Localized Surface Plasmon Resonance TheoryLocalized Surface Plasmon Resonance vs. Surface Plasmon Resonance
How is LSPR Different from SPR?
Localized surface plasmon resonance is generated by metal nanoparticles, typically gold and silver, as compared to a continuous film of gold as used in traditional SPR.
Localized surface plasmon resonance is generated by metal nanoparticles, typically gold and silver, as compared to a continuous film of gold as used in traditional SPR. LSPR produces a strong resonance absorbance peak in the visible range of light, with its position being highly sensitive to the local refractive index surrounding the particle. Therefore, OpenSPR measures small changes in the wavelength of the absorbance position, rather than the angle as in traditional SPR.
- The optical hardware needed for LSPR is much less complex since no prism is needed to couple the light, so the instrument can be made smaller and more affordable
- Since the angle is not important, the instrument is much more robust against vibration and mechanical noise
- LSPR is not as sensitive to bulk refractive index changes, which causes errors in experimental data, because it has a much shorter electromagnetic field decay length
- No strict temperature control is needed, simplifying the instrument
- The sensor chips can be manufactured at a much more affordable price
- Easier to use and maintain
The smaller decay length of SPR versus LSPR is illustrated in the image below. This smaller sensing volume means that LSPR is more sensitive to molecular binding and less sensitive to bulk effects. The smaller decay length and sensitivity associated with LSPR reduces artifacts caused by external variables such as temperature drift or buffer refractive index changes.