The ability to directly monitor biomolecular interactions (e.g. DNA-DNA, RNA-DNA, protein-protein) in real-time is of great importance to many areas of biology and medicine. At the cellular level, very few molecules can be responsible for inducing a significant biological response and there remains an urgent need for highly sensitive optical methods able to both identify and spatially track multiple target biomolecules simultaneously in complex and dynamic biological environments. To address this challenge we propose to develop a unique multi-imaging platform capable of monitoring large numbers of individual, freely moving nanoparticles and monitoring their interactions with target molecules and other nanoparticles. This new technology will initially be applied to the multiplexed detection of microRNAs with the distinct advantage of not requiring either target pre-modification or subsequent amplification steps to achieve the sensitivities necessary for the direct analysis of genomic RNA samples. The research takes advantage of the electronic properties of metallic nanoparticles that are associated with greatly enhancing the intensity of various types of spectroscopic signals such as scattering, Raman and fluorescence. These signals are highly responsive to changes in the immediate environment around each nanoparticle with Raman in particular providing a molecular fingerprint useful for identification. However, typical investigations involve applying only one of these spectroscopic modalities and either looking at select individual particles immobilised on a surface or acquiring an ensemble-averaged spectrum of the bulk sample. Imaging is a particularly powerful and intuitive approach for investigating complex systems. The radically different multi-spectroscopic methodology proposed here enabling the high-throughput visualisation of individual particles along with rapid optical discrimination between different particles sizes and clusters is expected to have a far-reaching impact. In addition to creating a powerful tool for bioanalytical investigation, this research will open up significant new opportunities to physicists, chemists and engineers interested in the functionalisation and assembly of nanoparticles to create next generation materials and devices.