The field of tissue engineering requires versatile scaffold fabrication technologies capable of inducing cell proliferation and differentiation to promote functional tissue regeneration. Traditional fabrication methods face inherent trade-offs among production speed, resolution, and cost, which hinder their ability to replicate the intricate hierarchical structures of biological tissues. To address these challenges, we developed a mask projection photolithography system with variable optical magnification. This system allows for precise control of the microscale feature size in the final product using a single mask, by adjusting the optical magnification with interchangeable objective lenses and a relay lens. With this system, we successfully fabricated porous scaffolds with reproducible pore sizes ranging from 25 to 100 μm, exposing a Poly (ethylene glycol) diacrylate (PEGDA, Mn = 700) hydrogel precursor solution through a honeycomb-patterned mask for durations of just 3 to 10 seconds. The mask projection system presented in this study offers a powerful and efficient platform for creating the microstructures essential for various advanced biomedical applications, including tissue engineering, drug delivery, and organoid-on-a-chip, thanks to its unique combination of speed, precision, and cost-effectiveness.

The practical application of Raman spectroscopy is often constrained by its low signal sensitivity, particularly for low-concentration liquid samples. This study introduces a straightforward platform that enhances Raman signals by physically concentrating analytes, providing an alternative to complex substrate fabrication and chemical treatments. We employed a femtosecond pulse laser to create functional micro-grid patterns on a silicon (Si) substrate. This laser process induces localized ablation and simultaneous oxidation, resulting in three-dimensional, hydrophilic microstructures of nonstoichiometric silicon oxide (SiO_2-x). These grid structures effectively confine aqueous sample droplets through a pinning effect, functioning as a microwell array that traps and concentrates suspended polystyrene (PS) particles. This physical concentration mechanism achieved a notable signal enhancement, with a maximum factor of 5.2 for PS particles, without the need for sample dehydration. This work presents a simple, cost-effective, and highly reproducible alternative to conventional SERS for analyzing low-concentration liquid samples, demonstrating strong potential for integration into microfluidic systems.