Correlating Mechanical Properties with Aggregation Processes in Electrochemically Fabricated Collagen Membranes

Abstract

We show that mechanical stiffness is a useful metric for characterizing complex collagen assemblies, providing insight about aggregation products and pathways in collagen-based materials.This study focuses on mechanically robust collagenous membranes produced by an electrochemical synthesis process. Changing the duration of the applied electric field, or adjusting the electrolyte composition (by adding Ca 2+ , K + , Na + or by changing pH), produces membranes with a range of Young's moduli as determined from force-displacement measurements with an atomic force microscope. The structural organization -characterized by UV-visible spectroscopy, Raman spectroscopy, optical microscopy and atomic force microscopy -correlates with the mechanical stiffness. These data provide insights into the relative importance of different aggregation pathways enabled by our multi-parameter electrochemically-induced collagen assembly process.

Nano-textured self-assembled aligned collagen hydrogels promote directional neurite guidance and overcome inhibition by myelin associated glycoprotein

“…32 AFM analysis of surface topography shows a network of non-aligned nano-sized fibrils as shown previously for iso-electrically focused thin collagen membranes. 27 In contrast to the previous study, we also show that with our standard buffer treatment the nanofibrils selfassemble into larger D-banded fibrils. Similar to the aforementioned study, to observe these fibrillar structures the surface needed to be slightly dehydrated (ethanol was used previously).…”

Modeling the Electromobility of Type-I Collagen Molecules in the Electrochemical Fabrication of Dense and Aligned Tissue Constructs

“…1,9,14,21,23,39 While IEF is routinely used for protein identification and separation, its utilization for fabricating materials is novel and significant. The significance of electrochemical fabrication is in its potential to generate collagenous biomaterials whose fabric is as dense, as aligned and as strong as collagenrich tissues such as tendons and ligaments.…”

Collagen-Membrane-Induced Calcium Phosphate Electrocrystallization

“…Elastic modulus values were obtained using an atomic force microscope (Asylum Research MFP-3D) using a method described elsewhere. 8 Our results show that the presence of the collagen membrane, in addition to the use of electrochemically controlled precipitation, impacts mineral phase selectivity. Table 1.…”

“…Figure 4 shows that composite membranes are stiffer (higher elastic modulus values) than for non-mineralized membranes. 8 Rinsing in water or ethanol does not degrade the composites in any way. Preparing an unmineralized membrane in the presence of higher amounts of Ca 2+ will lead to a slightly stiffer scaffold, but composite membranes are consistently more stiff.…”

“…Our previous works 7,8 describe the electrochemical aggregation of pure collagen into a membrane via isoelectric focusing. Here, we demonstrate that this electrochemically aggregated collagen can act as a scaffold for calcium phosphate mineralization, and that it also affects the nucleation and growth process of the mineral.…”