Our bodies are not just living cells stuck between other living cells. Tissue and organs are made not just of cells, but of a matrix of fibers, proteins, and small molecules that living cells secrete and live in. This material is called the extracellular matrix, which gives structure to our bodies and a pathway for cells to communicate with each other. When the cells are washed away, the extracellular matrix, or ECM, remains, and can be used as a material…
Collagen is a natural polymer familiar to everyone. Leather is collagen. Gelatin, the powder in every jello box, is collagen. Collagen gives structure and shape to all the tissues in the body, just as it does for leather and jello. It’s use in biomedical products is at least 2,000 years old, perhaps beginning when sutures were made of catgut. For at least 100 years, collagen has been used as a simple patch to aid skin wound healing. John A. M. Ramshaw…
Bioprinting is layer-by-layer manufacturing using living cells. Small groups of cells are “printed” in precise patterns that can be built up in layers by printing one layer on top of another. With the right materials, these layers can form complex 3-dimensional structures, designed using clinical images from MRI and CT scans, that approximate living tissue. There are grande claims made by those who’s research involves bioprinting, such as one day being able to print functional organs for transplant, but its real future…
Natural biomaterials inherently provide biological signals and stimuli. When chosen properly, those natural properties aid in different types of healing. With some amount of hard work, synthetic materials can be modified to mimic some of these natural signals. Cen Chen, et al., have produced an open access review in Biomaterials Research that summarizes the presentations from a 2015 Korea-China joint symposium on biomimetic materials. Their paper does not focus on natural materials, but illustrates the amount of work put in…
Stroke, the main cause of adult disability, leaves a hole, or cavity, in the brain, destroying tissue and cell networks. Physical therapy is the only approved treatment for stroke, relying on the brain’s ability to rewire itself to regain function without healing the damaged tissue. This highlights an opportunity for regenerative medicine to improve healing and long term outcomes for stroke patients. A possible solution to stroke therapy shortcomings Transplanting neural stem cells into the damaged tissue has not yet been able…
We discussed in an earlier post the application of natural polymers in clinical treatment of osteoarthritis and other injuries to articular cartilage. Those current therapies are all limited to treating small lesions or holes of only a few millimeters across. Material challenges remain when larger, curved areas of cartilage need to be regenerated in joints. Larger scaffold constructs are more difficult to evenly seed with cells, and are also prone to shrinking and changing shape as the cells grow inside…
Around 250,000 surgeries to repair articular cartilage are performed each year. Most of the damage surgeons are trying to fix begin as small lesions. Without treatment, small lesions become large holes that allow the bones of the joint to grind together. Sometimes these lesions are due to injury, but osteoarthritis is a large cause. Current Cartilage Repair If the lesion is small enough, the fix is just cleaning up the lesion by removing ragged tissue and waiting for healing to happen on…
Damage to joint cartilage from injury or osteoarthritis is challenging to repair because cartilage can’t repair itself. Joint cartilage doesn’t have blood vessels, so it isn’t regularly rejuvenated like other tissues, and there is no way for the body to transport new cells to an injury. Current treatments include microfracture, which breaks the bone under the injury to cause bleeding and presumably introduce new cells to start the healing process, and implanting autologous chondrocytes, also gathered by causing a secondary…
Hydrogels have been used successfully in many tissue engineering applications. However, because they are inherently soft materials, it is not always easy to get the large, interconnected pore network that enhances cell behavior and allows neovascularization of implants. Many techniques have been developed to try and create pore networks after the gelling process completes, like using salt or sugar porogens. But porogens must be removed to create the pore network, and the removal process has always been the Achilles heel…
All tissue engineering and regenerative medicine scaffolds try to mimic some characteristic of the natural extracellular matrix, or ECM. It supports growth of blood vessels, nerves, and allows sufficient diffusion of nutrients to keep native tissue healthy. Usually scientists and engineers try to isolate just a few of the characteristics of the ECM, such as mechanical properties, three dimensional structure, and inclusion of proteins or other functional molecules. A few researchers have decided to not to mimic ECM and instead…
