Chuang Gao

Spheroids, as three-dimensional (3D) cell aggregates, can be prepared using various methods, including hanging drops, microwells, microfluidics, magnetic manipulation, and bioreactors. However, current spheroid manufacturing techniques face challenges such as complex workflows, the need for specialized personnel, and poor batch reproducibility. In this study, we designed a support-free, 3D-printed microwell chip and developed a compatible low-cell-adhesion process. Through simulation and experimental validation, we rapidly optimized microwell size and the coating process. We successfully formed three types of spheroids—human immortalized epidermal cells (HaCaTs), umbilical cord mesenchymal stem cells (UC-MSCs), and human osteosarcoma cells (MG63s)—on the chip. Fluorescent viability staining confirmed the biocompatibility and reliability of the chip. Finally, drug response experiments were conducted using the chip. Compared to traditional methods, our proposed strategy enables high-throughput production of size-controlled spheroids with excellent shape retention, while enhanced gas exchange during culture improves differentiation marker expression. This platform provides an efficient and cost-effective solution for biosensing applications, such as drug screening, disease modeling, and personalized therapy monitoring. Furthermore, the chip shows significant potential for real-time in vitro monitoring of cellular viability, reaction kinetics, and drug sensitivity, offering valuable advancements in biosensor technology for life sciences and medical applications.

The dermal–epidermal junction (DEJ), located between the dermal–epidermal layers in human skin tissue, plays a significant role in its function. However, the limitations of biomaterial properties and microstructure fabrication methods mean that most current tissue engineered skin models do not consider the existence of DEJ. In this study, a nanofiber membrane that simulates the fluctuating structure of skin DEJ was prepared by the composite molding process. Electrospinning is a technique for the production of nanofibers, which can customize the physical and biological properties of biomaterials. At present, electrospinning technology is widely used in the simulation of customized natural skin DEJ. In this study, four different concentration ratios of poly (lactic-co-glycolic acid) (PLGA) and polycaprolactone (PCL) nanofiber membranes were prepared based on electrospinning technology. We selected a 15%PLGA + 5%PCL nanofiber membrane with mechanical properties, dimensional stability, hydrophilicity, and biocompatibility after physical properties and biological characterization. Then, the array-based microstructure model was prepared by three-dimensional (3D) printing. Subsequently, the microstructure was created on a 15%PLGA + 5%PCL membrane by the micro-imprinting process. Finally, the cell proliferation and live/dead tests of keratinocytes (HaCaTs) and fibroblasts (HSFs) were measured on the microstructural membrane and flat membrane. The results showed that 15%PLGA + 5%PCL microstructure membrane was more beneficial to promote the adhesion and proliferation of HaCaTs and HSFs than a flat membrane.