Current slow-freezing methods are too inefficient for cryopreservation of three-dimensional (3D) tissue constructs. Additionally, conventional vitrification methods use liquid nitrogen, which is inconvenient and increases the chance of crosscontamination. Herein, we have developed polyampholytes with various degrees of hydrophobicity and showed that they could successfully vitrify cell constructs including spheroids and cell monolayers without using liquid nitrogen. The polyampholytes prevented ice crystallization during both cooling and warming, demonstrating their potential to prevent freezing-induced damage. Monolayers and spheroids vitrified in the presence of polyampholytes yielded high viabilities post-thawing with monolayers vitrified with PLL-DMGA exhibiting more than 90% viability. Moreover, spheroids vitrified in the presence of polyampholytes retained their fusibilities, thus revealing the propensity of these polyampholytes to stabilize 3D cell constructs. This study is expected to open new avenues for the development of off-the-shelf tissue engineering constructs that can be prepared and preserved until needed.

Articles you may be interested inSimulation and experiment of substrate aluminum grain orientation dependent self-ordering in anodic porous alumina Fabrication of two-dimensional polymer photonic crystals by nanoimprinting using anodic porous alumina mold J. Vac. Sci. Technol. B 28, 398 (2010); 10.1116/1.3368481 High-speed growth and photoluminescence of porous anodic alumina films with controllable interpore distances over a large range Appl. Phys. Lett. 91, 073109 (2007); 10.1063/1.2772184 Fabrication and structural characterization of highly ordered sub-100 -nm planar magnetic nanodot arrays over 1 cm 2 coverage area Fabrication of ideally ordered anodic porous alumina with 63 nm hole periodicity using sulfuric acid L11 Nishio et al.: Fabrication of ideally ordered anodic porous alumina L11 JVST B -Microelectronics and Nanometer Structures Redistribution subject to AVS license or copyright; see http://scitation.aip.org/termsconditions. Download to IP: 193.0.65.67 On: Wed, 04 Feb 2015 10:44:32 L12 Nishio et al.: Fabrication of ideally ordered anodic porous alumina L12 J.

Nano-imprint lithography (NIL) is eminently suitable for low cost patterning for nanostructures. As feature sizes of the UV-NIL templates are the same as the wafer patterns, there are enormous challenges such as writing and inspecting smaller patterns for NIL template fabrication. In our previous works, we achieved less than 16nm resolution with a 100keV spot beam writer and non CAR. We also reported optimization of metrology for NIL templates and the characterization of anti-sticking layers with scanning probe microscopies.Normally the template is made from a 6025 photomask blank. After the blank undergoes a process similar to the photomask process, it is diced into 65 mm x 65 mm size and four pieces, and then each piece is polished into its final shape. Therefore it becomes difficult to inspect and clean them, because 65 mm substrates are unfamiliar in photomask industry. In order to reach the step for mass-production of the templates, the development of "back-end process", which includes not only cleaning and inspection but also repair, dicing, polishing, and coating anti-sticking layers, is essential. Especially keeping low contamination level during dicing and polishing processes is one of the critical issues.In this paper, we report our development status of "back-end process" for NIL templates. Especially, we focus on the techniques of reducing adder defects during dicing process and improving cleaning capability.

It was noted recently ulal the ADM diffeomorphism constraint does not generate all observed symmetries for several Bianchi models. We will suggest not using the ADM constraint restricted to homogeneaus variables, but Some equivalent. which is derived from a restricted aclion principle. This will generate all homogeneity preserving diffeomorphisms. which will L x shown to be automorphism generaling vector fields, in class A and class B models. Following Dim's constraint formalism one will naturally be restricted to the unimodular pwl of the automorphism group.

Most problems in photomask fabrication such as pattern collapse, haze, and cleaning damage are related to the behavior of surfaces and interfaces of resists, opaque layers, and quartz substrates. Therefore, it is important to control the corresponding surface and interface energies in photomask fabrication processes. In particular, adhesion analysis in microscopic regions is strongly desirable to optimize material and process designs in photomask fabrication. We applied the direct peeling (DP) method with a scanning probe microscope (SPM) tip and measured the adhesion of resist patterns on Cr and quartz surfaces for photomask process optimization. We also studied the effect of tip shape on the reproducibility of adhesion measurements and the dependence of collapse behavior on the resist profile. We measured lateral forces between the resulting collapsed resist pillar and the Cr or the quartz surface before and after the sliding and related these observed lateral forces to the static and kinetic frictional forces, respectively. We also studied the effect of surface modification of the Cr and quartz surfaces with silanization reagents on adhesion measured with the DP method. Resist adhesion could be controlled by surface modification using silanes. We also discuss the relationship between the adhesion observed with the DP method and the properties of the modified surfaces including water contact angles and local adhesive forces measured from force-distance curves with an SPM.