Site-Specific Attachment of a Protein to a Carbon Nanotube End without Loss of Protein Function

http://pubs.acs.org/doi/full/10.1021/bc300131w

Bioconjugate Chemistry

The authors attached calmodulin to the ends of carbon nanotubes and demonstrated that the binding capacity of calmodulin remained unchanged. Protein attachment was done via a site-specific mutation of Tyr80 to azido-tyrosine, which was then coupled to oxidized CNTs using a Staudinger-Bertozzi ligation. Calmodulin binding was demonstrated using an ECFP-calmodulin-binding peptide fusion protein. Treatment with ECFP-CBP showed binding only on the ends of the CNTs.

Spatial control of cell-mediated degradation to regulate vasculogenesis and angiogenesis in hyaluronon hydrogels

http://www.sciencedirect.com/science/article/pii/S014296121200556X

The authors make hyaluronic acid (HA) hydrogels cross-linked with a RGD containing peptides and MMP degradable peptides via conjugate addition to make "permissive gels" that could be degraded by cells. Gels were further cross-linked by exposure to UV light to initiate polymerization of remaining acrylate groups, making non-degradable kinetic chains; these gels were called "inhibitory." The authors found that permissive gels allowed endothelial colony-forming cells (ECFCs) to undergo vascular morphogenesis, while ECFC cultured in inhibitory gels could only form vacuoles with no branching. Thus morphogenesis and vascularization could be spatial controlled within these gels by using photolithography.

Preparation of Polymeric Nanoscale Networks form Cylindrical Molecular Bottlebrushes

Dingcai Wu, Alper Nese, Joanna Pietrasik, Yeru Liang, Hongkun He, Michal Kruk, Liang Huang, Tomasz Kowalewske, and Krzystof Matyjaszewski

http://pubs.acs.org/doi/full/10.1021/nn302096d#fig1

The authors prepared polymeric networks using cylindrical bottlebrushes with polystyrene sidechains. The polystyrene chains were crosslinked using Friedel-Crafts chemistry. The resulting networks showed both macropores and nanofibrous regions as seen by TEM.

Reversible Light-Triggered Transition of Amphiphilic Random Copolymers

Ke Feng, Nan Xie, Bin Chen, Li-Ping Zhang, Chen-Ho Tung, and Li-Zhu Wu
Macromolecules

http://pubs.acs.org/doi/full/10.1021/ma300734z

The authors prepared an amphiphilic random copolymer using ROMP. One of the monomers, the spiropyran, undergoes an ultraviolet-initiated change from hydrophobic to hydrophilic. This transition is reversible on irradiation with visible light. The authors found that in solution these polymers for micelles which shrink in size (and solution changes color) upon uv irradiation. They also studied the encapsulation and release of the hydrophobic dye Nile Red, which is used as a model for drug delivery.

Enantioselective synthesis of a chiral nitrogen-doped buckybowl

Tan, Q. et al. Enantioselective synthesis of a chiral nitrogen-doped buckybowl. Nat. Commun. 3:891 doi: 10.1038/ncomms1896 (2012).


http://www.nature.com/ncomms/journal/v3/n6/full/ncomms1896.html

The authors synthesized triazasumanene enantioselectively. They found that the incorporation of the three nitrogen atoms in the bowl increased the bowl depth relative to the all-carbon sumanene. This increase in depth also increased the energy barrier to inversion of the bowls. Sumanene undergoes rapid bowl inversion at room temperature, causing racemization. However, triazasumanene only shows any enantiomeric conversion after heating at 200 degrees for 12 hours.

Highly Orthogonal Functionalization of ADMET Polymers via Photo-Induced Diels-Alder Reactions

Matthias Winkler, Jan O. Mueller, Kim K. Oehlenschlaeger, Lucas Montero de Espinosa, Michael A. R. Meier, and Christopher Barner-Kowollik

Macromolecules Article ASAP

http://pubs.acs.org/doi/full/10.1021/ma3007043

In this paper, the authors use a photo-catalyzed Diels-Alder reaction (between a photoenol and an olefin) to make tri-block copolymers with PDI~1.2. The central block was made using ADMET for a selective head-to-tail polymerization, resulting hetero- end-functional polymers. The photocatalyzed Diels-Alder reaction is highly selective and efficient, and allowed for a one-pot synthesis of the tri-block copolymers.

Soft Nanotube Hydrogels Functioning as Artificial Chaperones

http://pubs.acs.org/doi/full/10.1021/nn301041y

Naohiro Kameta, Mitsutoshi Masuda, and Toshimi Shimizu, ACS Nano Article ASAP

In this paper, the authors create self-assembled nanotube hydrogels that are pH responsive. They were able to encapsulate denatured proteins inside the nanotubes, using denatured GFP as a model system. By reducing the concentration of denatured GFP and the concentration of the denaturing agent, they saw an increase in folded GFP, evidenced by fluorescence within the hydrogel. Folded protein remained inside the gel due to electrostatic interactions, but could be removed (properly folded) under basic conditions.