Modular Assembly of Metamaterials Using Light Gradients.

This is a report on a pilot study that tests the feasibility of assembling photonic metamaterials (PMs) using light gradient forces. Following a strategy that works like modular construction, light gradient forces, produced by a tightly focused, one-dimensional standing wave optical trap (SWOT), time-multiplexed across a two-dimensional lattice were used to assemble voxels consisting of prefabricated, monodispersed nanoparticles (NPs) with radii ranging from 30 to 500 nm into three-dimensional structures on a hydrogel scaffold. Hundreds of NPs can be manipulated concurrently into a complex heterogeneous voxel this way, and then the process can be repeated by stitching together voxels to form a metamaterial of any size, shape, and constituency although imperfectly. Imperfections introduce random phase-shifts and amplitude variations that can have an adverse effect on the band structure. Regardless, PMs were created this way using two different dielectric NPs, polystyrene and rutile, and then the near-infrared performance for each was analyzed with angle-, wavelength-, and polarization-dependent reflection spectroscopy. The cross-polarized spectra showed evidence of a resonance peak. Interestingly, whereas the line-shape from the polypropylene array was symmetric, the rutile array was not, which may be indicative of Fano resonance. So, even with the structural defects, reflection spectroscopy revealed a resonance. This article is protected by copyright. All rights reserved.

Host Mesothelin Expression Increases Ovarian Cancer Metastasis in the Peritoneal Microenvironment.

Mesothelin (MSLN), a glycoprotein normally expressed by mesothelial cells, is overexpressed in ovarian cancer (OvCa) suggesting a role in tumor progression, although the biological function is not fully understood. OvCa has a high mortality rate due to diagnosis at advanced stage disease with intraperitoneal metastasis. Tumor cells detach from the primary tumor as single cells or multicellular aggregates (MCAs) and attach to the mesothelium of organs within the peritoneal cavity producing widely disseminated secondary lesions. To investigate the role of host MSLN in the peritoneal cavity we used a mouse model with a null mutation in the MSLN gene (MSLNKO). The deletion of host MSLN expression modified the peritoneal ultrastructure resulting in abnormal mesothelial cell surface architecture and altered omental collagen fibril organization. Co-culture of murine OvCa cells with primary mesothelial cells regardless of MSLN expression formed compact MCAs. However, co-culture with MSLNKO mesothelial cells resulted in smaller MCAs. An allograft tumor study, using wild-type mice (MSLNWT) or MSLNKO mice injected intraperitoneally with murine OvCa cells demonstrated a significant decrease in peritoneal metastatic tumor burden in MSLNKO mice compared to MSLNWT mice. Together, these data support a role for host MSLN in the progression of OvCa metastasis.