An Atomic Force Microscopy Study of Ordered Molecular Assemblies and Concentric Ring Patterns from Evaporating Droplets of Collagen Solutions

Abstract

Ordered molecular assemblies spontaneously appeared from evaporating droplets of collagen solutions on glass substrates. Nanoscopic structures of the assemblies were examined using an atomic force microscope; well aligned collagen molecules oriented their ends toward the assembly surface and formed layered structures for concentrations >0.05 mg/mL, while the molecules, mostly curved, lay for concentrations <0.005 mg/mL. The layers exhibited a variety of morphological forms (e.g., regular, undulated, and rolled patterns) indicating their flexibility. For concentrations >5 mg/mL, concentric ring patterns additionally appeared in the assemblies; each ring consisted of multilayers of well-aligned tilting collagen molecules. The color of the rings alternatingly changed from blue to orange when using a color-sensitive plate. The ring width increased from 3 to 120 μm with increasing collagen concentration and also increased toward the center of the patterns. The observations of temporal and spatial evolution of the concentric ring patterns with a polarizing-light microscope showed the repetitive appearance of the multilayered region which underwent a subsequent transition into a pair of blue and orange concentric rings near the droplet edge during evaporation. The formation time of one concentric ring was dependent on collagen concentration; it was 37−50 s at an early stage of the formation process.

Modification of collagen with a natural cross-linker, procyanidin

“…The pure type I collagen (Fig. 5a) exhibit typical fibrillar structure on the mica substrate where many curved molecules or microfibrils lie and are overlapped with one another, similar to previous reports [41,42]. While in the presence of procyanidin (Fig.…”

Supramolecular assemblies of adsorbed collagen affect the adhesion of endothelial cells

“…In 1992, Chernoff and Chernoff 23 already showed the effect of pH on the formation of collagen fibrils on adsorption. Later, Mertig and colleagues 24 produced collagen layers with different geometries on the basis of dewetting, whereas Maeda 25 showed that ordered collagen structures could be formed on evaporation of concentrated collagen solutions. In our laboratory, the factors affecting the morphology and the physicochemical properties of adsorbed collagen layers have been thoroughly studied in the last few years and reviewed recently.…”

Dielectric Properties of Collagen on Plasma Modified Polyvinylidene Fluoride

“…Collagen is utilized for coating PVDF substrates. Collagen exhibits biodegradability, has excellent biocompatibility, as well as safe to use in medical field due to its biological characteristics (Maeda, 1999).…”