Taira Kajisa
@toyo.ac.jp
Associate Professor
Toyo University Graduate School of Interdisciplinary New Science
RESEARCH, TEACHING, or OTHER INTERESTS
Biochemistry, Genetics and Molecular Biology, Organic Chemistry, Electrochemistry, Materials Chemistry
Scopus Publications
Scopus Publications
Hui Zhang, Mayuna Abe, Fumiya Osawa, Yawei Qiu, Noriyasu Ohshima, Taira Kajisa, Toshiya Sakata, Takashi Izumi, and Hayato Sone
IOP Publishing
Abstract Silicon nanowire (SiNW) biosensors, operating as FETs, demonstrate remarkable capabilities for the ultrasensitive detection of specific biomolecules. Our prior work specifically explored the impact of SiNW widths on biosensor sensitivity, highlighting that narrower SiNWs significantly enhance detection sensitivity. While experimental studies provide valuable insights, theoretical investigations into the combined effect of multiple parameters on sensing performance are crucial. However, theoretical studies have been relatively scarce in the research of SiNW biosensors. In response to this gap, we developed a numerical model of SiNW biosensor using the finite-element method in COMSOL Multiphysics. By leveraging simulations, we explored the sensing performance of SiNW biosensors across various widths, thicknesses, impurity concentrations, and their combined effects, addressing a previously unexplored area in this research. Based on the simulations, the optimal structure that exhibits both high sensitivity and measurable current was predicted. To ascertain the reliability of our simulations, a subset of the results was compared with experimental data. Our findings indicate the potential for achieving ultrasensitive biomolecule detection using SiNW biosensors through structural optimization.
Taira Kajisa, Toshiya Kuroi, Hiroyuki Hara, and Toshiyuki Sakai
Elsevier BV
Shogo Miyamura, Ryo Oe, Takuya Nakahara, Hidenori Koresawa, Shota Okada, Shuji Taue, Yu Tokizane, Takeo Minamikawa, Taka-Aki Yano, Kunihiro Otsuka,et al.
Springer Science and Business Media LLC
AbstractRapid, sensitive detection of biomolecules is important for biosensing of infectious pathogens as well as biomarkers and pollutants. For example, biosensing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still strongly required for the fight against coronavirus disease 2019 (COVID-19) pandemic. Here, we aim to achieve the rapid and sensitive detection of SARS-CoV-2 nucleocapsid protein antigen by enhancing the performance of optical biosensing based on optical frequency combs (OFC). The virus-concentration-dependent optical spectrum shift produced by antigen–antibody interactions is transformed into a photonic radio-frequency (RF) shift by a frequency conversion between the optical and RF regions in the OFC, facilitating rapid and sensitive detection with well-established electrical frequency measurements. Furthermore, active-dummy temperature-drift compensation with a dual-comb configuration enables the very small change in the virus-concentration-dependent signal to be extracted from the large, variable background signal caused by temperature disturbance. The achieved performance of dual-comb biosensing will greatly enhance the applicability of biosensors to viruses, biomarkers, environmental hormones, and so on.
Hidenori Koresawa, Kota Seki, Kenji Nishimoto, Eiji Hase, Yu Tokizane, Taka-Aki Yano, Taira Kajisa, Takeo Minamikawa, and Takeshi Yasui
Springer Science and Business Media LLC
AbstractHerein, we integrated angle-scanning surface plasmon resonance (SPR) and angle-fixed SPR as a hybrid angular-interrogation SPR to enhance the sensing performance. Galvanometer-mirror-based beam angle scanning achieves a 100-Hz acquisition rate of both the angular SPR reflectance spectrum and the angle-fixed SPR reflectance, whereas the use of near-infrared light enhances the refractive index (RI) sensitivity, range, and precision compared with visible light. Simultaneous measurement of the angular SPR reflectance spectrum and angle-fixed SPR reflectance boosts the RI change range, RI resolution, and RI accuracy to 10–1–10–6 RIU, 2.24 × 10−6 RIU, and 5.22 × 10−6 RIU, respectively. The proposed hybrid SPR is a powerful tool for wide-dynamic-range RI sensing with various applications.
