Adhesives hold together an enormous share of disposable and external medical hardware, from fluid-path connectors and filter housings to wearable sensor enclosures and diagnostic cartridges. For these components, bond strength alone is not the deciding factor. The adhesive and everything it releases during cure or aging must also clear biological safety testing, which shapes both the chemistry you can use and the way you qualify it.
What Biological Safety Testing Covers
Material safety for device components is evaluated against ISO 10993, a framework that breaks down by contact type and duration. For the externally communicating and surface-contact parts discussed here, the most relevant single test is ISO 10993-5, which screens an extract of the cured material for cytotoxicity, its effect on cultured cells. Sensitization and irritation testing under related parts of the standard follow for skin-contact hardware such as wearable housings.
An adhesive supplier can only certify the raw material. Incure’s Cyro-Weld CM-series cyanoacrylates and 5000-series UV-curable adhesives are formulated to meet ISO 10993-5, which gives the device maker a documented starting point. The finished device still has to be tested as a whole, because processing, sterilization, and adjacent materials all influence the result. Nothing here supports implantable or long-term tissue-contact use; that is a separate qualification path outside this scope, and no adhesive should be described as FDA-approved.
Sterilization Compatibility
Most disposable hardware is sterilized after assembly, and the method constrains adhesive choice.
Ethylene oxide gas is mild on polymers and works for nearly all cured adhesives. Gamma and electron-beam irradiation can embrittle some chemistries or shift color, so grades intended for that route are validated for a stated dose. Incure lists CM-series and 5000-series grades that are validated for EtO and Gamma sterilization. Steam and dry-heat cycles matter mainly for reusable hardware and put the tightest limit on chemistry.
Confirm the specific grade against your sterilization route before committing, and re-test bond strength on sterilized samples rather than assuming the datasheet value holds.
The Cure Chemistries in Use
UV and visible-light-curable acrylates cure in seconds under a lamp and stay liquid until then, which gives unlimited time to align parts. They suit transparent and translucent housings and connectors, and they pair with focused UV LED spot lamps for point cures or UV LED flood lamps for larger assemblies. Our comparison of UV glue versus epoxy for transparent bonding covers the optical trade-offs.
Cyanoacrylates cure in seconds from surface moisture and bond a wide range of plastics with no mixing. Low-viscosity grades wick into tight joints; gel grades bridge gaps. They are common for high-volume disposable assembly.
Epoxies and silicones fill out the range where a two-part structural bond or a soft, flexible seal is needed, though cure times are longer.
For help matching a chemistry to your substrates and sterilization route, Email Us with the component, the plastics involved, and the contact classification.
Documentation to Request From a Supplier
Before a grade goes anywhere near a production line, request the underlying test report, not just a one-line claim of compliance. A proper ISO 10993-5 report states the extraction ratio and solvent used, the cell line, and the pass/fail criterion applied, because a cytotoxicity result generated under mild extraction conditions does not automatically transfer to a more aggressive one.
Ask for the specific sterilization validation data as well: the dose or cycle parameters used for EtO or Gamma qualification, and whether mechanical properties were re-measured after that exposure rather than only before it. A grade validated at one Gamma dose is not automatically validated at a higher one some sterilization providers may run by default. Keep this documentation on file alongside your own device history record, since a device audit will typically ask for the adhesive’s supporting data directly rather than accepting a supplier’s marketing claim at face value.
Qualifying the Bond
Treat qualification as an ongoing program rather than a one-time checkbox. Adhesive lots can vary slightly batch to batch even within specification, and a device program that only ran biological testing once, on the first qualification lot, has no evidence that a later lot behaves the same way. Building periodic lot verification into your supplier agreement, even a lighter-touch confirmation than the full battery of original testing, closes that gap.
Build a test plan that mirrors production. Bond real substrates with the real process, sterilize them by your intended method, age a subset, and then pull-test against your acceptance limit. Record the cure dose or fixture time you used, because biological and mechanical results are only valid for that process window.
Working With Incure
Incure supplies Cyro-Weld adhesives formulated for medical device component assembly, with grade documentation for ISO 10993-5 and for EtO and Gamma sterilization. Contact Our Team for grade data sheets, samples, and support building your qualification plan.
Visit www.incurelab.com for more information.