Numerical Modeling Studies on Photophysical Transitions of Autofluorescent Flavin Coenzymes with A Microfluidic-based Fluorescence Microscope System
Yıl 2025,
Cilt: 37 Sayı: 1, 73 - 91, 25.03.2025
Selim Can Dirican
,
Bahar Tezcan
,
Süleyman Yiğit Dölek
,
Barış Demirbay
Öz
In this research, numerical modeling studies are presented for a microfluidic-based fluorescence microscope system capable of resolving photophysical transitions of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) coenzymes that are very sensitive to light and solvent environment, have very small excitation cross-section and weak fluorescence. Different photophysical models were used for both molecules considering the molecular structure, photophysical properties and chemical reactions of FMN and FAD. The electronic states in these models were considered as a first order linear differential equation system and each electronic state population was solved in time, and image and signal data were obtained using the geometric dimensions of the laser excitation area and microscope parameters with the microfluidic chip. The laser excitation intensity at two different flow rates and the effects of redox agents such as ethanol, ascorbate and tryptophan added to the solvent on the normalized fluorescence signal and electronic state populations were simulated. In addition to signal and electronic state analyses, sCMOS image data used in generating the signals were simulated for different experimental conditions and compared with the laser excitation field. The method proposed in the study showed that it has the capacity to distinguish different dark state populations from each other at different flow rates and to resolve the effect of different dark states on normalized fluorescence signals and camera images under different experimental conditions. When compared with existing methods, the numerical findings demonstrate the potential of the method presented in the study to prevent flavin photodegradation to a large extent and enable optimization studies to be conducted regarding the conditions under which photophysical properties of different molecules can be observed.
Kaynakça
- T. Ozawa, H. Yoshimura, and S. B. Kim, (2013). "Advances in fluorescence and bioluminescence imaging," Analytical chemistry, 85(2), 590-609.
- C. Li, G. Chen, Y. Zhang, F. Wu, and Q. Wang, (2020). "Advanced fluorescence imaging technology in the near-infrared-II window for biomedical applications," Journal of the American Chemical Society, 142(35), 14789-14804.
- S. Saurabh, S. Maji, and M. P. Bruchez, (2012). "Evaluation of sCMOS cameras for detection and localization of single Cy5 molecules," Optics express, 20(7), 7338-7349.
- M. A. Albota, C. Xu, and W. W. Webb, (1998). "Two-photon fluorescence excitation cross sections of biomolecular probes from 690 to 960 nm," Applied optics, 37(31), 7352-7356.
- P. A. van den Berg, J. Widengren, M. A. Hink, R. Rigler, and A. J. Visser, (2001). "Fluorescence correlation spectroscopy of flavins and flavoenzymes: photochemical and photophysical aspects," Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 57(11), 2135-2144.
- J. Tornmalm, E. Sandberg, M. Rabasovic, and J. Widengren, (2019). "Local redox conditions in cells imaged via non-fluorescent transient states of NAD (P) H," Scientific Reports, 9(1), 15070.
- B. Demirbay et al., (2017). "Rheological properties of dextrin-riboflavin solutions under thermal and UV radiation effects," Journal of Molecular Liquids, 240, 597-603.
- B. Demirbay, C. Akaoğlu, İ. Ulusaraç, and F. G. Acar, (2017). "Thermal and UV radiation effects on dynamic viscosity of gelatin-based riboflavin solutions," Journal of Molecular Liquids, 225, 147-150.
- I. E. Kochevar, (1981). "Phototoxicity mechanisms: chlorpromazine photosensitized damage to DNA and cell membranes," Journal of Investigative Dermatology, 77(1), 59-64.
- J. Widengren, (2022). "Transient State (TRAST) Spectroscopy and Imaging: Exploiting the Rich Information Source of Fluorophore Dark State Transitions in Biomolecular and Cellular Studies," Springer.
- B. Demirbay, G. Baryshnikov, M. Haraldsson, J. Piguet, H. Ågren, and J. Widengren, (2023). "Photo-physical characterization of high triplet yield brominated fluoresceins by transient state (TRAST) spectroscopy," Methods and applications in fluorescence, 11(4), 045011.
