Abstract-Implantable, Degradable, Therapeutic Terahertz Metamaterial Devices

Long Sun, Zhitao Zhou, Junjie Zhong,   Zhifeng Shi, Ying Mao,  Hua Li,  Juncheng Cao, Tiger H. Tao,

https://onlinelibrary.wiley.com/doi/abs/10.1002/smll.202000294

Metamaterial (MM) sensors and devices, usually consisting of artificially structured composite materials with engineered responses that are mainly determined by the unit structure rather than the bulk properties or composition, offer new functionalities not readily available in nature. A set of implantable and resorbable therapeutic MM devices at terahertz (THz) frequencies are designed and fabricated by patterning magnesium split ring resonators on drug‐loaded silk protein substrates with controllable device degradation and drug release rates. To demonstrate proof‐of‐concept, a set of silk‐based, antibiotics‐loaded MM devices, which can serve as degradable antibacterial skin patches with capabilities to monitor drug‐release in real time are fabricated. The extent of drug release, which correlates with the degradation of the MM skin patch, can be monitored by analyzing the resonant responses in reflection during degradation using a portable THz camera. Animal experiments are performed to demonstrate the in vivo degradation process and the efficacy of the devices for antibacterial treatment. Thus, the implantable and resorbable therapeutic MM devices do not need to be retrieved once implanted, providing an appealing alternative for in‐vivo sensing and in situ treatment application

Abstract-Reconfigurable terahertz metamaterial device with pressure memory

Jinqi Wang, Shuchang Liu, Sivaraman Guruswamy, and Ajay Nahata  »View Author Affiliations

Optics Express, Vol. 22, Issue 4, pp. 4065-4074 (2014)
http://dx.doi.org/10.1364/OE.22.004065

We demonstrate a liquid metal-based reconfigurable terahertz (THz) metamaterial device that is not only pressure driven, but also exhibits pressure memory. The discrete THz response is obtained by injecting eutectic gallium indium (EGaIn) into a microfluidic structure that is fabricated in polydimethylsiloxane (PDMS) using conventional soft lithography techniques. The shape of the injected EGaIn is mechanically stabilized by the formation of a thin oxide surface layer that allows the fluid to maintain its configuration within the microchannels despite its high intrinsic surface energy. Although the viscosity of EGaIn is twice that of water, the formation of the surface oxide layer prevents flow into a microchannel unless a critical pressure is exceeded. Using a structure in which the lateral channel dimensions vary, we progressively increase the applied pressure beyond the relevant critical pressure for each section of the device, enabling switching from one geometry to another (split ring resonator to closed ring resonator to an irregular closed ring resonator). As the geometry changes, the transmission spectrum of the device changes dramatically. When the external applied pressure is removed between device geometry changes, the liquid metal morphology remains unchanged, which can be regarded as a form of pressure memory. Once the device is fully filled with liquid metal, it can be erased through the use of mechanical pressure and exposure to acid vapors.

© 2014 Optical Society of America