Recent development of biomedical devices based on microelectronics technologies are reviewed. Implantable biomedical devices are focused and discussed in detail. Two typical devices are demonstrated; one is for retinal prosthesis and the other is a deep brain implantable device. Future issues for implantable biomedical devices are addressed.
We are studying and developing biosensing techniques in order to analyze and monitor simply and easily biological phenomena such as DNA recognition events antigen-antibody interaction, and cell functions in vitro. Particularly, we focus on the direct detection of ions or ionized molecules with charges, because most of biological phenomena are closely related to ionic or ionized molecular behaviors such as sodium or potassium ions through ion channel at cell membrane which are based on cell-cell communication for example, and DNA molecules also have intrinsic molecular charges based on phosphate groups. Our research activities contain interesting information not only for researchers in biology and molecular biology, but also researchers in electronics and physics. We believe that novel tool and method based on material and device sciences should be studied and developed for discovery of unknown biological phenomenon in the interdisciplinary field.
In this paper, we developed a microfluidic device for formation of artificial cell membranes (lipid bilayer membranes) and for electrical recordings of transmembrane currents. We succeeded in observing electrical current together with formation of transmembrane α-hemolysin nanopores at the bilayer membrane. In addition, we applied glass for the device material to target long-term stability of the formed bilayer membranes. With further development, we believe that the device will contribute to lower the cost and enhance the data throughput of the functional analyses of membrane proteins related to the drug discovery.
This paper describes multiple ion-channel recordings through membrane proteins reconstituted in bilayer lipid membranes (BLMs) array. The BLMs array can be prepared by “Droplets Contacting Method” which forms BLMs at the interface of two lipid monolayers. Since this method does not require skilled techniques, it is highly reproducible and can be applied to automated system. We used a double well chip (DWC) for the droplets contacting method. We attempted to confine the BLMs forming areas with parylene micro-pore (parylene double well chip, PDWC) to augment the mechanical stability of BLMs. Subsequently, we arrayed the PDWC with electrodes for multiple recordings of channel proteins. We successfully demonstrated 14 channels simultaneous ion channel recordings through α-hemolysin.
Label-free detection principle for biomolecular interactions can be realized high-throughput screening for future medical diagnostics. In this study, localized surface plasmon resonance (LSPR) was applied for development of plasmonic nanoarray biochip. By using this plasmonic nanoarray biochip, high throughput screening can be performed on the single biochip without sophisticated labeling procedure using fluorescent dyes and enzymes. In addition, for more simplified screening applications, we developed analytical system which constructed with sample solution dispensing and optical characterization system simultaneously.
A novel clinical medical tool for surgical operation of deep brain stimulation was fabricated and evaluated. Dedicated micro-CMOS image sensor was mounted on the tip of quite fine probe tube. The probe has the same diameter as a probe that is utilized in surgical operation. A light source LED was also mounted on the tip of probe. Imaging trial using a postmortem brain was performed with the fabricated probe. The probe can be inserted into a brain easily and take still images of the brain.