Stiffening the backbone of DNA nanofibers

Jul 24, 2013
Top: Schematic showing association of two duplex precursors into a quadruplex fiber building block. The duplex regions of the building block are shown in red and blue; the quadruplex region is shown in gray. Bottom: AFM image of quadruplex DNA nanofibers. These fibers can be 2 micrometers or more in length.

An international collaboration including researchers from the NIST Center for Nanoscale Science and Technology and the Universidad San Francisco de Quito, Ecuador have fabricated a self-assembled nanofiber from a DNA building block that contains both duplex (two-stranded) and quadruplex (four-stranded) DNA. This work is a first step toward the creation of new structurally heterogeneous (quadruplex/duplex), yet controllable, DNA-based materials exhibiting novel properties suitable for bottom-to-top self-assembly for nanofabrication, including self-organization of both inorganic materials (nanoparticles) and molecular electronics components.

The new nanofibers are constructed from duplex DNA precursors that first form quadruplex DNA in the presence of potassium ions and then connect together to form a fiber. DNA quadruplexes are unusual structures that can form from DNA sequences that are rich in the nucleotide guanine. Each strand in the duplex DNA precursor contains an internal run of eight guanines, which creates a region of guanine-guanine mismatches, plus one segment that extends past the duplex region to create a single-stranded overhang. When are added, the duplex precursors self-assemble into quadruplex structures, and then into duplex/quadruplex fibers. These fibers were detected in bulk using electrospray and . Single-molecule analysis using revealed fiber lengths ranging from 250 nm to 2000 nm. Because interaction between four strands of DNA takes place in some fiber segments, the final structures appear to be stiffer than DNA-based structures built from duplex-only subunits. This increased stiffness should lead to improved DNA patterning for nanotechnology applications. In contrast to DNA origami and DNA tile structures that are based solely on duplex DNA, the researchers believe that by varying the sequence of duplex and quadruplex subunits they ultimately will be able to create DNA building blocks that remain intact at temperatures ranging from room temperature to 100 ºC.

According to CNST Project Leader Veronika Szalai, this work will allow future integration with other programmable self-assembly methods such as DNA origami, as well as with other nanomaterial components such as quantum dots, to create new multi-functional biological-based nanomaterials.

Explore further: Researchers use DNA origami technique to build nanoantennas with docking sites

More information: Synapsable quadruplex-mediated fibers, M. A. Mendez and V. A. Szalai, Nanoscale Research Letters 8, 210 (2013).

Related Stories

DNA gridlock: Cells undo glitches to prevent mutations

Jun 03, 2013

Roughly six feet of DNA are packed into every human cell, so it is not surprising that our genetic material occasionally folds into odd shapes such as hairpins, crosses and clover leafs. But these structures ...

'Quadruple helix' DNA discovered in human cells

Jan 20, 2013

In 1953, Cambridge researchers Watson and Crick published a paper describing the interweaving 'double helix' DNA structure - the chemical code for all life. Now, in the year of that scientific landmark's 60th Anniversary, ...

Novel technique reveals dynamics of telomere DNA structure

Jan 17, 2013

Biomedical researchers studying aging and cancer are intensely interested in telomeres, the protective caps on the ends of chromosomes. In a new study, scientists at UC Santa Cruz used a novel technique to reveal structural ...

Recommended for you

Innovative strategy to facilitate organ repair

Apr 18, 2014

A significant breakthrough could revolutionize surgical practice and regenerative medicine. A team led by Ludwik Leibler from the Laboratoire Matière Molle et Chimie (CNRS/ESPCI Paris Tech) and Didier Letourneur ...

Physicists create new nanoparticle for cancer therapy

Apr 16, 2014

A University of Texas at Arlington physicist working to create a luminescent nanoparticle to use in security-related radiation detection may have instead happened upon an advance in photodynamic cancer therapy.

User comments : 0

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...