We report that vertically aligned ZnO nanowire arrays (ZnO NWAs) were fabricated on 3D graphene foam (GF) and used to selectively detect uric acid (UA), dopamine (DA), and ascorbic acid (AA) by a differential pulse voltammetry method. The optimized ZnO NWA/GF electrode provided a high surface area and high selectivity with a detection limit of 1 nM for UA and DA. The high selectivity in the oxidation potential was explained by the gap difference between the lowest unoccupied and highest occupied molecular orbitals of a biomolecule for a set of given electrodes. This method was further used to detect UA levels in the serum of patients with Parkinson's disease (PD). The UA level was 25% lower in PD patients than in healthy individuals. This finding strongly implies that UA can be used as a biomarker for PD.
Chronic in vivo imaging and electrophysiology are important for better understanding of neural functions and circuits. We introduce the new cranial window using soft, penetrable, elastic, and transparent, silicone-based polydimethylsiloxane (PDMS) as a substitute for the skull and dura in both rats and mice. The PDMS can be readily tailored to any size and shape to cover large brain area. Clear and healthy cortical vasculatures were observed up to 15 weeks post-implantation. Real-time hemodynamic responses were successfully monitored during sensory stimulation. Furthermore, the PDMS window allowed for easy insertion of microelectrodes and micropipettes into the cortical tissue for electrophysiological recording and chemical injection at any location without causing any fluid leakage. Longitudinal two-photon microscopic imaging of Cx3Cr1+/− GFP transgenic mice was comparable with imaging via a conventional glass-type cranial window, even immediately following direct intracortical injection. This cranial window will facilitate direct probing and mapping for long-term brain studies.
Recording
neural activity from the living brain is of great interest
in neuroscience for interpreting cognitive processing or neurological
disorders. Despite recent advances in neural technologies, development
of a soft neural interface that integrates with neural tissues, increases
recording sensitivity, and prevents signal dissipation still remains
a major challenge. Here, we introduce a biocompatible, conductive,
and biostable neural interface, a supramolecular β-peptide-based
hydrogel that allows signal amplification via tight neural/hydrogel
contact without neuroinflammation. The non-biodegradable β-peptide
forms a multihierarchical structure with conductive nanomaterial,
creating a three-dimensional electrical network, which can augment
brain signal efficiently. By achieving seamless integration in brain
tissue with increased contact area and tight neural tissue coupling,
the epidural and intracortical neural signals recorded with the hydrogel
were augmented, especially in the high frequency range. Overall, our
tissuelike chronic neural interface will facilitate a deeper understanding
of brain oscillation in broad brain states and further lead to more
efficient brain–computer interfaces.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.