Deep UV image processing for 0.35 micron lithography in production JESSI subprogramme equipment and materials technology

For deep UV image processing in lithography for chip production a stable resist process was developed based on the SUCCESS resist concept of the joint European project 'JESSI E 162'. Starting from poly(p-hydroxystyrene) the formulation of delay-stable positive photoresists with good resolution capabilities and dry-etch resistance was obtained by applying additives against T-topping and by adjusting the protective group chemistry for linewidth stability. The major achievements are: linewidth stability for #>=# 0.35 #mu#m lines during delay times up to 120 min between exposure and post-exposure bake, 0.24 #mu#m lines stable for 30 min, linearity down to 0.35 #mu#m, resolution of 0.22 #mu#m with phase-shift mask, dry etch resistance better than conventional novolac resists. Chemically amplified resists have been modelled using the effective acid concept. (WEN)Available from TIB Hannover: F96B272+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Bildung, Wissenschaft, Forschung und Technologie, Bonn (Germany)DEGerman

Single Cell Kinetics of Intracellular, Nonviral, Nucleic Acid Delivery Vehicle Acidification and Trafficking

Mechanistic understanding of the intracellular trafficking of nonviral nucleic acid delivery vehicles remains elusive. A live, single cell-based assay is described here that is used to investigate and quantitate the spatiotemporal, intracellular pH microenvironment of polymeric-based nucleic acid delivery vehicles. Polycations such as polyethylenimine (PEI), poly-L-lysine (PLL), β-cyclodextrin-containing polymers lacking or possessing imidazole termini (CDP or CDP-imid), and cyclodextrin-grafted PEI (CD-PEI) are used to deliver an oligonucleotide containing a single fluorophore with two emission lines that can be employed to measure the pH. Delivery vehicles were also sterically stabilized by addition of poly(ethylene glycol) (PEG) and investigated. The intracellular trafficking data obtained via this new methodology show that vectors such as PEI and CDP-imid can buffer the endocytic vesicles while PLL and CDP do not. Additionally, the PEGylated vectors reveal the same buffering capacity as their unstabilized variants. Here, the live cell, spatiotemporal mapping of these behaviors is demonstrated and, when combined with cell uptake and luciferase expression data, shows that there is not a correlation between buffering capacity and gene expression

Virus-Inspired Approach to Nonviral Gene Delivery Vehicles

The basic TAT peptide, responsible for translocation of the HIV-TAT protein, has been conjugated to a variety of artificial nanoscopic materials to transport them across the cellular membrane. However, attempts to translocate genes using the TAT-peptide had met with limited success. We hypothesized that the cationic nature of the peptide does not allow for displaying these peptides on the surface of the polyplex. To circumvent this potential issue, we have developed a new molecular design strategy where the TAT-peptide can be effectively displayed on the surface of the polyplex, thus enhancing gene expression