Hui Zhang, Yawei Qiu, Fumiya Osawa, Meiko Itabashi, Noriyasu Ohshima, Taira Kajisa, Toshiya Sakata, Takashi Izumi, and Hayato Sone
American Chemical Society (ACS)
Silicon nanowire (SiNW) biosensors have attracted a lot of attention due to their superior sensitivity. Recently, the dependence of biomolecule detection sensitivity on the nanowire (NW) width, number, and doping density has been partially investigated. However, the primary reason for achieving ultrahigh sensitivity has not been elucidated thus far. In this study, we designed and fabricated SiNW biosensors with different widths (10.8-155 nm) by integrating a complementary metal-oxide-semiconductor process and electron beam lithography. We aimed to investigate the detection limit of SiNW biosensors and reveal the critical effect of the 10-nm-scaled SiNW width on the detection sensitivity. The sensing performance was evaluated by detecting antiovalbumin immunoglobulin G (IgG) with various concentrations (from 6 aM to 600 nM). The initial thickness of the depletion region of the SiNW and the changes in the depletion region due to biomolecule binding were calculated. The basis of this calculation are the resistance change ratios as functions of IgG concentrations using SiNWs with different widths. The calculation results reveal that the proportion of the depletion region over the entire SiNW channel is the essential reason for high-sensitivity detection. Therefore, this study is crucial for an indepth understanding on how to maximize the sensitivity of SiNW biosensors.
Shogo Miyamura, Ryo Oe, Takuya Nakahara, Shuji Taue, Yu Tokizane, Takeo Minamikawa, Taira Kajisa, and Takeshi Yasui
SPIE
One interesting feature of optical frequency comb (OFC) is a function of frequency conversion between region and electric regions. While such feature has been used for generation of correct electric signal in microwave or millimeter region, it can be further used for fiber biosensing; namely, biosensing OFC. In this paper, we demonstrated detection of SARS-CoV-2 antigen based on a combination of dual fiber combs, an intracavity multi-mode-interference fiber sensor, and sensor surface modification of SARS-CoV-2 antibody.
Taka-aki Yano, Taira Kajisa, Masayuki Ono, Yoshiya Miyasaka, Yuichi Hasegawa, Atsushi Saito, Kunihiro Otsuka, Ayuko Sakane, Takuya Sasaki, Koji Yasutomo,et al.
Springer Science and Business Media LLC
AbstractThe COVID-19 pandemic has created urgent demand for rapid detection of the SARS-CoV-2 coronavirus. Herein, we report highly sensitive detection of SARS-CoV-2 nucleocapsid protein (N protein) using nanoparticle-enhanced surface plasmon resonance (SPR) techniques. A crucial plasmonic role in significantly enhancing the limit of detection (LOD) is revealed for exceptionally large gold nanoparticles (AuNPs) with diameters of hundreds of nm. SPR enhanced by these large nanoparticles lowered the LOD of SARS-CoV-2 N protein to 85 fM, resulting in the highest SPR detection sensitivity ever obtained for SARS-CoV-2 N protein.
Taira Kajisa, Taka-aki Yano, Hidenori Koresawa, Kunihiro Otsuka, Ayuko Sakane, Takuya Sasaki, Koji Yasutomo, and Takeshi Yasui
Optica Publishing Group
We report a near-infrared surface plasmon resonance (SPR) system to achieve highly sensitive, unlabeled detection of the SARS-CoV-2 nucleocapsid protein antigen. Use of the near-infrared light in SPR makes the SPR dip of the angular spectrum sharp and causes a large change of the reflected light intensity at a fixed incident angle. The present SPR system achieves the resolution of 10−5 refractive index unit in the refractive index measurement of glycerol solution samples. Additionally, we measured the nucleocapsid protein antigen of SARS-CoV-2 down to a molar concentration of 1 fM by immobilizing its corresponding antibody on the SPR sensor surface. This demonstration indicates a high potential of the present system for highly sensitive biosensing in medical diagnostics.
