Optical pH regulation using photochromic material for selective cell injection of nanosensors

We developed Optical pH regulation using gel tool impregnated with photochromic material for selective cell injection of nanosensor for intracellular measurement. The nanosensor was included in the fusogenic liposome. Membrane fusion of the liposome to the cell membrane was used for invasive cell injection of the nanosensor. The liposome fuses to the cell in weak acidic condition. Local pH regulation inside the liposome was developed using photochromic material included in the nanotool. The nanosensor was modified by fluorescent dye for environment measurement. The nanosensor was also modified by Leuco crystal violet (LCV). LCV is photochromic material. LCV emits the proton by ultraviolet (UV) illumination. The emitted proton decreases the pH value in the liposome. This pH regulation is reversible by UV/VIS illumination. The nanosensor included in the liposome was manipulated by optical tweezers. After contact of the liposome to the cell membrane, the liposome was adhered to the cell membrane by UV induced membrane fusion. The nanosensor was injected into the cell. Injected nanosensor was manipulated by optical tweezers. Intracellular temperature was detected by measuring the fluorescence intensity of the nanosensor. We demonstrated optical pH regulation, UV induced cell injection of the nanosensor, and manipulation of the nanosensor in the cell.