Journal: bioRxiv

Article Title: Preclinical shortwave infrared tumor screening and resection via pHLIP ICG under ambient lighting conditions

doi: 10.1101/2022.09.07.506973

Figure Lengend Snippet: A) A dedicated preclinical SWIR imager was adapted for ambient light imaging of pHLIP ICG. An LED controlled via an Arduino provided illumination like that of room lighting (<650 nm) within the enclosure. SWIR pHLIP ICG fluorescence was excited with an 808 nm laser and detected using an InGaAs sensor. Recorded images were then converted to tiff files in Fiji (ImageJ) where automated scripts performed image correction and analysis. B) Histogram response of the SWIR sensor without LED illumination, with the LED in a blue, green (BG) state and with the LED in a red, green, and blue (RGB) state. No significant difference was found between these states highlighting the detectors insensitivity to ambient lighting under these imaging conditions. C) The absorption profile of 100 μL of an 8 μM pHLIP ICG solution with (fluorescent) and without (essentially non-fluorescent) the presence of POPC-liposomes. The excitation wavelengths of NIR (745 nm) and SWIR (808 nm) systems are shown. D) The extended SWIR emission of pHLIP ICG in both low (no POPC) and highly (with POPC) fluorescent states.

Article Snippet: In vivo fluorescence imaging of pHLIP ICG was performed using a preclinical SWIR hyperspectral mouse imaging system (IR-VIVO & PHySpec, Photon Etc., Canada).

Techniques: Imaging, Fluorescence

Journal: bioRxiv

Article Title: Preclinical shortwave infrared tumor screening and resection via pHLIP ICG under ambient lighting conditions

doi: 10.1101/2022.09.07.506973

Figure Lengend Snippet: A) Left, quantification of the reported mean gray values of both the commercial NIR (IVIS, 745 Exc, 840 Em) and SWIR (808 nm Exc, 900 – 1700 nm Em) systems at exposure times from 1 – 0.1 ms. Images are taken from a 96 well plate with a single well containing 100 μL of an 8 μM pHLIP ICG solution in PBS containing 10% POPC-liposomes. Right, representative images of both modalities highlighting SWIRs improved sensitivity. B) Left, quantification of the reported mean gray values of both modalities when imaging through 5 mm of scattering tissue (raw chicken breast). Right, representative images of both modalities with SWIR capably imaging through tissue at 10 ms exposure times.

Article Snippet: In vivo fluorescence imaging of pHLIP ICG was performed using a preclinical SWIR hyperspectral mouse imaging system (IR-VIVO & PHySpec, Photon Etc., Canada).

Techniques: Imaging

Journal: bioRxiv

Article Title: Preclinical shortwave infrared tumor screening and resection via pHLIP ICG under ambient lighting conditions

doi: 10.1101/2022.09.07.506973

Figure Lengend Snippet: A) White light (WL, 1300 nm LED illumination) SWIR images of pHLIP ICG injected mice (0.5 mg/kg) at 1 hr post injection. The solid arrow indicates the ambient light source (LED). SWIR fluorescence images of injected mice (n = 4) at 10 ms exposure times under 808 nm excitation at 1, 24, 48, 72 and 96 hrs post pHLIP ICG injection. Images are thresholded to respective min and max values with mice positioned to show brightest fluorescence locations e.g., the liver at 1 hr and tumor at 48 hrs (ROI 2). The dotted arrow highlights a fluorescence reflection in the image. Regions of interest (ROIs) are shown by the dotted gray lines where 1 represents system noise, 2 the tumor values and 3 the body values. Negligible signal was detected from a control mouse, data not shown (non-injected, n=1). B) The signal to noise ratio (SNR) of the brightest point in dB from all mice from 1 to 96 hrs. A threshold of 5 dB was chosen for image acceptability. C) Comparative SWIR fluorescence values (10 ms exposure) from all mice comparing tumor and body fluorescence levels. Tumor fluorescence is retained up to 96 hrs with brighter fluorescence past 24 hrs. D) Contrast to noise ratios (CNR) in dB of the tumor to body SWIR fluorescence highlighting the increase in contrast past 24 hrs at exposure times of 10, 1 and 0.1 ms. Data from n = 4 biological replicates are shown in all cases aside from D, 24 hrs where only n = 1 value is shown for all. Mean and standard deviation are shown in all cases.

Article Snippet: In vivo fluorescence imaging of pHLIP ICG was performed using a preclinical SWIR hyperspectral mouse imaging system (IR-VIVO & PHySpec, Photon Etc., Canada).

Techniques: Injection, Fluorescence, Standard Deviation

Journal: bioRxiv

Article Title: Preclinical shortwave infrared tumor screening and resection via pHLIP ICG under ambient lighting conditions

doi: 10.1101/2022.09.07.506973

Figure Lengend Snippet: A) WL overlaid SWIR fluorescence images of post euthanasia resection via pHLIP ICG, 96 hrs post injection. In all cases the tumor is clearly delineated from the body. Mice are the same as those in . B) Quantified SNR of the resected tumors at all exposure times. C) Quantified CNR levels of the tumor compared to body fluorescence for all exposure times. Acceptable levels are defined by the 5 dB level in both graphs. Data for n = 4 biological replicates is shown in all cases along with the mean.

Article Snippet: In vivo fluorescence imaging of pHLIP ICG was performed using a preclinical SWIR hyperspectral mouse imaging system (IR-VIVO & PHySpec, Photon Etc., Canada).

Techniques: Fluorescence, Injection

Journal: bioRxiv

Article Title: Preclinical shortwave infrared tumor screening and resection via pHLIP ICG under ambient lighting conditions

doi: 10.1101/2022.09.07.506973

Figure Lengend Snippet: A) Representative SWIR pHLIP ICG images of the tumor, liver, kidneys, stomach, skin, and spleen post biodistribution. Images are thresholded to show signal from other organs. B) Decreasing SWIR fluorescence values of all organs from all mice. Endogenous signal values from a non-injected control mouse, have been respectively subtracted for each tissue type. The mean (gray bar), SEM (black bars) and individual values (n = 4, red dots) are shown in all cases. P values comparing the tumor to other tissues are shown for those in A). Organs are from mice used in and .

Article Snippet: In vivo fluorescence imaging of pHLIP ICG was performed using a preclinical SWIR hyperspectral mouse imaging system (IR-VIVO & PHySpec, Photon Etc., Canada).

Techniques: Fluorescence, Injection