Improved PDMS mold fabrication by direct etch with nanosphere self-assembly mask for Soft UV-NIL subwavelength metasurfaces fabrication

International audienceWith the increased relevance of metasurface for optical applications, a fabrication method that allows for both large surface and 100 nm range dimensions at a low cost is required for their development. Due to its high throughput and small structuration capabilities, Soft Nanoimprint Lithography is a good canditate as fabrication method for these type of devices. But its application for metasurfaces at visible wavelengths has been hindered by the necessity to use low-viscosity PDMS in order to reach the dimensions required, making the final stamp more fragile and the process more expensive. Here we propose a PDMS mold fabrication method which relies on selfassembly masking of the PDMS followed by direct etching of the mold, decorrelating the minimum dimension attainable from the PDMS viscosity. We characterize a metasurface fabricated using a mold obtained with our method validating its use for nanofabrication of large surface devices

Comparison between conventional and next generation lithography for bimodal SPRI-SERS biosensors

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Hard UV-NIL nanostructures for bimodal SPRI-SERS biosensors

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La nanophotonique : des solutions pour des systèmes de visualisation améliorés et compactés

La nanophotonique a un rôle à jouer pour compacter, alléger et améliorer les systèmes optiques pour les applications de mobilité. Elle offre des solutions non accessibles à l’optique réfractive du fait de son caractère modulaire et de sa compatibilité avec les technologies planaires. En retour, de nouvelles problématiques scientifiques et technologiques lui sont posées, dont nous présentons ici quelques exemples : fonctionnalisation plasmonique d’écrans transparents, émetteur cohérent planaire vectorisé par des plasmons, adressage matriciel de pixels submicroniques

Investigating the genetic diversity of Echinococcus granulosus sensu stricto with new microsatellites

International audienceCystic echinococcosis is a zoonotic disease with worldwide distribution caused by the larval stage of the Cestode parasite Echinococcus granulosus sensu lato. Due to the predominance or even the exclusive presence of E. granulosus sensu stricto (s.s.) among E. granulosus species in many areas, the genetic diversity needs to be further investigated at the species level to better understand the inter-and intra-focus epidemiological features. Short sequences of mitochondrial or nuclear genes generally lack or have limited discriminatory power, hindering the detection of polymorphisms to reflect geographically based peculiarities and/or any history of infection. A high discriminatory power can only be reached by sequencing complete or near complete mitogenomes or relatively long nuclear sequences, which is time-consuming and onerous. To overcome this issue, a systematic research for single-locus microsatellites was performed on the nuclear genome of E. granulosus s.s. in order to investigate its intra-species genetic diversity. Two microsatellites, EgSca6 and EgSca11, were selected and characterized. The test of a panel of 75 cystic echinococcosis samples revealed a very high discrimination index of 0.824 for EgSca6, 0.987 for EgSca11, and 0.994 when multiplexing both microsatellites. Testing cystic echinococcosis samples from both liver and lungs in five sheep revealed that these two microsatellites appear to be of particular interest for investigating genetic diversity at the intra-individual host level. As this method has many advantages compared to classical sequencing, the availability of other targets means that it is potentially possible to constitute a panel facilitating large-scale molecular epidemiology studies for E. granulosus s.l

Comparison between conventional and next generation lithography for bimodal SPRI-SERS biosensors

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Hard UV-NIL nanostructures for bimodal SPRI-SERS biosensors

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Soft nanoimprint lithography on SiO2 sol-gel to elaborate sensitive substrates for SERS detection

This paper presents a new alternative fabrication of biochemical sensor based on surface enhanced Raman scattering (SERS) by soft nanoimprint lithography (S-NIL) on SiO2 sol-gel. Stabilization of the sol-gel film is obtained by annealing which simplifies the manufacturing of these biosensors and is compatible with mass production at low cost. This detector relies on a specific pattern of gold nanodisks on a thin gold film to obtain a better sensitivity of molecules’ detection. Characterizations of SERS devices were performed on a confocal Raman microspectrophotometer after a chemical functionalization. We report a lateral collapse effect on poly(diméthylsiloxane) (PDMS) stamp for specific nanostructure dimensions. This unintentional effect is used to evaluate S-NIL resolution in SiO2 sol-gel

Mother-young bonding in prolific D'man and Romanov sheep

The effect of prolificacy on mother-young mutual recognition is still largely unknown in sheep. The aim of the present study was to investigate the ability of prolific ewes to develop an exclusive bond with their neonate and to recognize each other from alien subjects. Observations were performed on 11 D'man and 16 Romanov ewes with, respectively, 19 and 37 of their lambs. Maternal selectivity was tested at 24 h postpartum during two consecutive periods of 3 min. All mothers accepted their own lambs at suckling, while 21 out of 27 (78%) rejected the alien, thus displaying mostly selective nursing. To assess mother-young recognition, a two-choice test was performed at 36 h postpartum. Ewes clearly preferred their own lambs to an alien lamb and behavioral differences were not found between mothers of small (singletons and twins) and large litters (triplets and quadruplets). Romanov ewes reached their own lambsmore rapidly and spent more time near them than D'man ewes. Lambs from small litters, in particular light lambs, clearly preferred their mothers to an alien dam; however, both light and heavy lambs in large litters did not discriminate between the two stimulus ewes. D'man lambs clearly preferred their mothers to an alien dam; in contrast, such a preference was not as clearly demonstrated in Romanov lambs

Experimental and numerical investigation of biosensors plasmonic substrates differences induced by e-beam, soft and hard UV-NIL fabrication techniques

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