Huaping Xu and Jurriaan Huskens Chem. Eur. J., 2010, 16, 2342-2348. Microcontact printing is a heavily used surface modification method in materials and life science applications. This concept article focuses on the development of versatile stamps for microcontact printing that can be used to bind and release inks through molecular recognition or through an ink reservoir, the latter being used for the transfer of heavy inks, such as biomolecules and particles. Conceptually, such stamp properties can be introduced at the stamp surface or by changing the bulk stamp material; both lines of ...

Ning Ma, Ying Li, Huaping Xu, Zhiqiang Wang, and Xi Zhang J. Am. Chem. Soc., 2010, 132, 442-443. A block copolymer with diselenide bonds in the polymer backbone was reported. This block copolymer was capable of forming micellar aggregates that were responsive to redox stimuli. Compared with other redox responsive aggregates, this type of diselenide-containing block copolymer aggregates could be responsive to both oxidants and reductants even in a solution with a very low concentration under mild conditions.

Jian Gao, Yiliu Liu, Huaping Xu, Zhiqiang Wang, and Xi Zhang Langmuir, 2010, 26, 9673–9676. We present a very efficient and convenient approach to obtain smart biosurfaces by directly replicating biological surface structures. It is realized by a two-step replication process combining regular replica molding and tempetature-induced phase separation micromolding (PSμM). The negative replicas of biological surface structures using poly(dimethylsiloxane) as the replication material are durable molds for further replication. The positive replicas of biological surface structures are obtained...

Zhihua Liu, Yu Yi, Huaping Xu, Xi Zhang, Thien Huynh Ngo, and Mario Smet Adv. Mater., 2010, 22, 2689-2693. Cation-selective microcontact printing (μCP) is achieved by the combination of a surface-molecular-imprinted layer-by-layer (SMILbL) films with μCP. The SMILbL film greatly enhances the charge selectivity of the imprinted-film-modified stamp and the PDMS stamp modified by the SMILbL film shows a high selectivity to multiply charged cations. The SMILbL-film-modified stamp can also be used for selective transfer of single-charged chemical species.

Ning Ma, Ying Li, Huifeng Ren, Huaping Xu, Zhibo Li, and Xi Zhang Polym. Chem., 2010, 1, 1609-1614. A selenium-containing amphiphilic block copolymer (PEG-PUSe-PEG) with a hydrophobic polyselenide block and two hydrophilic poly(ethylene glycol) (PEG) blocks was synthesized via polymerization of toluene diisocyanate (TDI) with monoselenide-containing diols and subsequent termination with PEG monomethylether. PEG-PUSe-PEG is able to self-assemble in aqueous solution to form block copolymer aggregates. Interestingly, it was found that the aggregates have a good oxidation-responsiveness and ...

Peng Han, Ning Ma, Huifeng Ren, Huaping Xu, Zhibo Li, Zhiqiang Wang, and Xi Zhang Langmuir, 2010, 26, 14414-14418. We have fabricated a polymeric superamphiphile based on the electrostatic interaction between the double hydrophilic block copolymer of poly(ethylene glycol)-b-acrylic acid (PEG-b-PAA) and a selenium-containing surfactant (SeQTA). The polymeric superamphiphiles are able to self-assemble to form micelles in solution. The micelles can be disassembled with the addition of 0.1% H2O2 because SeQTA is very sensitive to oxidation. The selenide group in SeQTA is oxidized into seleno...

Ning Ma, Huaping Xu, Liping An, Juan Li, Zhiwei Sun, and Xi Zhang Langmuir, 2011, 27, 5874–5878. We have developed a potential radiation-sensitive drug-delivery system using active diselenide-containing block co-polymer aggregates in aqueous solution that can load and release anticancer drugs. These aggregates were sensitive to even a low dose of γ-radiation, such as 5 Gy, which is close to the radiation dose received by patients during a single radiotherapy treatment. This line of research may open an avenue for the combination of radiotherapy and chemotherapy.

Huifeng Ren, Yaoting Wu, Ning Ma, Huaping Xu, and Xi Zhang Soft Matter, 2012, 8, 1460-1466. In this paper we report the synthesis and study of a series of side-chain selenium-containing amphiphilic poly(ethylene oxide-b-acrylic acid) block copolymers PEO-b-PAA-Se. These block copolymers can selfassemble in aqueous solution and form spherical micellar aggregates. The selenide group of PEO-bPAA-Se can change into hydrophilic selenoxide under mild oxidation of 0.1% hydrogen peroxide, leading to the disassembly of the spherical micellar aggregates. Small compounds like Nile Red can be encaps...

Huaping Xu, Monika Schönhoff, and Xi Zhang Small, 2012, 8, 517-523. Layer-by-layer assembly (LbL) is a rich, versatile, and powerful technique for fabricating multilayer thin films with controlled architecture and functions. Singly charged, uncharged, or water-repellent molecules cannot be used directly in conventional LbL assembly. This problem can be solved with unconventional LbL methods, by employing the preassembly of building blocks in solution and the use of these assemblies for LbL formation at the interface. This Concept summarizes different methods of unconventional LbL assembl...

Yu Fu, Junyi Chen, Huaping Xu, Chantal Van Oosterwijck, Xi Zhang, Wim Dehaen, and Mario Smet Macromol. Rapid Commun., 2012, 33, 798-804. A novel glutathione peroxidase (GPx) mimic has been prepared by incorporation of a selenium-based catalytic unit into the focal point of a fully-branched hyperbranched polymer. First, an AB2 monomer consisting of isatin and an electron rich aromatic moiety was polycondensed in the presence of 5-nitroisatin as a core reagent, resulting in a polymer with 100% degree of branching. The latter was coupled to the catalytically active moiety, Br(CH2)5SeSe(CH2)...