- G. Donnert, C. Eggeling, and S. W. Hell, (2007). "Major signal increase in fluorescence microscopy through dark-state relaxation," Nature methods, 4(1), 81-86.
- R. Zondervan, F. Kulzer, S. B. Orlinskii, and M. Orrit, (2003). "Photoblinking of rhodamine 6G in poly (vinyl alcohol): Radical dark state formed through the triplet," The Journal of Physical Chemistry A, 107(35), 6770-6776.
- P. Changenet, H. Zhang, M. Van der Meer, M. Glasbeek, P. Plaza, and M. Martin, (1998). "Ultrafast twisting dynamics of photoexcited auramine in solution," The Journal of Physical Chemistry A, 102(34), 6716-6721.
- Y. Sasaki, N. Yanai, and N. Kimizuka, (2022). "Osmium complex–chromophore conjugates with both singlet-to-triplet absorption and long triplet lifetime through tuning of the heavy-atom effect," Inorganic chemistry, 61(16), 5982-5990.
- S. C. Dirican and B. Demirbay, (2025). "A Novel Microfluidic‐Based Fluorescence Detection Method Reveals Heavy Atom Effects on Photophysics of Fluorophores With High Triplet Quantum Yield: A Numerical Simulation Study," Luminescence, 40(1), e70090.
- Y. Dong et al., (2021). "Twisted BODIPY derivative: Intersystem crossing, electron spin polarization and application as a novel photodynamic therapy reagent," Physical Chemistry Chemical Physics, 23(14), 8641-8652.
- E. Sandberg, J. Piguet, U. Kostiv, G. Baryshnikov, H. Liu, and J. Widengren, (2023). "Photoisomerization of Heptamethine Cyanine Dyes Results in Red-Emissive Species: Implications for Near-IR, Single-Molecule, and Super-Resolution Fluorescence Spectroscopy and Imaging," The Journal of Physical Chemistry B, 127(14), 3208-3222.
- E. Sandberg, B. Demirbay, A. Kulkarni, H. Liu, J. Piguet, and J. Widengren, (2023). "Fluorescence Bar-Coding and Flowmetry Based on Dark State Transitions in Fluorescence Emitters," The Journal of Physical Chemistry B, 128(1), 125-136.
- A. Kitamura, J. Tornmalm, B. Demirbay, J. Piguet, M. Kinjo, and J. Widengren, (2023). "Trans-cis isomerization kinetics of cyanine dyes reports on the folding states of exogeneous RNA G-quadruplexes in live cells," Nucleic acids research, 51(5), e27-e27.
- E. Sandberg, C. V. Srambickal, J. Piguet, H. Liu, and J. Widengren, (2023). "Local monitoring of photosensitizer transient states provides feedback for enhanced efficiency and targeting selectivity in photodynamic therapy," Scientific Reports, 13(1), 16829.
- H. Hevekerl, J. Tornmalm, and J. Widengren, (2016). "Fluorescence-based characterization of non-fluorescent transient states of tryptophan–prospects for protein conformation and interaction studies," Scientific Reports, 6(1), 35052.
- D. Magde, E. Elson, and W. W. Webb, (1972). "Thermodynamic fluctuations in a reacting system—measurement by fluorescence correlation spectroscopy," Physical review letters, 29(11), 705.
- D. Magde, E. L. Elson, and W. W. Webb, (1974). "Fluorescence correlation spectroscopy. II. An experimental realization," Biopolymers: Original Research on Biomolecules, 13(1), 29-61.
- S. A. Kim, K. G. Heinze, and P. Schwille, (2007). "Fluorescence correlation spectroscopy in living cells," Nature methods, 4(11), 963-973.
- E. L. Elson, (2011). "Fluorescence correlation spectroscopy: past, present, future," Biophysical journal, 101(12), 2855-2870.
- E. L. Elson, (2018). "Introduction to fluorescence correlation Spectroscopy—Brief and simple," Methods, 140, 3-9.
- S. Sterrer and K. Henco, (1997). "Minireview: Fluorescence correlation spectroscopy (FCS)-A highly sensitive method to analyze drug/target interactions," Journal of Receptors and Signal Transduction, 17(1-3), 511-520.
