Biomaterials: what are they, types and characteristics?
Biomaterials are very useful technological developments used in the field of medicine.
Humans (and most animals) have some ability to heal wounds and injuries. Normally, openings of the epidermis by mechanical processes follow a medically predictable healing mechanism: clot formation, inflammation, cell proliferation and differentiation of new strains, with the aim of remodeling the tissue and returning it to its original state as much as possible.
However, it is not only the epidermis that is repaired. Bone consolidation and mobilization of myocyte satellite cells (in bone and muscle, respectively) are examples of other physiological mechanisms that try to heal microtears and fractures in our locomotor system.
For example, when a bone fracture occurs, cell bodies (osteocytes, osteoblasts, osteoclasts and osteoprogenitor cells) secrete and remodel the bone matrix, with the aim of restoring the bone to its normal shape in the shortest possible time. Typically, a significant improvement can be observed within 6 to 8 weeks.
Unfortunately, not all tissues heal well and some lack perfect regenerative capacity altogether, as is the case with the Heart or other organs. To challenge the limits of human physiological capabilities and potentially save millions of lives, biomaterials have arrived in our time, biomaterials have arrived in our time.. Learn all about them, because the future of medicine is promising to say the least.
What are biomaterials?
A biomaterial, from a medical point of view, is any natural or synthetic material intended to be introduced into a living tissue, especially as part of a surgical element or implant. At the physiological level, these materials have unique properties compared to the rest, since they can be put in contact with a living tissue immediately without causing negative immune responses in the patient.
In addition, it should be noted that biomaterials do not achieve their function by secreting pharmacological substances and do not depend on metabolization by the organism to achieve the desired effect (but, rather, they do to achieve the desired effect (otherwise we would be talking about drugs). Their mere functionality and magic lies in being (and adapting) in the right place, as they ideally serve to replace any hard or soft tissue that has suffered some kind of damage. In addition to their typical use, they are also increasingly used as diagnostic methods and other clinical events.
The first generation of biomaterials was conceived in approximately 1940, with a peak of utility and function in the 1960s and 1970s. As materials and medical knowledge have been refined, the capabilities of these elements have improved over time, leading to second and third generation composites. Some of their ideal properties are as follows:
- Appropriate mechanical properties: a highly rigid biomaterial cannot be introduced into a lax natural tissue, as its proper functionality would be impeded.
- Corrosion resistance in an aqueous environment: the human body is 60% water. Therefore, it is essential that the biomaterial is resistant to water stress.
- It must not be conducive to local toxicity or carcinogenic events in the tissue in which it is placed.
- From the second generation onwards, the aim was for the materials to be bioactive. These should induce a physiological response that supports the function and performance of the biomaterial.
- Another of the new characteristics sought is that some of the materials should be capable of being reabsorbed. This means that they disappear or change drastically over time and can be metabolized by the body.
- Finally, some of them are now expected to stimulate specific responses at the cellular level.
As you can imagine the ideal properties of a biomaterial are entirely dependent on the functionality. For example, a surgeon would want a screw used to fix a graft in ligament injuries to be resorbed over time, so that the patient does not have to be operated on again. On the other hand, if the biomaterial replaces a vital structure, the idea is that it should be permanent and withstand all the inclemencies of the body's ecosystem.
In addition, some biomaterials are interesting from a cellular point of view, as they can develop their growth and differentiation.. For example, some third-generation bioactive crystals are designed to activate certain genes in damaged tissue cells in order to promote rapid regeneration. It sounds like a technology out of a dystopian future, but this is a reality today.
Types of biomaterials
So that all of the above does not remain a series of ethereal concepts, we present evidence of the usefulness of biomaterials. We cannot cover them all (as the list is very long), but we do include some of the most interesting ones. Don't miss them.
1. Calcium phosphate ceramics
Porous calcium phosphate ceramics can be used to repair certain intraosseous defects, since they are non-toxic, biocompatible with the body and do not significantly alter calcium and phosphorus levels in the blood.. However, as bioceramics are eminently hard and degrade very slowly, it is usually necessary to combine them with biodegradable polymers to achieve better results.
This type of implant is used to promote bone healing in fractures, for example. As a curious fact, it has been observed that imbuing these biomaterials with mesenchymal stem cells can promote faster and improved tissue regeneration in certain animals. As you can see, a biomaterial is not just a mineral or compound, but a mixture of organic and inorganic elements that try to find the perfect balance to achieve their functionality.
2. Bioactive crystals
Bioactive crystals are also ideal for certain regenerative processes at the bone level, because their degradation rate can be controlled, they secrete certain ionic materials with osteogenic potential and have a more than correct affinity meeting with bone tissue.. For example, multiple studies have shown that some bioactive crystals promote the activation of osteoblasts, bone tissue cells that secrete intercellular matrix that give bone its hardness and functionality.
3. Bicortical resorbable screws
Resorbable plates and screws based on polylactic and polyglycolic acids are the order of the day, since increasingly replacing the hard titanium elements that used to cause so many problems when welding lesions..
Polyglycolate, for example, is a tough, non-rigid material that does not fray and offers good security as an abutment during suturing. These materials outperform titanium by far, as they cause much less discomfort to the patient, are less expensive and do not require surgical removal.
4. Biomaterial patches
So far we have mentioned biomaterials that are used for bone regeneration, but they are also used in soft tissues. For example, the National Institute of Biomedical Imaging and Bioengineering is developing alginate patches, based on brown algae, as therapeutic sealants to treat soft tissue infiltrates. therapeutic sealants to treat lung infiltrates from trauma, surgery, or conditions such as pneumonia and cystic fibrosis..
The results of these technologies are promising, as it appears that the alginate patches respond well to lung-like pressures and support tissue regeneration in these life-essential organs.
5. Hydrogel "bandage" for burns
People suffering from severe burns experience real agony when their bandages are manipulated and, in addition, they delay epidermal growth and tissue regeneration. By using hydrogels that are currently being studied, this series of problems could disappear.
The hydrogel would act as an ideal film to prevent infection and environmental degradation of the wound.. In addition, it could dissolve under certain controlled procedures and expose the lesion without the mechanical stress that this entails. Undoubtedly, this would infinitely improve the hospital stay of patients with severe burns.
Everything we have told you is not based on conjecture and hypothesis: many of these materials are already in use today, while others are currently under active development..
As you can see, the future of medicine is, to say the least, promising. With the discovery and refinement of biomaterials, infinite possibilities are opening up, from the reabsorption of screws and sutures to the integration of elements in tissues that promote the activation of their own healing mechanisms. Undoubtedly, fact trumps fiction in the field of medicine.
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(Updated at Mar 28 / 2023)