Fabrication of controlled magnet based microparticles on a microfluidic platform

Abstract

Droplet microfluidics is a multidisciplinary platform useful to investigate basic physics, synthesis of novel materials and a range of biomedical applications. Fabrication of Janus structures containing two or more phases in a single (symmetric or asymmetric) particles was realized with droplet microfluidics, utilized for the detection of DNA, proteins and cell encapsulations. If one constitute phase is magnetic, then wireless manipulation capabilities can be realized on droplet microfluidic platform.

We first studied Janus water droplets, containing two different food dyes. Role of flow rate ratios on the generation and size of droplets was investigated. Size of Janus water droplets decreases with increasing in flow rate ratio. After studying basic droplets behavior manipu-lation of ferrofluid droplets with an applied magnetic field was demonstrated. We investi-gated the effect of magnetic field on ferrofluid droplets. We utilized our findings for merg-ing and re-pumping of ferrofluid droplets. We have demonstrated that with increasing mag-netic field (i) merged volume of droplets increases (ii) re-pumped volume of droplets de-creases (iii) spacing between re-pumped droplets decreases.

We have successfully investigated the behavior of Janus droplets in various magnetic fields, viscosities and flow ratios. We have successfully demonstrated for the first time the manip-ulation of size and configuration of Janus droplets with an applied magnetic field at higher viscosity and high flow rate ratios. Also, role of volume force on droplet generation was in-vestigated experimentally, concluding with increasing magnetic field (i) increase in % amount of magnetic particles in droplets at high flow rate ratios (ii) decrease in droplet size at high flow rate ratio and high viscosity. Synthesis of controlled magnetic Janus particles was successfully demonstrated with control on magnetic and fluorescence phases. Increased in magnetic content was utilized for the synthesis of particles and its properties were demonstrated by VSM, TGA, DSC, FTIR and SEM analysis.

We have demonstrated fabrication of controlled magnetic based microparticles. Investiga-tions performed will contribute to understanding the behavior of Janus droplets in magnetic field. Synthesized particles could be useful for 3D bioprinting, bio-assays, tissue culture, sensors and drug delivery with wireless manipulation capabilities along with fluorescent tagging.