Tuesday, November 6, 2012

Magnetic Hydrogels and Their Potential Biomedical Applications

Li, Y., Huang, G., Zhang, X., Li, B., Chen, Y., Lu, T., Lu, T. J. and Xu, F. (2012), Magnetic Hydrogels and Their Potential Biomedical Applications. Adv. Funct. Mater.





This interesting review covers the synthesis and the various biomedical applications of magnetic hydrogels including tissue engineering, 3D cell culture, soft actuators, and in drug delivery. All of these applications rely on external magnetic forces to remotely control the behavior of the gels. I found the use of magnetic nanoparticle cross linkers to create these gels especially interesting.

Oligothienyl-BODIPYs: Red and Near-Infrared Emitters

Arnaud Poirel, Antoinette De Nicola,* and Raymond Ziessel* 
http://pubs.acs.org/doi/abs/10.1021/ol302710z 


This report describes newly-functionalized BODIPY fluorophores.  The emission of the reported compounds extends into the NIR region.

Photoinduced Ullmann C−N Coupling: Demonstrating the Viability of a Radical Pathway

Sidney E. Creutz,1* Kenneth J. Lotito,1* Gregory C. Fu,1,2† Jonas C. Peters 

http://www.sciencemag.org/content/338/6107/647.short 

In this paper, the authors demonstrate the viability of a radical-based mechanism in Ullmann C-N couplingAs in traditional Ullmann coupling, the reaction involves a copper reagent, but in the present report, the reaction is driven by light.  This allows the reaction to be carried out at or below RT, and substoichiometric amounts of copper do a reasonably good job (10% [Cu] affords 64% yield).  This report contrasts the one by Hartwig in 2008 which demonstrated ox.add. based Ullmann coupling.

Reservoir-based drug delivery systems utilizing microtechnology

Reservoir-based drug delivery systems utilizing microtechnology
Cynthia L. Stevenson a, John T. Santini Jr. a,⁎, Robert Langer

http://www.sciencedirect.com/science/article/pii/S0169409X12000282


This paper discusses various types of drug delivery systems: from microneedle-based ones, to microchannel implants, membrane-based ones, as well as active delivery systems (stimulus-based). 


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Self-folding polymeric containers for encapsulation and delivery of drugs

Rohan Fernandesa, David H. Graciasa,

http://www.sciencedirect.com/science/article/pii/S0169409X12000919

This review discusses a topic related to one we recently heard a talk about (the one about encoding 3D-shape into materials using selective photocrosslinking).  In this case, materials are encoded to fold up into containers of specific shape, with selectively-derivatized faces.  The interior could be used to transport drugs.

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Ultrafast Photoinduced Processes in Subphthalocyanine Electron Donor Acceptor Conjugates Linked by a Single B N Bond

Carlos Romero-Nieto,† Julia Guilleme,‡ Javier Fern andez-Ariza,‡ M. Salom e Rodr ́─▒guez-Morgade,‡ David Gonz alez-Rodr ́─▒guez,‡ Tom as Torres,*,‡,§ and Dirk M. Guldi*,† 

http://pubs.acs.org/doi/abs/10.1021/ol302632u 

This paper is interesting because it presents interesting boron-containing lewis acids, in which the boron is embedded into a photo-active structure. 


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Nitroso-Dienophile Additions to Dendralenes: A Short Synthesis of Branched Aminosugars

Ruomeng Wang,† Gomotsang Bojase,† Anthony C. Willis,†,§ Michael N. Paddon-Row,*,‡ and Michael S. Sherburn*,†

http://pubs.acs.org/doi/abs/10.1021/ol302619r

This paper serves as a good example of [n]dendralene reactivity.  These might be useful as Diels-Alder crosslinking agents, although the reactivity of the "dienes" embedded within the dendralene is not necessarily equivalent (so equivalent reactivity of termini might not hold).

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Autonomous motors of a metal-organic framework powered by reorganization of self-assembled peptides at interfaces

http://www.nature.com/nmat/journal/vaop/ncurrent/full/nmat3461.html

The authors made a copper-containing MOF loaded with diphenylalanine (DPA) peptides. When the MOFs are placed in an EDTA solution, EDTA chelates copper out of the MOF, releasing DPA in a controlled unidirectional manner. The DPA self-assembles at the MOF/water interface into a region of lower surface tension. The MOFs then move away from the self-assembled DPA toward the region of higher surface tension, as per the Marangoni Effect. MOF lifetime and velocity increase with increasing DPA loading.


Glucose-Responsive Disassembly of Polymersomes of Sequence- Specific Boroxole-Containing Block Copolymers under Physiologically Relevant Conditions

Hyunkyu Kim, Young Ji Kang, Eun Sun Jeong, Sebyung Kang, and Kyoung Taek Kim

http://pubs.acs.org/doi/abs/10.1021/mz3004192

This group co-polymerized organicboronic acid functionalized styrene with functionalized maleimide groups through RAFT. This polymer self-assembled into polymersomes in water and was shown to bind sugars in water at neutral pH. At a high concentration of glucose (>0.3M), the polymersomes would dissassemble.


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