No abstract

Optical scattering coefficient from ex vivo unfixed normal and malignant ovarian tissue was quantitatively extracted by fitting optical coherence tomography (OCT) A-line signals to a single scattering model. 1097 average A-line measurements at a wavelength of 1310 nm were performed at 108 sites obtained from 18 ovaries. The average scattering coefficient obtained from the normal tissue group consisted of 833 measurements from 88 sites was 2.41 mm(-1) (± 0.59), while the average coefficient obtained from the malignant tissue group consisted of 264 measurements from 20 sites was 1.55 mm(-1) (± 0.46). The malignant ovarian tissue showed significant lower scattering than the normal group (p < 0.001). The amount of collagen within OCT imaging depth was analyzed from the tissue histological section stained with Sirius Red. The average collagen area fraction (CAF) obtained from the normal tissue group was 48.4% (± 12.3%), while the average CAF obtained from the malignant tissue group was 11.4% (± 4.7%). A statistical significance of the collagen content was found between the two groups (p < 0.001). These results demonstrated that quantitative measurements of optical scattering coefficient from OCT images could be a potential powerful method for ovarian cancer detection.

Fluorescence from fluorophores embedded in a turbid medium like biological tissue gets strongly modulated by the wavelength dependent absorption and scattering properties of tissue. This makes it extremely difficult to extract valuable biochemical information from tissue which is present in the intrinsic line shape and intensity of fluorescence from tissue fluorophores. We present an experimental approach to remove the distorting effect of scattering and absorption on intrinsic fluorescence of fluorophores embedded in a turbid medium like tissue. The method is based on simultaneous measurement of polarized fluorescence and polarized elastic scattering spectra from a turbid medium. The polarized fluorescence normalized by the polarized elastic scattering spectra (in the wavelength range of fluorescence emission) was found to be free from the distorting effect of absorption and scattering properties of the medium. The applicability range of this technique to recover intensity and line shape information of intrinsic fluorescence has been investigated by carrying out studies on a variety of tissue phantoms having different absorption and scattering properties. The results obtained show that this technique can be used to recover intrinsic line shape and intensity information of fluorescence from fluorophores embedded in a scattering medium for the range of optical transport parameters typically found in biological tissue.

Aim We report a magneto-fluorescent theranostic nanocomplex targeted to neutrophil gelatinase associated lipocalin (NGAL) for imaging and therapy of pancreatic cancer. Materials and Methods Gold nanoshells resonant at 810 nm were encapsulated in silica epilayers doped with iron oxide and the NIR dye ICG, resulting in theranostic gold nanoshells (TGNS), which were subsequently conjugated with antibodies targeting NGAL in AsPC-1-derived xenografts in nude mice. Results AntiNGAL-conjugated TGNS specifically targeted pancreatic cancer cells in vitro and in vivo providing contrast for both NIR fluorescence and T2 weighted MR imaging with higher tumor contrast than can be obtained using long-circulating but non-targeted PEGylated nanoparticles. The nanocomplexes also enabled highly specific cancer cell death via NIR photothermal therapy in vitro. Conclusions Theranostic gold nanoshells with embedded NIR and MR contrasts can be specifically targeted to pancreatic cancer cells with expression of early disease marker NGAL, and enable molecularly targeted imaging and photothermal therapy.

Six free base tetrapyrrolic chromophores, three quinoline-annulated porphyrins and three morpholinobacteriochlorins, that absorb light in the near-IR range and possess, in comparison to regular porphyrins, unusually low fluorescence emission and 1O2 quantum yields were tested with respect to their efficacy as novel molecular photo-acoustic imaging contrast agents in a tissue phantom, providing an up to ~2.5-fold contrast enhancement over that of the benchmark contrast agent ICG. The testing protocol compares the photoacoustic signal output strength upon absorption of approximately the same light energy. Some relationships between photophysical parameters of the dyes and the resulting photoacoustic signal strength could be derived.