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In-Depth Market Research and Trend Analysis

Covering Innovative and Emerging Technologies

News

Healthcare and Biomedical Engineering


The global market for bioresorbable polymers (BPs) is estimated at $896 million in 2018. Bioresorbable polymers are gaining increasing attention in the medical industry for their ability to completely and naturally dissolve in the human body, while contributing to the formation of new tissue.  


BPs consist of two categories of materials: biopolyesters and agro-polymers. Biopolyesters currently represent the largest segment at 82% of the total market and include materials such as polylactic acid (PLA, or polylactide), polyglycolic acid (PGA), polycaprolactone (PCL), polydioxanone (PDO), and their copolymers (e.g., PLA/PGA and PLA/PCL) and derivatives (e.g., PLLA and PDLA).  Polylactic acid is the most popular in this category. PLA decomposes into lactic acid, a compound that already forms in muscle tissue during exercise and that is naturally eliminated by the body.


Although less popular, agro-polymers, which comprise polysaccharides and proteins, also find various uses as biodegradable implants, drug delivery products, and surgical threads.


To date, BPs have been primarily applied in the fabrication of medical products for orthopedics,  drug delivery, surgery, and dentistry, as summarized in the next table.

 


However, there are several technological trends that are reshaping this market. The most relevant relates to the introduction of bioresorbable polymers in the manufacturing of stents.  Stents are implantable devices whose function is to restore adequate flow of biological fluids in cardiovascular, urethral, esophageal, biliary, and pancreatic vessels. Cardiovascular bioresorbable stents, in particular, have become the subject of numerous research and development activities in recent years.  

Originally, stents were made from metals such as platinum, chromium and stainless steel. They were  not biodegradable and over time they caused new tissue overgrowth resulting in restenosis (narrowing of the artery) and aggregation of platelets leading to thrombosis. In the early 2000s, drug-eluting stents based on metal alloys (e.g., nitinol) were introduced comprising immunosuppressants and antiproliferative agents , the most common of which are sirolimus and everolimus. These drugs prevent excessive proliferation of vascular smooth muscle cells but also delay growth of endothelial cells.


In 2016, the FDA approved a bioresorbable vascular scaffold (BVS) based on PLLA that re-establishes normal blood flow while supporting the artery for three to six months. The BVS slowly degrades within 3 years, leaving behind a completely healed artery with restored vasomotion.  This absorbable coronary DES, which contains everolimus, is called Absorb GT1 BVS and was introduced by Abbott Vascular ( Santa Clara, CA).

However, in 2017, the FDA issued a safety alert for this product due to the occurrence of adverse cardiac events, leading Abbott to halt sales. Since then, the company has continued to work on the development of a new generation of bioresorbable devices.


Current issues with biodegradable stents are incomplete endothelialization, fragmentation of the stent, and severe inflammation, but there are some products on the market that have shown good performance to date.  Elixir Medical (Milpitas, CA) manufactures DESolve, a fully bioresorbable PLLA novolimus-eluting scaffold that degrades in 1 year. The device is CE-mark approved, but not yet available in the U.S. Arterial Remodeling Technologies (Paris, France), a division of Terumo (Tokyo, Japan), produces ART PBS, a PDLLA-based bioresorbable stent that received its CE-mark approval in 2015. The device is completely absorbed in 2 years.


Development of bioresorbable DES is continuing at full speed worldwide, as these devices are considered a very promising alternative to conventional metal stents. Improvements are being achieved by the addition of nitric oxide-releasing nanoparticles to prevent platelet adhesion and through BP patterning by ultrashort pulsed laser technology to promote adhesion and proliferation of endothelial cells.


In addition to anti-inflammatory drugs, bioactive agents are being incorporated into these devices including platelet-derived growth factors with the function of stimulating growth of endothelial, muscle and fibroplastic cells. Bioresorbable polymers encapsulate these therapeutic agents and also ensure that they are gradually released.


Other emerging cardiovascular applications for BPs include prosthetic heart valves and coatings for metal stents. Also, composite bioresorbable membranes are being introduced as barriers to prevent post-cardiac surgical sternal and epicardial adhesions. During resorption, these membranes act as scaffolds for new cell growth, forming a natural barrier once they are completely degraded.


Bioresorbable polymers are also being adopted in the fabrication of probes for evaluating neural activities. Existing probes are made from metals and are rigid. Since the brain is made of a soft tissue, metallic probes cause irreversible tissue damage if inserted for long periods, leading to electrode failures. Probes made from bioresorbable polymers become softer as they degrade and eventually are completely resorbed, thus improving the long-term performance of depth probes.

Another application of BPs in neurology is for producing nerve guidance channels (or conduits) to connect the ends of damaged nerves located in the peripheral nervous system. Nerve conduits provide axons with space where they can grow while being protected from new traumatic events. Nerve channels made from BPs can be engineered so that the time of their degradation matches the time needed for functional recovery of the injured nerve.


BPs are finding additional uses as embolic coils and particles to control bleeding  during surgery, restrict blood supply to tumors, and stop hemorrhages. Typically, these coils are made from metals and work by promoting clot formation around the coil. Although metal coils have desirable properties such as radiopacity and shape memory, they also show drawbacks including chronic tissue damage, tissue overgrowth, and permanent incorporation into the tissue. BPs are attractive materials for embolotherapy since they are inherently radiopaque, degradable, and applicable in repeated treatments.


In drug delivery, bioresorbable polymers are becoming popular as drug carriers for cancer therapy. They are being engineered to respond more effectively to physical and chemical stimuli such as temperature, light, ultrasound, electric current, pH changes, and enzymatic activities, so that targeting of cancerous cells can be optimized.  


Electrospun nonwoven fabrics based on BPs are being manufactured for wound treatment and repair of soft and hard tissues. These products incorporate growth factors and proteins that can be delivered to the wound area with good spatial and temporal control.


3D printing is being investigated for fabrication of scaffolds with complex and customized shapes. Currently, one of the main issues with 3D printing is that common bioresorbable polymers can only be formed at relatively high temperatures. For example, PLA requires processing temperatures greater than 200°C, which negatively impact the biological properties of this material.


Biocomposites are gaining traction in bone tissue regeneration applications. Bioresorbable polymers are combined with calcium phosphate-based materials, such as hydroxyapatite (HA), to create products with improved load-bearing properties and biocompatibility. Polymers with different properties can be mixed together before addition to calcium phosphate compounds. For example, PLA, which is characterized by fast degradation behavior, can be blended with PCL, which exhibits a ductile behavior, to optimize biological and mechanical properties of the composite product. Composites based on PLA/PCL are generating strong interest because PCL reduces the brittleness of PLA, providing a material with characteristics similar to cancellous bone and easier to form by 3D printing. Nanomaterials, such nanohydroxyapatite, are also being added to BPs to fabricate composite membranes, fixation devices, and other advanced biomedical products with enhanced performance.


All these trends are projected to contribute to healthy market growth during the next five years, with BP revenues estimated to rise at a CAGR of 13.8% through 2023. BPs for cardiovascular products are expected to account for approximately 10% of the market by the end of the forecast period.




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