University of Oulu

Lintinen, K., Luiro, S., Figueiredo, P., Sakarinen, E., Mousavi, Z., Seitsonen, J., Rivière, G., Mattinen, U., Niemelä, M., Tammela, P., Österberg, M., Johansson, L., Bobacka, J., Santos, H., Kostiainen, M. (2019) Antimicrobial Colloidal Silver–Lignin Particles via Ion and Solvent Exchange. ACS Sustainable Chem. Eng., 7 (18), 15297-15303. doi:10.1021/acssuschemeng.9b02498

Antimicrobial colloidal silver-lignin particles via ion and solvent exchange

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Author: Lintinen, Kalle1; Luiro, Sanna1; Figueiredo, Patrícia2;
Organizations: 1Biohybrid Materials, Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
2Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland
3Laboratory of Analytical Chemistry, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Biskopsgatan 8, FI-20500 Turku, Finland
4Nanomicroscopy Center, Department of Applied Physics, School of Science, Aalto University, P.O. Box 15100, FI-00076 Espoo, Finland
5Bioproduct Chemistry, Department of Bioproducts and Biosystems, Aalto University, Vuorimiehentie 1, 02150 Espoo, Finland
6Research Unit of Sustainable Chemistry, University of Oulu, P.O. Box 3000, FI-90014 Oulu, Finland
7Centre for Drug Research, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland
8Helsinki Institute of Life Science, HiLIFE, University of Helsinki, FI-00014 Helsinki, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3 MB)
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Language: English
Published: American Chemical Society, 2019
Publish Date: 2019-10-28


Acid-precipitated lignin nanoparticles with a cationic polymer coating exhibit antibacterial activity when infused with silver. While the use of such particles would be beneficial due to their high antibacterial activity with a low silver content, their production holds steps that are difficult to scale up to inexpensive industrial manufacture. For example, the production of acid-precipitated lignin nanoparticles requires the use of ethylene glycol, which is not easily recycled. Furthermore, the binding of silver to these particles is weak, and thus the particles need to be used rapidly after preparation. Here, we show that with a deprotonation reaction of an organic solution of anhydrous lignin and subsequent ion exchange with silver nitrate and colloid formation by solvent exchange, highly spherical silver carboxylate colloidal lignin particles (AgCLPs) can be prepared. Silver is not released from the particles in deionized water but can be released in physiological conditions, shown by their high antibacterial efficacy with low silver loading. In comparison to lignin nanoparticles with weakly bound silver, AgCLPs have high antibacterial activity even without cationic polyelectrolyte coating, and they retain their antibacterial activity for days. While the rapid depletion of silver from silver-infused lignin nanoparticles can be considered beneficial for some applications, the sustained antibacterial activity of the AgCLPs with ionically bound silver will enable their use in applications where silver nanoparticles have been previously used. Our results demonstrate that CLPs, which can be produced with a closed cycle process on a large scale, can be rapidly and quantitatively functionalized into active materials.

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Series: ACS sustainable chemistry & engineering
ISSN: 2168-0485
ISSN-E: 2168-0485
ISSN-L: 2168-0485
Volume: 7
Issue: 18
Pages: 15297 - 15303
DOI: 10.1021/acssuschemeng.9b02498
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
Funding: The financial support through the Academy of Finland (grants 267497, 286845, and 308578) is gratefully acknowledged. This work was carried out under the Academy of Finland Centers of Excellence Programme (2014-2019) and made use of the Aalto University Nanomicroscopy Center (Aalto-NMC).
Copyright information: © American Chemical Society. This is an open access article published under a Creative Commons Attribution (CC-BY)License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited