Rapid injection of fluorescence sensor into a target cell by local mechanical stimulus of optical tweezers

Multi-fluorescent sensor has been synthetized using two different fluorescent indicators (Rhodamine B and FITC) which can respond to both pH and temperature. A method of selective adhesion and rapid injection of the sensor into the individual cell have also been proposed. The sensor was encapsulated in the liposome layers containing photochromic material, 1, 3, 3-Trimethylindolino-6´- nitrobenzopyrylospiran (SP), for optical control of zeta potential. Zeta potential of the liposome can be switched from negative to positive by photoisomerization of SP under UV illumination. Then positive-charged liposome manipulated by optical tweezers can selectively adhere to the negative- charged cell membrane by electrostatic force. We also propose rapid sensor injection into cell by applying local vibration stimulus on the sensor using optical tweezers with displacement of 4 μm and frequency of 1Hz. We also used confocal microscope to take 3D fluorescent image to see the exact position of the sensor. The result showed that the sensor can be injected into a cell in 30 min by vibration stimulus with a high injection rate of 80%. So the fluorescent sensor has a potential application in cell measurement.