Athletes often suffer from injuries to the ligaments in their knees, particularly the anterior cruciate ligament or ACL. While surgery to replace these torn ligaments is becoming increasingly common worldwide, it often needs to be repeated. This is because it has proven difficult to anchor fibrous, soft, and wet ligament grafting materials in hard bone.

Now, McGill University researchers have new information from the eggshell membrane in chicken eggs that could help change that picture, thanks to the potential it offers for improving tissue engineering and biomaterial grafts.

Their results also have the potential to reduce losses for commercial egg and poultry producers.

Anchoring soft and wet fibers in place with “nails”.

The researchers discovered how the hard shell of a bird’s egg connects to the egg’s underlying moist fibrous membrane (the thin membrane layer visible inside the shell when you peel a hard-boiled egg). Using advanced 3D imaging X-ray and electron microscopes with cryopreservation methods, the research team was able to visualize this interface in three dimensions to visualize and quantify the cross-linking phenomenon.

Professor Mark McKee of the Faculty of Dentistry says, “Until now, no one had considered how this interface could be formed between these two very different materials, one a hard bioreactor, and the other a soft fibrous membrane. , can be preserved at the nanoscale.” in Medicine and Oral Health Sciences, and the Department of Anatomy and Cell Biology, and doctoral student Daniel Buss, principal investigator of the recently published study. iScience. “What we found about this soft-hard interface is quite remarkable.”

Nano spikes increase the contact surface between soft and hard materials and ensure food safety.

The McGill team discovered that, at a specific stage before egg laying, the shell sends mineral nanospikes into the soft and flexible surface fibers of the egg’s basement membrane. This membrane surrounds the soft contents of the egg’s interior, either the egg white and yolk of table eggs, or the developing chick embryo in a fertilized and incubated egg.

This nanospiking attachment process between two very different materials greatly increases the surface area of ​​the interface between the soft and wet organic fibers and the hard and largely dry inorganic minerals. Such attachment essentially anchors and secures this soft-hard interface to prevent slipping and sliding of the fibers within the shell.

Otherwise, separation of the membrane from the shell can be fatal to the embryo chick, weaken the shell, and/or allow the invasion of pathogens (such as Salmonella) into the internal contents of the egg. The food safety of table eggs depends on an intact shell that is well integrated with its primary membrane.

Implications for clinical practice and commercial egg production

With this new understanding of the shell-membrane interface as a characteristic of strong, safe and healthy eggs, losses to table egg producers and poultry farmers can be reduced by establishing commercial genetic breeding programs that maintain or maximize this interfacial structure.

The results may also lead to the design of new engineered, hybrid composite materials, and new procedures to improve the outcomes of various medical and dental reconstructive surgeries, both in which soft wet fibers are combined with hard materials. may need to be attached to