- P. Rigler and W. Meier, (2006). "Encapsulation of fluorescent molecules by functionalized polymeric nanocontainers: investigation by confocal fluorescence imaging and fluorescence correlation spectroscopy," Journal of the American Chemical Society, 128(1), 367-373.
- J. Widengren, (2010). "Fluorescence-based transient state monitoring for biomolecular spectroscopy and imaging," Journal of the Royal Society Interface, 7(49), 1135-1144.
- T. Spielmann, H. Blom, M. Geissbuehler, T. Lasser, and J. Widengren, (2010). "Transient state monitoring by total internal reflection fluorescence microscopy," The Journal of Physical Chemistry B, 114(11), 4035-4046.
- V. Chmyrov, T. Spielmann, H. Hevekerl, and J. Widengren, (2015). "Trans–cis isomerization of lipophilic dyes probing membrane microviscosity in biological membranes and in live cells," Analytical chemistry, 87(11), 5690-5697.
- Z. Du et al., (2022). "Imaging Fluorescence Blinking of a Mitochondrial Localization Probe: Cellular Localization Probes Turned into Multifunctional Sensors," The Journal of Physical Chemistry B, 126(16), 3048-3058.
- J. Mücksch, T. Spielmann, E. Sisamakis, and J. Widengren, (2015). "Transient state imaging of live cells using single plane illumination and arbitrary duty cycle excitation pulse trains," Journal of Biophotonics, 8(5), 392-400.
- J. Tornmalm and J. Widengren, (2018). "Label-free monitoring of ambient oxygenation and redox conditions using the photodynamics of flavin compounds and transient state (TRAST) spectroscopy," Methods, 140, 178-187.
- E. Sandberg, J. Piguet, H. Liu, and J. Widengren, (2023). "Combined Fluorescence Fluctuation and Spectrofluorometric Measurements Reveal a Red-Shifted, Near-IR Emissive Photo-Isomerized Form of Cyanine 5," International Journal of Molecular Sciences, 24(3), 1990.
- N. Silaparasetty, (2020). Machine learning concepts with python and the jupyter notebook environment: Using tensorflow 2.0. Springer.
- N. Silaparasetty and N. Silaparasetty, (2020). "Python programming in jupyter notebook," Machine Learning Concepts with Python and the Jupyter Notebook Environment: Using Tensorflow 2.0, 119-145.
- B. Fowler et al., (2009). "Wide dynamic range low light level CMOS image sensor," in Proc. Int. Image Sensor Workshop, 1-4.
- N. Blow, (2007). "Microfluidics: in search of a killer application," Nature Methods, 4(8), 665-670.
- R. Chityala and S. Pudipeddi, (2020). Image processing and acquisition using Python. CRC Press.
- K. Gillen-Christandl, G. D. Gillen, M. Piotrowicz, and M. Saffman, (2016). "Comparison of Gaussian and super Gaussian laser beams for addressing atomic qubits," Applied Physics B, 122, 1-20.
- R. Vidunas, (2005). "Expressions for values of the gamma function," Kyushu Journal of Mathematics, 59(2), 267-283.
- M. Ehrenberg and R. Rigler, (1974). "Rotational brownian motion and fluorescence intensify fluctuations," Chemical Physics, 4(3), 390-401.
- Ü. Mets, J. Widengren, and R. Rigler, (1997). "Application of the antibunching in dye fluorescence: measuringthe excitation rates in solution," Chemical Physics, 218(1-2), 191-198.
- P. Kask, P. Piksarv, and Ü. Mets, (1985). "Fluorescence correlation spectroscopy in the nanosecond time range: Photon antibunching in dye fluorescence," European Biophysics Journal, 12, 163-166.
- T. Basché, W. Moerner, M. Orrit, and H. Talon, (1992). "Photon antibunching in the fluorescence of a single dye molecule trapped in a solid," Physical review letters, 69(10), 1516.
- W. Holzer et al., (2005). "Photo-induced degradation of some flavins in aqueous solution," Chemical Physics, 308(1-2), 69-78.
