Shear-flow directed self-assembly of diacetylene liposomes of controlled size

Abstract

This study addresses a novel microfluidic method to fabricate diacetylene (DA) liposomes and control their size. Polydiacetylene (PDA) is a conjugated polymer sensor with unique optical properties which are color (blue-to-red) and fluorescence change under the application of thermal or chemical stress. The liposome size distribution is important because they significantly affect the phase transition and the fluorescent emission. So far, DA liposomes are prepared by mixing of bulk phases. As a result, they are polydisperse in size and require post-processes to improve the size uniformity. Here, we report a novel strategy to generate uniform PDA sensor liposomes and control their size using a microfluidic chip and hydrodynamic focusing technique. PDA liposomes fabricated on a chip are analyzed using scanning electron microscope (SEM) and dynamic light scattering (DLS). The results present that the microfluidic strategy generates more monodispersed liposomes than a bulk method. It is also observed that the PDA liposomes size becomes smaller and their size distribution becomes more homogeneous as the flow rate ratio of inlet flows increases