Generation of Tissue Spheroids via a 3D Printed Stamp-Like Device.

Advances in 3D cell culture have developed more physiologically relevant in vitro models, such as tissue spheroids. Cells cultivated as spheroids have more realistic biological responses that resemble the in vivo environment. Due to their advantages, tissue spheroids represent an emerging trend toward superior, more reliable, and more predictive study models with a broad range of biotechnological applicability. However, reproducible platforms that can achieve large-scale production of tissue spheroids have become an unmet need in fully exploring and boosting their potential. Herein, the large-scale production of homogeneous tissue spheroids is reported using a low-cost and time-effective methodology. A 3D printed stamp-like device is developed to generate up to 4,716 spheroids per 6-well plate. The device is fabricated by the stereolithography method using a photocurable resin. The final device is composed of cylindrical micropins, with a height of 1.3 mm and a width of 650 µm. This approach allows the fast generation of homogeneous spheroids and co-cultured spheroids with uniform shape and size and >95% cell viability. Moreover, the stamp-like device is tunable for different sizes of well plates and Petri dishes. It is easily sterilized and can be reused for long periods. The efficient large-scale production of homogeneous tissue spheroids is essential to leverage their translation for multiple areas of industry, such as tissue engineering, drug development, disease modeling, and on-demand personalized medicine.

Engineering mechanobiology through organoids-on-chip: A strategy to boost therapeutics.

The mechanical environment of living cells is as critical as chemical signaling. Mechanical stimuli play a pivotal role in organogenesis and tissue homeostasis. Unbalances in mechanotransduction pathways often lead to diseases, such as cancer, cystic fibrosis, and neurodevelopmental disorders. Despite its inherent relevance, there is a lack of proper mechanoresponsive in vitro study systems. In this context, there is an urge to engineer innovative, robust, dynamic, and reliable organotypic technologies to better connect cellular processes to organ-level function and multi-tissue cross-talk. Mechanically active organoid-on-chip has the potential to surpass this challenge. These systems converge microfabrication, microfluidics, biophysics, and tissue engineering fields to emulate key features of living organisms, hence, reducing costs, time, and animal testing. In this review, we intended to present cutting-edge organ-on-chip platforms that integrate biomechanical stimuli as well as novel multicellular culture, such as organoids. We focused on its application in two main fields: precision medicine and drug development. Moreover, we also discussed the state of the art for the development of an engineered model to assess patient-derived tumor organoid metastatic potential. Finally, we highlighted the current drawbacks and emerging opportunities to match the industry needs. We envision the use of mechanoresponsive organotypic-on-chip microdevices as an indispensable tool for precision medicine, drug development, disease modeling, tissue engineering, and developmental biology.

Biologically produced silver chloride nanoparticles from B. megaterium modulate interleukin secretion by human adipose stem cell spheroids.

Stem cell tissue constructs are likely to come into contact with silver-based nanoparticles-such as silver chloride nanoparticles (AgCl-NPs)-used as microbicidals at the implant site or in cosmetics. However, the effect of silver-based nanoparticles on 3D cell cultures with potential for tissue engineering has received little attention. Here, we examined the effect of sub-lethal doses (5, 10 and 25 µg/mL, for 1, 7 and 21 days) of AgCl-NPs produced by 'green' bacterial-based synthesis on spheroid 3D cultures of human adipose tissue stem cells (ASCs). Light microscopy analysis revealed that the shape and diameter of ASC spheroids remained largely unchanged after AgCl-NP treatment. Flow cytometry analysis with 7-AAD and 2',7'-dichlorofluorescein diacetate revealed no statistically significant differences in cell death but showed an increase of ROS levels for the untreated group and significant differences for the groups treated with 5 and 10 µg/mL at day 7 (p = 0.0395, p = 0.0266, respectively). Electron microscopy analysis showed limited cell damage in the periphery of AgCl-NP-treated spheroids. However, treatment with AgCl-NP had statistically significant effects on the secretion of IL-6, IL-8, IL-1ß and IL-10 by spheroids, at specific treatment periods and concentrations, and particularly for IL-6, IL-8 and IL-1ß. TGF-ß1 and -ß2 secretion also changed significantly throughout the treatment period. Our results indicate that, despite having little effect on cell viability and morphology, sub-lethal AgCL-NP doses modulate ROS production at day 7 for the groups treated with 5 and 10 µg/mL and also modulate the secretory profile of ASC spheroids. Thus, the use of skin implants or products containing Ag-NPs may promote long-term disturbances in subcutaneous adipose tissue homeostasis.