Anion-Specific Effects on the Assembly of Collagen Layers Mediated by Magnesium Ion on Mica Surface

Abstract

The well-ordered assembly of collagen molecules on mica surface has attracted extensive attention because it has great potential applications or can be served as a model system for study on the assembly process. Although the epitaxially guided collagen assembly mediated by potassium ion on mica surface has been reported several times over these years, specific effects of anions in this field has never been surveyed and discussed before now. In this work, atomic force microscopy was employed to visually follow the assembly of collagen on mica surface mediated by three kinds of Mg(2+) salts with different anions, including MgAc2, MgSO4, and MgCl2. It was found that at high ionic concentration anions could critically affect the interaction between collagen microfibrils and mica surface and accordingly resulted in different structures. Almost parallelly aligned collagen fibrils in one direction were achieved for acetates, sparse and small fibrils in two main directions rotated by 120° were acquired for sulfate, while flat film with some defects was obtained for chloride, respectively. The Hofmeister series and Collins' model were used to interpret the results. This study would be useful for controlling the morphologies of assembled collagen on a surface.

Magnesium Modifies the Structural Features of Enzymatically Mineralized Collagen Gels Affecting the Retraction Capabilities of Human Dermal Fibroblasts Embedded within This 3D System

“…Pi supplementation). Moreover, it has been reported that Mg 2+ salts can modify collagen assembly [23]. Consistently, we have noticed a striking effect of MgCl 2 on size and organization of collagen fibrils.…”

“…, glycosaminoglycans) [18,19,20,21], all experimental conditions were accurately controlled. In the present study, MgCl 2 was also added to the collagen solution (Figure 1) since it has been suggested that magnesium: (i) interferes with mineral deposition possibly preventing ectopic calcification [22]; (ii) can be a modifier of collagen assembly [23]; and (iii) is present in calcified nodules in clinical contexts [24,25]. …”

Cation-Specific Effects on the Self-Assembly of Collagen Molecules Mediated by Acetate on Mica Surface Observed with Atomic Force Microscopy

“…In contrast, the effects of Na + and Mg 2+ on collagen selfassembly were typically chaotropic and will cause collagen assembly homogeneous dense network or flat membrane and the increase of collagen solubility. In this study, Hofmeister series [11] and Collins' model [12][13][14][15] were used to explain the interaction mechanism of collagen and different cations at the molecular level. It provides theoretical guidance and data supports for the biological, medical, food, and cosmetic manufacturing industries.…”

“…The numbers of papers involved in Hofmeister series related to various fields especially biomedicine are large and still keep growing every year [8][9][10]. Wang et al demonstrated a sequence (SO 4 2− > Ac − > Cl − ) which has the stabilizing and salting-out effects on proteins and macromolecules [11]. Acetate was selected to investigate the effect of cations on 2 Journal of Food Quality collagen self-assembly in this study.…”

Harnessing Hierarchical Nano‐ and Micro‐Fabrication Technologies for Musculoskeletal Tissue Engineering

“…The addition of magnetic beads into a collagen solution has also been investigated as means to produce aligned thin and thick hydrogels . Alternative, yet underinvestigated methods to produce aligned collagen hydrogels include molecular crowding, dynamic shear, mica surfaces, mechanical loading, centrifugation, followed by self‐assembly at 37 °C, and cyclic stretching …”