Optical tweezers (OT) allow to probe and manipulate micro-metric samples in a liquid environment. OT have successfully been applied in a large range of in-vivo and in-vitro bio-manipulation experiments such as the trapping of red blood cells in living animals and the immobilization of bacterial cells for nanoscopy. Furthermore, the linearity of the restoring optical forces on spherical objects, has led to the use of optical trapping for quantitative force measurements, such as the strength of inter-molecular bonds or the stiffness of a cell membrane. The ambition of this thesis is to provide a complete robotic optical tweezer sys- tem designed from scratch, that gives to an operator without engineering skills direct physical access to biophysical interactions at the microscale in a 3D workspace, with a flexible and intuitive user interface. The proposed innovative robotic platform for dexterous cell manipulation and force measurement through optical tweezers has the following major contributions: • The generation of multiple optical traps in a three-dimensional working space with nanometrical resolution and high bandwidth. • A 3D real-time force sensing of optical trap with sub-picoNewton (pN) reso- lution suitable for closed-loop control. • A tele-robotic system, providing a straightforward human/machine interac- tion, and intuitive control of biological and synthetic micro objects in six degrees of freedom (three translations and three rotations). • The so-called “Optobots”, 3D swimming micro-structures actioned by OT with 6-DoF and with a built-in force sensor. Those capabilities are beyond the state-of-the-art, among commercial systems and academic literature. Such an interactive robotic instrument is particularly rel- evant to use-cases in experimental biology and constitutes a unique platform for probing the micro-world.