Advanced Nanomaterials, Printing Processes, and Applications for Flexible Hybrid Electronics

Abstract

Recent advances in nanomaterial preparation and printing technologies provide unique opportunities to develop flexible hybrid electronics (FHE) for various healthcare applications. Unlike the costly, multi-step, and error-prone cleanroom-based nano-microfabrication, the printing of nanomaterials offers advantages, including cost-effectiveness, high-throughput, reliability, and scalability. Here, this review summarizes the most up-to-date nanomaterials, methods of nanomaterial printing, and system integrations to fabricate advanced FHE in wearable and implantable applications. Detailed strategies to enhance the resolution, uniformity, flexibility, and durability of nanomaterial printing are summarized. We discuss the sensitivity, functionality, and performance of recently reported printed electronics with application areas in wearable sensors, prosthetics, and health monitoring implantable systems. Collectively, the main contribution of this paper is in the summary of the essential requirements of material properties, mechanisms for printed sensors, and electronics.

Flexible Wearable Sensors for Cardiovascular Health Monitoring

“…In fact, traditional conducting polymers without addition or modifications are inherently rigid with low stretchability of about 5%. [ 39,42 ] To gain flexibility and even stretchability, strategies such as adding nonionic and ionic small molecules [ 43 ] and incorporating with elastomers or hydrogels [ 44 ] have been utilized. Carbons and metal nano/micro particles, in the forms of carbon nanotubes, graphene particles, metal nano/micro plates, and metallic nano/microwires, are often rigid and disinterconnected.…”

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

“…However, the scope is narrowed to manufacturing technologies. [ 44–50 ] In this review, we provide a more selective scope by focusing on recent advancements in nanomaterials and printing technologies aimed toward wireless implantable devices. Nanomaterials are summarized with a focus on essential characteristics and requirements for implantable concerns.…”

Layer-Scale and Chip-Scale Transfer Techniques for Functional Devices and Systems: A Review

“…The development of flexible or wearable devices is another major factor driving the need for developing cost-effective layer transfer and chip transfer techniques [ 124 , 129 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 ]. Flexible electronics can find a wide range of applications, such as flexible or stretchable displays [ 137 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 ], flexible transistors [ 154 , 155 , 156 , 157 , 158 , 159 , 160 ], flexible solar cells [ 77 , 92 , 161 ], flexible sensors [ 162 , 163 , 164 , 165 , 166 ], wearable medical devices [ 127 , 167 , 168 , 169 ], and human–machine interfaces [ 170 , 171 , 172 , 173 , 174 ].…”