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Tuning the properties of high molecular weight chitosans to develop full water.pdf (609.96 kB)
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Tuning the Properties of High Molecular Weight Chitosans to Develop Full Water Solubility Within a Wide pH Range

preprint
submitted on 14.02.2020 and posted on 17.02.2020 by Anderson Fiamingo, Sergio Paulo Campana Filho, Osvaldo Novais Oliveira Junior

The preparation of chitosans soluble in physiological conditions has been sought for years, but so far solubility in non-acidic aqueous media has only been achieved at the expense of lowering chitosan molecular weight. In this work, we applied the multistep ultrasound-assisted deacetylation process (USAD process) to β-chitin and obtained extensively deacetylated chitosans with high molecular weights (Mw ≥ 1,000,000 g mol-1). The homogeneous N-acetylation of a chitosan sample resulting from three consecutive USAD procedures allowed us to produce chitosans with a high weight average degree of polymerization (DPw ≈ 6,000) and tunable degrees of acetylation (DA from 5 to 80%). N-acetylation was carried out under mild conditions to minimize depolymerization, while preserving a predominantly random distribution of 2-amino-2-deoxy-D-glucopyanose (GlcN) and 2-acetamido-2-deoxy-D-glucopyanose (GlcNAc) units. This close to random distribution, inferred with deconvolution of nuclear magnetic resonance (1H NMR) spectra, is considered as responsible for the solubility within a wide pH range. Two of the highly N-acetylated chitosans (DA ≈ 60 % and ≈ 70 %) exhibited full water solubility even at neutral pH, which can expand the biomedical applications of chitosans.

History

Email Address of Submitting Author

anderson_fiamingo@yahoo.com.br

Institution

University of São Paulo (USP)

Country

Brazil

ORCID For Submitting Author

0000-0002-3437-2617

Declaration of Conflict of Interest

There is no conflict of interest associated with this research

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