Functionalized nanoparticles for bioanalysis by SERRS.

Metallic nanoparticles can be used as basic materials for a wide variety of purposes including building blocks for nanoassemblies, substrates for enhanced spectroscopies such as fluorescence and Raman and as labels for biomolecules. In the present paper, we report how silver and gold nanoparticles can be functionalized with specific biomolecular probes to interact in a specific manner with a target molecule to provide a change in the properties of the nanoparticles which can be measured to indicate the molecular recognition event. Examples of this approach include DNA hybridization to switch on SERRS (surface-enhanced resonance Raman scattering) when a specific target sequence is present, the use of nanoparticles for in vivo SERRS imaging and the use of nanoparticles functionalized with antibodies to provide a new type of immunoassay. These examples indicate how nanoparticles can be used to provide highly sensitive and informative data from a variety of biological systems when used in combination with SERRS.

Combining functionalised nanoparticles and SERS for the detection of DNA relating to disease.

DNA functionalised nanoparticle probes offer new opportunities in analyte detection. Ultrasensitive, molecularly specific targeting of analytes is possible through the use of metallic nanoparticles and their ability to generate a surface enhanced Raman scattering (SERS) response. This is leading to a new range of diagnostic clinical probes based on SERS detection. Our approaches have shown how such probes can detect specific DNA sequences by using a biomolecular recognition event to 'turn on' a SERS response through a controlled assembly process of the DNA functionalised nanoparticles. Further, we have prepared DNA aptamer functionalised SERS probes and demonstrated how introduction of a protein target can change the aggregation state of the nanoparticles in a dose-dependant manner. These approaches are being used as methods to detect biomolecules that indicate a specific disease being present with a view to improving disease management.