Tissue Engineering And Nanotheranostics

b2815 Tissue Engineering and Nanotheranostics “9.61x6.69”

174 Tissue Engineering and Nanotheranostics

5.2. Particle Plasmon-Coupled Localized Surface

Plasmon Resonance

Advances in DNA nanotechnology allow us to organize nanoparticles

with specific distance, and this distance change also affects their plas­

monic effect. For example, when two plasmonic particles approach

each other within one particles’ diameter, these particles’ plasmon

couples, resulting in enhancing the electromagnetic field between two

nanoparticles and a visible red­shift in the scattering spectral.

Therefore, DFM and Rayleigh spectroscopy find great applications in

determination of the distance between each other.

5.2.1. Applications in assembles and disassembles

Taking advantage of the color change of AuNPs solution from red to

blue caused by the aggregation of AuNPs,126–128 Fan et al. developed

a series of aptamer sensors to exploit interactions between aptamers

and AuNPs by observing its color change, such as potassium ion­

specific G­quartet probe, T­rich DNA probe, C­rich DNA probe,

anti­ATP aptamer and anticocaine aptamer.129–131 For example, Fan

et al. developed a biosensor assay based on cocaine–AuNPs to identify

cocaine in latent fingerprints (LFPs).^132 Briefly, two pieces of rationally

engineered anticocaine aptamers were attached to different AuNPs.

The presence of cocaine in LFPs, working as a molecular linker,

induces the aggregation of AuNPs by reassembling the two pieces of

aptamers, resulting in green­to­red color change of the scattered light

in DFM images (Fig. 4). This strategy provides a quasi­quantitative

method to identify cocaine loadings in LFPs. Similarly, Long’s group

designed a sensor through the status of AuNPs aggregation to moni­

tor Cu+­catalyzed click reaction at the single­nanoparticle level by

DFM.^133 By contrast, Lee and the coworkers applied a core­satellite

nanoassembled substrate for colorimetric biomolecular detection

through red­to­green changes in the DFM images.^134 In the presence

of target biomolecules, the core­satellite nanoassembled substrate dis­

assembled and a blue shift in the spectrum was demonstrated by

DFM. Furthermore, stepwise peak shifts in LSPR were monitored by