Structured Biodegradable Polymeric Microparticles for Drug Delivery Produced Using Flow Focusing Glass Microfluidic Devices

Ekanem E. Ekanem, Seyed Ali Nabavi, Goran T. Vladisavljević, Sai Gu

Research output: Contribution to journalArticlepeer-review

70 Citations (SciVal)


Biodegradable poly(dl-lactic acid) (PLA) and poly(lactic-co-glycolic acid) (PLGA) microparticles with tunable size, shape, internal structure and surface morphology were produced by counter-current flow focusing in axisymmetric (3D) glass capillary devices. The dispersed phase was composed of 0.5-2 wt % polymer solution in a volatile organic solvent (ethyl acetate or dichloromethane) and the continuous phase was 5 wt % aqueous poly(vinyl alcohol) solution. The droplets with a coefficient of variation in dripping regime below 2.5% were evaporated to form polymeric particles with uniform sizes ranging between 4 and 30 μm. The particle microstructure and surface roughness were modified by adding nanofiller (montmorillonite nanoclay) or porogen (2-methylpentane) in the dispersed phase to form less porous polymer matrix or porous particles with golf-ball-like dimpled surface, respectively. The presence of 2-4 wt % nanoclay in the host polymer significantly reduced the release rate of paracetamol and prevented the early burst release, as a result of reduced polymer porosity and tortuous path for the diffusing drug molecules. Numerical modeling results using the volume of fluid-continuum surface force model agreed well with experimental behavior and revealed trapping of nanoclay particles in the dispersed phase upstream of the orifice at low dispersed phase flow rates and for 4 wt % nanoclay content, due to vortex formation. Janus PLA/PCL (polycaprolactone) particles were produced by solvent evaporation-induced phase separation within organic phase droplets containing 3% (v/v) PLA/PCL (30/70 or 70/30) mixture in dichloromethane. A strong preferential adsorption of Rhodamine 6G dye onto PLA was utilized to identify PLA portions of the Janus particles by confocal laser scanning microscopy (CLSM). Uniform hemispherical PCL particles were produced by dissolution of PLA domes with acetone.

Original languageEnglish
Pages (from-to)23132-23143
Number of pages12
JournalACS Applied Materials and Interfaces
Issue number41
Publication statusPublished - 21 Oct 2015


  • biodegradable microspheres
  • drug delivery systems
  • hemispherical particle
  • Janus particle
  • microfluidic flow focusing
  • nanoclay
  • poly(lactic acid)
  • poly(lactic-co-glycolic acid)

ASJC Scopus subject areas

  • Materials Science(all)
  • Medicine(all)


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