Paper Number
AR8 

Session
Applied Rheology for Pharmaceuticals, Food, and Consumer Products

Title
Embedded droplet printing in yield-stress fluids for pharmaceutical materials manufacturing

Presentation Date and Time
October 23, 2019 (Wednesday) 4:35

Track / Room
Track 6 / Room 306B

Authors (Click on name to view author profile)

1. Nelson, Arif Z. (Singapore-MIT Alliance for Research and Technology)
2. Khan, Saif A. (National University of Singapore, Department of Chemical and Biomolecular Engineering)
3. Doyle, Patrick S. (Massachusetts Institute of Technology, Department of Chemical Engineering)

Author and Affiliation Lines (in printed abstract book)
Arif Z. Nelson¹, Saif A. Khan², and Patrick S. Doyle^3
1Singapore-MIT Alliance for Research and Technology, Singapore 138602, Singapore; ²Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576, Singapore; ³Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02142

Speaker / Presenter 
Nelson, Arif Z.

Text of Abstract
We report a method for the formation of uniform pharmaceutical particles through the crystallization of droplets embedded within a yield-stress fluid. Yield-stress fluids are a class of rheologically complex material that are solid-like below a critical stress but undergo a dramatic drop in viscosity and flow above their yield stress. Many current pharmaceutical manufacturing processes consist of outdated grinding and mixing processes which are wasteful, energy intensive, and inflexible. Our method effectively integrates several secondary manufacturing processes which will afford drug products with increased quality control and reduced waste.

Beyond pharmaceutical crystallization, the method we demonstrate constitutes a completely new platform for droplet generation, processing, and experimentation which extends and improves on microfluidic technologies through the use of yield-stress fluid materials. Droplets embedded in specified locations within a bath of yield-stress fluid may be processed for essentially an indefinite period of time with no risk of coalescence or contamination, and with no influence from exterior convective forces or solid boundaries. We investigate fundamental physical aspects of controlling droplet size in a model yield-stress fluid system. In addition to pharmaceutical crystallization, we demonstrate applications of our platform that include biological assays and chemical microreactors.