08-04-2009: A collaboration of scientists from various Beijing institutes, have made a pH-switchable, DNA-quantum dot hybrid that can also generate a photocurrent depending on the pH, allowing DNA to change conformation from a quadruplex to a double strand.
Zhiyong Tang, Dongsheng Liu and colleagues from the National Center for Nanoscience and Technology are working with Lei Jiang from Chinese Academy of Sciences and colleagues from Peking University. They have designed a biomimetic photoelectric conversion system by immobilizing CdSe/ZnS core shell quantum dots and functionalized i-motif motor DNA on the surface of a gold electrode. Through combining the broad absorption of the core shell nanoparticles and the pH sensitive i-motif DNA motor; dynamic modulation of photocurrent generation has been achieved. This so called ‘photoelectric switch’ could have potential applications in photovoltaic devices and functional smart materials.
Tang and co-workers took their inspiration for this work from the photosynthetic behaviour of a typical submerged aquatic plant, Hydrilla verticillata, which photosynthesizes at different rates, depending on the pH of the surrounding aqueous environment. ‘We were curious to see whether we could find a way to realize dynamic modulation of photoelectric conversion in devices, with a similar change in pH value,’ says Tang. This was achieved by changing the pH value (of the electrolyte), so that the change in the conformation of motor DNA altered the electron transfer distance between the photo-excited quantum dots and the gold electrode.
Dynamic modulation is of great importance in many fields because, in addition to DNA, many artificial polymers undergo similar configuration changes after exposure to external stimuli. Tang expects that the combination of quantum dots and polymers will dramatically enrich the study on dynamic modulation of photoelectric conversion and will speed up their practical applications in smart devices.
The biggest challenge facing scientists in this field will be to make this device on a larger scale while still preserving the exact configuration change of the DNA or polymer, even after several application cycles.
Original article:Meng et al.; "Photoelectric conversion switch based on quantum dots with i-motif DNA scaffolds"; Chem. Commun. 2009
Chinese scientists have combined interfacing dark field microscopy (DFM) with capillary electrophoresis (CE) and used it to “see” single gold nanoparticle (AuNPs) movement visually and in real time. The study also served to confirm the separation rules and fundamental theories of CE. more
It may soon be easier to protect consumers from dangerous condiments thanks to an electrochemical method developed by Chinese scientists that can spot the toxic azo dye, Orange II. They were able to spot the dye at nanomolar concentrations in ketchup and chilli products using the sensor.
O ... more
A graphene inspired electrode material that could help batteries hold more power has been developed by Chinese scientists. The large surface area of these cobalt oxide nanosheets is key to their electrochemical performance.
As technology advances, the search is on for batteries that can pac ... more
The RSC is a leading international publisher of highly regarded journals and books in the chemical sciences. The RSC is also the professional body for chemists with a global membership of over 46,000. more
More about Chinese Academy of Sciences
Chinese Academy of Sciences
52 Sanlihe Rd.
A low-carbon solution to high-carbon energy resources such as coal is proposed by their high efficient integration with either nuclear or renewable energy, which may figure out the strategic solution to China's future energy development. Coal dominated energy resource and consumption struct ... more
A reusable, natural and cheap amylose-functionalised graphene sensor was developed for highly sensitive and visual fluorescent chiral sensing by a team in China.The team found that the sensor’s detection sensitivity toward L-tryptophan was over 100 times higher than that of recently reporte ... more
A world premiere: a material which changes its strength, virtually at the touch of a button. This transformation can be achieved in a matter of seconds through changes in the electron structure of a material; thus hard and brittle matter, for example, can become soft and malleable. What mak ... more
An international team of researchers has identified a new theoretical approach that may one day make the synthesis of hydrogen fuel storage materials less complicated and improve the thermodynamics and reversibility of the system.
Many researchers have their sights set on hydrogen as an al ... more
Scientists have invented a carbon-based sponge that can soak up organic pollutants, such as oils and solvents, from the surface of water. No water is absorbed and the sponge can then be wrung out and reused, like an ordinary household sponge. Absorbing up to 180 times its own weight in orga ... more
An international team of researchers has designed a new graphite-based, magnetic nano-material that acts as a semiconductor and could help material scientists create the next generation of electronic devices like microchips.
The team of researchers from Virginia Commonwealth University; Pe ... more