressing the current pandemic. This could enable facile advances of important tools, diagnostics, and better physiologically representative in vitro models specific to individuals allowing for faster and more accurate screening of therapeutics evaluating their efficacy and toxicity. This review will cover such technological advances and highlight what is needed for the field to mature for tackling the various needs for current and future pandemics as well as their relevancy towards precision medicine.