We report the activity, stability, and reusability of enzyme-carbon nanotube conjugates in aqueous solutions. A variety of enzymes were covalently attached to oxidized multi-walled carbon nanotubes (MWNTs). These conjugates were soluble in aqueous buffer, retained a high fraction of their native activity, and were stable at higher temperatures relative to their solution phase counterparts. Furthermore, the high surface area of MWNTs afforded high enzyme loadings, yet the intrinsic high length of the MWNT led to facile filtration. These water-soluble carbon nanotube-enzyme conjugates represent novel preparations that possess the virtues of both soluble and immobilized enzymes, thus providing a unique combination of useful attributes such as low mass transfer resistance, high activity and stability, and reusability.

We present an analytical description of the energy density of chiral magnetic domain walls (DWs) that considers variations in DW width. Surprisingly, under the application of a longitudinal in-plane magnetic field, the DW width varies abnormally, resulting in an asymmetric variation of the DW energy density. Such asymmetry is attributable to the nonlinear contribution to the effective magnetic field from the Dzyaloshinskii–Moriya interaction. The formation of such asymmetric DWs is confirmed by a micromagnetic simulation. The present prediction proposes a possible origin of the experimental asymmetry related to chiral damping.

A combinatorial strategy for biocatalytic polymer synthesis is demonstrated. A library of polymers was synthesized in 96 deep-well plates using AA-BB polycondensations of acyl donors and acceptors. The library was based on four straight-chain diesters as acyl donors (C(3)-C(10)) with aliphatic/aromatic diols as well as more diverse structures including carbohydrates, nucleic acids, and a natural steroid diol used as acyl acceptors. The lipase from Candida antarctica was active in acetonitrile and was capable of catalyzing the polycondensation of the aforementioned monomers to polymers with M(w)'s reaching as high as 20,000 Da, including the preparation of novel sugar-containing polyesters. The combinatorial approach to biocatalytic polymer synthesis described herein serves as a foundation for polymeric materials discovery by demonstrating that polymer arrays can be produced from structurally complex monomers.