Recently, new and more advanced solutions have been developed to restore mobility in the missing and non-functioning body parts of patients, changing lives. These artificial technological implants of joints and even entire limbs are called prosthetics [1]. However, the effectiveness of these devices is heavily reliant on the materials used to create them, specifically biocompatible materials that can contact the body safely. Biomedical engineers and prosthetic designers use these anti-inflammatory materials to design prosthetics that are both safe and comfortable. In recent years, prosthetics have become increasingly user-friendly and responsive.
Scientists go to great lengths to make sure prosthetics are safe for daily contact. This is kept in mind when using biocompatible materials, which are substances that will not cause toxic reactions, inflammation, or immune rejection [2][3]. This is important in fields like prosthetic creation because these devices are made to be used for periods of time in contact with or inside the body. Biocompatibility will also vary from person to person. Specific measures must be taken to see if the individual is able to successfully produce a protein layer between the blood cells and material through a process called protein adsorption. This process allows the human cells to recognize the material as its own and develop the correct tissue or bone to connect it to the body. The type of material used has a direct effect on how quickly and sufficiently the first protein layer develops. If protein adsorption is insufficient or fails altogether, the prosthetic can either not correctly attach to the body or will be encased by a fibrous material produced by the body rather than tissue, ultimately causing instability and pain [4]. In addition, it is important that the patient has no allergic reactions causing inflammation. However, even after these personal factors are considered, not all other materials can be used.
Deciding what materials to use for prosthetics, especially implants, becomes complicated when biocompatibility is taken into consideration. Scientists need to choose materials that are both non-decaying and prevent all negative side effects. These materials commonly include: metals like titanium and cobalt-chromium alloys, which have strong wear-resistance; ceramics like alumina and hydroxyapatite, which are low-friction; and polymers like polypropylene and polyethylene, which are flexible and provide cushioning. Engineers use many processes to further improve biocompatibility. Despite the frequent use of metals, they can sometimes release unwanted particles into surrounding tissues. Because of this, ceramic and polymer compounds have also been created and utilized. On these materials, surface coating and texturing are used because they can encourage surrounding tissue to grow and bond with implants, in addition to the preliminary protein adsorption. Techniques like material polishing and chemical treatments are also used to prevent other reactions inside the body. Before a biomaterial is introduced in a medical device, it will go through several rounds of testing. Typically, this process involves in vitro testing, analytical chemistry, and in vivo testing. In vitro testing refers to test tube experiments in which the materials being tested are placed in environments that mimic the human body. Often, this data will be used in analytical chemistry, which is when material chemical make-up and toxicity are taken into account to predict possible reactions in the use of that material. In Vivo testing is usually the last and most controversial step, involving the testing of how a material would integrate and be processed by an organism, conducted through tests on animals[5].
Once material compatibility has been achieved, prosthetic fabrication involves patient physical compatibility. After an initial consultation has occurred discussing goals and measurements, prosthetists begin to analyze patient movement to determine the necessary mechanics and shape for a prosthetic. Then, once the prosthetic goes into production, a process of fittings and adjustments begins to fine tune the device. Eventually, once the instrument is completed, intermittent follow up appointments are held to ensure that the prosthetic is functioning properly. [6]
In recent years, there have been significant advancements in prosthetic manufacturing. Some of these developments allow prosthetics limbs to mimic human movements more naturally and to replace manual movements with reactive movements that respond to the individual. One such innovation is myoelectric prosthetics, which uses neurological signals sent to the muscle to control movement automatically when sensed by the electrodes in the prosthetic. Another example is biomimetic prosthetics, which are engineered to replicate natural human movements as closely as possible through computer algorithms that control them. These algorithms are usually used in addition to myoelectric functions. Researchers are also looking to integrate better neural control and artificial intelligence into prosthetic creation. Neurally controlled prosthetics are connected directly to the nervous system through implanted electrodes, allowing users to control limbs with their thoughts alone. The incorporation of artificial intelligence into prosthetics will help prosthetics learn and adapt to the behavior of the user over time. Pliable materials and touch sensors are also being developed to better prosthetic experiences [7]. Although prosthetics offer many benefits, at this moment, they are extremely expensive. In response to these costs, 3D printed prosthetics are slowly being explored and introduced, potentially decreasing costs and increasing the speed of device generation. As it stands, durability, biocompatible, and cost efficiency are still issues in this area of prosthetic modernization [8].
Prosthetics and biocompatible materials are essential parts of biomedical engineering. Through careful material selection and designs, scientists are able to create devices that restore function while also ensuring patient safety and comfort. Technological advancements like neural control, AI integration, and 3D printing will further help restore function. These developments are important because they are not only advancements in science, but they also return autonomy and a sense of normalcy to patients who have lost function of their limbs.