- H. Görner, (2007). "Oxygen uptake after electron transfer from amines, amino acids and ascorbic acid to triplet flavins in air-saturated aqueous solution," Journal of Photochemistry and Photobiology B: Biology, 87(2), 73-80.
- P. Heelis, (1982). "The photophysical and photochemical properties of flavins (isoalloxazines)," Chemical Society Reviews, 11(1), 15-39.
- H. Chosrowjan, S. Taniguchi, N. Mataga, F. Tanaka, and A. J. Visser, (2003). "The stacked flavin adenine dinucleotide conformation in water is fluorescent on picosecond timescale," Chemical physics letters, 378(3-4), 354-358.
- P. A. Van den Berg, K. A. Feenstra, A. E. Mark, H. J. Berendsen, and A. J. Visser, (2002). "Dynamic conformations of flavin adenine dinucleotide: simulated molecular dynamics of the flavin cofactor related to the time-resolved fluorescence characteristics," The Journal of Physical Chemistry B, 106(34), 8858-8869.
- T. Nakabayashi, M. S. Islam, and N. Ohta, (2010). "Fluorescence decay dynamics of flavin adenine dinucleotide in a mixture of alcohol and water in the femtosecond and nanosecond time range," The Journal of Physical Chemistry B, 114(46), 15254-15260.
Mikroakışkan Temelli Floresans Mikroskop Sistemi ile Otofloresan Flavin Koenzimlerinin Fotofiziksel Geçişleri Üzerine Nümerik Modelleme Çalışmaları
Yıl 2025,
Cilt: 37 Sayı: 1, 73 - 91, 25.03.2025
Selim Can Dirican
,
Bahar Tezcan
,
Süleyman Yiğit Dölek
,
Barış Demirbay
Öz
Bu araştırmada ışığa ve çözücü ortamına oldukça hassas, çok küçük uyarım kesit alanına sahip ve zayıf floresan ışıma yapabilen flavin mononükleotit (FMN) ve flavin adenin dinükleotit (FAD) koenzimlerinin fotofiziksel geçişlerini çözümleme kapasitesine sahip mikroakışkan temelli bir floresans mikroskop sistemi için nümerik modelleme çalışmaları sunulmuştur. FMN ve FAD’nin moleküler yapısı, fotofiziksel özellikleri ve girdikleri kimyasal reaksiyonlar dikkate alınarak her iki molekül için farklı fotofiziksel modeller kullanılmıştır. Bu modellerde yer alan elektronik durumlar 1. mertebeden lineer diferansiyel denklem sistemi olarak ele alınmış olup her bir elektronik durum popülasyonu zamana bağlı olarak çözülmüş, mikroakışkan çip ile lazer uyarım alanının geometrik boyutları ve mikroskop parametreleri kullanılarak görüntü ve sinyal verisi olarak elde edilmiştir. İki farklı akış hızında lazer uyarım şiddeti, çözücüye eklenen etanol, askorbat ve triptofan gibi redoks ajanlarının normalize floresan sinyaline ve elektronik durum popülasyonlarına olan etkisi simüle edilmiştir. Sinyal ve elektronik durum analizlerine ek olarak sinyallerin oluşturulmasında kullanılan sCMOS görüntü verileri farklı deneysel koşullar için simüle edilmiş ve lazer uyarım alanıyla kıyaslanmıştır. Araştırmada önerilen yöntem farklı akış hızlarında farklı karanlık durum popülasyonlarının birbirinden ayırt edilebilirliğini ve farklı deneysel koşullarda değişen karanlık durumların normalize floresan sinyaline ve kamera görüntülerine olan etkisini çözümleme kapasitesine sahip olduğunu göstermiştir. Mevcut yöntemlerle kıyaslandığında, elde edilen sayısal bulgular, çalışmada sunulan yöntemin flavin foto-bozunumunu büyük ölçüde önleyebilme potansiyelini ispatlamıştır ve farklı moleküllerin fotofiziksel özelliklerinin hangi koşullarda gözlemlenebileceği ile ilgili optimizasyon çalışmalarının yapılmasına olanak sağlamaktadır.
