BioPhotonics Workstation supporting 3D joystick-control of microplatforms [invited]

Optical trapping have established a track record for cell handling in small volumes. However, methods like fluorescent labelling are often utilized to measure single·cell properties in the trapping experiments. These methods require extra steps in the cell preparation process, and might innuence the experimental outcome.

To circumvent these issues, we are pursuing a novel idea; applying microscopic tools in the sample volume, which enable direct probing of specific cell properties. Here we present the initial experiments, simplifying introduction of microtools to the sample and precision positioning of several microtools simultaneously near one single cell.

The experiments are performed in our BioPhotonics Workstation with counterpropagating beam geometry. This geometry provides a large manipulation area and allows realtime manipulation or a plurality or traps (euITenl1y 100 independently reconfigurable traps), facilitating precise control and a rapid response of the optically manipulated microtools • The microtools are prefabricated by two-photon polymerization.

The tools consist of a tip with submicron features, connected to three spheres functioning as trapping handles. The separation of handles provides leverage enabling submicron positioning accuracy of the tip. The tip can be joystick positioned in 3D with full rotational freedom, as close to the cell as desired.

Using microtools allows experiments on cells without requiring extensive sample preparation. Furthermore, each tip of the microtools can be chemically activated; this provides an abundance of new opportunities, e.g. by applying enzymes that allows the tip to penetrate the cell walls or utilizing a Ph-sensing fluorochrome to measure on specific sites in or around biological cells.