A simple cell patterning method using magnetic particle-containing photosensitive poly (ethylene glycol) hydrogel blocks: a technical note.

All human organs consist of multiple types of cells organized in a complex pattern to meet specific functional needs. One possible approach for reconstructing human organs in vitro is to generate cell sheets of a specific pattern and later stack them systematically by layer into a three-dimensional organoid. However, many commonly used cell patterning techniques suffer drawbacks such as dependence on sophisticated instruments and manipulation of cells under suboptimal growth conditions. Here, we describe a simple cell patterning method that may overcome these problems. This method is based on magnetic force and photoresponsive poly (ethylene glycol) diacrylate (PEG-DA) hydrogels. The PEG-DA hydrogel was magnetized by mixing with iron ferrous microparticles and then fabricated into blocks with a specific pattern by photolithography. The resolution of the hydrogel empty space pattern was approximately 150  μm and the generated hydrogel blocks can be remotely manipulated with a magnet. The magnetic PEG-DA blocks were used as a stencil to define the area for cell adhesion in the cell culture dish, and the second types of cells could be seeded after the magnetic block was removed to create heterotypic cell patterns. Cell viability assay has demonstrated that magnetic PEG-DA and the patterning process produced negligible effects on cell growth. Together, our results indicate that this magnetic hydrogel-based cell patterning method is simple to perform and is a useful tool for tissue surrogate assembly for disease mechanism study and drug screening.