Characterization of micrometer thick layers
of spin-coated chitin

Application Note #163


Multi-Parametric Surface Plasmon Resonance (MP-SPR) instruments
can measure optical properties and address surface interactions from
very thin films (down to Ångstroms) up to micrometer thick layers.
The measurement of thicker sensor coatings is based on a SPR
waveguide mode.
Micrometer thick chitin layers were spin-coated onto gold (Au) and
polystyrene (PS) substrates and subsequently assessed through
MP-SPR waveguide signal. Thickness and refractive index (RI) of chitin
layer were determined in dry and liquid conditions using the same
instrument set-up (Figure 1). The polymer thickness was almost 2 μm
in air but less than 200 nm in buffer and in addition it was thicker on
gold when compared to polystyrene. The affinity constant of a chitin
binding domain of Bacillus circulans (CBD-INN) was determined and
evidenced to be higher on chitin deposited on the polystyrene-coated
sensor when compared to chitin on gold. Additionally, split-intein
protein (INC-eGFP) affinity on CBD-INN was determined.

Recommended MP-SPR instruments for this application:


             green-tick.png            green-tick.png   green-tick.png   

Further reading


  • Do you want to see MP-SPR animation about thick layers? Click here.
  • See also AN#128 thickness and refractive index of thin films, AN#149 polymer characterization and AN#165 functionalized cellulose fiber to capture hormone residues from aqueous matrices.
  • Do you want to see how MP-SPR instruments work? Click here.

  • Do you want to see MP-SPR instruments comparison? Click here.

  • Here is the original publication.


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