Nano-liter perfusion microfluidic device made entirely by two-photon polymerization for dynamic cell culture with easy cell recovery

Abstract Polydimethylsiloxane (PDMS) has been the material of choice for microfluidic applications in cell biology for many years. However, PDMS limits further advancement because it lacks sub-micron lithographic ‘precision’ and the capability to deliver complex geometry in three dimensions. Further, PDMS microfluidic devices for cell culture have limited capacity for cell retrieval following culture without severely compromising cell health. This study presents a designed and entirely 3D-printed microfluidic chip (8.8 mm x 8.2 mm x 3.6 mm) using two-photon polymerization (2PP). The ‘nest’ chip is composed of ten channels that deliver sub-microliter volume flowrates (to ~ 600 nL/min per channel) to 10 individual retrievable cell sample ‘cradles’ that interlock with the nest to create the microfluidic device. Computational fluid dynamics modelling predicted medium flow in the device, which was accurately validated by real-time microbead tracking. Functional capability of the device was assessed, and demonstrated the capability to deliver culture medium, dyes, and biological molecules to support cell growth, staining and cell phenotype changes, respectively. Therefore, 2PP 3D-printing provides the precision needed for nanoliter fluidic devices constructed from multiple interlocking parts for cell culture application.