Colorectal and prostate cancers are major causes of cancer-related death, with early detection key to increased survival. However, as symptoms occur during advanced stages and current diagnostic methods have limitations, there is a need for new fluorescent probes that remain bright, are biocompatible and can be targeted. Conjugated polymer nanoparticles have shown great promise in biological imaging due to their unique optical properties. We have synthesised small, bright, photo-stable CN-PPV, nanoparticles encapsulated with poloxamer polymer and a thin silica shell. By incubating the CN-PPV silica shelled cross-linked (SSCL) nanoparticles in mammalian (HeLa) cells; we were able to show that cellular uptake occurred. Uptake was also shown by incubating the nanoparticles in RWPE-1, WPE1-NB26 and WPE1- NA22 prostate cancer cell lines. Finally, HEK cells were used to show the particles had limited cytotoxicity.
We demonstrateWide-Field Time-Correlated Single Photon Counting (WiFi TCSPC) imaging based on an image
intensifier and a high-speed camera running at 30,000 frames per second. The timing of photon events is thus
performed in parallel, simultaneously on every pixel. The system is applied to lanthanide lifetime measurements
and time-resolved imaging of the lanthanide complex Europium Polyoxometalate (Eu POMs). We measure a
lifetime of 2.98 ms for Eu POMs in solid state, which is in excellent agreement with the literature value.
Fluorescence imaging techniques are powerful tools in the biological and biomedical sciences, because they are
minimally invasive and can be applied to live cells and tissues. The fluorescence emission can be characterized not only
by its intensity and position, by also by its fluorescence lifetime, polarization and wavelength. Fluorescence Lifetime
Imaging (FLIM) in particular has emerged as a key technique to image the environment and interaction of specific
proteins in living cells. Using a time-correlated single photon counting (TCSPC)-based FLIM set-up, we find that the
fluorescence lifetime of GFP-tagged proteins in cells is a function of the refractive index of the medium the cells are
suspended in. In addition, combining Fluorescence Recovery After Photobleaching (FRAP) of fluorescently labeled
proteins of different sizes in sol gels with time-resolved fluorescence anisotropy measurements, we demonstrate that we
can measure their lateral and rotational diffusion. This allows us to infer the size and connectivity of the pores in the sol
gel matrix. Moreover, wide-field photon counting imaging, originally developed for astronomical applications, is a
powerful imaging method because of its high sensitivity and excellent signal-to-noise ratio. It has a distinct advantage
over CCD-based imaging due to the ability to time the arrival of individual photons. The potential of time-resolved wide-field
photon counting imaging with a fast CMOS camera applied to luminescence microscopy is demonstrated.
We present a novel time-resolved photon counting imaging technique and its use in multi-dimensional luminescence
spectroscopy. By using an ultrafast camera coupled to an image intensifier on a microscope, we demonstrate
the potential of wide-field time-correlated single photon counting, with a count rate of up to 5 Mhz. This system
has the advantage of allowing the detection of single photons in parallel in every pixel. We measured the
luminescence decay of Europium Polyoxometalate (POM), and observed contrast on lifetime images of Eu-POM
on silver nanocrystals.