Screens have been instrumental in advancing our understanding of biology, by assigning functions to specific proteins or generally by linking genotypes to phenotypes. Screens are also very useful in synthetic biology, since our knowledge of biological systems, their parts and how they interact with each other is still very limited. Many powerful tools have been developed, such as flow assisted cell screening (FACS), but they have been generally limited to static snapshots. In this project, we implement a technique that enables us to screen single cells after time lapse microscopy using microfluidics and optical tweezers, based on our previous work. A microfluidic platform named the mother machine enables imaging thousands of individual lineages of bacteria for hundreds of cell division under constant growth conditions. The platform is modified such that cells of interests can be moved to a pre-sterilized collection channel using an optical tweezer, while sterilization is enabled using push-down valves. A proof of concept for single cell screening is shown, and current work screening genetic oscillator is discussed. Applications to screen non-adherent mammalian cells are also discussed.