A Three-Dimensional Structured Brain-Injectable Device with a Curved Pathway

In the past few decades, diverse classes of novel bio-integrated electronic devices have emerged to enhance biomedical technology with unique and convenient medical and pharmaceutical capabilities such as monitoring of biosignals, diagnosis and treatment of diseases. A paramount focus in developing new bioelectronics has been in investigating minimally invasive monitoring and therapy techniques with improved quality. A widely utilized design implantable electronics using bulk metalized cases or ultrathin stretchable planar form, presents postsurgical complications due to open surgery and bulk device structures and limitations to apply on organs deep inside the body. In contrast, utilizing miniaturized needle-like carriers to deliver tiny sensors and stimulation tools inside the body can overcome these challenges. Biomedical devices fabricated in high aspect ratio structures or integrated on catheter-shaped carriers empowered accurate and minimally invasive insertion of high-performance devices into soft, inhomogeneous tissues. As a result, tools with high aspect ratio forms are rapidly developing for minimally invasive targeted sensors and therapy systems within the field of biomedical electronics, especially the brain-injectable devices. Although the minimally invasive needle-like form, the present brain-injectable devices have no choice but to damage other areas of the brain when the deep brain is the targeted area. In particular, the use of the devices is limited when the insertion pathway passes through a critical part of the brain.<br/>Here, we present the brain-injectable neural probes that have curved pathway to overcome these limitations. Since the device has an inclined tip and a hinge-like three-dimensional structure, it follows a curved path as it is inserted into the brain. The insertion path of the neural probes is determined by the three-dimensional structure such as thickness, angle of the tip, and width of the hinge and shank. It was confirmed through experiments and FEM simulations that the neural probes with an optimized curved insertion path to the target region of deep brain can be designed. Through this, it is possible to develop a device that can effectively reach and deliver various electronic devices like light-emitting diode and sensors to the deep brain for PDT, optogenetics, and oximetry.