3D Printed Bioresorbable Implantable Devices

The biocompatibility requirement is a given. But that still leaves a wide range of biomaterials to choose from. Oftentimes, the second major consideration is the degradation rate. How fast do you need the material to degrade? This question does not have an obvious answer. Don’t be quick to rule out a certain biomaterial altogether because of its degradation rate. For example, copolymers can be used to design the desired degradation profile when each polymer alone would not meet the requirement. While poly(l-lactic acid) takes longer than 24 months to degrade and poly(glycolic acid) 3-4 months, copolymers of the two can be developed to target degradation within 5 to 6 months. Longer degradation timeframes can be achieved with poly(caprolactone), >24 months, and fast degradation within 1-2 months with 50/50 poly(DL-lactide-co-glycolide). So decide on your desired degradation rate but don’t rule out any materials yet. 

The third major consideration is the material’s mechanical properties. Depending on the application and implantation site, a range of properties may be on your requirements list including tensile, compressive, torsional, and flexural strength, compliance, creep and stress relaxation, and durability. For example, biodegradable polyurethanes have high uniaxial tensile strength (7000 psi), while poly(ethylene glycol) diacrylates have fairly low tensile strength. Setting targets for each critical mechanical property helps narrow down the materials or combinations used to reach those targets. 

Next requirement is how cell friendly you need your device to be. If it is a cell-based device, cell attachment, migration, proliferation, and differentiation are all critical components. But even for acellular implantable devices, you may desire cell infiltration at the implant interface and extracellular matrix deposition as the device degrades. Or you may want no cell adhesion. This cell friendliness requirement is important as each biomaterial varies considerably in how cells interact with it. For example, poly(p-dioxanone) and poly(trimethylene carbonate) more cell friendly more than poly(caprolactone) that is hydrophobic and poly(lactide-co-glycolide) that release acidic byproducts.

Finally, depending on your application, you may have additional requirements. Color and contrast with surrounding tissue may be important, and compatibility with your desired sterilization method is also a key consideration.

3D printed biodegradable implantable devices are being developed for many applications: vascular stents and grafts, heart valves, orthopedic devices, artificial joint prostheses, whole organs, etc. The explosion of commercially available 3D printers has allowed manufacturers the flexibility of proof-of-concept designs, feasibility testing, and manufacturing of novel devices in a fast and efficient manner. 

However, the availability of suitable biodegradable biomaterials as bioinks for 3D printing remains limited. That’s the gap that Bezwada Biomedical has filled with our broad range of synthetic biodegradable polymers that can also be combined with biologic materials as needed during 3D printing. 

While we covered that biocompatibility is a given for any implantable medical device, we can’t gloss over its importance, especially when working with biodegradable biomaterials. In addition to all the biocompatibility testing of the starting materials, the device’s degradation products also need to be studied, both spatially and temporally. How the material degrades, over what period of time, degradation mechanism of action (e.g., hydrolytic, enzymatic), and how degradation products are metabolized by the body both locally and systemically all need to be studied and understood. 

At Bezwada, we specialize in bioabsorbable polymers for medical devices. 

With the broadest range of biocompatible and biodegradable synthetic polymers and decades of expertise, our team is poised to meet your application requirements. Schedule a call with our technical team to find the right polymer for your device.