Integration of PDMS microfilters and micromixers bonded onto APTES-functionalized polymeric films for size sorting and mixing of microparticles

In this work, 3-(aminopropyl)triethoxysilane (APTES) was applied to functionalize flexible non-porous polymer substrates of polyimide (PI), polyethylene naphthalate (PEN), and polyethylene terephthalate (PET) that were bonded onto oxygen activated poly(dimethylsiloxane) (PDMS) microfiltering and micromixer devices. The feasibility of filtering using pillar filters was observable with poly(lactic-co-glycolic acid) (PLGA) microparticles (MPS), followed by the mixing capabilities of the micromixer with MPS in poly(vinyl alcohol) (MPS-PVA). A mixing performance of 17.6 % at 5 mm was observed. Finally, the PDMS microfilter was connected to the PDMS micromixer for filtration of MPS with dimensions of <; 11 μm. Those particles which were smaller then entered into the mixer and a mixing performance of 62.5% at 3 mm was observed. To our knowledge, we have exhibited the first complex PDMS microfilter and micromixer that has been integrated for MPS size sorting and mixing based on PI, PEN, and PET. These results demonstrate the development of microfluidic components using APTES for PDMS-thermoplastic film bonding that is based on a simple connection for lab-on-a-chip (LoC) devices where real samples require filtering and mixing of particles or suspensions.