Hierarchical 3D immunoassays – higher loading, lower fouling

Iain Larmour is a guest web writer for ChemSci. He has researched a wide variety of topics during his years in the lab including nanostructured surfaces for water repellency and developing nanoparticle systems for bioanalysis by surface enhanced optical spectroscopies. He currently works in science management. In his spare time he enjoys reading, photography, art and inventing.

If you are producing an immunoassay there are two key parameters you need to understand and optimise: surface structure and surface chemistry. Get these two parameters right and you will optimise the sensitivity of your immunoassay. 

Although there have been a multitude of 3D surface generation routes reported, they are generally complicated and require a lot of additional steps. Although these 3D surfaces lead to high probe loading levels they also often lead to high levels of non-specific protein absorption, undoing any good the surface structure would have led to. 

Jinghua Yin and team from the State Key Laboratory of Polymer Physics and Chemistry at the Changchun Institute of Applied Chemistry have focussed on both properties to generate a much improved immunoassay. 

 Firstly they generated a 3D surface using UV irradiation of polystyrene spheres onto a substrate; they then grafted polymer brushes to the sphere surface. The polymer brushes not only further increased the surface area (more than doubling it from the bare sphere surface) but also acted as an anti-fouling agent, reducing the amount of non-specific binding observed by up to 90%. 

Antibody loading on different surface types showing increasing loading levels


The commonality of the functional groups on the polymer brushes mean that any antibody can be attached to the prepared surface. To find out the details of how to make these surfaces and try them out on your own immunoassays, read the paper today!

To read the details, check out the ChemComm article in full:
Facile fabrication of microsphere-polymer brush hierarchically three-dimensional (3D) substrates for immunoassays
Jiao Ma, Shifang Luan, Lingjie Song, Shuaishuai Yuan, Shunjie Yan, Jing Jin and Jinghua Yin
Chem. Commun., 2015, 51, 6749-6752
DOI: 10.1039/C5CC01250C

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