A class of biocompatible upconverting nanoparticles (UCNPs) with largely amplified red-emissions was developed. The optimal UCNP shows a high absolute upconversion quantum yield of 3.2% in red-emission, which is 15-fold stronger than the known optimal β-phase core/shell UCNPs. When conjugated to aminolevulinic acid, a clinically used photodynamic therapy (PDT) prodrug, significant PDT effect in...

We report the Raman spectra of silicon nanowires (SiNWs) in a wide temperature range, between 2 K and 850 K. At room temperature we find a strong influence on the spectrum from applied laser excitation powers. These effects can be attributed a laser heated sample, leading to an inhomogeneous temperature distribution within the laser-spot. If the laser excitation power is small (below 100 μW) su...

It is often anticipated that two-photon excitation (TPE) laser scanning microscopy should improve cell survival and tissue penetration relative to conventional one-photon excitation (OPE) confocal scanning laser microscopy (CLSM). However few studies have directly compared live cell imaging using one- vs two-photon laser scanning microscopy. We have used calcein-loaded in situ chondrocytes with...

With a focus on low-cost and low-power consumption, a miniature laser-induced fluorescence (LIF) detection system was assembled using a 635 nm red diode laser as the excitation source and a photodiode element coupled with an operational amplifier for signal collection. The primary elements of the miniature system, namely the laser and the detection system, cost a combined $70 and required only ...

A novel fluorescence resonance energy transfer (FRET) system containing a two-photon absorbing dye and a nile red chromophore has been synthesized. Upon two-photon excitation by laser at 815 nm this molecule displays efficient energy transfer from the two-photon absorbing dye to the nile red moiety, with an 8-fold increase in emission compared to the model compound. Similarly, single-photon exc...

Reversible conformational changes have been photo-induced in the red fluorescent protein DsRed at low temperature by wavelength-selective laser irradiation. We have found two new fluorescent forms: a shifted-red (SR-) and a new green (G0-) form that absorb and emit, respectively, B14 nm to the red and B80 nm to the blue of the ‘mature’ red (R-) form present in an un-illuminated sample of DsRed....

The aim of this work was to characterizes, by the non-destructive technique based on laser-backscattering imaging analysis, effect pre-treatment with papain enzyme (1% w/w), action time (0, 3, 6 and 24 h at 4 °C) cooking (80 °C for 3 min) pork loin tenderness. Texture image analyses were run untreated treated samples, uncooked cooked samples. Images laser pattern generated meat surface decompos...

A homemade Static Light scattering studies has been used to determine angle resolved scattered intensity for different polarization states of the incident laser light. Classical light scattering set ups are being used to study morphological aspects of scatterers using simple set ups using low power lasers. Red blood cells form rather interesting as well as a challenging system for scattering ex...