Can we visualize protein produced by topically applied engineered bacteria using 3D skin model? I plan to topically apply the engineered bacteria on the3D skin model and visualize distribution through immunostaining. The protein is tagged with poly-histidine. I intend to use anti-his Ab to locate it and see the production visually. How feasible is this approach? I am not sure the protein can be internalized or uptaken by the mammalian cells. Any suggestion/recommendation would be highly appreciated.