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Updated: Jul 16, 2025

Characterization of pH-Dependent Reversible Self-Assembly of Amyloid Beta 1-40-Coated Gold Colloids
Published on: March 21, 2025
The effects of pH, temperature, and buffer concentration on the self-assembling behavior, secondary structure, and
Jingjing Zhang1, Silvia Vincenzetti2, Paolo Polidori3
1School of Biosciences and Veterinary Medicine, University of Camerino, Via Gentile III da Varano, 62032 Camerino, MC, Italy; College of Agronomy, Shandong Engineering Technology Research Center for Efficient Breeding and Ecological Feeding of Black Donkey, Shandong Donkey Industry Technology Collaborative Innovation Center, Liaocheng University, 252000 Liaocheng, Shandong, China.
Abstract:
The self-assembling behavior, secondary structure, and surface hydrophobicity of purified donkey β-casein in terms of pH, temperature, and buffer concentration were investigated in comparison with commercial bovine β-casein. Critical micelle concentration of both β-caseins decreased with the lowering of pH (pH 8.0-6.0) and the increasing temperatures (25-50 °C). Critical micelle temperature of both β-caseins increased moving from pH 6.0 to 8.0 and aggregates larger than micelles formed at pH 6.0 that is close to their isoelectric point. Fluorescence spectroscopy analysis demonstrated that the maximum surface hydrophobicity was achieved at pH 6.0. The secondary structure was examined using circular dichroism spectroscopy, highlighting an increase of α-helix content and a decrease of unordered structures with the decrease of pH and increase of temperature. This work provides insights on parameters promoting molecular interactions involved in donkey β-CN self-association, useful to develop nanocarriers for encapsulating bioactive compounds in pharmaceutical and nutraceutical applications.
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