Microlenses fabricated by two-photon laser polymerization for cell imaging with non-linear excitation microscopy

Non-linear excitation microscopy offers several advantages for in-vivo imaging compared to conventional confocal techniques. However, tissue penetration can still be an issue due to scattering and spherical aberrations induced on focused beams by the tissue. The use of low numerical aperture objectives to pass through the outer layers of the skin, together with high dioptric power microlenses implanted in-vivo close to the observation volume, can be beneficial to the reduction of optical aberrations. Here, Fibroblast cell culture plano-convex microlenses to be used for non-linear imaging of biological tissue are developed and tested. The microlenses can be used as single lenses or multiplexed in an array. A thorough test of the lenses wavefront is reported together with the modulation transfer function and wavefront profile. Magnified fluorescence images can be retrieved through the microlenses coupled to commercial confocal and two-photon excitation scanning microscopes. The signal-to-noise ratio of the images is not substantially affected by the use of the microlenses and the magnification can be adjusted by changing the relative position of the microlens array to the microscope objective and the immersion medium. These results are opening the way to the application of implanted micro-optics for optical in-vivo inspection of biological processes

GENETIC ASSOCIATION AND FUNCTIONAL CONSEQUENCES OF A COMMON SNP IN THE CD40 REGION WITH SYSTEMIC LUPUS ERYTHEMATOSUS AND RHEUMATOID ARTHRITIS IN A HOMOGENEOUS GREEK POPULATION

Pathophysiology and treatment of rheumatic disease

Two-photon laser polymerized microlenses for nonlinear excitation microscopy of biological samples

We report new methods of two-photon polymerization of microlenses with high numerical aperture, large diameter and good optical quality. We characterize the aberrations of these lenses that, coupled to raster scanning optical microscopes, allow two-photon excitation imaging of cells. In-vivo non-linear imaging will be also discussed, opening the possibility to use these micro-lenses in implants for the continuous inspection of biological dynamics in vivo

Differential Expression of miR-4520a Associated With Pyrin Mutations in Familial Mediterranean Fever (FMF)

Familial Mediterranean fever (FMF) is an autosomal recessive disease characterized by recurrent, acute, and self-limiting attacks of fever. Mutations in MEFV gene encoding pyrin account for FMF, but the high number of heterozygote patients with typical symptoms of the disease has driven a number of alternative aetiopathogenic hypotheses. The MEFV gene was knocked down in human myelomonocytic cells that express endogenous pyrin to identify deregulated microRNAs (miRNAs). Microarray analyses revealed 29 significantly differentially expressed miRNAs implicated in pathways associated with cellular integrity and survival. Implementation of in silico gene network prediction algorithms and bioinformatics analyses showed that miR-4520a is predicted to target genes implicated in autophagy through regulation of RHEB/mTOR signaling. Differential expression levels of RHEB were confirmed by luciferase reporter gene assays providing further evidence that is directly targeted by miR-4520a. Although the relative expression levels of miR-4520a were variable among FMF patients, the statistical expression of miR-4520a was different between FMF mutation carriers and controls (P = 0.0061), indicating an association between miR-4520a expression and MEFV mutations. Comparison between FMF patients bearing the M694V mutation, associated with severe disease, and healthy controls showed a significant increase in miR-4520a expression levels (P = 0.00545). These data suggest that RHEB, the main activator of mTOR signaling, is a valid target of miR-4520a with the relative expression levels of the latter being significantly deregulated in FMF patients and highly dependent on the presence of pyrin mutations, especially of the M694V type. These results suggest a role of deregulated autophagy in the pathogenesis of FMF. J. Cell. Physiol. 232: 1326–1336, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc

A decade of advances in femtosecond laser fabrication of polymers: mechanisms and applications

We overview principles and developments of three-dimensional (3D) direct laser writing in polymers. Challenges to reach efficient structuring with sub- 100 nm spatial resolution are presented. Research into the structuring by ultrashort laser pulses has seen an immense growth over the last decade due to its flexibility, easy handling and variety of applications. Here, a discussion regarding the mechanisms of the linear and nonlinear light absorption at tight focusing conditions and typical writing parameters are provided. The traditional and novel polymers together with their photosensitization and sample developing strategies are reviewed. Sub- 1 ps pulses are capable to create cross-linkable species by direct absorption and bond breaking at ∼TW/cm2 irradiance. Confined thermal and linear absorption via avalanche ionization is an efficient use of light energy for localized polymerization. This is a unique feature of ultrashort laser. Applications in microoptics, photonics, microfluidics and cell scaffolds are presented. Directions of up-scaling the fabrication throughput for industrial demands are introduced. 3D laser writing is becoming a part of wider field of additive manufacturing techniques which is innovating for creation of microdevices