Biocompatible Plating for Medical Use

Plating for implantable medical devices (implants) requires High-End Medical Biocompatibility. North America is the largest market, accounting for 44% of the global market in 2024, and the availability of technical data supporting FDA approval and compliance with ISO standards can significantly affect development timelines.

What Is Biocompatibility?

Biocompatibility is the property of a material that does not cause toxicity, inflammation, or allergic reactions in the body. For implants, the plated surface comes into direct contact with body fluids and tissues, so not only the base material but also the surface treatment itself must meet stringent safety requirements.

Plating Requirements for Implants

To ensure safety in the body, plating must meet all of the following requirements.

• Constituents of the plating must not leach into the body. (Nickel and other substances that pose toxicity risks are subject to regulation.)
• The plating must not corrode or degrade even after prolonged exposure to blood or physiological saline.
• The plating must not be recognized as a foreign body by the immune system or trigger excessive inflammation or rejection.
• The plating must maintain its physical and electrical properties throughout implantation periods ranging from several years to several decades.
• The plating must be free of pinholes and other defects that can initiate corrosion, and the coating thickness must be controlled to ensure uniformity.

Main Applications and Device Types

Depending on the anatomical site and intended purpose, the functional requirements for the plating, including its mechanical, electrical, and chemical properties, vary significantly.

Orthopedic Implants

Implants such as artificial hip joints, which must function under heavy loads for extended periods, must deliver the performance expected of a “mechanical component within the human body.” Both “corrosion and wear resistance” under severe frictional conditions and “affinity” that enables bonding with surrounding bone tissue are essential.

Cardiac Pacemakers and Implantable Electrodes

Devices that detect weak bioelectrical signals or deliver electrical stimulation require long-term “electrical stability.” Gold plating does not oxidize in body fluids and can maintain extremely low contact resistance, making it a critical surface treatment for medical electronic devices.

Dental Implants

Dental implants must function in a harsh oral environment where they are constantly exposed to saliva, temperature fluctuations, and high chewing forces. In addition to high corrosion resistance and esthetics, dental implants require a surface treatment that does not interfere with the osseointegration (bone bonding) of the underlying titanium or other substrate material.

Types of Plating with Excellent Biocompatibility

Note: The appropriate plating depends on the implantation site and applicable regulatory requirements. Expert input is required when developing detailed specifications.

Technical Data for a Smooth Approval Process

In medical device approval processes conducted by the FDA and other regulatory authorities, manufacturers are required not only to claim that a device is “safe,” but also to submit test data that objectively demonstrates its safety. Passing the following tests based on the ISO 10993 series is a prerequisite for commercialization.

• Cytotoxicity Test (ISO 10993-5): Evaluates damage to cells caused by plating constituents and leachables.
• Sensitization Test (ISO 10993-10): Assesses the risk of triggering an allergic reaction in the body.
• Metal Ion Release Test: Quantitatively measures the amount of metal ions released under simulated body fluid conditions.
• Corrosion Test: Demonstrates long-term electrochemical stability and corrosion resistance in simulated body fluid.
• Coating Thickness and Uniformity Data: Documents and verifies the uniformity of the plating layer on each product through non-destructive measurement and other methods.

Key Points When Requesting Plating Services

When requesting medical plating services, drawings alone are not enough. The key is sharing detailed information, including regulatory requirements, to prevent rework.

• Clearly identify the implantation site, implantation period, and tissues in contact, such as bone, blood, and nerves.
• Specify the applicable regulatory requirements and standards, such as ISO 10993, FDA requirements, and the MDR.
• Specify the required plating type, tight coating thickness tolerances, and the purity of the metals used.
• Confirm whether biocompatibility test data is available or can be provided.
• Define requirements for manufacturing lot control, cleanroom processing, and traceability documentation.