OBJECTIVE: To compare spatial distributions of radiopaque glass (RG) microspheres, tris-acryl gelatin (TAG) microspheres, and polyvinyl alcohol (PVA) nonspherical foam particles within a planar in vitro microvascular model of the hyperplastic hemiprostate.
METHODS: A microvascular model simulating hyperplastic hemiprostate was perfused with a water-glycerin mixture. A microcatheter was positioned distal to the model\'s prostatic artery origin, and embolic particles (RG, 50 μm, 100 μm, and 150 μm; TAG, 100-300 μm and 300-500 μm; and PVA, 90-180 μm and 180-300 μm) were administered using a syringe pump. Microscopic imaging and subsequent semantic segmentation were performed to quantify particle distributions within the models. Distal penetrations were quantified statistically via modal analysis of the particle distributions.
RESULTS: Maximum distal penetration was observed for RG microspheres of 50 μm, followed by RG microspheres of 100 μm and then TAG microspheres of 100-300 μm and RG microspheres of 150 μm. TAG microspheres of 300-500 μm, PVA particles of 90-180 μm, and PVA particles of 180-300 μm exhibited the lowest distal penetrations. The distal penetration metrics between groups were significantly different (P < .05) except between TAG microspheres of 100-300 μm and RG microspheres of 150 μm and between PVA particles of 90-180 and 180-300 μm.
CONCLUSIONS: Comparing the spatial distributions of embolic particles in an in vitro microvascular model simulating the hyperplastic hemiprostate revealed that noncompressible particles and those with narrower size calibrations and smaller relative diameters exhibited higher degrees of distal packing. The embolization front was less distinct for particles with wider size calibrations, which resulted in smaller, more distal emboli along with larger, more proximal emboli. Both PVA particles and TAG microspheres of 300-500 μm exhibited relatively low overall distal penetration.

We developed a dual-compartment neurofluidic system with inter-connecting microchannels to connect neurons from their respective compartments, placed on a planar microelectrode arrays. The design and development of the compartmented microfluidic device for neuronal cell culture, protocol for sustaining long-term cultures, and neurite growth through microchannels in such a closed compartment device are presented. Using electrophysiological measurements of spontaneous network activity in the compartments and selective pharmacological manipulation of cells in one compartment, the biological origin of network activity and the fluidic isolation between the compartments are demonstrated. The connectivity between neuronal populations via the microchannels and the crossing-over of neurites are verified using transfection experiments and immunofluorescence staining. In addition to the neurite cross-over to the adjacent compartment, functional connectivity between cells in both the compartments is verified using cross-correlation (CC) based techniques. Bidirectional signal propagation between the compartments is demonstrated using functional connectivity maps. CC analysis and connectivity maps demonstrate that the two neuronal populations are not only functionally connected within each compartment but also with each other and a well connected functional network was formed between the compartments despite the physical barrier introduced by the microchannels.