About

Masahiko Taniguchi is an Associate Research Professor in the Department of Chemistry at NC State University. He holds a Ph.D. in Engineering from Kyushu University, obtained in 2000, and a B.S. in Pharmacy Science from the University of Tokyo, earned in 1995. His research focuses on various aspects of chemistry, including the development and application of spectral databases, photochemistry, and photobiology, with particular attention to carotenoids, tetrapyrrole macrocycles, and photosynthetic organisms. His work involves creating digital databases of absorption spectra, fluorescence, and molecular orbitals, as well as exploring noninvasive cardiac modulation through phototherapeutic techniques. Taniguchi has contributed to advancing understanding in these areas through his publications and research activities, supporting the department's broader mission in chemical research and education.

Research topics

• Chemistry
• Physics
• Organic chemistry
• Photochemistry
• Optics
• Computer Science
• Biology
• Materials science
• Database
• Chromatography
• Atomic physics
• Computational biology

Selected publications

• Digital Database of Absorption Spectra of Carotenoids Found in Food and Photosynthetic Organisms

  ACS Food Science & Technology · 2026-03-04

  articleOpen access

  Carotenoids─ubiquitous pigments in the plant and animal kingdom─play roles in coloration, light-harvesting, photoprotection, and nutrition. More than 1200 carotenoids are known. The yellow, orange, or red color of carotenoids stems from absorption of light by the linear polyene chromophore. Here, a digital database of absorption spectra has been assembled for 44 naturally occurring carotenoids, which range from astaxanthin to zeaxanthin and encompass conjugation pathlengths from 7 (ζ-carotene) to 13 (spirilloxanthin) carbon–carbon double bonds. Three spectra are included for carotenoids that contain a central cis-configuration. The spectra encompass the often-neglected ultraviolet region (to 230 nm) and the well-known visible region (to 650 nm). An absorption spectrum of each carotenoid was recorded at room temperature in one or more solvents, and 27 carotenoids were examined at 77 K in frozen media. Altogether, 121 spectra were collected and have been made available in PhotochemCAD. The availability of curated digital spectra of diverse carotenoids enables comparison of structural effects and photophysical features, and should be particularly useful in studies of agriculture, ecology, nutrition, and photosynthesis.

  PublisherOA PDFDOI

• Inactivation of Indoor Environmental Allergy-Related Substances by Ozone Gas in a Small Chamber

  Trends in Immunotherapy · 2026-01-19

  articleOpen access

  Allergic diseases are increasingly recognized as a worldwide public health problem, affecting countries at all levels of economic growth. In recent years, it has been proposed that allergic diseases result from excessive type 2 inflammation, which is driven by cooperative interactions between the innate and acquired immune systems. In this model, allergens, pathogen-associated molecular patterns (PAMPs), and proteases would all be considered allergen-associated substances. In this study, the Japanese ceder allergen Cry j1 and the house dust mite (HDM) allergen Der f1 were selected as representative allergens; lipoteichoic acid (LTA) from Staphylococcus aureus as a PAMP; and V8 protease (V8) from S. aureus, fungal Alternaria extract (Alt), and HDM fecal extract Dff as proteases. The effects of ozone gas on these substances were investigated in terms of allergenicity, proinflammatory activity via innate immunity, and protease activity. Ozone gas inactivated the allergenicity of both Cry j1 and Der f1, and the protease activities of V8, Alt, and Dff, in a CT value (the product of concentration [C] and exposure time [T])-dependent manner. The proinflammatory activity of LTA via innate immunity was significantly inactivated after ozone exposure (301 ppm·min). Although this study was carried out in a small chamber at the basic research level, the results suggest that ozone gas can inactivate indoor allergy-related substances and may help alleviate allergic symptoms. With appropriate safety measures, such as using it in a closed system, this technology has great potential for practical application to allergy management.

  PublisherDOI

• Synthesis and characterization of 5,15-bis(hydroxymethyl)porphyrins – simple compounds distantly inspired by the chlorosomal bacteriochlorophylls

  New Journal of Chemistry · 2026-01-01

  articleOpen access

  Small changes in substituents of synthetic porphyrins profoundly alter the crystalline self-assembly patterns.

