Browsing by Author "Lee, Yi-Chao"

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Gene-Embedded Nanostructural Biotic-Abiotic Optoelectrode Arrays Applied for Synchronous Brain Optogenetics and Neural Signal Recording
(2019-03-27)
Huang, Wei-Chen
;
Chi, Hui-Shang
;
Lee, Yi-Chao
;
Lo, Yu-Chun
;
Liu, Ta-Chung
Optogenetics is a recently established neuromodulation technique in which photostimulation is used to manipulate neurons with high temporal and spatial precision. However, sequential genetic and optical insertion with double brain implantation tends to cause excessive tissue damage. In addition, the incorporation of light-sensitive genes requires the utilization of viral vectors, which remains a safety concern. Here, by combining device fabrication design, nanotechnology, and cell targeting technology, we developed a new gene-embedded optoelectrode array for neural implantation to enable spatiotemporal electroporation (EP) for gene delivery/transfection, photomodulation, and synchronous electrical monitoring of neural signals in the brain via one-time implantation. A biotic-abiotic neural interface (called PG) composed of reduced graphene oxide and conductive polyelectrolyte 3,4-ethylenedioxythiophene-modified amphiphilic chitosan was developed to form a nanostructural hydrogel with assembled nanodomains for encapsulating nonviral gene vectors (called PEI-NT-pDNA) formulated by neurotensin (NT) and polyethylenimine (PEI)-coupled plasmid DNA (pDNA). The PG can maintain high charge storage ability to respond to a minimal current of 125 mu A for controllable gene delivery. The in vitro analysis of PG-PEI-NT-pDNA on the microelectrode array chip showed that the microelectrodes provided electrically inductive electropermeabilization, which permitted gene transfection into localized rat adrenal pheochromocytoma cells with a strong green fluorescent protein expression that was up to 8-fold higher than that in nontreated cells. Furthermore, the in vivo implantation enabled on-demand spatiotemporal gene transfection to neurons with 10-fold enhancement of targeting ability compared with astrocytes. Finally, using the real optogenetic opsin channelrhodopsin-2, the flexible neural probe incorporated with an optical waveguide fiber displayed photoevoked extracellular spikes in the thalamic ventrobasal region after focal EP for only 7 days, which provided a proof of concept for the use of photomodulation to facilitate neural therapies.
Highly sensitive/selective 3D nanostructured immunoparticle-based interface on a multichannel sensor array for detecting amyloid-beta in Alzheimer's disease
(2018-01-01)
Liu, Ta-Chung
;
Lee, Yi-Chao
;
Ko, Chiung-Yuan
;
Liu, Ren-Shyan
;
Ke, Chien-Chih
Accumulation of beta-amyloid (A beta) peptides is highly associated with Alzheimer's disease (AD) progression in prevailing studies. The successful development of an ultrasensitive detection assay for A beta is a challenging task, especially from blood-based samples. Methods: We have developed a one-step electrophoresis/electropolymerization strategy for preparing a CSIP hierarchical immunoelectrochemical interface that is easily integrated into a PoCT device. The interface includes conductive silk fibroin-based immunoparticles (CSIPs) via electropolymerized Poly(3,4-ethylenedioxythiophene) (PEDOT) bridging to enable on-site electrochemical detection of serum amyloid-beta(42) (A beta(42)) and -beta(40) (A beta(40)) peptides from an AD blood test. In addition, micro-positron emission tomography (microPET) neuroimaging and behavioral tests were simultaneously performed. Results: This nanostructured conductive interface favors penetration of water-soluble biomolecules and catalyzes a redox reaction, providing limits of detection (LOD) of 6.63 pg/mL for A beta(40) and 3.74 pg/mL for A beta(42). Our proof-of-concept study confirms that the multi-sensing electrochemical immunosensor array (MEIA) platform enables simultaneous measurement of serum A beta(42) and A beta(40) peptide levels and is more informative in early stage AD animals than amyloid-labeling A beta plaque PET imaging and behavioral tests. Conclusion: We believe this study greatly expands the applications of silk fibroin-based materials, is an important contribution to the advancement of biomaterials, and would also be valuable in the design of new types of multichannel electrochemical immunosensor arrays for the detection of other diseases.