In the science fiction movie Fantastic Voyage, the PROTEUS is a submarine that is miniaturised with all its crew to “about the size of a microbe” and sent into the body of a scientist to remove a blood clot from his brain. Although miniaturisation of a human body is clearly impossible, the dream of “touching” single cells has become partially true after the invention of optical tweezers, for which Arthur Ashkin was awarded the Nobel Prize in Physics this year. Optical tweezers can hold microscopic particles or cells in the focus of a laser beam using optical forces arising from radiation pressure. Using optical tweezers we can move organelles inside larger cells to probe intracellular environment, we can diagnose cancer by mechanical phenotyping individual cells, we can stretch a single DNA filament to study the dynamics of DNA binding proteins. All this is usually done while sitting at a desk, watching a 2D projection of the system through the “window” of a computer display and moving traps with a mouse or joystick.
The PROTEUS project will fully realise the “Fantastic voyage” vision: if we cannot miniaturise a man to size of a microbe we can use Virtual Reality technologies to reproduce a live virtual replica of a microscopic system, send the user in this virtual microscopic world where he will use his hands to manipulate real cells that are simultaneously present under the microscope objective. In our lab, we have have developed unique holographic techniques that will make this possible. Our algorithm for the computer generation of holographic optical trap arrays allows the quick generation of multiple optical traps in 3D which will smoothly follow, as tiny “light” hands, the real movements of the user hands as detected by hand tracking devices. At the same time, using our 3-axis digital holographic microscopy, we will be able to obtain 3D volumetric reconstructions of the microscopic system under the microscope, so that we what we will “see” in front of us will be the actual configuration of the system while we manipulate it.
The main objective of the PROTEUS project will be then to integrate these two holographic technologies by a Virtual Reality game engine that will exchange data with a holographic trapping/imaging instrument connected via the internet. Through the PROTEUS system we will be able to explore and manipulate real cells that are simultaneously present under a microscope that is located in a different lab room or even in a different country. By integrating advanced optical hardware with cutting-edge computing and 3D graphics, our technology will bring optical tweezers into the virtual reality era, enabling many opportunities for biomedical applications, physics and engineering of micro-system and even for education.