Multifunctional Uniform Nanoparticles Composed of a Magnetite Nanocrystal Core and a Mesoporous Silica Shell for Magnetic Resonance and Fluorescence Imaging and for Drug Delivery

Jaeyun Kim, Hoe Suk Kim, Nohyun Lee, Taeho Kim, Hyoungsu Kim, Taekyung Yu, In Chan Song, Woo Kyung Moon, Taeghwan Hyeon
Published Online: Aug 25 2008 7:50AM
DOI: 10.1002/anie.200802469

Magnetic, fluorescent core-shell nanoparticles consist of a single Fe3O4 nanocrystal core and a dye-doped mesoporous silica shell with a poly(ethylene glycol) coating (see picture of TEM images and schematic depictions). These nanoparticles can be used as magnetic resonance and fluorescence imaging agents, and as drug delivery vehicles, thus making them novel candidates for simultaneous cancer diagnosis and therapy.

DNA-Coated AFM Cantilevers for the Investigation of Cell Adhesion and the Patterning of Live Cells

Sonny C. Hsiao, Ailey K. Crow, Wilbur A. Lam, Carolyn R. Bertozzi, Daniel A. Fletcher, Matthew B. Francis
Published Online: Sep 16 2008 9:46AM
DOI: 10.1002/anie.200802525

Get a grip: Measurement of receptor adhesion strength requires the precise manipulation of single cells on a contact surface. To attach live cells to a moveable probe, DNA sequences complementary to strands displayed on the plasma membrane are introduced onto AFM cantilevers (see picture, bp=base pairs). The strength of the resulting linkages can be tuned by varying the length of DNA strands, allowing for controlled transport of the cells.

Bioreversible Protection of Nucleoside Diphosphates

Henning Jacob Jessen, Tilmann Schulz, Jan Balzarini, Chris Meier
Published Online: Oct 2 2008 9:17AM
DOI: 10.1002/anie.200803100

	Going incognito: A new prodrug approach has been developed to facilitate the diffusion of highly polar polyphosphorylated nucleosides across cell membranes (see scheme). Inside the cell, the masking groups on the nucleoside diphosphate should be cleaved rapidly by enzymes to release the antiviral active cargo.

Enzymatic Synthesis of Multiple Spin-Labeled DNA

Samra Obeid, Maxim Yulikov, Gunnar Jeschke, Andreas Marx
Published Online: Jul 31 2008 8:02AM
DOI: 10.1002/anie.200802314

	Multi-spinning: The use of modified triphosphates and DNA polymerases has resulted in the multiple spin-labeling of DNA (see picture). A DNA helix entirely labeled with paramagnetic centers has been generated in this way and investigated by EPR spectroscopy.

A Contractile DNA Machine

Daniel Lubrich, Jie Lin, Jie Yan
Published Online: Aug 4 2008 2:34AM
DOI: 10.1002/anie.200800476

	Machine tool: A molecular machine built from DNA utilizes the cooperative actions of many molecular tweezers units to achieve larger-scale movements. The device is able to contract to 75 % of its fully extended length (see picture), is driven by a set of two fuel strands, and can be cycled.

Super Robust Nanoparticles for Biology and Biomedicine

Rongchao Jin
Published Online: Aug 4 2008 2:34AM
DOI: 10.1002/anie.200801301

The preparation of nanoparticles with sufficient chemical and thermal stability for bio-related applications has long been a major issue in nanobiotechnology. New types of highly stable Au, CdSe/ZnS, and F3O4 nanoparticles have been stabilized with Tween derivatives through coordination to the particle surface as well as van der Waals interaction with the primary ligands on the nanoparticle surface. The Au nanoparticles are more stable than the corresponding Au nanoparticles functionalized with thiolated DNA.

Electronic Aptamer-Based Sensors

The selection of aptamers—nucleic acids that specifically bind low-molecular-weight substrates or proteins—by the SELEX has attracted recent efforts directed to the development of new specific recognition units. In particular, extensive activities have been directed to the application of aptamers as versatile materials for the design of biosensors. The Minireview summarizes the recent accomplishments in developing electronic aptamer-based sensors (aptasensors), which include electrochemical, field-effect transistor, and microgravimetric quartz crystal microbalance sensors, and describes methods to develop amplified aptasensor devices and label-free aptasensors