Biopolymers in medical applications: how implants benefit from their surprising properties

What do bacteria, silkworms and lobsters have in common? They are all sources of valuable biopolymers. Biopolymers, such as cotton, fibre or starch, are used since ancient times by humans. Given their biocompatible properties and technological progress, biopolymers are also a promising component for medical applications. In particular for implantable devices, this biomaterial has already gained the market. In this article, Alcimed provides an overview of current biopolymer application fields and possible future healthcare applications.

What are biopolymers?

Polymers are large molecules composed of repeating units. Traditional polymers are synthetically produced, while biopolymers are naturally sourced. Biopolymers are either chemically synthesized from materials occurring in nature, or directly extracted from living organisms.

Biopolymers have proven their effectiveness in medical applications

Important advantages for surgery

A key priority for any medical device is safety. When it comes to implants that remain in the body for long periods of time, safety includes not altering the normal function of tissues, causing allergic reactions or leaving inorganic residues.

Biopolymers and their medical applications are of high interest to answer these requirements. Due to their biological origin, biopolymers have a high compatibility with the human body combined with low immunogenicity. They are also either biodurable or biodegradable, depending on the required property of the implant. This ensures safe long-term presence of the implant or resorption by hydrolysis without inorganic traces in the body, while supporting cell proliferation and tissue healing .

How are biopolymers used in medical applications?

For sutures

Sutures are probably the best known example of biomaterials used in surgery. Silk fibroin has been used since hundreds of years and is now often replaced by biodegradable polymers, such as polylactic acid (PLA) or polyglutamic acid (PGA) . Indeed, suturing is a critical step in most surgeries with high risk of infection. Biopolymer-based sutures have therefore been improved by the development of drug-releasing structures. This offers further benefits in promoting healing and new alternatives continue to be developed .

For soft tissue replacement

Biomaterials can also replace materials in commonly used implants. Surgical meshes, for example, are sheets used to provide permanent or temporary support for damaged or weakened organs and tissues. They are typically used for hernias and more generally for soft tissue reconstruction and repair. While synthetic polymers or animal tissue are often used, biopolymers such as poly-4-hydroxybutyrate or bio nanocellulose offer interesting and more organic alternatives.

For fracture fixation

Screws and plates made of Poly-d,l-lactic acid (PDLLA) or poly L-lactic acid (PLLA) and polyglycolic acid (PLLA-PGA) have also been developed for operations requiring bone fixation . For example after facial-cranial fractures, as the implants degrade over time, there is no need for re-operation, allowing significant cost reduction and positive impact on the patient burden.

For improving existing implants

Researchers are also aiming to improve stainless steel or titanium implants coating them with biopolymers. This could improve the interaction of the implant with its environment and provide antimicrobial properties . These are just few examples of how biopolymer-based materials can be used in surgery.

What are the potential uses of biopolymers beyond surgical implants?

Because of their interesting properties, biopolymers can be extended from surgical implants to many other types of healthcare applications. Similarly as for sutures, biopolymers and their medical applications can facilitate targeted drug delivery for the treatment of diseases such as cancer. This is a great challenge for the pharmaceutical industry. In fact, biopolymers can be formulated into nanoparticles such as liposomes, micelles, or hydrogels, to allow targeted delivery of a treatment.

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Biopolymers are also promising delivery systems for genetic vaccines, as they improve immunisation efficiency . In tissue engineering, biopolymers can be used as scaffolds for cell culture. As a final example, biosensors for diagnostics using stretchable biopolymers that mimic biological tissue are being researched.

The high diversity of organic polymers’ medical applications offers an interesting playground for the medical industry. Surgical implants are already available on the market and offer natural and innovative alternatives to synthetic materials. In addition to their organic properties of biocompatibility, biopolymers have the advantage to confer additional and innovative functions to medical technologies. There is a surprisingly wide range of potential applications to develop, including drug delivery, diagnostics or tissue engineering. Biopolymers in medical applications truly hold a surprising advantages to solve challenges in the healthcare industry. And Alcimed is here to follow these developments, to support you in exploring opportunities and your potential projects on the topic.

About the author, 

Christina, Consultant in Alcimed’s Life Sciences team in Switzerland