  PublisherOA PDFDOI

• Effects of four methoxy-flavones isolated  from Scutellaria baicalensis  roots on irritable bowel syndrome with predominant diarrhea (IBS-D) in chronic restraint stress-loaded C57BL/6J mice

  SSRN Electronic Journal · 2026-01-01

  preprintOpen accessSenior author
  PublisherDOI

• Structural features of 11 synthetic bacteriochlorins — comparisons with chlorins and porphyrins

  Journal of Porphyrins and Phthalocyanines · 2025-09-01

  article

  As part of a program to develop the fundamental science of synthetic bacteriochlorins — analogues of Nature’s light-harvesting pigments in anoxygenic photosynthesis — 11 synthetic free base bacteriochlorins have been examined by single-crystal X-ray diffraction analysis. In each bacteriochlorin, each pyrroline ring contains a gem-dimethyl group to block adventitious (aerobic) dehydrogenation. The structural features of the bacteriochlorins (tetrahydroporphyrins) are compared with the less saturated counterparts, chlorins (dihydroporphyrins) and porphyrins. Only slight structural perturbation accrues due to the presence of the gem-dimethyl groups. The results presented herein may aid in understanding metal chelation processes and underpin the development of functional solid-state molecular assemblies.

  PublisherDOI

• Amino Acid Betaxanthins: Absorption, Fluorescence, And Stability

  Journal of Natural Products · 2025-06-20 · 1 citations

  articleOpen accessCorresponding

  . All spectral data have been made accessible in a PhotochemCAD absorption/fluorescence spectral database, enabling streamlined analysis and quantification.

  PublisherDOI

• Chatbots can guide measurement of absorption spectra with improved quality

  2025-01-23

  article1st authorCorresponding

  Absorption spectroscopy is a long-standing instrumental method for qualitative and quantitative analyses, yet is prone to errors given the richness of sample type, suite of instrumental limitations, and scope of possible human errors; hence, guidance for proper on-the-fly measurements is essential. Recent advances in transformer-based large language models have yielded conversational artificial intelligence (AI) chatbots. Here, the capabilities of six major chatbots (ChatGPT 4o, Gemini Advanced 1.5 Pro, Microsoft Copilot, Meta AI, Claude 3.5 Sonnet, and Grok 2) have been examined by requesting practical advice to achieve improved quality in the measurement of absorption spectra, where verbal descriptions were provided concerning the features of a poor-quality, experimentally collected spectrum already in hand. The suggestions by the chatbots were surprisingly on point in most cases. The results here imply a valuable role for chatbots in support of human analysts as well as automated experimental systems during the measurement of absorption spectra.

  PublisherDOI

• Noninvasive cardiac modulation via triplet-sensitized photoswitching in the phototherapeutic window

  Nature Communications · 2025-07-10 · 4 citations

  articleOpen access

  Red, far red, or near-infrared photoswitchable drugs offer immense photo-pharmacological advantages due to the higher light penetration through the skin. Such photoactivation is achieved using processes such as two- and three-photon absorption, excited-state absorption, and triplet-triplet annihilation upconversion, which require higher photon fluences (W to kW cm−2) than the resilience constraints of skin (200 mW cm−2). Herein, a generalized approach of cis-to-trans photoisomerization of azobenzenes is demonstrated via triplet sensitization with NIR-I illumination (850 nm) of a new Zn-octa-substituted phthalocyanine photosensitizer, in aqueous medium at 2.62 mW cm−2. The approach is applied to control the heart rate of a frog tadpole via cis-to-trans photoisomerization of an azobenzene-functionalized muscarinic acetylcholine receptor M2 agonist in the phototherapeutic window (730 nm excitation: 42 mW cm−2). This advance highlights a powerful photo-pharmacological strategy for modulation of in vivo activity at 2-4 orders of magnitude lower photon fluences of NIR light compared to established methods. Azobenzene-based photoswitchable drugs traditionally require activation with UV-blue light having poor tissue penetration. Here, the authors show triplet sensitized photoisomerization of an azo drug with far-red and NIR light, allowing deep tissue penetration and in vivo heart rate control in frog tadpoles.