Hidenori Koresawa, Kota Seki, Eiji Hase, Yu Tokizane, Takeo Minamikawa, Taka-Aki Yano, Taira Kajisa, and Takeshi Yasui
Optica Publishing Group
Surface plasmon resonance (SPR) sensors are powerful tools for optical sensing of refractive index (RI) and bio-molecules due to their high sensitivity. In this article, we demonstrate a beam-angle-scanning SPR system using a combined galvanometer mirror and relay lens optics. Use of a photodetector in the galvanometer mirror scanning of the incident beam angle enables both high precision and rapid data acquisition. RI resolution of 2.306×10−5 refractive index unit (RIU) and RI accuracy of 8.984×10−5 RIU were achieved at a data acquisition rate of 100 Hz. Furthermore, we performed real-time monitoring of the avidin-biotin antigen-antibody reaction. The results show the high potential of this beam-angle-scanning SPR system.
Shogo Miyamura, Ryo Oe, Taira Kajisa, Yu Tokizane, Takeo Minamikawa, Shuji Taue, and Takeshi Yasui
IEEE
We suppress the temperature drift in the refractive-index-sensing optical frequency comb (RI-sensing OFC) by using the difference of repetition frequency between an active RIsensing OFC and a dummy one in the mechanical-sharing dual-fiber-cavity configuration. © 2022 The Author(s)
Shogo Miyamura, Ryo Oe, Taira Kajisa, Yu Tokizane, Takeo Minamikawa, Shuji Taue, and Takeshi Yasui
Optica Publishing Group
We suppress the temperature drift in the refractive-index-sensing optical frequency comb (RI-sensing OFC) by using the difference of repetition frequency between an active RI-sensing OFC and a dummy one in the mechanical-sharing dual-fiber-cavity configuration.
Taira Kajisa and Shota Hosoyamada
American Chemical Society (ACS)
To construct an electrochemical biosensing platform, we propose a glucose sensor whose electrode interface was modified by mesoporous silica (MPSi) as an electronic signal transmission interface between a biomarker and an electrochemical device. We develop an enzyme-free glucose sensor using an MPSi-coated Ta2O5 electrode in an actual biological fluid such as blood serum. MPSi includes a phenylboronic acid (PBA) molecule, in which glucose binds to a synthesized PBA-silane compound in an ca. 150 nm thick MPSi nanolayer, which changes the density of molecular charges of the PBA/glucose complex on the surface of MPSi. The charge changes derived from the equilibrium reaction of PBA with glucose lead to changes in surface potential of the Ta2O5 electrode, and the surface potential changes depending on glucose concentration were measured by a potentiometric detector. As a result, a remarkable surface potential response was observed in the vicinity of neutral pH. Kd = 6.0 mM and Vmax = 194 mV were obtained from the fitting curve of the Langmuir adsorption isotherm. Finally, we confirmed the glucose response of the PBA-MPSi-coated Ta2O5 substrate in human serum by considering the influence of various contaminants. Although the surface potential change was suppressed by approximately one-third of that in the buffer system, it was suggested that it could be applied to measurements in the blood glucose concentration range. From the results of this study, it was clarified that blood-level glucose response could be monitored using a PBA-MPSi-coated Ta2O5 substrate, which suggests the possibility of using a nonenzymatic glucose sensor as an alternative to the existing enzyme sensor.