Destekleyen Kurum
TÜBİTAK
Teşekkür
Bu makale Türkiye Bilimsel ve Teknolojik Araştırma Kurumu (TUBİTAK) tarafından fon desteğine hak kazanan 124F110 numaralı 3501 projesinin bilimsel bir ürünüdür. Yazarlar ve proje ekibi olarak bu araştırmaya katkılarından dolayı TÜBİTAK’a teşekkür ederiz.
Kaynakça
- T. Ozawa, H. Yoshimura, and S. B. Kim, (2013). "Advances in fluorescence and bioluminescence imaging," Analytical chemistry, 85(2), 590-609.
- C. Li, G. Chen, Y. Zhang, F. Wu, and Q. Wang, (2020). "Advanced fluorescence imaging technology in the near-infrared-II window for biomedical applications," Journal of the American Chemical Society, 142(35), 14789-14804.
- S. Saurabh, S. Maji, and M. P. Bruchez, (2012). "Evaluation of sCMOS cameras for detection and localization of single Cy5 molecules," Optics express, 20(7), 7338-7349.
- M. A. Albota, C. Xu, and W. W. Webb, (1998). "Two-photon fluorescence excitation cross sections of biomolecular probes from 690 to 960 nm," Applied optics, 37(31), 7352-7356.
- P. A. van den Berg, J. Widengren, M. A. Hink, R. Rigler, and A. J. Visser, (2001). "Fluorescence correlation spectroscopy of flavins and flavoenzymes: photochemical and photophysical aspects," Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 57(11), 2135-2144.
- J. Tornmalm, E. Sandberg, M. Rabasovic, and J. Widengren, (2019). "Local redox conditions in cells imaged via non-fluorescent transient states of NAD (P) H," Scientific Reports, 9(1), 15070.
- B. Demirbay et al., (2017). "Rheological properties of dextrin-riboflavin solutions under thermal and UV radiation effects," Journal of Molecular Liquids, 240, 597-603.
- B. Demirbay, C. Akaoğlu, İ. Ulusaraç, and F. G. Acar, (2017). "Thermal and UV radiation effects on dynamic viscosity of gelatin-based riboflavin solutions," Journal of Molecular Liquids, 225, 147-150.
- I. E. Kochevar, (1981). "Phototoxicity mechanisms: chlorpromazine photosensitized damage to DNA and cell membranes," Journal of Investigative Dermatology, 77(1), 59-64.
- J. Widengren, (2022). "Transient State (TRAST) Spectroscopy and Imaging: Exploiting the Rich Information Source of Fluorophore Dark State Transitions in Biomolecular and Cellular Studies," Springer.
- B. Demirbay, G. Baryshnikov, M. Haraldsson, J. Piguet, H. Ågren, and J. Widengren, (2023). "Photo-physical characterization of high triplet yield brominated fluoresceins by transient state (TRAST) spectroscopy," Methods and applications in fluorescence, 11(4), 045011.
- G. Donnert, C. Eggeling, and S. W. Hell, (2007). "Major signal increase in fluorescence microscopy through dark-state relaxation," Nature methods, 4(1), 81-86.
- R. Zondervan, F. Kulzer, S. B. Orlinskii, and M. Orrit, (2003). "Photoblinking of rhodamine 6G in poly (vinyl alcohol): Radical dark state formed through the triplet," The Journal of Physical Chemistry A, 107(35), 6770-6776.
- P. Changenet, H. Zhang, M. Van der Meer, M. Glasbeek, P. Plaza, and M. Martin, (1998). "Ultrafast twisting dynamics of photoexcited auramine in solution," The Journal of Physical Chemistry A, 102(34), 6716-6721.
- Y. Sasaki, N. Yanai, and N. Kimizuka, (2022). "Osmium complex–chromophore conjugates with both singlet-to-triplet absorption and long triplet lifetime through tuning of the heavy-atom effect," Inorganic chemistry, 61(16), 5982-5990.
- S. C. Dirican and B. Demirbay, (2025). "A Novel Microfluidic‐Based Fluorescence Detection Method Reveals Heavy Atom Effects on Photophysics of Fluorophores With High Triplet Quantum Yield: A Numerical Simulation Study," Luminescence, 40(1), e70090.
