3D Heterogeneous Device Arrays for Multiplexed Sensing Platforms Using Transfer of Perovskites.

Despite recent substantial advances in perovskite materials, their 3D integration capability for next-generation electronic devices is limited owing to their inherent vulnerability to heat and moisture with degradation of their remarkable optoelectronic properties during fabrication processing. Herein, a facile method to transfer the patterns of perovskites to planar or nonplanar surfaces using a removable polymer is reported. After fabricating perovskite devices on this removable polymer film, the conformal attachment of this film on target surfaces can place the entire devices on various substrates by removing this sacrificial film. This transfer method enables the formation of a perovskite image sensor array on a soft contact lens, and in vivo tests using rabbits demonstrate its wearability. Furthermore, 3D heterogeneous integration of a perovskite photodetector array with an active-matrix array of pressure-sensitive silicon transistors using this transfer method demonstrates the formation of a multiplexed sensing platform detecting distributions of light and tactile pressure simultaneously.

A soft and transparent contact lens for the wireless quantitative monitoring of intraocular pressure.

Continuous detection of raised intraocular pressure (IOP) could benefit the monitoring of patients with glaucoma. Current contact lenses with embedded sensors for measuring IOP are rigid, bulky, partially block vision or are insufficiently sensitive. Here, we report the design and testing in volunteers of a soft and transparent contact lens for the quantitative monitoring of IOP in real time using a smartphone. The contact lens incorporates a strain sensor, a wireless antenna, capacitors, resistors, stretchable metal interconnects and an integrated circuit for wireless communication. In rabbits, the lens provided measurements that match those of a commercial tonometer. In ten human participants, the lens proved to be safe, and reliably provided accurate quantitative measurements of IOP without inducing inflammation.

Long-term Intracellular Recording of Optogenetically-induced Electrical Activities using Vertical Nanowire Multi Electrode Array.

Continuous recording of intracellular activities in single cells is required for deciphering rare, dynamic and heterogeneous cell responses, which are missed by population or brief single-cell recording. Even if the field of intracellular recording is constantly proceeding, several technical challenges are still remained to conquer this important approach. Here, we demonstrate long-term intracellular recording by combining a vertical nanowire multi electrode array (VNMEA) with optogenetic stimulation to minimally disrupt cell survival and functions during intracellular access and measurement. We synthesized small-diameter and high-aspect-ratio silicon nanowires to spontaneously penetrate into single cells, and used light to modulate the cell's responsiveness. The light-induced intra- and extracellular activities of individual optogenetically-modified cells were measured simultaneously, and each cell showed distinctly different measurement characteristics according to the cell-electrode configuration. Intracellular recordings were achieved continuously and reliably without signal interference and attenuation over 24 hours. The integration of two controllable techniques, vertically grown nanowire electrodes and optogenetics, expands the strategies for discovering the mechanisms for crucial physiological and dynamic processes in various types of cells.

Intraocular Pressure Monitoring Following Islet Transplantation to the Anterior Chamber of the Eye.

Intraocular islet transplantation was investigated as a new procedure to treat diabetes. The development of this procedure requires close monitoring of the function of both eye and islet graft. We developed a soft, smart contact lens to monitor the intraocular pressure and applied this for noninvasive monitoring in association with the intraocular islet transplantation in diabetes. A strain sensor inside the lens can detect detailed changes in intraocular pressure by focusing the strain only in the desired, selective area of the contact lens. In addition, this smart contact lens can transmit the real-time value of the intraocular pressure wirelessly using an antenna. The wireless measurement of intraocular pressure that was obtained using this contact lens had a high correlation with the intraocular pressure measured by a rebound tonometer, thereby proving the good accuracy of the contact lens sensor. In the initial period, a slight elevation of intraocular pressure was observed, but the pressure returned to normal in the initial period after the transplantation. This type of monitoring will provide important information on potential changes in the intraocular pressure associated with the transplantation procedure, and it enables appropriate clinical safety steps to be taken, if needed.

Printing of wirelessly rechargeable solid-state supercapacitors for soft, smart contact lenses with continuous operations.

Recent advances in smart contact lenses are essential to the realization of medical applications and vision imaging for augmented reality through wireless communication systems. However, previous research on smart contact lenses has been driven by a wired system or wireless power transfer with temporal and spatial restrictions, which can limit their continuous use and require energy storage devices. Also, the rigidity, heat, and large sizes of conventional batteries are not suitable for the soft, smart contact lens. Here, we describe a human pilot trial of a soft, smart contact lens with a wirelessly rechargeable, solid-state supercapacitor for continuous operation. After printing the supercapacitor, all device components (antenna, rectifier, and light-emitting diode) are fully integrated with stretchable structures for this soft lens without obstructing vision. The good reliability against thermal and electromagnetic radiations and the results of the in vivo tests provide the substantial promise of future smart contact lenses.