  PublisherOA PDFDOI

• Inactivation of Indoor Environmental Allergy‑Related Substances by Ozonated Water In Vitro

  Trends in Immunotherapy · 2025-12-02

  articleOpen access

  Allergic diseases are thought to be caused by a combination of acquired immune activation, excessive activation of innate immunity, and disruption of epithelial barrier function due to scratching, proteases, and more. The removal and inactivation of allergy-related substances in indoor environments are considered effective for reducing allergic disease symptoms. The typical allergens in Japan are Japanese cedar pollen and house dust mites (HDM), and together with bacteria and fungi, HDM are the main sources of proteases in indoor environments. We investigated the inactivating effects of ozonated water on these substances in vitro in terms of allergenicity, inflammation induction in epithelial and immune cell lines (i.e., HaCaT, A549, and RAW 264 cells), and protease activity. We observed that ozonated water inactivated the Japanese cedar pollen allergen Cry j1 and the HDM allergen Der f1, the innate immune activator lipoteichoic acid from the bacterium Staphylococcus aureus, and proteases from S. aureus, HDM, and the fungus Alternaria in an ozone concentration-dependent manner. In all experiments, ozonated water at 7.5 mg/L significantly inactivated allergy-related substances compared to the untreated group (p < 0.01). The comparison of the effects of ozonated water treatment and thermal treatment at 80 °C revealed that ozonated water treatment is superior to thermal treatment in terms of both effectiveness and reaction time. Together, our findings demonstrate that ozonated water can inactivate allergy-related substances in the indoor environment. The management of indoor environments using ozonated water can thus be expected to contribute to the alleviation of symptoms and suppression of allergic diseases.

  PublisherDOI

• Database of low‐temperature absorption and fluorescence spectra of native photosynthetic tetrapyrrole macrocycles

  Photochemistry and Photobiology · 2025-08-10 · 2 citations

  articleOpen access

  Abstract Low‐temperature (77 K) absorption and fluorescence spectra of 12 naturally occurring photosynthetic tetrapyrrole macrocycles have been recorded in a frozen glass (2‐methyltetrahydrofuran). The compounds encompass distinct chromophore classes: porphyrin, chlorophyll c 2 ; chlorin, chlorophylls a , b , d , f and bacteriochlorophylls c , d , e , f ; and bacteriochlorin, bacteriochlorophylls a , b , g . The spectra are compared with those of the same pigment in liquid solution (predominantly 2‐methyltetrahydrofuran) at room temperature (293 K). The measured Stokes shifts at 77 K across the 12 macrocycles range from ~30 to 300 cm −1 . The spectral data in digital form are made available as part of the PhotochemCAD databases. Literature searches have revealed extensive published data for Chl a (often in biological matrices) but at best rather limited data for less common macrocycles. The availability of a systematic collection of curated spectral data collected at low temperature should be useful for a variety of assessments, including reconstruction of absorption spectra of (bacterio)chlorophyll‐containing protein complexes, vibrational analysis of absorption and fluorescence spectra, and calculations where knowledge of energy levels is important.

  PublisherOA PDFDOI

Frequent coauthors

• Jonathan S. Lindsey

  204 shared

• David F. Bocian

  University of California, Riverside

  94 shared

• Kimiye Baba

  Osaka University of Pharmaceutical Sciences

  84 shared

• Dewey Holten

  Washington University in St. Louis

  82 shared

• Hajime Fujisawa

  Yokohama Municipal Minato Red Cross Hospital

  78 shared

• Satoru Todo

  74 shared

• Tsuyoshi Shimamura

  Hokkaido University Hospital

  68 shared

• Hiroyuki Furukawa

  67 shared

Labs

• Masahiko Taniguchi LabPI

Education

• PhD in Engineering, Graduate School of Engineering and Sciences

  Kyushu University, Graduate School of Engineering and Sciences

  2000

• Bs in Pharmacy, Faculty of Pharmaceutical Sciences

  Science University of Tokyo

  1995