SUBJECT: M.S. Thesis Presentation
BY: Yuhan Xiao
TIME: Friday, April 12, 2019, 10:00 a.m.
PLACE: MARC Building, 201
TITLE: Developing Aerosol Jet Printable Regenerated Silk Fibroin Solution
COMMITTEE: Dr. Tequila A.L. Harris, Chair (ME)
Dr. Kyriyaki Kalaitzidou (ME)
Dr. Donggang Yao (MSE)


In recent year, an ancient and natural material, silk fibroin, has gained a lot of attention due to its strong mechanical properties and biocompatibility and biodegradability. Non-contact, maskless printing methods are highly desirable for fabricating silk fibroin solution, due to the advantages over micro-contact printing methods. Inkjet printing (IJP) has been the preferred choice for fabricating various materials. However, additives are typically required to successfully print using IJP, thereby, changing the chemistry of the solution. Novel additive manufacturing techniques are emerging that have the potential of replacing IJP, which is also prone to clogging. In this work, the feasibility and fidelity of using Aerosol Jet Printing (AJP) to fabricate regenerated silk fibroin (RSF) solutions made from Bombyx mori is explored and the process protocols developed, using experimental methods.

It has been found that printable RSF solutions require a unique combination of degumming, dissolving (concentration) and dialysis times to prevent the inability to spray or defects. It has been shown that AJP can be used to fabricate RSF solutions without additives at low concentrations. By investigating fundamental influences of processing parameters (sheath rate and ink rate which forms the focus ratio (FR)) on the morphology of printed patterns, an operating window and quality criteria with across micro- to macro- scales was established. Consistent with other materials, it has been shown that increasing FR reduces overspray, one of the major defects associated with AJP. The results of this work provide a framework for using AJP to print RSF solutions into patterns for a variety of fields, such as drug delivery, packaging, biosensor among others.