Collagen Scaffolds: Slice, Stack, and Roll

Tufts University researchers have invented a new method for creating collagen scaffolds officially called bioskiving and colloquially referred to as "slice, stack, and roll" that would enable it to be more useful than in its normal form. Collagen is a protein present in the flesh and connective tissue that is often utilized for tissue engineering purposes because of its strength and biocompatibility. However, it can be inefficient because production techniques often lower its natural strength.

In bioskiving, the first step is to decellularize cut sections of collagen with a detergent, which leaves behind a matrix of bundled collagen nanofibers without any excess. Next, the sections are sliced into very thin sheets and stacked in such a way that the alignment of the fibers alternates throughout the stacks in order to increase the tensile strength. Finally, the stacks are rolled around Teflon-coated glass rods to maintain the fiber structure, which is important for the strength of the overall material.

A picture of this process is shown below:

Collagen's strength is due to its chemical structure, which consists of three polypeptide chains, each of which are in the shape of a helix. This strength is further compounded by the fact that the amino acids in this protein are very small, allowing each chain to be twisted together tightly. In the chemical structure, it can be seen that hydrogen bonding is present because of the electronegative oxygen and nitrogen. This helps keep the strands tightly together.

There are also cross-links between the three-stranded collagen molecules, which lends the protein high tensile strength. This means it is very resistant to breaking apart under pulling forces, while still retaining some measure of elasticity. Because of all these different types of strength, collagen remains the ideal protein to use for such application, and the slice-stack-roll process was able to retain these properties.

In a somewhat different vein, collagen has one other important property: its relative solubility in water. As seen in the structure, collagen is a very polar molecule, with the hydroxide groups and electronegative elements. Since like dissolves like, it is not hard to make solutions with collagen in water, which makes it a good choice for biological applications. If collagen was insoluble, it would not be suited for this work.