- Y. Dong et al., (2021). "Twisted BODIPY derivative: Intersystem crossing, electron spin polarization and application as a novel photodynamic therapy reagent," Physical Chemistry Chemical Physics, 23(14), 8641-8652.
- E. Sandberg, J. Piguet, U. Kostiv, G. Baryshnikov, H. Liu, and J. Widengren, (2023). "Photoisomerization of Heptamethine Cyanine Dyes Results in Red-Emissive Species: Implications for Near-IR, Single-Molecule, and Super-Resolution Fluorescence Spectroscopy and Imaging," The Journal of Physical Chemistry B, 127(14), 3208-3222.
- E. Sandberg, B. Demirbay, A. Kulkarni, H. Liu, J. Piguet, and J. Widengren, (2023). "Fluorescence Bar-Coding and Flowmetry Based on Dark State Transitions in Fluorescence Emitters," The Journal of Physical Chemistry B, 128(1), 125-136.
- A. Kitamura, J. Tornmalm, B. Demirbay, J. Piguet, M. Kinjo, and J. Widengren, (2023). "Trans-cis isomerization kinetics of cyanine dyes reports on the folding states of exogeneous RNA G-quadruplexes in live cells," Nucleic acids research, 51(5), e27-e27.
- E. Sandberg, C. V. Srambickal, J. Piguet, H. Liu, and J. Widengren, (2023). "Local monitoring of photosensitizer transient states provides feedback for enhanced efficiency and targeting selectivity in photodynamic therapy," Scientific Reports, 13(1), 16829.
- H. Hevekerl, J. Tornmalm, and J. Widengren, (2016). "Fluorescence-based characterization of non-fluorescent transient states of tryptophan–prospects for protein conformation and interaction studies," Scientific Reports, 6(1), 35052.
- D. Magde, E. Elson, and W. W. Webb, (1972). "Thermodynamic fluctuations in a reacting system—measurement by fluorescence correlation spectroscopy," Physical review letters, 29(11), 705.
- D. Magde, E. L. Elson, and W. W. Webb, (1974). "Fluorescence correlation spectroscopy. II. An experimental realization," Biopolymers: Original Research on Biomolecules, 13(1), 29-61.
- S. A. Kim, K. G. Heinze, and P. Schwille, (2007). "Fluorescence correlation spectroscopy in living cells," Nature methods, 4(11), 963-973.
- E. L. Elson, (2011). "Fluorescence correlation spectroscopy: past, present, future," Biophysical journal, 101(12), 2855-2870.
- E. L. Elson, (2018). "Introduction to fluorescence correlation Spectroscopy—Brief and simple," Methods, 140, 3-9.
- S. Sterrer and K. Henco, (1997). "Minireview: Fluorescence correlation spectroscopy (FCS)-A highly sensitive method to analyze drug/target interactions," Journal of Receptors and Signal Transduction, 17(1-3), 511-520.
- P. Rigler and W. Meier, (2006). "Encapsulation of fluorescent molecules by functionalized polymeric nanocontainers: investigation by confocal fluorescence imaging and fluorescence correlation spectroscopy," Journal of the American Chemical Society, 128(1), 367-373.
- J. Widengren, (2010). "Fluorescence-based transient state monitoring for biomolecular spectroscopy and imaging," Journal of the Royal Society Interface, 7(49), 1135-1144.
- T. Spielmann, H. Blom, M. Geissbuehler, T. Lasser, and J. Widengren, (2010). "Transient state monitoring by total internal reflection fluorescence microscopy," The Journal of Physical Chemistry B, 114(11), 4035-4046.
- V. Chmyrov, T. Spielmann, H. Hevekerl, and J. Widengren, (2015). "Trans–cis isomerization of lipophilic dyes probing membrane microviscosity in biological membranes and in live cells," Analytical chemistry, 87(11), 5690-5697.
- Z. Du et al., (2022). "Imaging Fluorescence Blinking of a Mitochondrial Localization Probe: Cellular Localization Probes Turned into Multifunctional Sensors," The Journal of Physical Chemistry B, 126(16), 3048-3058.
