I am working on making PC-3 spheroids in microfluidic chips and wanted to test whether adding collagen to cell suspension would help form better PC-3 spheroids in the chip. For this, I want to test different concentrations of collagen solution. I could only find protocols for coating well plates with collagen, which was not helpful for me. If anyone who works with collagen can share the steps to making the cell-collagen mixture, it would be a great help. Thank you in advance.