Publications by authors named "Hong-Chang Tian"

A series of novel trimethoxyphenyl-derived chalcone-benzimidazolium salts were synthesized. The biological properties of the compounds were screened in vitro against five different human tumor cell lines. The results suggest that the 5,6-dimethyl-benzimidazole or 2-methyl-benzimidazole ring as well as the 2-naphthylmethyl, 4-methylbenzyl, or 2-naphthylacyl substituent at position-3 of the benzimidazole ring was important to the cytotoxic activity.

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With the rapid development of Micro-electro-mechanical Systems (MEMS) fabrication technologies, many microelectrodes with various structures and functions have been designed and fabricated for applications in biomedical research, diagnosis and treatment through electrical stimulation and electrophysiological signal recording. The flexible MEMS microelectrodes exhibit excellent characteristics in many aspects beyond stiff microelectrodes based on silicon or metal, including: lighter weight, smaller volume, better conforming to neural tissue and lower fabrication cost. In this paper, we reviewed the key technologies in flexible MEMS microelectrodes for neural interface in recent years, including: design and fabrication technology, flexible MEMS microelectrodes with fluidic channels and electrode⁻tissue interface modification technology for performance improvement.

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Engineering of neural interface with nanomaterials for high spatial resolution neural recording and stimulation is still hindered by materials properties and modification methods. Recently, poly(3,4-ethylene-dioxythiophene) (PEDOT) has been widely used as an electrode-tissue interface material for its good electrochemical property. However, cracks and delamination of PEDOT film under pulse stimulation are found which restrict its long-term applications.

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Implantable biomedical microdevices enable the restoration of body function and improvement of health condition. As the interface between artificial machines and natural tissue, various kinds of microelectrodes with high density and tiny size were developed to undertake precise and complex medical tasks through electrical stimulation and electrophysiological recording. However, if only the electrical interaction existed between electrodes and muscle or nerve tissue without nutrition factor delivery, it would eventually lead to a significant symptom of denervation-induced skeletal muscle atrophy.

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With the rapidly developed micromachining technology, various kinds of sophisticated microelectrodes integrated with micro fluidic channels are design and fabricated for not only electrophysiological recording and stimulation, but also chemical drug delivery. As many efforts have been devoted to develop rigid microprobes for neural research of brain, few researchers concentrate on fabrication of flexible microelectrodes for intramuscular electrophysiology and chemical interfacing. Since crude wire electrodes still prevail in functional electrical stimulation (FES) and electromyography (EMG) recording of muscle, here we introduce a flexible micro tube electrode combining electrical and chemical pathway.

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Owing to interacting with the living tissue directly, the electrode-tissue interface largely determines the performance of the whole bioelectronics devices. The miniaturization of biomedical electronic components requires interface materials to possess properties including excellent electrical performance, good biocompatibility and compatibility with microelectronic fabrication process. Considering the unique characteristics and wide applications in biomedical domain of conducting polymer and graphene, composite film consists of poly(3,4-ethylenedioxythiophene) (PEDOT) and graphene oxide (GO) is proposed as electrode-tissue interface in this work.

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Iridium oxide has been widely used in neural recording and stimulation due to its good stability and large charge storage capacity (CSC). In general, the iridium oxide film used in the electrophysiological application can be grouped into three principal classifications: sputtering iridium oxide film (SIROF), activated iridium oxide film (AIROF) and electrodeposited iridium oxide film (EIROF). Although these kinds of iridium oxide all can remarkably reduce the impedance and increase the CSC of the microelectrode, they also exhibit markedly differences in electrochemical performances.

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One of the most significant components for implantable bioelectronic devices is the interface between the microelectrodes and the tissue or cells for disease diagnosis or treatment. To make the devices work efficiently and safely in vivo, the electrode-tissue interface should not only be confined in micro scale, but also possesses excellent electrochemical characteristic, stability and biocompatibility. Considering the enhancement of many composite materials by combining graphene oxide (GO) for its multiple advantages, we dope graphene oxide into poly(3,4-ethylenedioxythiophene) (PEDOT) forming a composite film by electrochemical deposition for electrode site modification.

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