Nanoparticle-based colormetric biosensors allow onsite, real-time qualitative or semi-quantitative detection without complicated analytical instruments. Their applications include environmental testing, industrial process monitoring, biomedical diagnostics and biodefense among others. Few biosensors currently permit simultaneous detection of multiple analytes within a single sample.
This invention allows detection of multiple molecules in the same solution. Quantum dots are fluorescent semiconductor nanocrystals. Quantum dots have an advantage over traditional organic fluorophores because under the same excitation light, difference emission wavelengths can be obtained based on the size and composition of quantum dots.
The emission of quantum dots was quenched in aggregates by incorporating quantum dots into gold nanoparticle aggregates linked by DNA aptamers. The addition of target molecules such as adenosine can disassemble the nanoparticle aggregates and thus increase the distance between gold nanoparticles and quantum dots, resulting in increased emission.