A simple, scalable, and reproducible technology that allows direct formation of large numbers of homogeneous and synchronized embryoid bodies (EBs) of defined sizes from dissociated human induced pluripotent stem cells (hiPSCs) was developed. Non-cell-adhesive hydrogels were used to create round-bottom microwells to host dissociated hiPSCs. No Rho-associated kinase inhibitor (ROCK-i), or centrifugation was needed and the side effects of ROCK-i can be avoided. The key requirement for the successful EB formation in addition to the non-cell-adhesive round-bottom microwells is the input cell density per microwell. Too few or too many cells loaded into the microwells will compromise the EB formation process. In parallel, we have tested our microwell-based system for homogeneous hEB formation from dissociated human embryonic stem cells (hESCs). Successful production of homogeneous hEBs from dissociated hESCs in the absence of ROCK-i and centrifugation was achieved within an optimal range of input cell density per microwell. Both the hiPSC- and hESC-derived hEBs expressed key proteins characteristic of all the three developmental germ layers, confirming their EB identity. This novel EB production technology may represent a versatile platform for the production of homogeneous EBs from dissociated human pluripotent stem cells (hPSCs).

Neurodegenerative diseases are common, incurable neurological disorders with high prevalence, and lead to memory, movement, language, and intelligence impairments, threatening the lives and health of patients worldwide. The blood–brain barrier (BBB), a physiological barrier between the central nervous system and peripheral blood circulation, plays an important role in maintaining the homeostasis of the intracerebral environment by strictly regulating the transport of substances between the blood and brain. Therefore, it is difficult for therapeutic drugs to penetrate the BBB and reach the brain, and this affects their efficacy. Nanoparticles (NPs) can be used as drug transport carriers and are also known as nanoparticle-based drug delivery systems (NDDSs). These systems not only increase the stability of drugs but also facilitate the crossing of drugs through the BBB and improve their efficacy. In this article, we provided an overview of the types and administration routes of NPs, highlighted the preclinical and clinical studies of NDDSs in neurodegenerative diseases, and summarized the combined therapeutic strategies in the management of neurodegenerative diseases. Finally, the prospects and challenges of NDDSs in recent basic and clinical research were also discussed. Above all, NDDSs provide an inspiring therapeutic strategy for the treatment of neurodegenerative diseases.

Human pluripotent stem cells (hPSCs) are powerful tools for regenerative therapy and studying human developmental biology, attributing to their ability to differentiate into many functional cell types in the body. The main challenge in realizing hPSC potential is to guide their differentiation in a well-controlled manner. One way to control the cell differentiation process is to recapitulate during in vitro culture the key events in embryogenesis to obtain the three developmental germ layers from which all cell types arise. To achieve this goal, many techniques have been tested to obtain a cellular cluster, an embryoid body (EB), from both mouse and hPSCs. Generation of EBs that are homogeneous in size and shape would allow directed hPSC differentiation into desired cell types in a more synchronous manner and define the roles of cell–cell interaction and spatial organization in lineage specification in a setting similar to in vivo embryonic development. However, previous success in uniform EB formation from mouse PSCs cannot be extrapolated to hPSCs possibly due to the destabilization of adherens junctions on cell surfaces during the dissociation into single cells, making hPSCs extremely vulnerable to cell death. Recently, new advances have emerged to form uniform human embryoid bodies (hEBs) from dissociated single cells of hPSCs. In this review, the existing methods for hEB production from hPSCs and the results on the downstream differentiation of the hEBs are described with emphases on the efficiency, homogeneity, scalability, and reproducibility of the hEB formation process and the yield in terminal differentiation. New trends in hEB production and directed differentiation are discussed.

Treatment of acute liver failure by cell transplantation is hindered by a shortage of human hepatocytes. Current protocols for hepatic differentiation of human induced pluripotent stem cells (hiPSCs) result in low yields, cellular heterogeneity, and limited scalability. In the present study, we have developed a novel multicellular spheroid-based hepatic differentiation protocol starting from embryoid bodies of hiPSCs (hiPSC-EBs) for robust mass production of human hepatocyte-like cells (HLCs) using two novel inhibitors of the Wnt pathway. The resultant hiPSC-EB-HLCs expressed liver-specific genes, secreted hepatic proteins such as Albumin, Alpha Fetoprotein, and Fibrinogen, metabolized ammonia, and displayed cytochrome P450 activities and functional activities typical of mature primary hepatocytes, such as LDL storage and uptake, ICG uptake and release, and glycogen storage. Cell transplantation of hiPSC-EB-HLC in a rat model of acute liver failure significantly prolonged the mean survival time and resolved the liver injury when compared to the no-transplantation control animals. The transplanted hiPSC-EB-HLCs secreted human albumin into the host plasma throughout the examination period (2 weeks). Transplantation successfully bridged the animals through the critical period for survival after acute liver failure, providing promising clues of integration and fullin vivofunctionality of these cells after treatment with WIF-1 and DKK-1.