Grown diamonds—specifically lab-grown polycrystalline diamond (PCD) and nanodiamonds—are at the cutting edge of MedTech.
1. Key Properties of Lab-Grown Diamonds
The reason diamond is favored for internal devices lies in its unique physical and chemical profile:
Extreme Biocompatibility: Diamond is made of pure carbon, the same building block as human life. The body generally does not recognize it as a “foreign” object, which significantly reduces the risk of inflammation, rejection, or allergic reactions.
Zero Wear Debris: Traditional implants (like hips and knees) use metal or plastic. Over time, these grind together, releasing microscopic particles called “wear debris” into the bloodstream. Diamond is so hard (10 on the Mohs scale) that it virtually never wears down, eliminating this risk.
Bio-inertness: It does not react with bodily fluids or corrode, a common issue with titanium or cobalt-chrome alloys over decades of use.
Tunable Conductivity: Unlike most stones, lab-grown diamonds can be “doped” (infused with other elements like boron) to conduct electricity. This allows them to act as electrodes that can stimulate nerves or sense biological signals.
2. Major Applications in the Body
Grown diamond technology is currently being applied in three primary areas:
Orthopedics & Spine
This is the most mature application. Synthetic diamond is used to create the “bearing surfaces” of artificial joints. Because of its low friction coefficient—similar to that of natural cartilage—diamond-on-diamond joints can theoretically last for 30+ years, potentially ending the need for “revision surgeries” in younger patients.
Neural & Retinal Implants
Because diamond can conduct electricity and is transparent, it is used in high-tech sensors.
Bionic Eyes: Diamond-based electrodes are used in retinal implants to stimulate the optic nerve.
Brain-Machine Interfaces: Diamond’s stability allows for long-term placement in the brain to monitor or treat conditions like Parkinson’s without the material degrading or causing scarring.
Cardiovascular Devices
Diamond-Like Carbon (DLC) coatings are applied to heart valves and stents. The diamond surface is so smooth that blood cells are less likely to stick to it, which reduces the risk of blood clots (thrombosis) and the need for heavy doses of blood-thinning medication.
3. Current Challenges
While the technology is revolutionary, it faces a few hurdles:
Manufacturing Complexity: Growing diamond onto a complex, curved shape (like a hip ball or a dental screw) is much harder than growing a flat sheet.
Cost: While lab-grown diamond is cheaper than natural diamond, the high-temperature reactors and specialized gases required for medical-grade growth still make these devices more expensive than traditional titanium versions.
Adhesion: Ensuring a thin diamond coating sticks permanently to a metal base without peeling (delamination) over 20 years of movement is a significant engineering feat.
Summary Table
| Feature | Impact on the Patient |
|---|---|
| Durability | Reduces the need for second "redo" surgeries. |
| Low Friction | Smoother, more natural joint movement. |
| Carbon-Base | Lowest possible risk of allergic reaction or rejection. |
| Electrical Pulse | Enables advanced "smart" implants like bionic eyes. |