Challenges and Advances in Aerosol Jet Printing of Regenerated Silk Fibroin Solutions

Abstract

Silk fibroin materials are manufactured using printing and coating techniques at resolutions 1–2 µm. However, current processes are unstable, of low printability and versatility, and of limited feature size, and often require use of additives to process, which can impact material functionality and performance. Although there exist well established material synthesis and formulation approaches for making processable solutions from silkworm cocoons, these approaches do not translate to the emerging fabrication processes, such as aerosol jet printing (AJP). Here, a new approach is introduced to formulate silk‐worm solutions for AJP and subsequently analyze the processing limits, due to defects such as overspray, pooling, and cloudiness. It is found that the degumming step is critical and can lead to defects such as gelling and pooling. Furthermore, it is found that there exists a narrow processing window (sheath rate as a function of ink rate) for AJP formulations without defects. As with other materials (such as metal inks), overspray is an issue during the fabrication process; however, it is minimized within the processing window. This work stands to open a pathway for manufacturing new and emerging biodegradable materials suitable for pharmaceuticals, food packaging, and electronics, among others.

Flexible Wearables for Plants

“…[ 92 ] The aerosol jet printing can realize the printing of all layers of flexible electronic devices. [ 93–95 ] Cao et al. [ 96 ] successfully printed a completely printed, flexible, stable, and hysteresis‐free sensor via this printing technology.…”

“…Recently, the emerged flexible electronics could enable intimate contact to curvilinear surfaces and high adaptability to the shape changes of the surfaces, which has already been applied to healthcare management, human‐machine interface, and soft robotics. [ 15 ] In agriculture, flexible electronics are expected to not only solve the incompatibility between the sensors and the fragile parts of a plant but also conformably adhere to the plant surface to achieve continuous and accurate detection of growth state, physiological or biochemical parameters of plants. It is also noteworthy that there are some obvious challenges in flexible wearables.…”

Recent Advances in Printing Technologies of Nanomaterials for Implantable Wireless Systems in Health Monitoring and Diagnosis

“…A new method developed a biodegradable silk fibroin ink for aerosol jet printing. [ 106 ] The silk fibroin ink could be printed onto copper foil without the use of ink additives.…”

High-Resolution Bioprinting of Recombinant Human Collagen Type III

“…Aerosol jet ® printing (AJP) is a printing technique more commonly associated with printed electronics, but AJP has also been used to deposit biological materials such as DNA, enzymes, and silk fibroin [ 15 , 16 , 17 , 18 ]. An AJP system can be viewed as three critical modules: the mass flow controller (MFC) module, which controls the flow of carrier and sheath gas lines (containing nitrogen gas), the atomiser, seen in Figure 1 a, which forms the aerosol ultrasonically, and the deposition head, seen in Figure 1 b, which aerodynamically focuses the aerosol and directs it towards the substrate.…”