Cytotoxicity Testing

Q: Are single-use medical devices coated?

Yes, many single-use medical devices are coated — especially when performance, sterilization resistance, or biocompatibility is required. Coatings such as biocompatible chromium (like Armoloy ME-92), PTFE, and Parylene are commonly used depending on the application. ME-92 is typically used on reusable surgical tools, but may also be applied to high-performance single-use components requiring ISO 10993 compliance.

Q: Can welded areas of a component be ME-92 coated?

Yes, ME-92 can be applied to welded areas of components, provided the surface is properly prepared to ensure adhesion. The coating uniformly covers complex geometries and bonded seams, making it suitable for assembled or fabricated medical tools.

Q: What are the benefits of biocompatible coatings for surgical instruments?

Biocompatible coatings like ME-92 enhance surgical instruments by reducing friction, resisting corrosion, improving sterilization compatibility, and minimizing cytotoxic risk — all contributing to better performance and patient safety.

Q: Why would a disposable medical instrument be coated?

Disposable medical instruments may be coated to enhance cutting efficiency, ensure temporary biocompatibility, or prevent corrosion during use. When performance and sterility are critical even for single-use items, coatings like ME-92 provide essential protection.

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What is Cytotoxicity?

Cytotoxicity is the ability of a material to cause damage to living cells. For medical devices—especially those intended for direct or indirect contact with tissue or fluids—assessing cytotoxicity is critical to ensure that no toxic substances leach from the material and harm surrounding cells.

Cytotoxicity testing is part of the biological evaluation of medical devices under ISO 10993-5 standards. A cytotoxic reaction can lead to inflammation, poor healing, or implant failure, so proving non-cytotoxicity is essential for regulatory approval and patient safety.

What is a Cytotoxicity Test?

A cytotoxicity test evaluates whether a material (or its extract) causes cell death or damage when introduced to cultured mammalian cells. In this study, ME-92 was tested using the ISO Elution Method, which involves:

Preparing a test extract in culture medium (1X MEM)
Dosing cultured L-929 mouse fibroblast cells with the extract
Incubating for 48 hours at 37°C in 5% CO₂
Observing cell morphology, growth, and lysis under a microscope

The response is graded on a scale from 0 (no reactivity) to 4 (severe reactivity). A grade of 2 or below is considered non-cytotoxic.

ME-92 Cytotoxicity Study Summary

ME-92’s thin dense chrome coating applied to 304 stainless steel (Lot #38408) was tested by NAMSA, an ISO 13485- and ISO 17025-accredited laboratory.

Test Result: Grade 0 – No cell damage, lysis, or morphological changes
Control Performance: All controls functioned as expected, validating the test
pH Observation: No shift, indicating a stable and non-reactive environment

This confirms ME-92 is non-cytotoxic, safe for cell-contact environments, and compliant with ISO 10993-5 testing requirements.

Why Cytotoxicity Matters

Cytotoxicity testing confirms that ME-92 coatings do not release harmful substances into the body. This ensures material safety for surgical, implantable, or other medical devices—contributing to better healing, reduced complications, and stronger patient outcomes.