Current techniques for mimicking the Blood-Brain Barrier (BBB) largely use incubation chambers (Transwell) separated with a filter and matrix coating to represent and to study barrier permeability. These devices have several critical shortcomings; (a) they do not reproduce critical microenvironmental parameters, primarily anatomical size or hemodynamic shear stress, (b) they often do not provide real-time visualization capability, and (c) they require a large amount of consumables. To overcome these limitations, we have developed a microfluidics based Synthetic Microvasculature model of the Blood-Brain Barrier (SyM-BBB). The SyM-BBB platform is comprised of a plastic, disposable and optically clear microfluidic chip with a microcirculation sized two-compartment chamber. The chamber is designed in such a way as to permit the realization of side-by-side apical and basolateral compartments, thereby simplifying fabrication and facilitating integration with standard instrumentation. The individually addressable apical side is seeded with endothelial cells and the basolateral side can support neuronal cells or conditioned media. In the present study, an immortalized Rat Brain Endothelial cell line (RBE4) was cultured in SyM-BBB with a perfusate of Astrocyte Conditioned Media (ACM). Biochemical analysis showed upregulation of tight junction molecules while permeation studies showed an intact BBB. Finally, transporter assay was successfully demonstrated in SyM-BBB indicating a functional model.

Tumor drug delivery is a complex phenomenon affected by several elements in addition to drug or delivery vehicle’s physico-chemical properties. A key factor is tumor microvasculature with complex effects including convective transport, high interstitial pressure and enhanced vascular permeability due to the presence of “leaky vessels”. Current in vitro models of the tumor microenvironment for evaluating drug delivery are oversimplified and, as a result, show poor correlation with in vivo performance. In this study, we report on the development of a novel microfluidic platform that models the tumor microenvironment more accurately, with physiologically and morphologically realistic microvasculature including endothelial cell lined leaky capillary vessels along with 3D solid tumors. Endothelial cells and 3D spheroids of cervical tumor cells were co-cultured in the networks. Drug vehicle screening was demonstrated using GFP gene delivery by different formulations of nanopolymers. The synthetic tumor network was successful in predicting in vivo delivery efficiencies of the drug vehicles. The developed assay will have critical applications both in basic research, where it can be used to develop next generation delivery vehicles, and in drug discovery where it can be used to study drug transport and delivery efficacy in realistic tumor microenvironment, thereby enabling drug compound and/or delivery vehicle screening.

No abstract

Beamline 11.3.1 at the Advanced Light Source is a tender/hard (6-17 keV) X-ray beamline recently repurposed with a new full-field, nanoscale transmission X-ray microscope (nTXM). The endstation is suited to 50-250 µm samples of (generally) non-biological materials and has a theoretical resolution of 55 nm. The microscope is used in tandem with a 25 nm eccentricity rotation stage for high-resolution volume imaging using nanoscale computed tomography (nCT). The system also features a novel bipolar illumination condenser for the illumination of a ~100 µm spot of interest of the sample, followed by a phase-type zone plate magnifying objective with a ~52 m field of view, and a phase detection ring. The zone plate serves as the system objective and magnifies the sample with projection onto an indirect X-ray detection system, consisting of a polished single crystal CsI(Tl) scintillator and a range of high-quality plan fluorite visible light objectives that in turn project the final visible light image onto a water-cooled CMOS 2048x2048 pixel 2 detector. Here we will discuss the salient features of this instrument, and describe our initial efforts to experimentally observe the internal 3D micro-and nanostructure of some highlighted materials, including composites and rocks.