SU-8 as a Material for Microfabricated Particle Physics Detectors

Several recent detector technologies developed for particle physics applications are based on microfabricated structures. Detectors built with this approach generally exhibit the overall best performance in terms of spatial and time resolution. Many properties of the SU-8 photoepoxy make it suitable for the manufacturing of microstructured particle detectors. This article aims to review some emerging detector technologies making use of SU-8 microstructuring, namely micropattern gaseous detectors and microfluidic scintillation detectors. The general working principle and main process steps for the fabrication of each device are reported, with a focus on the advantages brought to the device functionality by the use of SU-8. A novel process based on multiple bonding steps for the fabrication of thin multilayer microfluidic scintillation detectors developed by the authors is presented. Finally, a brief overview of the applications for the discussed devices is given

Preparation and characterization of SU8-carbon nanotube composites

SU8-carbon nanotube composites have been produced to enhance the mechanical, electrical, and thermal properties of SU8 photoresists. Homogeneous composites materials have been obtained when multiwalled carbon nanotubes (MWCNTs) functionalized with COOH groups were used. Indeed, COOH groups can react with the epoxy ring of the SU8 molecule yielding an improved interaction between carbon nanotubes (CNTs) and the polymer matrix. Impedance spectroscopy was used to study the conducting percolation path in the composites, that is the quality of the nanotube dispersion in the epoxy matrix. It turns out that propylene glycol methyl ether acetate (PGMEA) as well as gamma-butyrolacton (GBL) are very suitable solvent to prepare SU8-MWCNTs composites of good homogeneity. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Study of the mechanical response of carbon nanotubes-SU8 composites by nanoindentation

Multiwalled carbon nanotubes (MWCNTs)/SU8 composites have been produced to enhance the mechanical properties of SU8 photoresist. We have studied the influence of SU8 solvent on the structural homogeneity of composites through nano-indentation testing. It is found that acetone and propylene glycol methyl ether acetate (PGMEA) are very suitable solvents to prepare MWCNTs/SU8 composites with significant increase of the Young's modulus (E-Y). The highest increase of E-Y in respect to the parent material of 104% was obtained with acetone as solvent. It was noticed that the remaining solvent in the composite influences strongly E-Y, as well. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei

Carbon nanotubes nanocomposites for microfabrication applications

A composite epoxy resin consisting in a SU-8 epoxy resin, a solvent, with or without photoinitiator and carbon nanotubes in powder. When the resin is combined with the carbon nanotubes, the mechanical, thermal and electrical properties of the nanocomposite are enhanced. That offers a wide range of composites which can be used with different microfabrication techniques, such as: lamination, spin-coating, spraying and screening for assembly, interconnect and packaging applications

Prognostic value of the Hippo pathway transcriptional coactivators ă YAP/TAZ and beta 1-integrin in conventional osteosarcoma

International audienceIntroduction: Currently, very few studies are available concerning the ă mammalian Hippo pathway in bone sarcomas. YAP/TAZ transcription ă co-activators are key downstream effectors of this pathway and may also ă have oncogenic properties. Additionally, recent in-vitro experiments ă showed that expression of beta 1-integrin promoted metastasis in ă osteosarcomas. This study investigated the expression of YAP/TAZ and ă beta 1-integrin in human osteosarcomas. Materials and methods: We performed automated immunohistochemistry on ă tissue-microarrays (TMA) in which 69 conventional osteosarcomas biopsies ă performed prior to chemotherapy were embedded. Cellular localization and ă semi-quantitative analysis of each immunostain was performed using ă Immunoreactive Score (IRS) and correlated to clinico-pathological data.Results: Cytoplasmic expression of beta 1-integrin was noted in 54/59 ă osteosarcomas (92%), with 33/59 cases (56%) displaying membranous ă staining. YAP/TAZ was expressed in 27/45 osteosarcomas (60%), with 14 ă cases (31%) showing cytoplasmic expression while 13 other cases (28%) ă displayed nuclear expression. No link was found between YAP/TAZ or beta ă 1-integrin expression and response to chemotherapy. In univariate ă analysis, YAP/TAZ immunoreactive score was pejoratively correlated with ă overall survival (p = 0.01). Expression of beta 1-integrin on cell ă membrane was also pejorative for OS (p = 0.045). In multivariate ă analysis, YAP/TAZ nuclear expression was an independent prognostic ă factor for PFS (p = 0.035).Conclusion: this study indicates that beta 1-integrin and YAP/TAZ ă proteins are linked to prognosis and therefore could be therapeutic ă targets in conventional osteosarcomas

Plasmatic MMP9 released from tumor-infiltrating neutrophils is predictive for bevacizumab efficacy in glioblastoma patients: an AVAglio ancillary study

International audienceAbstract We previously identified matrix metalloproteinase 2 (MMP2) and MMP9 plasma levels as candidate biomarkers of bevacizumab activity in patients with recurrent glioblastoma. The aim of this study was to assess the predictive value of MMP2 and MMP9 in a randomized phase III trial in patients with newly diagnosed glioblastoma and to explore their tumor source. In this post hoc analysis of the AVAglio trial (AVAGlio/NCT00943826), plasma samples from 577 patients (bevacizumab, n = 283; placebo, n = 294) were analyzed for plasma MMP9 and MMP2 levels by enzyme-linked immunosorbent assay. A prospective local cohort of 38 patients with newly diagnosed glioblastoma was developed for analysis of tumor characteristics by magnetic resonance imaging and measurement of plasma and tumor levels of MMP9 and MMP2. In this AVAglio study, MMP9, but not MMP2, was correlated with bevacizumab efficacy. Patients with low MMP9 derived a significant 5.2-month overall survival (OS) benefit with bevacizumab (HR 0.51, 95% CI 0.34–0.76, p = 0.0009; median 13.6 vs. 18.8 months). In multivariate analysis, a significant interaction was seen between treatment and MMP9 ( p = 0.03) for OS. In the local cohort, we showed that preoperative MMP9 plasma levels decreased after tumor resection and were correlated with tumor levels of MMP9 mRNA ( p = 0.03). However, plasma MMP9 was not correlated with tumor size, invasive pattern, or angiogenesis. Using immunohistochemistry, we showed that MMP9 was expressed by inflammatory cells but not by tumor cells. After cell sorting, we showed that MMP9 was expressed by CD45+ immune cells. Finally, using flow cytometry, we showed that MMP9 was expressed by tumor-infiltrating neutrophils. In conclusion, circulating MMP9 is predictive of bevacizumab efficacy and is released by tumor-infiltrating neutrophils