Huang

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Huang

  1. 1. Formation of Biological Microspheres Using Ink Jetting and Laser Transfer Yong Huang Associate Professor of Mechanical Engineering Adjunct Associate Professor of Bioengineering Clemson University, Clemson, SC 29634 http://www.ces.clemson.edu/camsil/ http://www.ces.clemson.edu/camsil/ Outline  Background  Fabrication Methods  Results and Conclusions  Summary and Future Collaborations  Acknowledgements 2
  2. 2. Introduction and Motivation Encapsulated materials (drug or cell) Biomedical applications of microspheres:  Controlled drug/cell delivery  Cell encapsulation for transplantation Matrix  Cellular spheroid-based tissue engineering material (polymer) Microsphere Challenges in microsphere fabrication  Formability of size controllable microspheres using various low and high viscosity biological materials  Monodisperse distribution of fabricated microspheres 3 Potential Fabrication Technologies  Size controllability  Good for low viscosity materials Ink jetting (thermal and Nozzle jetting-based piezoelectric) Nozzleless Modified LIFT (Laser-Induced jetting-based Forward Transfer)  Clog free  Good for viscous materials 4
  3. 3. Outline  Background  Fabrication Methods  Results and Conclusions  Summary and Future Collaborations  Acknowledgements 5 1. Vibration-Assisted Ink Jetting Pressure pulse For low viscosity materials Piezoelectric via piezoelectric transducer device Chamber with liquid solution dN Fluid reservoir Orifice dD Microspheres Air gap Nozzle Stir bar Drop-on-demand jetting schematic 6
  4. 4. 2. Modified LIFT (Laser) For high viscosity materials Mechanism Excimer UV laser pulse (12 ns) Objective Focused UV laser pulse Transparent Optional energy quartz support conversion layer System Demagnified Cell/protein setup UV laser pulse coating Quartz support Laser pulse Quartz Adhesive conversion layer Flexible foil Workpiece Direct-writing NaAlg suspension Cells Vacuum /substrate height Forming droplet chuck CaCl2 solution Proposed metallic foil-assisted LIFT 7 Outline  Background  Fabrication Methods  Results and Conclusions  Summary and Future Collaborations  Acknowledgements 8
  5. 5. Vibration-Assisted Inkjet-Based Method Good 100 µm Formability 100 µm Bad 100 µm Sodium alginate concentration (%) Microsphere formability as a function of sodium alginate concentration (and other operating conditions) 9 Vibration-Assisted Inkjet-Based Method (cont’d) Encapsulated fluorescent beads Microspheres (alginate-based) 100 µm Encapsulated monodisperse microsphere can be formed as a function of sodium alginate concentration and other operating conditions 10
  6. 6. Laser-Based Method A B C Sodium alginate (NaAlg) concentration: (A) 2 %; (B) 4 %; (C) 6 %(w/v) under laser fluence: 3858±34 mJ/cm2 Microsphere size Slightly NaAlg concentration Size uniformity Effect of NaAlg concentration 11 Laser-Based Method (cont’d) A B Microsphere size Laser fluence Number of satellite C D droplets Effect of laser fluence Laser fluence: (A) 2030±29; (B) 3858±34; (C) 5734±43; (D) 7436±48 mJ/cm² uisng 6 % (w/v) NaAlg solution 12
  7. 7. Laser-Based Method (cont’d) Using modified LIFT Using proposed metallic foil - assisted LIFT 2 % (w/v) NaAlg solution with 1.8 ×106 beads/ml Better encapsulation effect using proposed metallic foil-assisted LIFT (laser-based) 13 Outline  Background  Fabrication Methods  Results and Conclusions  Summary and Future Collaborations  Acknowledgements 14
  8. 8. Summary  Encapsulated biological microspheres can be effectively fabricated using proposed vibration-assisted ink jetting (for low viscosity materials) and laser transfer (for high viscosity materials) based approaches  Future work - size control and size distribution control (monodispersity) Future collaborations envisioned  Encapsulated microspheres for controlled drug delivery  Tissue microspheroids for cell transplantation and organ printing  Encapsulated cellular microspheroids for controlled stem cell differentiation study under matrix material-defined microenvironments  More … 15 Outline  Background  Fabrication Methods  Results and Conclusions  Summary and Future Collaborations  Acknowledgements 16
  9. 9. Acknowledgements  Financial support: the National Textile Center, the National Science Foundation (CMMI-CAREER and EPS), the National Institutes of Health (P20), and the South Carolina EPSCoR/IDeA office (CCD grant).  Special thanks: Dr. Scott Little of the State EPSCoR office, Dr. Douglas B. Chrisey of RPI, Drs. Roger Markwald, Vladimir Mironov, and Joann Sullivan of MUSC, and Dr. Jeremy Tzeng of Clemson  Students: Yafu Lin, Leigh Herran, Wei Wang, Nicole Coutris, and Wenxuan Chai 17

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