Qigang Wang

Faking it: The use of a supramolecular hydrogel as the structural component of artificial enzymes provides a new and useful approach to the development of biomimetic catalysts. In toluene, hemin chloride encapsulated in such a hydrogel achieves about 60 % nascent catalytic activity of horseradish peroxidase. Additionally, the activity of hemin in the hydrogel is 387.1 times greater than that of free hemin. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2007/z700404_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Efficient photocatalytic nanocrystals with high-ratio exposure of active facets have aroused a great number of research interests in recent years. However, most preparations of such materials need the addition of special capping agents (like surfactants) or harsh reaction conditions (such as hydrothermal reactions). In this work, a controllable synthesis of BiOBr nanosheets with a thickness from 9 nm to 32 nm was easily achieved in a hydrolysis system through adjusting temperature and solvent, without adding any surfactant or capping agents. As the thickness of the nanosheets decreases from 32 nm to 9 nm, the ratio of exposed {001} facets, the active photocatalysis facets in BiOBr crystals, increases from 83% to 94%, along with an increased photocatalytic efficiency over rhodamine B (RhB) under visible-light. Various methods such as SEM, TEM, AFM, DRS and Raman spectroscopy were used to fully characterize the as-obtained BiOBr nanosheets. More importantly, the obtained BiOBr nanosheets exhibit a selective visible-light photocatalytic behavior as the activity over RhB is much higher than that over Methyl Orange (MO) or Methylene Blue (MB). This phenomenon was studied with in situ electron paramagnetic resonance (EPR) measurements and the potential mechanism was explored.

Enzymes, together with the process of self-assembly, constitute necessary components of the foundation of life on the nanometre scale. The exceedingly high efficiency and selectivity exhibited by enzymes for catalyzing biotransformations naturally lead to the exploration of enzyme mimics and the applications of enzymes in industrial biotransformations. While the mimicking of enzymes aims to preserve the essence of enzymes in a simpler system than proteins, industrial biotransformations demand high activity and stability of enzymes. Recent research suggests that small peptide-based nanofibers in the form of molecular hydrogels can provide a general platform to achieve both important goals. This tutorial review will introduce the recent progress of these research activities on small peptide-based nanomaterials for catalysis and hopes to provide a starting point for further explorations that ultimately may lead to practical applications of enzymes and enzyme mimics for addressing important societal problems in energy, environment, and health.

This paper reports the rational design and synthesis of a β-lactam conjugate. Treating the conjugate with β-lactamase cleaves the scissile β-lactam amide bond, releases a hydrogelator, and results in enzymatic formation of a supramolecular hydrogel. The process involves the use of a bacterial enzymethe one causes antibiotic inactivation and accounts for resistance to β-lactams in many clinical important pathogensto catalyze the formation of the hydrogel. It offers an opportunity to investigate the kinetics of these types of enzymatic reactions, screen inhibitors of the enzyme, and provides a new candidate to generate hydrogels for biomedical applications.