FRET for lab-on-a-chip devices - current trends and future prospects.

This review focuses on the use of Förster Resonance Energy Transfer (FRET) to monitor intra- and intermolecular reactions occurring in microfluidic reactors. Microfluidic devices have recently been used for performing highly efficient and miniaturised biological assays for the analysis of biological entities such as cells, proteins and nucleic acids. Microfluidic assays are characterised by nanolitre to femtolitre reaction volumes, which necessitates the adoption of a sensitive optical detection scheme. FRET serves as a strong 'spectroscopic ruler' for elucidating the tertiary structure of biomolecules, as the efficiency of the non-radiative energy transfer is extremely sensitive to nanoscale changes in the separation between donor and acceptor markers attached to the biomolecule of interest. In this review, we will review the implementation of various microfluidic assays which employ FRET for diverse applications in the biomedical field, along with the advantages and disadvantages of the various approaches. The future prospects for development of microfluidic devices incorporating FRET detection will be discussed.

Optical micromanipulations in the non-diffractive regime.

The ever-evolving topic of optical micromanipulation has established itself as a discipline over the last three decades, and is of much interest to a wide research community due to constantly emerging new applications across the various key disciplines. Performing optical manipulation using evanescent waves is termed near-field optical manipulation, which is essentially the manipulation of particles in the non-diffractive regime. The concept of the breaking of diffraction limit is the spur driving near-field optics studies, as opposed to all far field optical applications where light cannot be focused to a spot smaller than the diffraction limited value, which is about half the wavelength of light in the medium. The authors present a review of the various near-field optical manipulation techniques and then report on the observation of erythrocyte pearl chains by a near-field optical tweezer.