Thanks to their adaptability, resilience, and cost-effectiveness, biomaterials have long been a mainstay in medical device manufacturing. However, the environmental impact of traditional plastics has sparked a quest for sustainable and biodegradable alternatives. This is where plastic biomaterials step in – they’re not just innovative but game-changers. These materials retain the benefits of conventional plastics while significantly reducing their negative environmental footprint.
There are two types:
1. Naturals biomaterials
2. Synthetic biomaterials
Natural biomaterials
Natural materials include starch, collagen, bone, or chitosan, while synthetic materials are created in laboratories from metals, polymers, and ceramics. Hybrid materials use both types of materials. These are chosen to be biomaterials because of their combination of physical, chemical, biological, and mechanical properties, which make them suited for proper function and human body applications.
Source: https://www.sciencedirect.com/science/article/abs/pii/S0197018621000796 (Natural biomaterials in brain repair: A focus on collagen)
Biomaterials are used to aid in wound healing by providing physical support, promoting cell growth and migration, and forming new tissue. Biomaterials have appropriate mechanical strength, flexibility, porosity, structure, biodegradation, and biocompatibility for such applications.
Cell therapy is a new and emerging approach to repairing a damaged heart. Tissue engineering can create cardiac patches, modified and seeded with bone marrow or mesenchymal stem cells to form a near-natural repair. Natural and synthetic biomaterials are also being explored in this area.
Osseo induction is becoming a preferred technique for bone repair. It involves using surface modification or introducing growth factors or bone marrow stem cells into the damaged area to induce new bone growth. This could accelerate bone healing without painful and extensive surgery.
Bone marrow stem cells are potentially very useful for skin tissue engineering, while mesenchymal stem cells may give rise to ligament fibroblasts. Fat-derived stem cells may enhance both collagen synthesis and the movement of skin fibroblasts in wounded tissue, promoting rapid wound closure.
Synthetic biomaterials
The modification of materials using synthetic method has provide a longstanding approach to customizable. The rational design of properties and functionalities is a major advantage of synthetic methodologies, while the bioactivity and resorption are challenges.
Source:https://link.springer.com/chapter/10.1007/978-3-031-35832-6_4 (Biomaterials and Tissue Engineering)
A. Bioceramics
Bioceramics are being widely used in hip replacement, for bone grafts, dental implants, and to create artificial tendons. Black pyrolytic carbons are unsuitable for externally visible implants, as in the mouth, but are easy to manufacture and highly compatible with the body’s tissues. They are used for heart valves, ligaments, tendons, and composite implants, all of which require great tensile strength.
Bioceramics are biocompatible, non-carcinogenic, non-inflammatory, non-allergenic, and non-toxic. They are also pleasing to the eye and can be tinted to any desired colour. Their compressive strength is high, and they are resistant to corrosion. They make excellent articulating surfaces.
Calcium aluminate and calcium phosphate are examples of the first, which are resorbable; hydroxyapatites and glass ceramics are examples of the second; and alumina, zirconia, and carbons are examples of the third.
Where electrical conduction is a priority, inactive metals of the third sort are typically preferred, but biodegradable materials are a better choice for suture materials. Bioabsorbable materials are used in areas such as vascular stents, intended to provide a long-term but not permanent framework for repair processes.
Resorbable materials (calcium aluminate) are used in dental and orthopaedic procedures, as well as for artificial bones, teeth, knees, hips, tendons, and ligaments (calcium phosphate).
Bioactive or semi-inert biomaterials like glass ceramics are used to add in bone where required, while hydroxyapatite is used to create bone grafts, fillers and metal implant coatings.
B. Polymers
Natural polymers like starch and collagen are easy to source and break down rapidly, making them suitable for biomaterial use. Synthetic polymers are more commonly useful in making dental and prosthetic materials, implants and single-use medical equipments.
Interestingly, though created for non-medical uses, compounds like polypropylene (PP), polyethene (PE), polymethyl methacrylate (PMA), polyethylene terephthalate (PET), and polyurethane (PU) are now extensively used in the manufacturing of medical devices.
Polyvinylidene fluoride, polyethylene, polypropylene, polyamide, and polytetrafluoroethylene are synthetic polymers mostly used in packaging medical devices.
PP is used to create meshes to repair hernias, membranes for extracorporeal membrane oxygenation (ECMO), artificial blood vessel grafts, and suture material. PMA is also used to construct dental implants, bone cements and vascular grafts from PET.
PU is used to make breast implants, wound dressings, patches for heart muscle, and blood vessel grafts, besides drug delivery vehicles. PE is commonly used in making tubes for catheters and drains, hip socket liners and surgical implants.
Source: https://www.mdpi.com/2073-4360/13/17/3015 (A critical review on Polymeric biomaterials for Biomedical application)
Polymers are used to make probes that could improve positron emission tomography (PET) imaging. Microelectron mechanical systems (MEMS), better known as lab-on-a-chip, are made of polymer, bringing down the cost of single-use devices.
C. Metals
Metals are often used to make pacemaker wires, vascular stents and implants for the hip and knee joints which require high corrosion resistance and mechanical strength. Both pure metals and alloys are used for such purposes.
The alloys are coated with Bioceramics or thin polymer films. Sometimes the surface is engineered for these properties. These biomaterials are easy to sterilize and to build to specifications, with high shape memory. Conversely, they are cytotoxic in some cases; may cause allergic reactions; and are stiff and difficult to shape which can hamper osseointegration.
Most metallic biomaterials fall into the following groups: pure titanium or its alloys, stainless steel, and cobalt-chromium alloys. Stainless steel works well for blood vessel grafts, plates to reunite fractured bones, and guide wires in endoscopic procedures. Cobalt-chromium alloys are used in artificial heart valves, joint prostheses, plates and screws for treating fractures, and teeth.
Plastic biomaterials
Plastic biomaterials are derived from renewable resources such as plants, algae, or bacteria, making them biodegradable and compostable. These materials are designed to break down naturally over time, reducing the amount of plastic waste that ends up in landfills or oceans. In the medical device industry, plastic biomaterials are used to create a wide range of products, from surgical instruments to implantable, effective and eco-friendly devices.
One of the key advantages of plastic biomaterials is their biocompatibility, meaning they are well-tolerated by the human body and pose minimal risk of adverse reactions. This makes them ideal for medical devices that contact biological tissues or fluids. Additionally, plastic biomaterials can be engineered to have specific properties, such as flexibility, strength, or antimicrobial properties, to suit the requirements of different medical applications.
Plastic biomaterials also play a role in developing personalised and regenerative medicine. These materials can be used to create scaffolds and 3D-printed structures that support tissue regeneration and repair, offering new possibilities for treating injuries and diseases. By harnessing the potential of plastic biomaterials, researchers and medical device manufacturers are pushing the boundaries of what is possible in healthcare.
Like any innovation, plastic biomaterials have challenges. Producing these materials can require significant resources and energy, raising important questions about their overall sustainability. Additionally, some plastic biomaterials may have mechanical strength or degradation rate limitations, necessitating careful consideration of their design and application. Being fully aware of these challenges is crucial as we navigate the path to a more sustainable healthcare future.
In conclusion, plastic biomaterials are not just a promising avenue for innovation in the medical device industry; they are a beacon of hope. They offer an unparalleled blend of performance, biocompatibility, and sustainability. As research in this field continues to advance, we can expect to see an increasing number of medical devices that are not only effective and safe but also environmentally friendly. By embracing plastic biomaterials, we can ensure that healthcare continues to progress in a way that is not just mindful but respectful of the planet and its resources.
