Video-rate imaging of microcirculation with single-exposure oblique back-illumination microscopy

Abstract

Abstract. Oblique back-illumination microscopy (OBM) is a new technique for simultaneous, independent measurements of phase gradients and absorption in thick scattering tissues based on widefield imaging. To date, OBM has been used with sequential camera exposures, which reduces temporal resolution, and can produce motion artifacts in dynamic samples. Here, a variation of OBM that allows single-exposure operation with wavelength multiplexing and image splitting with a Wollaston prism is introduced. Asymmetric anamorphic distortion induced by the prism is characterized and corrected in real time using a graphics-processing unit. To demonstrate the capacity of single-exposure OBM to perform artifact-free imaging of blood flow, video-rate movies of microcirculation in ovo in the chorioallantoic membrane of the developing chick are presented. Imaging is performed with a highresolution rigid Hopkins lens suitable for endoscopy.

Cardio-respiratory development in bird embryos: new insights from a venerable animal model

“…Indeed, as we identify similarities between all vertebrates from molecular to organismal levels, the use of the bird embryo continues to expand, including animal modeling for areas as diverse as nonclinical safety studies of pharmaceuticals and vaccines (Saw et al, 2008;Bjornstad et al, 2015) to toxicology (Kopf and Walker, 2009;Smith et al, 2012) to prototyping surgical and measurement apparatus (Filas et al, 2011;Ford and Mertz, 2013;Lee and Ha, 2013). Moreover, the structure of the bird embryo within its egg has allowed focus on specific organs, such as the chorioallantoic membrane (Branum et al, 2013;Nowak-Sliwinska et al, 2014;Yuan et al, 2014), or on large specific and circumscribed energy and nutrient pools, such as albumin and yolk (Williams, 1994;Dzialowski et al, 2009;Nangsuay et al, 2015).…”

Vascular Fragility and the Endothelial Glycocalyx in the Tissues Lining the Healthy Gingival Crevice

“…This enhances the phase contrast of the images and produces a pseudo‐relief image. The technique is similar to back‐illuminated microvascular imaging described using a Hopkins lens 26 …”

Imaging human blood cells in vivo with oblique back-illumination capillaroscopy

“…Recently, epi-illumination gradient light interference microscopy (epi-GLIM) demonstrated tomographic reconstructions of thick, scattering biological specimens, though at an imaging speed of only 4 Hz [16]. In 2012 Ford et al introduced oblique back-illumination microscopy (OBM), a technique that enables phase contrast in thick, turbid media with epi-illumination, which was further developed for video-rate acquisition and quantitative reconstruction [17][18][19]. The offset of illumination and detection axes produces an intensity gradient across the imaging field of view, and results in phase contrast due to the net oblique orientation of light backscattered through the focal plane.…”