Diffusion and Binding of Laponite Clay Nanoparticles into Collagen Fibers for the Formation of Leather Matrix

Abstract

Understanding accessibility and interactions of clay nanoparticles with collagen fibers is an important fundamental issue for the conversion of collagen to leather matrix. In this study, we have investigated the diffusion and binding of Laponite into the collagen fiber network. Our results indicate that the diffusion behaviors of Laponite into the collagen exhibit the Langmuir adsorption, verifying its affinity for collagen. The introduction of Laponite leads to a shift in the isoelectric point of collagen from ∼6.8 to ∼4.5, indicating the ionic bonding between the positively charged amino groups of the collagen and negatively charged Laponite under the tanning conditions. Fluorescence microscopy, atomic force microscopy, field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and wide-angle X-ray diffraction analyses reveal that Laponite nanoparticles can penetrate into collagen microstructure and evenly distributed onto collagen fibrils, not altering native D-periodic banding patterns of collagen fibrils. Attenuated total reflectance-Fourier transform infrared and Raman spectroscopy detections further demonstrate the presence of noncovalent interactions, namely, ionic and hydrogen bonding, between Laponite and collagen. These findings provide a theoretical basis for the use of Laponite as an emerging tanning agent in leather manufacture.

De Novo Design of Functional Coassembling Organic–Inorganic Hydrogels for Hierarchical Mineralization and Neovascularization

“…Although ThT coassembled with the Lap nanodisk suspension, the Lap–ThT complex exhibited no CD signal, suggesting that ThT acquired an induced chirality due to surface adsorption to Lap nanodisks templated by PAH3 nanofibers (Figure b inset). Such nanofiber templating of Lap nanodisks has been previously demonstrated with collagen nanofibers due to electrostatic interactions between the positively charged amino acid groups on the periphery of the collagen nanofibrils and negatively charged Lap surfaces …”

“…Such nanofiber templating of Lap nanodisks has been previously demonstrated with collagen nanofibers due to electrostatic interactions between the positively charged amino acid groups on the periphery of the collagen nanofibrils and negatively charged Lap surfaces. 50 …”

Modification of PA/PU superfine non-woven fiber for “breath” property using collagen and vegetable tannins

“…Therefore, the interaction types of ionic and covalent bonds between the collagen and vegetable tannins were not considered. The presence of hydrogen donors in the form of phenolic hydroxyl groups in the vegetable tannins and of hydrogen acceptors in the form of carbonyl functions of the collagen would naturally lead to a possibility of formation of hydrogen bonds [36][37][38][39][40]. The hydrophobic amino acid side chains on collagen, such as aromatic ring, pyrrolidine ring, and aliphatic chain are prone to become concentrated and form a hydrophobic pocket [32].…”

Interaction between retanning agents and wet white tanned by a novel bimetal complex tanning agent

“…Moreover, the uniform penetration and distribution of retanning agents in chrome tanned leather were observed by using fluorescent tracing technique, which led to satisfactory organoleptic properties of crust leather [12,15]. In fact, the current retanning agents and retanning technologies are designed to match up with chrome tanning system and may be not suitable for chrome-free tannage in consideration of the changed pI of wet white (mostly less than 5.0) [14,16]. Therefore, the retanning process for chrome-free tanning system should be systematically investigated and redesigned to upgrade the quality of chrome-free leather.…”