Imaging in three dimensions of paper structure using confocal laser scanning microscopy

Document Type : Research Paper

Authors

Department of Wood and Paper Science and Technology, Faculty of Natural Resources, Tarbiat Modares University, Noor, Iran.

10.22059/jfwp.2024.374304.1288

Abstract

The paper is a thin, wide sheet formed from the entanglement, flocculation, and bonding of fibers, filaments, and cellulose components. It is produced in various dimensions for numerous applications. Building on a previous study on the fluorescent staining methods of cellulose fibers, the present research investigates the microscopic structure of the sheet and its components in three dimensions (length, width, and depth) using a confocal laser scanning microscope. This study also examines the distribution of cellulose fibers and components within the paper structure's three dimensions using fluorescent properties and confocal microscopy. The cellulosic components of the paper structure exhibited a green fluorescent reflection (420-500 nm) in the visible light region when excited at a wavelength of 405 nm. Beyond the two-dimensional analysis of paper planes, the confocal laser scanning microscope provided a wide array of intriguing images, revealing how fibers or cellulose fiber fractions are distributed within the paper's thickness without the need for layer-by-layer slicing. Depth imaging of paper was successful for samples with basis weights of both 20 and 60 g/m². The resulting images showed increased flocculation and accumulation of fiber elements and segments with depth. Overall, images obtained from the confocal laser scanning microscope demonstrated that the apparatus is suitable for investigating the distribution of labeled fibers and fiber fractions in all three dimensions of the paper structure.

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References

[1] Azizi Samir, M.A.S., Alloin, F., & Dufresne, A. (2005). Review of recent research into cellulosic whiskers, their properties and their application in nanocomposite field. Biomacromolecules, 6(2), 612-626.
[2] Jose, M. (2013). The study of cell wall structure and cellulose-cellulase interactions through fluorescence microscopy. Cellulose, 20, 2291-2309.
[3] Hubbe, A. M., Chandra, R.P., Dogu, D., & Velzen, S.T.J. (2019). Analytical staining of cellulosic materials: A Review. BioResources, 14(3), 7387-7464.
[4] Ding, Q., Han, W., Li, X., Jiang, Y., & Zhao, C. (2020). New insights into the autofluorescence properties of cellulose/ Nanocellulose. Scientific Reports, 10, 21387-21395.
[5] Olmstead, J.A., Zhu, J.A., & Gray, D.G. (1995). Fluorescence spectroscopy of mechanical pulps III: Effect of chlorite delignification. Canadian Journal of Chemistry, 73(11), 1955-1959.
[6] Hobisch, M.A., Bossu, J., Mandlez, D., Spirk, S., Eckhart, R., & Bauer, W. (2019). Localization of cellulose fines in paper via fluorescent labeling. Cellulose, 26, 6933-6942.
[7] Coletta, V.C., Rezende, C.A., da Conceição, F.R., Polikarpov, I., & Guimarães, F.E.G. (2013). Mapping the lignin distribution in pretreated sugarcane bagasse by confocal and fluorescence lifetime imaging microscopy. Biotechnology for Biofuels, 6(1), 43.
[8] Stockert, J.C., and Blázquez-Castro., A. (2017). Fluorescence Microscopy in Life Sciences. Bentham Science Publishers, Sharjah, UAE, ISBN 978-1-68108-519-7.
[9] Hell, S.W., Stelzer, E.H.K., Lindek, S., & Cremer, C. (1994). Confocal microscopy with an increased detection aperture: Type-B 4Pi confocal microscopy. Optics Letters, 19(3), 222-224.
[10] Vicidomini, G. (2005). Image Formation in Fluorescence Microscopy. In: Evangelista, V., Barsanti, L., Passarelli, V., & Gualtieri, P. (eds) From Cells to Proteins: Imaging Nature across Dimensions. NATO Security through Science Series. Springer, Dordrecht. https://doi.org/10.1007/1-4020-3616-7_18.
[11] Ding, Q., Zeng, J., Wang, B., Gao, W., Chen, K., Yuan, Z., Xu, J., & Tang, D. (2018). Effect of retention rate of fluorescent cellulose nanofibrils on paper properties and structure. Carbohydrate Polymers, 186, 73-81.
[12] Sheikhali, H., & Khosravani, A. (2023). Fluorescent labeling methods by rhodamine B isothiocyanate in cellulose materials. Iranian Journal of Wood and Paper Industries, 13(4), 405-417. (In Persian) 
[13] Donaldson, L. (2020). Autofluorescence in plants, Molecules, 25(10), 2393.
[14] Liukko, S., Tasapuro, V., & Liitiä., T. (2007). Fluorescence spectroscopy for chromophore studies on bleached kraft pulps. Holzforschung, 61(5), 509-515.
[15] Olmstead, J.A., & Gray, D.G. (1993). Fluorescence emission from mechanical pulp sheets. Journal of Photochemistry and Photobiology A: Chemistry, 73(1), 59-65.
[16] Castellan, A., Ruggiero, R., Frollini, E., Ramos, L.A., & Chirat, C. (2007). Studies on fluorescence of cellulosics. Holzforschung, 61, 504-508.
[17] Valeur, B., & Berberan-Santos, M.N. (2013). Molecular Fluorescence: Principles and Applications (2nd ed.), Wiley-VCH.
[18] Wang, S., Gao, W., Chen, K., Zeng, J., Xu, J., & Wang, B. (2018). An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling. Tappi Journal, 17(3), 157-164.
[19] Whipple, W.L., & Maltesh, C. (2000). Visualizing flocculation and adsorbtion processes in papermaking using fluorescence microscopy. Langmuir, 16(7), 3124-3132.
[20] Ding, Q., Zeng, J., Wang, B., Gao, W., Chen, K., Yuan, Z. & Xu, J. (2017). Influence of binding mechanism on labeling efficiency and luminous properties of fluorescent cellulose nanocrystals. Carbohydrate Polymers, 175, 105-112.
Forest and Wood Products
Volume 77, Issue 1
June 2024
Pages 73-84

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