Laser Driven Miniature Diamond Implant for Wireless Retinal Prostheses

Abstract

developments have coincided with advances in minimally invasive surgical interventions, such as keyhole surgical procedures. The combination of these breakthroughs has supported a growing worldwide effort toward miniature electronic implants which can be surgically placed in a minimally invasive manner. Examples of these include deep brain neurostimulators, cochlear, and retinal implants. [6-8] However, one remaining challenge which has hindered efforts toward miniaturization is centered on methods of delivering power to these implants. While surgical techniques and the ASIC technologies are well evolved to address the requirements of minimally invasive implants, methods of delivering energy to the implant have broadly not followed this trend. Currently, the majority of implants dedicate a significant portion of their volume to power harvesting or storage units. [9] In this work, we report on optical power delivery to a retinal stimulator entirely housed within a diamond capsule. Moreover, the light intensity modulation is used as a means of data telemetry to the stimulator. This approach enables an implant with small dimensions to be wirelessly operated. While low power prostheses, such as pacemakers with sub-100 µW consumption, can use implanted nonrechargeable batteries to meet their energy needs, [10] higher power consumption prostheses (e.g., cochlear or visual implants) require power The design and benchtop operation of a wireless miniature epiretinal stimulator implant is reported. The implant is optically powered and controlled using safe illumination at near-infrared wavelengths. An application-specific integrated circuit (ASIC) hosting a digital control unit is used to control the implant's electrodes. The ASIC is powered using an advanced photovoltaic (PV) cell and programmed using a single photodiode. Diamond packaging technology is utilized to achieve high-density integration of the implant optoelectronic circuitry, as well as individual connections between a stimulator chip and 256 electrodes, within a 4.6 mm × 3.7 mm × 0.9 mm implant package. An ultrahigh efficiency PV cell with a monochromatic power conversion efficiency of 55% is used to power the implant. On-board photodetection circuity with a bandwidth of 3.7 MHz is used for forward data telemetry of stimulation parameters. In comparison to implants which utilize inductively coupled coils, laser power delivery enables a high degree of miniaturization and lower surgical complexity. The device presented combines the benefits of implant miniaturization and a flexible stimulation strategy provided by a dedicated stimulator chip. This development provides a route to fully wireless miniaturized minimally invasive implants with sophisticated functionalities.

68.9% Efficient GaAs‐Based Photonic Power Conversion Enabled by Photon Recycling and Optical Resonance

“…Another key advantage is the prospect of a purely optical power and data transmission link when combined with optical communication. [1][2][3][4][5] The application space for this technology includes sensors in special environments (structural health monitoring of wind turbines, [6] monitoring of high-voltage transmission lines [7][8][9][10] ), wireless powering of medical implants, [11][12][13][14][15] optically isolated power supply for electronic systems, [16][17][18] optical powering of remote antenna units, [2,[19][20][21] optically powered networks, [22,23] Internetof-Things devices, [24] and optical wireless power transfer. [25][26][27][28][29] Several groups have demonstrated PPCs based on III-V compound semiconductor materials with remarkable power conversion efficiencies well above 50%.…”

70 years of bilirubin sensing: towards the point-of-care bilirubin monitoring in cirrhosis and hyperbilirubinemia

“…Titanium has a good record as a biocompatible material due to its passive oxide layer 164 . Diamond has been used in orthopaedic implants for a long time with no adverse reaction in the body and is currently being used in bionic eye implants 165,166 . Biochemical inertness: For long term implantation, the performance of polymers such as UHMWPE is compromised by low stiffness and creep compliance 167 .…”

“…164 Diamond has been used in orthopaedic implants for a long time with no adverse reaction in the body and is currently being used in bionic eye implants. 165,166…”

68.9% Efficient GaAs‐Based Photonic Power Conversion Enabled by Photon Recycling and Optical Resonance

“…Another key advantage is the prospect of a purely optical power and data transmission link when combined with optical communication. [1][2][3][4][5] The application space for this technology includes sensors in special environments (structural health monitoring of wind turbines, [6] monitoring of high-voltage transmission lines [7][8][9][10] ), wireless powering of medical implants, [11][12][13][14][15] optically isolated power supply for electronic systems, [16][17][18] optical powering of remote antenna units, [2,[19][20][21] optically powered networks, [22,23] Internetof-Things devices, [24] and optical wireless power transfer. [25][26][27][28][29] Several groups have demonstrated PPCs based on III-V compound semiconductor materials with remarkable power conversion efficiencies well above 50%.…”