Measuring the Mechanical Properties of Medical Tubings with FLEX-ANA

A number of medical devices include or consist of tubings, such as urological retrieval devices, infusion or injection sets, or catheters. It is essential to customize the surfaces of medical tubings for their specific application.

Polymeric coatings are capable of assisting functional requirements such as improved wettability and lubrication, reduced blood coagulation, or enhanced anti-fouling properties. Mechanical properties that are similar to the typically soft biological tissue environment are also provided.

Mechanical testing at the nanoscale provides significant information related to the properties of polymeric coatings needed for both surface design and optimization.

Nanosurf Flex-ANA System

In this article, the Nanosurf Flex-ANA system was used to examine the mechanical properties of three varied medical tubings in one run. Two of the tubings were bearing varied polymeric coatings and one tubing was uncoated.

The sample’s overview image (Figure 1) displays the three pieces of tubing overlayed with the locations at which the system will conduct the mechanical testing experiments (numbered 1-12) in an automatic manner.

Optical sample overview image with predefined measurement locations.

Figure 1. Optical sample overview image with predefined measurement locations.

Elastic modulus is recorded on the varied medical tubings. The polymeric coatings render elastic moduli to the tubing surfaces that are orders of magnitude under the uncoated tubing. This modulus can be compared to that identified in soft biological tissue.

The pooled results of almost three varied areas probed on all tubings are shown by the histogram (Figure 2). Using a Nanosensors PPP-ContSCAuD cantilever, samples were both equillibrated and submerged in PBS buffer nanomechanical measurements.

Elastic modulus distribution of the three different medical tubings.

Figure 2. Elastic modulus distribution of the three different medical tubings.

AFM Capabilities

The Flex-ANA system retains its complete research AFM capabilities that enable recording e.g. the sample topography and determining the roughness of the sample. The bottom AFM topography was recorded on an uncoated tubing, while the top AFM topography matches with a coated tubing (Figure 3). The coating influences the sample roughness, and also influences the surface’s friction.

AFM topography recorded on different tubings

Figure 3. AFM topography recorded on different tubings

Recording AFM images was performed in dynamic mode with the samples placed submerged in PBS buffer. The Nanosurf Report Software was used to process the images.


In addition to using medical tubings in contemporary medical treatments of diseases and various other conditions, a variety of synthetic materials and devices come into contact with parts of the body. These devices include prostheses, renal dialyzers, vascular grafts, stents, and a wide range of other implants.

The surfaces of these devices that interact with biological material are expected to meet varied requirements based on the application. For implants that need to remain in the body for a prolonged time, surface coatings and surfaces must be customized to enhance biocompatibility and thus e.g. decrease unwanted blood coagulation or reduce foreign body response. The mechanical surface properties serve as a vital parameter for biocompatibility.

This information has been sourced, reviewed and adapted from materials provided by Nanosurf AG.

For more information on this source, please visit Nanosurf AG.

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