Hui Zhang, Naoki Kikuchi, Noriyasu Ohshima, Taira Kajisa, Toshiya Sakata, Takashi Izumi, and Hayato Sone
American Chemical Society (ACS)
As critical factors affecting the sensing performance of silicon nanowire (SiNW) biosensors, the structure, functional interface, and detection target were analyzed and designed to improve sensing performance. For an improved understanding of the dependence of sensor structure on sensitivity, a simple theoretical analysis was proposed to predict the sensitivity of biosensors with different SiNW types, widths, and doping concentrations. Based on the theoretical analysis, a biosensor integrating optimized critical factors was designed and fabricated. Optimizations focusing on the following aspects are considered: (1) employing n-type SiNW and controlling the impurity doping concentration of SiNW at approximately 2 × 1016-6 × 1016 atoms/cm3 to obtain a suitable charge density, (2) minimizing the SiNW width to 16.0 nm to increase the surface area-to-volume ratio, (3) using a native oxide layer on SiNW as a gate insulator to transport the captured charge molecules closer to the SiNW surface, (4) modifying the SiNW surface by 2-aminoethylphosphonic acid coupling to form a high-density self-assembled monolayer for enhancing the stability bound molecules, and (5) functionalizing the SiNW with ovalbumin molecules for specifically capturing the target immunoglobulin G (IgG) molecules. The sensing performance was evaluated by detecting IgG with concentrations ranging from 6 aM to 600 nM and control experiments. The SiNW biosensor revealed ultrahigh sensitivity and specific detection of target IgG with a measured limit of detection of 6 aM. The integration of the critical SiNW biosensor factors provides a significant possibility of a rapid and ultrasensitive diagnosis of diseases at their early stages.
Takuya Nakahara, Ryo Oe, Takeo Minamikawa, Shuji Taue, Taira Kajisa, and Takeshi Yasui
Optica Publishing Group
We combined refractive-index-sensing optical comb with biotin surface modification for fiber biosensor of avidin. A repetition frequency signal of optical comb in RF region is read out as s sensor signal of biomolecules.
Toshiya Sakata, Shoichi Nishitani, and Taira Kajisa
Royal Society of Chemistry (RSC)
A molecularly imprinted polymer (MIP)-based membrane with phenylboronic acid (PBA) molecules, which induces the change in the density of molecular charges, is suitable for the bioelectrical interface of field-effect transistor (FET) sensors.
Taira Kajisa and Toshiya Sakata
American Chemical Society (ACS)
A platform based on a highly selective and sensitive detection device functionalized with a well-designed artificial biointerface is required for versatile biosensors. We develop a molecularly imprinted polymer (MIP)-coated gate field-effect transistor (FET) biosensor for low-concentration glucose detection in biological fluid samples such as tears in an enzyme-free manner. The MIP includes glucose templates (GluMIP), in which glucose binds to vinylphenylboronic acid in the copolymerized membrane, resulting in the change in the density of molecular charges of the phenylboronic acid (PBA)/glucose complex. The FET biosensor can detect small biomolecules as long as biomolecular recognition events cause intrinsic changes in the density of molecular charges. As a result, the changes in the output voltage detected using the GluMIP-based FET sensor are fitted to the Langmuir adsorption isotherm equation at various concentrations of sugars, showing the low detection limit of 3 μM and the high sensitivity of 115 mV/decade from 100 μM to 4 mM glucose. On the basis of the equation, the stability constant ( Ka) of PBA with glucose is calculated and found to markedly increase to Ka = 1192 M-1, which is higher by a factor of a few hundreds than Ka = 4.6 M-1 obtained by nonelectrical detection methods. Moreover, the GluMIP-coated gate FET sensor shows an approximately 200-fold higher selectivity for glucose than for fructose. This is because glucose binds to PBA more selectively than fructose in the templates, resulting in the generation of negative charges. The electrical properties of the MIP-coated electrode are also evaluated by measuring capacitance. Our work suggests a new strategy of designing a platform based on the MIP-coated gate FET biosensor, which is suitable for a highly selective, sensitive, enzyme-free biosensing system.