Writing in the granular gel medium

Tapomoy Bhattacharjee; Steven M Zehnder; Kyle G Rowe; Suhani Jain; Ryan M Nixon; W Gregory Sawyer; Thomas E Angelini

doi:10.1126/sciadv.1500655

Writing in the granular gel medium

Sci Adv. 2015 Sep 25;1(8):e1500655. doi: 10.1126/sciadv.1500655. eCollection 2015 Sep.

Authors

Tapomoy Bhattacharjee¹, Steven M Zehnder¹, Kyle G Rowe¹, Suhani Jain², Ryan M Nixon¹, W Gregory Sawyer³, Thomas E Angelini⁴

Affiliations

¹ Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611, USA.
² Stanton College Preparatory, Jacksonville, FL 32209, USA.
³ Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611, USA. ; Department of Materials Science and Engineering, University of Florida, Gainesville, FL 32611, USA.
⁴ Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, FL 32611, USA. ; J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL 32611, USA. ; Institute for Cell and Regenerative Medicine, University of Florida, Gainesville, FL 32611, USA.

Abstract

Gels made from soft microscale particles smoothly transition between the fluid and solid states, making them an ideal medium in which to create macroscopic structures with microscopic precision. While tracing out spatial paths with an injection tip, the granular gel fluidizes at the point of injection and then rapidly solidifies, trapping injected material in place. This physical approach to creating three-dimensional (3D) structures negates the effects of surface tension, gravity, and particle diffusion, allowing a limitless breadth of materials to be written. With this method, we used silicones, hydrogels, colloids, and living cells to create complex large aspect ratio 3D objects, thin closed shells, and hierarchically branched tubular networks. We crosslinked polymeric materials and removed them from the granular gel, whereas uncrosslinked particulate systems were left supported within the medium for long times. This approach can be immediately used in diverse areas, contributing to tissue engineering, flexible electronics, particle engineering, smart materials, and encapsulation technologies.

Keywords: 3D printin; carbopol; cell printing; granular gel; manufacturing; microgel; rapid prototyping; soft matter physics; yield stress.