Coatings for Needles and Invitro Diagnostic Probes

September 10 2021 bio-medical

invitro diagnostic header copy

We discuss coating small bore flow paths used in invitro diagnostics and learn about the benefits and performance of our coatings.

Coatings for Needles and Invitro Diagnostic Probes

SilcoTek’s coating technology has a long history of improving performance of very narrow
and precise instrumentation.  Our customers who manufacture probes understand
the importance of proper surface technology and are constantly looking for ways to enhance the performance of IVD flow paths.  Let's discuss coating performance and benefits of coating probes and other small bore flow paths.

In this blog post you will learn:

Coating Small Bore Surfaces

Needles-624623-editedWhy is SilcoTek able to coat small bore tubing and precision components?  Because our unique chemical vapor deposition process is performed in the gas phase, so even the smallest channels and tightest tolerances will be adequately coated.  We also have the ability to coat certain tube configurations internally-only, so we can assure even long tube lengths are coated.  Basically, if we can get our process gasses into the tube or expose the part surface to our process gas we're able to coat the part.  For long but extremely narrow tubes we'll restrict the tube length to be sure we're able to achieve the desired coating performance.  Even narrow bore needles can be coated!

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How We Tested Our Coating in Small Tubes

We proved coating aspect ratio capabilities by coating a 1/16" OD, .4mm ID tube with multiple bends both internally and externally.  After coating, the tube was cut open to examine the coating at the center-most point inside the tube.  In addition to the external coating on the tube, a quick visual inspection shows the vibrant purple-colored SilcoTek coating inside the narrow bore.  



The thickness of the coating throughout the tube was verified by a Filmetrics F40-Series Thin Film Analyzer and it was confirmed to meet our specifications.  SilcoTek coatings are not applied with line-of-sight processes that lead to inconsistent deposition and uncoated areas.  With our process, 100% of your parts are coated, even if the design is complex or the pathways or tortuous.  





About Dursan and the Benefits of Coating Flow Paths

Our Dursan coating has proven benefits to analysts in medical diagnostic, HPLC, and IVD applications. The Dursan® process is a chemically inert, silicon-based coating that improves corrosion resistance and reduces protein carryover, promoting more accurate test results as well as more thorough cleaning, disinfection, and sterilization processing.  Applying an inert, non reactive barrier coating to stainless steel surfaces prevents the interaction of stainless steel with potentially reactive or corrosive analyte materials. 

SilcoTek® solves common problems in medical diagnostics with stainless steel flow path surfaces and probes like:

• Poor performance caused by carryover of proteins
• High cost due to corrosion, especially from bleach
• Contamination from leaching of metal ions out of equipment
• Poor analytical sensitivity for challenging samples
• Downtime caused by frequent maintenance and cleaning

Learn more about how our coatings can benefit your process or products.  Read our introduction to CVD coatings.  

Learn More About Our Coatings Get SilcoTek 101

SilcoTek’s Dursan technology has been rigorously tested to ensure proper performance and  earned an NSF Certification and a USP Class VI Certification.  Performance benefits of a Dursan® coated surface for invitro diagnostic applications include:

  • Improve Cleaning - Dursan’s inert barrier reduces contamination and buildup of biological material, while making standard rinsing easier and more effective.
  • Easy Integration - Run processes as normal while enjoying the coating benefits. SilcoTek coatings hold up to steam and conform to parts, creating no appreciable changes to tolerances or surface morphology.
  • Enhance Performance - Improve diagnostic sensitivity by reducing non-specific protein binding and carryover.
  • Increase Efficiency - By improving corrosion and contamination problems, cleaning will be more effective and parts will need to be replaced less often.
  • Reduce Contamination - An inert barrier will prevent contamination commonly caused by the sample, the reagent, or ions leaching from probe metal.

Supporting Data

Dursan® has been tested under real world conditions and has shown consistent performance gains in inertness, contamination prevention, and corrosion resistance. 

We tested Dursan on commonly used substrates including alloy MP35N and stainless steel to demonstrate how a coated part will perform under various test conditions.  We found the Dursan coated surface reduced material binding, ion contamination, corrosion, and substrate adsorption when applied to common HPLC, medical diagnostic, and IVD flow paths surfaces.  Let's review some of the data.

Prevent Biologics and Protein Sticking on Metal


When trying to eliminate biologic material from a surface, Dursan showed a more effective reduction of protein loss than stainless steel and when combined with a washing step using a non-ionic surfactant, 100% of tested proteins were removed.

Get Our Latest Protein Analysis Whitepaper

Reduce Metal Ion Leaching and Contamination

ion leaching mp35n in methanol

SilcoTek measured metal ions leaching in methanol after a month of soaking to compare MP35N and SilcoTek coatings performance. Coated samples all showed less than 1 ppb metal ion content leached into the methanol, while MP35N measured significantly worse at roughly 12 ppb of metal ions.

Learn More About Coating Applications for HPLC

Prevent Bleach Corrosion and Variability


ASTM G31 72 hour comparative bleach immersion studies prove that Dursan significantly reduces the risk of corrosion in diagnostic probes, thus reducing any variability.

Get Our Corrosion Resistance Application Guide

Ensure Sensitive, Fast and Accurate Analysis

Tetracycline Broken HPLC Data

These chromatograms show Dursan-coated hardware outperforming stainless steel and titanium while measuring a tricky, chelating agent. In image B, the analysis is more sensitive and accurate while maintaining a faster response.

Get our Medical Diagnostics Application Guide

Enjoy Performance After Steam Sterilization

Dursan FTIR

FTIR analysis shows there was little significant change in material composition observable before (blue line) and after the autoclave exposure (red line) for the Dursan surface.  A slight increase in Si-OH functional groups accounts for ~10° decrease in DI water contact angle.

Get Our Coating Properties Quick Reference Guide

The data show that SilcoTek is able to effectively coat the internal surfaces of small bore tubing and intricate parts.  Additionally studies show that Dursan coated surface help to prevent carryover, contamination, and surface corrosion while improving test resolution.  We offer many other coatings designed to improve the performance of your products and process.  If our standard coatings don't fit your material performance needs, our technology group can tailor fit a coating for your application.

SilcoTek specializes in customizing our coatings for your application.  Instrument manufacturers only have to contact our Technical Service Team and discuss your performance needs.  Our staff will evaluate your needs and determine the best coating fit for your application.  

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