Ever since their introduction two decades ago, single-molecule (SM) fluorescence methods have matured and branched out to address numerous biological questions, which were inaccessible via ensemble measurements. Among the current arsenal, SM fluorescence techniques have capabilities of probing the dynamic interactions of nucleic acids and proteins via Förster (fluorescence) resonance energy transfer (FRET), tracking single particles over microns of distances, and deciphering the rotational motion of multisubunit systems. In this exciting era of transitioning from in vitro to in vivo and in situ conditions, it is anticipated that SM fluorescence methodology will become a common tool of molecular biology.

A spinning disk confocal attachment is added to a full-field real-time frequency-domain fluorescence lifetime-resolved imaging microscope (FLIM). This provides confocal 3-D imaging while retaining all the characteristics of the normal 2-D FLIM. The spinning disk arrangement allows us to retain the speed of the normal 2-D full field FLIM while gaining true 3-D resolution. We also introduce the use of wavelet image transformations into the FLIM analysis. Wavelets prove useful for selecting objects according to their morphology, denoising and background subtraction. The performance of the instrument and the analysis routines are tested with quantitative physical samples and examples are presented with complex biological samples.

We constructed a DNA-based nanomechanical device called the nanometronome. Our device is made by introducing complementary single-stranded overhangs at the two arms of the DNA four-way junction. The ticking rates of this stochastic metronome depend on ion concentrations and can be changed by a set of DNA-based switches to deactivate/reactivate the sticky end. Since the device displays clearly distinguishable responses even with a single base pair difference, it may lead to a single molecule sensor of minute sequence differences of a target DNA.

The incidence of physiological and/or pathological defects in many fresh produce types is still unacceptably high and accounts for a large proportion of waste. With increasing interest in food security their remains strong demand in developing reliable and cost effective technologies for non-destructive screening of internal defects and rots, these being deemed unacceptable by consumers. It is well recognized that the internal defects and structure of turbid scattering media can be effectively visualized by using optical coherence tomography (OCT). In the present study, the high spatial resolution and advantages of OCT have been demonstrated for imaging the skins and outer laminae (concentric tissue layers) of intact whole onion bulbs with a view to non-invasively visualizing potential incidence/severity of internal defects.Example of typical OCT image (3×1.6 mm 2 ) through outer onion skin near the root region (basal plate -left hand side) The increasing global demand for high quality agricultural products is set to continue. With rising interest in food security in recent years their remains strong demand in developing both inexpensive and reliable technologies for non-destructive screening of internal defects and rots.A number of tomographic techniques such as computed X-ray tomography [1], positron emission tomography (PET) [2], ultrasound [3], or magnetic resonance imaging (MRI) [4] have been well established and have great advantages and potential over other non-invasive techniques in that they lend themselves to rapid screening of various fresh products including fruit and vegetables. However, many of the techniques described are too costly for routine practical use and, thus, suffer by being cost prohibitive.Due to the recent intense development of high technologies and miniaturization of solid-state optical/laser devices a number of new revolutionary applications have arisen. This area is commonly known as "Photonics" since it has many parallels to electronics. A more recent trend has been the mapping of these new technologies to the lifesciences and medicine, hence the name "Bio-photonics" was coined. Bio-photonics is proving to be a fast moving and very exciting area of research, which has the potential to offer new tools and diagnostic methods for life-sciences, health care and clinical requirements. Bio-photonic methods are fast/real-time and often non-contact, thus, offer-