How SEM analysis helps understanding new nanofiber applications

By Dr. Jasmin Zahn - Oct 26, 2017

How to transfer drugs into human bodies efficient and while doing that minimizing side effects, has been studied intensively, and many different techniques have been developed over the past few years. Electrospun nanofibers are one of such new systems that have attracted a lot of attention recently. This is thanks to the exceptional properties of these fibers: they have highly porous three-dimensional surfaces, a high surface-to-volume ratio, and interconnected porosity with tunable pore dimensions. Scanning electron microscopy (SEM) proved to be helpful as an analytical tool to understand how fiber properties can be altered and enhanced.

 

Discover extensive possibilities for the analysis of fiber morphologies 
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How nanofiber properties are shaped

Various electrospinning parameters modulate the fiber diameter and thickness. These two fiber characteristics are very important since they affect the controlled release profiles in a drug carrier application. In another blog on polymer nanocompositeswe have already demonstrated the use of SEM in fiber technology introducing you to the concept of nanofibers. In that example, chromatography was used on poly-(lactic acid) (PLA) nanofibers intended for pharmaceutical applications.

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Figure 1: Nanofibers imaged with a scanning electron microscope.


To improve the concept of nanofibers as drug carriers, the idea of multi-layered electrospun fibers was implemented, which enabled drugs to be released in a more controlled way. The idea behind preparing a multi-layered electrospun mesh is to get sustained molecular release for a prolonged period by controlling the drug mobility.

By locating the drug in the middle layer of the “sandwich” (between two adjacent electrospun layers), all layers have dedicated tasks. One layer can then control the kinetics of water uptake. This, in turn, promotes the sustained release of drug molecules through precise control in both degradation, as well as osmotic pressure.

 

Multi-layer nanofibers as drug carriers

In a recent publication Laha et al. (Sustained drug release from multi-layered sequentially crosslinked electrospun gelatin nanofiber mesh, Laha et al., Materials Science and Engineering: C, Volume 76, 1 July 2017, Pages 782-786showed electrospun gelatin nanofibers produced as a multi-layered mesh. These gelatin nanofibers were examined and characterized in terms of morphology, water resistivity, degradation, chemical and thermal stability. This was done to be able to alter and optimize their properties.

SEM and fiber morphology analysis

By observing the morphology of the fibers with a desktop SEM, Laha et al. were able to show how differently fibers are fused due to different lengths of crosslinking time. Due to careful analysis, their study gives a basic proof of concept for a systematic design of multi-layer nanofiber mesh of a cheap biopolymer (gelatin). Such nanofiber meshes can be used as a drug delivery vehicle for hydrophobic drugs with a desired signature of zero order release for long hours.

SEM provides extensive possibilities for the analysis of fiber morphologies; the available software can further analyze fiber properties in a semi-automated mode. If you are interested in an efficient and easy tool to measure your fibers, we recommend looking into our FiberMetric software. For more information and applications, you can download the free FiberMetric specification sheet here:

Download the FiberMetric software specification sheet


About the author

Dr. Jasmin Zahn is an Application Engineer at Thermo Fisher Scientific, the world leader in serving science. She is highly engaged in finding out more about the possibilities for Thermo Fisher Scientific products in various applications. In addition, Jasmin is active in sharing best practices with the outside world to encourage them to look outside their standard scope of use and to improve in their work.

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