- J. Mücksch, T. Spielmann, E. Sisamakis, and J. Widengren, (2015). "Transient state imaging of live cells using single plane illumination and arbitrary duty cycle excitation pulse trains," Journal of Biophotonics, 8(5), 392-400.
- J. Tornmalm and J. Widengren, (2018). "Label-free monitoring of ambient oxygenation and redox conditions using the photodynamics of flavin compounds and transient state (TRAST) spectroscopy," Methods, 140, 178-187.
- E. Sandberg, J. Piguet, H. Liu, and J. Widengren, (2023). "Combined Fluorescence Fluctuation and Spectrofluorometric Measurements Reveal a Red-Shifted, Near-IR Emissive Photo-Isomerized Form of Cyanine 5," International Journal of Molecular Sciences, 24(3), 1990.
- N. Silaparasetty, (2020). Machine learning concepts with python and the jupyter notebook environment: Using tensorflow 2.0. Springer.
- N. Silaparasetty and N. Silaparasetty, (2020). "Python programming in jupyter notebook," Machine Learning Concepts with Python and the Jupyter Notebook Environment: Using Tensorflow 2.0, 119-145.
- B. Fowler et al., (2009). "Wide dynamic range low light level CMOS image sensor," in Proc. Int. Image Sensor Workshop, 1-4.
- N. Blow, (2007). "Microfluidics: in search of a killer application," Nature Methods, 4(8), 665-670.
- R. Chityala and S. Pudipeddi, (2020). Image processing and acquisition using Python. CRC Press.
- K. Gillen-Christandl, G. D. Gillen, M. Piotrowicz, and M. Saffman, (2016). "Comparison of Gaussian and super Gaussian laser beams for addressing atomic qubits," Applied Physics B, 122, 1-20.
- R. Vidunas, (2005). "Expressions for values of the gamma function," Kyushu Journal of Mathematics, 59(2), 267-283.
- M. Ehrenberg and R. Rigler, (1974). "Rotational brownian motion and fluorescence intensify fluctuations," Chemical Physics, 4(3), 390-401.
- Ü. Mets, J. Widengren, and R. Rigler, (1997). "Application of the antibunching in dye fluorescence: measuringthe excitation rates in solution," Chemical Physics, 218(1-2), 191-198.
- P. Kask, P. Piksarv, and Ü. Mets, (1985). "Fluorescence correlation spectroscopy in the nanosecond time range: Photon antibunching in dye fluorescence," European Biophysics Journal, 12, 163-166.
- T. Basché, W. Moerner, M. Orrit, and H. Talon, (1992). "Photon antibunching in the fluorescence of a single dye molecule trapped in a solid," Physical review letters, 69(10), 1516.
- W. Holzer et al., (2005). "Photo-induced degradation of some flavins in aqueous solution," Chemical Physics, 308(1-2), 69-78.
- H. Görner, (2007). "Oxygen uptake after electron transfer from amines, amino acids and ascorbic acid to triplet flavins in air-saturated aqueous solution," Journal of Photochemistry and Photobiology B: Biology, 87(2), 73-80.
- P. Heelis, (1982). "The photophysical and photochemical properties of flavins (isoalloxazines)," Chemical Society Reviews, 11(1), 15-39.
- H. Chosrowjan, S. Taniguchi, N. Mataga, F. Tanaka, and A. J. Visser, (2003). "The stacked flavin adenine dinucleotide conformation in water is fluorescent on picosecond timescale," Chemical physics letters, 378(3-4), 354-358.
- P. A. Van den Berg, K. A. Feenstra, A. E. Mark, H. J. Berendsen, and A. J. Visser, (2002). "Dynamic conformations of flavin adenine dinucleotide: simulated molecular dynamics of the flavin cofactor related to the time-resolved fluorescence characteristics," The Journal of Physical Chemistry B, 106(34), 8858-8869.
- T. Nakabayashi, M. S. Islam, and N. Ohta, (2010). "Fluorescence decay dynamics of flavin adenine dinucleotide in a mixture of alcohol and water in the femtosecond and nanosecond time range," The Journal of Physical Chemistry B, 114(46), 15254-15260.