Implantable, Bioresorbable Radio Frequency Resonant Circuits for Magnetic Resonance Imaging

Abstract

Magnetic resonance imaging (MRI) is widely used in clinical care and medical research. The signal‐to‐noise ratio (SNR) in the measurement affects parameters that determine the diagnostic value of the image, such as the spatial resolution, contrast, and scan time. Surgically implanted radiofrequency coils can increase SNR of subsequent MRI studies of adjacent tissues. The resulting benefits in SNR are, however, balanced by significant risks associated with surgically removing these coils or with leaving them in place permanently. As an alternative, here the authors report classes of implantable inductor–capacitor circuits made entirely of bioresorbable organic and inorganic materials. Engineering choices for the designs of an inductor and a capacitor provide the ability to select the resonant frequency of the devices to meet MRI specifications (e.g., 200 MHz at 4.7 T MRI). Such devices enhance the SNR and improve the associated imaging capabilities. These simple, small bioelectronic systems function over clinically relevant time frames (up to 1 month) at physiological conditions and then disappear completely by natural mechanisms of bioresorption, thereby eliminating the need for surgical extraction. Imaging demonstrations in a nerve phantom and a human cadaver suggest that this technology has broad potential for post‐surgical monitoring/evaluation of recovery processes.

Materials and Device Designs for Wireless Monitoring of Temperature and Thermal Transport Properties of Wound Beds during Healing

“…All of these materials are bioresorbable. [32][33][34] SiN x O y /Si 3 N 4 and Mo layers lie close to the neutral mechanical plane of a multilayer structure that involves the top and bottom layers of PA. [35] Water penetration into the PA and SiN x O y /Si 3 N 4 encapsulation layers lead to dissolution of Mo in DPBS (pH 7.4) at 75 °C (Figure S24, Supporting Information). Figure 6d confirms the operation as a temperature sensor through changes in resistance.…”

Organic Electronics in Biosensing: A Promising Frontier for Medical and Environmental Applications

“…This technology is essential for genetic screening, personalized medicine, and pathogen identification. In medical imaging, organic bioelectronics have shown promise in developing imaging probes and contrast agents, thereby enhancing the resolution and sensitivity of imaging techniques like magnetic resonance imaging (MRI) [204,205]. Additionally, organic bioelectronics have contributed to advancing microfluidic systems for cell analysis, thereby enabling cell sorting, counting, and characterizing cellular responses to external stimuli [206][207][208].…”

A Sewing Approach to the Fabrication of Eco/bioresorbable Electronics

“…The lifetime of the device could be extended by coating additional inorganic materials, such as SiO 2 , onto the PU encapsulation layer or by using a oil/polyanhydride structure as an encapsulation layer as recently reported in the literature. [38] Replacing the LED with a radio-frequency identification (RFID) chip (NXP P60 chipset) yields an RFID tag, capable of wirelessly unlocking a car (Figure 3e,f). This system dissolves in PBS solution (1×, pH 7.4) with 50 × 10 −3 M H 2 O 2 at 90 °C, leaving only the chip, which corresponds to ≈3% of the total mass of the system (Figure S10, Supporting Information).…”