A Versatile Multichannel Instrument for Measurement of Ratiometric Fluorescence Intensity and Phosphorescence Lifetime.

Optical biosensing is being actively investigated for minimally-invasive monitoring of key biomarkers both and . However, typical benchtop instruments are not portable and are not well suited to high-throughput, real-time analysis. This paper presents a versatile multichannel instrument for measurement of emission intensity and lifetime values arising from luminescent biosensor materials.

Noninvasive Optical Assessment of Implanted Tissue-Engineered Construct Success .

Quantitative diffuse reflectance spectroscopy (DRS) was developed for label-free, noninvasive, and real-time assessment of implanted tissue-engineered devices manufactured from primary human oral keratinocytes (six batches in two 5-patient cohorts). Constructs were implanted in a murine model for 1 and 3 weeks. DRS evaluated construct success using optical absorption (hemoglobin concentration and oxygenation, attributed to revascularization) and optical scattering (attributed to cellular density and layer thickness).

Noninvasive Optical Assessment of Implanted Engineered Tissues Correlates with Cytokine Secretion.

Fluorescence lifetime sensing has been shown to noninvasively characterize the preimplantation health and viability of engineered tissue constructs. However, current practices to monitor postimplantation construct integration are either qualitative (visual assessment) or destructive (tissue histology). We employed label-free fluorescence lifetime spectroscopy for quantitative, noninvasive optical assessment of engineered tissue constructs that were implanted into a murine model.

Characterization of squamous cell carcinoma in an organotypic culture via subsurface non-linear optical molecular imaging.

Tristetraprolin (TTP) is an RNA-binding protein which downregulates multiple cytokines that mediate progression of head and neck squamous cell carcinoma (HNSCC). We previously showed that HNSCC cells with shRNA-mediated knockdown of TTP are more invasive than controls. In this study, we use control and TTP-deficient cells to present a novel subsurface non-linear optical molecular imaging method using a three-dimensional (3D) organotypic construct, and compare the live cell imaging data to histology of fixed tissue specimens.

Near-infrared-labeled peptide multimer functions as phage mimic for high affinity, specific targeting of colonic adenomas in vivo (with videos).

Background: Fluorescent-labeled peptides are being developed to improve the endoscopic detection of colonic dysplasia.

Objective: To demonstrate a near-infrared peptide multimer that functions as a phage mimic for in vivo detection of colonic adenomas.

Design: A peptide multimer was synthesized by using trilysine as a dendritic wedge to mimic the presentation of peptides on phage, and all peptides, including the multimer, were fluorescent-labeled with Cy5.

Future and advances in endoscopy.

The future of endoscopy will be dictated by rapid technological advances in the development of light sources, optical fibers, and miniature scanners that will allow for images to be collected in multiple spectral regimes, with greater tissue penetration, and in three dimensions. These engineering breakthroughs will be integrated with novel molecular probes that are highly specific for unique proteins to target diseased tissues. Applications include early cancer detection by imaging molecular changes that occur before gross morphological abnormalities, personalized medicine by visualizing molecular targets specific to individual patients, and image guided therapy by localizing tumor margins and monitoring for recurrence.

Targeted imaging of colorectal dysplasia in living mice with fluorescence microendoscopy.

We validate specific binding activity of a fluorescence-labeled peptide to colorectal dysplasia in living mice using a miniature, flexible, fiber microendoscope that passes through the instrument channel of an endoscope. The microendoscope delivers excitation light at 473 nm through a fiber-optic bundle with outer diameter of 680 µm to collect en face images at 10 Hz with 4 µm lateral resolution. We applied the FITC-labeled peptide QPIHPNNM topically to colonic mucosa in genetically engineered mice that spontaneously develop adenomas.

Longitudinal molecular imaging with single cell resolution of disseminated ovarian cancer in mice with a LED-based confocal microendoscope.

Purpose: We engineered a flexible fiber-optic microendoscope for longitudinal optical imaging studies in a mouse model of disseminated ovarian cancer.

Procedures: The microendoscope delivers 470 nm excitation light from a light-emitting diode through a fiber-optic bundle with outer diameter of 680 μm. Optics were optimized to maximize power and lateral resolution.