Viva 2

Question 1

Convince the panel and me that with a bit of investment, switching the biomaterial used to manufacture the medical device with the material chosen will enable your company to occupy a substantial proportion of the market share to make the investment worthwhile.

Answer 1

• Currently, BMS and DES are utilised to treat CAD and reduce the risk of life-threatening conditions. However, restenosis can greatly hinder this goal as ISR accounts for up to 50% of all restenosis and often indicates severe morbidity and even 4-year mortality after detection.
• Even though DES provides some resolution to the restenosis issue, the market for BMS is still very high, accounting for 34% of new stents in Australia in 2021. BMS are more prone to restenosis and as such there is an unfilled gap in the market as an alternate to polymer coatings. Our chosen biomaterial showed a decreased risk of restenosis of only 13.2% after 3 months, and a necessary shift in the market to provide greater outcomes and improve efficacy.

CAD bad, restenosis bad
BMS still widely used - higher prone to restenosis
ours showed better outcomes
improves efficacy

Question 2

After having done your investigation, what are the most common limitations of existing materials that these new materials you found in your investigation were trying to address?

Answer 2

• A key issue with stents is ensuring long term efficacy and as with all long-term devices, it is important to ensure that there is a manageable inflammatory response. Taking immunosuppressants is far from ideal, so developing a coating which can inhibit inflammatory macrophages provided a good alternative to existing devices as most lacked this capability. These materials are able to provide an anti-inflammatory response while still ensuring SMC and EC can proliferate at a healthy level.

long term efficacy –> manage inflammatory response
immunosuppressants bad
still ensure cell proliferation

Question 3

What’s so good about this biomaterial for your new device? Why is it better than the other ones you reported?

Answer 3

• The chosen biomaterial showed great biocompatibility while still retaining mechanical properties. While the Mg alloys had good biocompatibility and mechanical strength as well, they are known for their biodegradation. The 2 Mg alloys mentioned in our report lacked any information regarding the controlled degradation and/or production of hydrogen gas. They also failed to provide long-term in-vivo testing meaning the efficacy of the stent is in doubt, while the dopamine-copper material outlined an effective 3 month trial.

biocompatible while still being strong
mg had no info about degradation - hydrogen gas
long-term efficacy unknown but ours had 3 month trial

Question 4

How much better is your chosen biomaterial than the existing biomaterials used for your medical device component?

Answer 4

• Currently, ISR accounts for more than 50% of restenosis and generally occurs in the first 3-6 months. Our chosen biomaterial identified a risk of 13.2% when studying it over 3 months, which is a reliable time frame. When comparing our chosen biomaterial to traditional BMS, it far outperforms compared to the 17-41% found in BMS, which accounts for 34% of the market. Compared to DES, it has a similar efficacy, outperforming some in other properties while still maintaining restenosis prevention. Many existing coatings lack the ability to provide beneficial mechanical strength while still ensuring restenosis is adequately addressed. By doing both, it offers a unique avenue to pursue.

restenosis is mainly 3-6 months
far out performs bms
many can’t provide mechanical strength as well as biocompatibility and restenosis prevention

Question 5

Is your chosen biomaterial similar to any existing FDA-approved materials from which any regulatory documentation required can be based? If so, elaborate; if not, what tests need to be done to get the chosen material to be FDA-approved?

Answer 5

• The copper IUD utilises a PE structure with copper wire wrapped around it, releasing copper ions into the environment. This is utilised as a more hostile environment by inducing an inflammatory response. While this is not the ideal reaction the device wants to induce, it can provide information regarding the limit of copper concentration and provide a guide to a safer dosage for coronary stents. Similar to Rosie’s material, this is not a coating, but rather a wrapping around a polymer structure, so there would require testing regarding the copper leaching and whether the ion concentration would vary with the one-pot method outlined by the dopamine-copper biomaterial we chose.

copper IUD
upper limit
wrapping rather than coating

Question 6

Does it have similar properties to existing biomaterials used in the industry to enable the use of existing manufacturing techniques without significant modifications or overhauls to the manufacturing process? If so, elaborate; if not, what infrastructure needs to be built to support the manufacture of your device with the new material?

Answer 6

• As mentioned by Rosie, this article utilises the one-pot method. After coating it with the copper ions and dopamine, it is dipped into another solution for the NO coatings. These are then ultrasonically rinsed with distilled water and dried with N2 gas. This specific coating method has been identified by a range of other articles currently in research, however it has not been industrialised yet. For the rinsing and drying, this is completed by some implant methods (e.g. many implants utilise the same rinsing and drying procedure). Therefore, in order to industrialise this coating, it would mainly focus on developing adequate solution structures to ensure accurate coatings.