Fully implantable and battery-free wireless optoelectronic system for modulable cancer therapy and real-time monitoring

Photodynamic therapy(PDT)is attracting attention as a next-generation cancer treatment that can selectively destroy malignant tissues,exhibit fewer side effects,and lack pain during treatments.Implantable PDT systems have recently been developed to resolve the issues of bulky and expensive conventional PDT systems and to implement continuous and repetitive treatment.Existing implantable PDT systems,however,are not able to perform multiple functions simultaneously,such as modulating light intensity,measuring,and transmitting tumor-related data,resulting in the complexity of cancer treatment.Here,we introduce a flexible and fully implantable wireless optoelectronic system capable of continuous and effective cancer treatment by fusing PDT and hyperthermia and enabling tumor size monitoring in real-time.This system exploits micro inorganic light-emitting diodes(μ-LED)that emit light with a wavelength of 624 nm,designed not to affect surrounding normal tissues by utilizing a fully programmable light intensity ofμ-LED and precisely monitoring the tumor size by Si phototransistor during a long-term implantation(2–3 weeks).The superiority of simultaneous cancer treatment and tumor size monitoring capabilities of our system operated by wireless power and data transmissions with a cell phone was confirmed through in vitro experiments,ray-tracing simulation results,and a tumor xenograft mouse model in vivo.This all-in-one single system for cancer treatment offers opportunities to not only enable effective treatment of tumors located deep in the tissue but also enable precise and continuous monitoring of tumor size in real-time.

Foldable three dimensional neural electrode arrays for simultaneous brain interfacing of cortical surface and intracortical multilayers

Challenges in the understanding of three-dimensional(3D)brain networks by simultaneously recording both surface and intracortical areas of brain signals remain due to the difficulties of constructing mechanical design and spatial limitations of the implanted sites.Here,we present a foldable and flexible 3D neural prosthetic that facilitates the 3D mapping of complex neural circuits with high spatiotemporal dynamics from the intracortical to cortical region.This device is the tool to map the 3D neural transmission through sophisticatedly designed four flexible penetrating shanks and surface electrode arrays in one integrated system.We demonstrate the potential possibilities of identifying correlations of neural activities from the intracortical area to cortical regions through continuous monitoring of electrophysiological signals.We also exploited the structural properties of the device to record synchronized signals of single spikes evoked by unidirectional total whisker stimulation.This platform offers opportunities to clarify unpredictable 3D neural pathways and provides a next-generation neural interface.

Transparent neural implantable devices:a comprehensive review of challenges and progress

The key to designing an implantable device lies in condensing the synergistic effects of diagnostic and therapeutic methods in a single tool.In conjunction with the integration of electrophysiology and optical modalities,a transparent neural interface alleviates challenges of conventional metal-based microelectrodes.In this review,the multimodal sensing and stimulation functionalities of recent research are addressed.Next,issues that arise when combining functionalities of conventional metal-based,opaque electrode arrays together with optical modalities—(1)photoelectric artifacts,(2)optical image blocking,and(3)light transmission efficiency—are introduced.Then,an introduction of advancing material candidates for transparent neural interfaces follows with the latest research.