Taking the Uncertainty out of Bioseparations

Test uncertainty is not acceptable in bioseparation life sciences and HPLC applications.  We found ways to minimize test errors and improve results. 

A bioinert sampling flow path is critical to consistent bioseparations in medical diagnostics and HPLC analysis.  But over time inert surfaces can degrade and test flow paths can corrode due to frequent rinse cycles from aggressive chemicals like bleach.  Additionally corroded and pitted surfaces are perfect hiding places for sticky compounds like proteins, making carryover and contamination a real concern.  Here are some tips on how to improve bioinert flow paths.

Key Factors To Consider When Selecting A Coating for Bioinert Applications

Stainless steel, a common medical diagnostic flow path material, is an active surface that can be prone to protein retention, adsorption and is prone to corrosion.  That's why various types of coatings have been used to improve the surface properties of medical diagnostic instruments for decades.  Fluoropolymers (PEEK, AF1600) are commonly used in flow paths but are not acceptable for high durability, complex or precision geometries, or small bore surfaces like needles, valves or fittings.  Instrument manufacturers have gone to great lengths to evaluate alternative materials to solve non specific protein binding, protein carryover, fouling and rust problems.  Manufacturers take into account several key factors when selecting a bioinert coating.

Factors to consider when selecting bioinert materials:

• Improved analytical sensitivity, eliminating interaction with metal
• Coating is nontoxic, inert and produced with environmentally friendly process.
• Prevents non-specific protein binding for many target proteins, preventing false positive results.
• Rust resistant and durable.
• Able to be applied to surfaces without changing part tolerance or performance.

Learn more about bioinert coatings.  Download our coatings guide.

An inert, non-stick, nontoxic, high durability carboxysilane CVD coating, like Dursan®, prevents protein binding, corrosion and fouling in bioseparation applications. A recent study by Abbott Laboratories in Applied Surface Science demonstrates the inertness performance and corrosion resistance of Dursan. 

Improve the bioinertness of your sample system.  

Read the Abbott Laboratories paper.

Comparative QCMD (quartz crystal microbalance  with dissipation monitoring) characterization of the Dursan coating shows significant reduction in protein surface retention, preventing carryover and potential false positive test results.  The graph below shows the Dursan surface (top line) returns to baseline weight after contact with the test protein analyte.  The bottom line shows the stainless steel surface retaining the protein sample and not returning to baseline weight; indicating retention of protein and protein sticking.  Read the entire paper.

How Corrosion Resistance Can Improve Bioinertness.
A pitted surface can impact analyte flow, hide trace contaminants and result in excessive maintenance or system failures. A carboxysilane material deposited by chemical vapor deposition prevents interaction with stainless steel surfaces while maintaining precision tolerances.  Improving rust resistance by an order of magnitude.  A high performance bioinert capable surface will benefit the flow path:

• Add reliable protection against pitting which can be a source of protein retention and carryover.

• Improve rust resistance of stainless steel.  Bleach is commonly used as a cleaning agent but is corrosive to stainless steel.  The coating should be inert as well as durable.

Comparative ASTM bleach immersion studies show Dursan ( a carboxysilane CVD coating) prevents surface attack by preventing interaction of corrosive analytes or cleaning agents with the surface; outperforming other coatings or stainless steel surfaces by an order of magnitude.
 
Prevent fouling.
Preventing buildup or fouling in flow paths will improve test accuracy and system flow performance.  Dursan facilitates surfactant rinse performance; eliminating the potential of contaminant buildup.  Benefits of an anti-fouling surface include:

• Proteins, blood, and bio-molecules should not stick to the coated surface.  
• A non-stick surface will improve analytical sensitivity and reliability
• Increase device/instrument uptime and overall efficiency.  
• Allow for easy and complete rinsing with a non-ionic surfactant.

Coat places most coatings can't reach.
Find a coating that can improve performance and work within HPLC system tolerance and architecture.  That means being able to coat flow path needles, tubing, fittings and precision components without changing the flow, function, or capability.  Benefits of precision coatings include:

♦  Can coat the interior and exterior of narrow bore needles, narrow tubing, complex component designs, etc.  Customers now have the ability to improve inertness and protect the entire sample flow path.   
♦  High tolerance coating does not significantly change part dimensions or tolerances.  The user can coat existing components and significantly improve performance without part redesign.

Coating Durability

Analytical instrumentation surfaces must be durable as well as inert.  The surface must survive hundreds of injections, abrasion, and surface wear while remaining non reactive.  Coatings must not flake or fail when the surface is flexed or suffers an impact.  Watch our durability video and see how inert CVD coatings withstand abrasion and wear.

Coating applications for optimizing bioseparation.

Typical applications for high durability inert coatings in bioinert applications include:

Dursan® offers three critical surface properties in one along with a chemical vapor deposition (CVD) coating process that makes application easy and effective even on complex geometry components.  

Learn more about bioinert coatings.  Download our coatings guide.