Wirelessly powered microdevices are being miniaturized to improve safety, longevity, and spatial resolution in a wide range of biomedical applications. Some wireless microdevices have reached a point where they can be injected whole into the central nervous system. However, the state-of-the-art floating microdevices have not yet been tested in chronic brain applications, and there is a growing concern that the implants might migrate through neural tissue over time. Using a 9.4T MRI scanner, we attempt to address the migration question by tracking ultra-small devices injected in different areas of the brain (cortico-subcortical) of rats over 5 months. We demonstrate that injectable microdevices smaller than 0.01 mm remain anchored in the brain at the targeted injection site over this time period. Based on CD68 (microglia) and GFAP (astrocytes) immunoreactivity to the microdevice, we hypothesize that glial scar formation is preventing the migration of chronically implanted microdevices in the brain over time.
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http://dx.doi.org/10.3389/fnins.2021.738589 | DOI Listing |
Biomed Microdevices
January 2025
Chakri Naruebodindra Medical Institute, Faculty of Medicine Ramathibodi Hospital, Mahidol University, 111 Suwannabhumi Canal Rd, Bang Pla, Bang Phli District, Samut Prakan, 10540, Thailand.
Microfluidic chips often face challenges related to the formation and accumulation of air bubbles, which can hinder their performance. This study investigated a bubble trapping mechanism integrated into microfluidic chip to address this issue. Microfluidic chip design includes a high shear stress section of fluid flow that can generate up to 2.
View Article and Find Full Text PDFNat Commun
January 2025
Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, China.
Micro actuators are widely used in NEMS/MEMS for control and sensing. However, most are designed with suspended beams anchored at fixed points, causing two main issues: restricted actuated stroke and movement modes, and reduced lifespan due to fatigue from repeated beam deformation, contact wear and stiction. Here, we develop an electrostatic in-plane actuator leveraging structural superlubric sliding interfaces, characterized by zero wear, ultralow friction, and no fixed anchor.
View Article and Find Full Text PDFCurr Protoc
December 2024
Research Unit of Health Sciences and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.
Osteoarthritis (OA) is one of the most prevalent joint diseases globally, characterized by the progressive breakdown of articular cartilage, resulting in chronic pain, stiffness, and loss of joint function. Despite its significant socioeconomic impact, therapeutic options remain limited, largely due to an incomplete understanding of the molecular mechanisms driving cartilage degradation and OA pathogenesis. Recent advances in in vitro modeling have revolutionized joint tissue research, transitioning from simplistic two-dimensional cell cultures to sophisticated three-dimensional (3D) constructs that more accurately mimic the physiological microenvironment of native cartilage.
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November 2024
School of Engineering, Brown University, Providence, RI, USA.
Transmitting meaningful information into brain circuits by electronic means is a challenge facing brain-computer interfaces. A key goal is to find an approach to inject spatially structured local current stimuli across swaths of sensory areas of the cortex. Here, we introduce a wireless approach to multipoint patterned electrical microstimulation by a spatially distributed epicortically implanted network of silicon microchips to target specific areas of the cortex.
View Article and Find Full Text PDFBiomed Microdevices
September 2024
Institut FEMTO-ST, Université de Franche-Comté, CNRS, Besançon, F-25000, France.
Microbubbles are widely used for biomedical applications, ranging from imagery to therapy. In these applications, microbubbles can be functionalized to allow targeted drug delivery or imaging of the human body. However, functionalization of the microbubbles is quite difficult, due to the unstable nature of the gas/liquid interface.
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