The University of Southampton

Optical Biosensors & Biophotonics

Our research

Quantum dot switches for biomolecular sensing

Semiconductor quantum dots, such as ZnS-capped CdSe nanocrystals, are extremely attractive fluorescent probes for biosensing applications possessing: very high fluorescence yields, extinction coefficients several times higher than convention organic fluorophores, low photobleaching, but most importantly narrow, symmetric emission peaks (approx 25-35nm, full width at half maximum) which can be tuned as a function of the particle size. We have recently demonstrated that the emission of CdSe quantum dots linked to the 5’-end of a DNA sequence is efficiently quenched by hybridisation with a complementary DNA strand with a gold nanoparticle attached at the 3’-end; contact of the quantum dot and gold nanoparticle occurs.

Present activities include exploitation of the patterned surfaces for 

  • Biomolecular sensing of low copy numbers of DNA in integrated devices, (in collaboration with Prof. Tom Brown from Chemistry)
  • Self-assembly strategies for nanophotonic/electronic devices (in collaboration with Prof. Jeremy Baumberg from Physics)

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