Developments of microfluidic-based time/space domain PCR, digital PCR, and isothermal nucleic acid amplification.

Even though in vitro co-culture tumor spheroid model plays an important role in screening drug candidates, its wide applications are currently limited due to the lack of reliable and high throughput methods for generating well-defined and 3D complex co-culture structures. Herein, we report the development of a hydrogel microwell array to generate uniform-sized multicellular tumor spheroids. Our developed multicellular tumor spheroids are structurally well-defined, robust and can be easily transferred into the widely used 2D culture substrates while maintaining our designed multicellular 3D-sphere structures. Moreover, to develop effective anti-cancer therapeutics we integrated our recently developed gold-graphene hybrid nanomaterial (Au@GO)-based photothermal cancer therapy into a series of multicellular tumor spheroid co-culture system. The multicellular tumor spheroids were harvested onto a two-dimensional (2D) substrate, under preservation of their three-dimensional (3D) structure, to evaluate the photothermal therapy effectiveness of graphene oxide (GO)-wrapped gold nanoparticles (Au@GO). From the model of co-culture spheroids of HeLa/Ovarian cancer and HeLa/human umbilical vein endothelial cell (HUVEC), we observed that Au@GO nanoparticles displayed selectivity towards the fast-dividing HeLa cells, which could not be observed to this extent in 2D cultures. Overall, our developed uniform-sized 3D multicellular tumor spheroid could be a powerful tool for anticancer drug screening applications.

Kidney organoids derived from the human pluripotent stem cells (hPSCs) recapitulating human kidney are the attractive tool for kidney regeneration, disease modeling, and drug screening. However, the kidney organoids cultured by static conditions have the limited vascular networks and immature nephron-like structures unlike human kidney. Here, we developed a kidney organoid-on-a-chip system providing fluidic flow mimicking shear stress with optimized extracellular matrix (ECM) conditions. We demonstrated that the kidney organoids cultured in our microfluidic system showed more matured podocytes and vascular structures as compared to the static culture condition. Additionally, the kidney organoids cultured in microfluidic systems showed higher sensitivity to nephrotoxic drugs as compared with those cultured in static conditions. We also demonstrated that the physiological flow played an important role in maintaining a number of physiological functions of kidney organoids. Therefore, our kidney organoid-on-a-chip system could provide an organoid culture platform for in vitro vascularization in formation of functional three-dimensional (3D) tissues.

Poly-N-isopropyl acrylamide (PNIPAM) nanogels have been modified with different acrylic acid (AAc) contents for the efficient control of lower critical solution temperature (LCST). In this study, PNIPAM-co-AAc nanogels nanogels showed two volume phase transitions in comparison with PNIPAM. The transition temperature of PNIPAM nanogels was increased with AAc contents. The controlled drug release performance of PNIPAM-co-AAc nanogels loaded with β-lapachone was attributed to the AAc content ratio and was efficiently triggered in response to temperature and pH. Moreover, a colorimetric cell proliferation assay and direct fluorescence-based live/dead staining were used to confirm the concurrence on drug release profiles. Finally, PNIPAM-co-AAc20 showed a relatively low level of drug release in the range of acidic to neutral pH at body temperature, while maximizing drug release at basic pH. Therefore, we demonstrated that the PNIPAM-based nanogel with the temperature- and pH-responsive features could be a promising nanocarrier for potential intestine-specific drug delivery.