Nav: Home

The brighter side of twisted polymers

May 16, 2017

A strategy to produce highly fluorescent nanoparticles through careful molecular design of conjugated polymers has been developed by KAUST researchers. Such tiny polymer-based particles could offer alternatives to conventional organic dyes and inorganic semiconductor quantum dots as fluorescent tags for medical imaging.

Conjugated polymer-derived nanoparticles, called Pdots, are expected to transform several areas, including optoelectronics, bio-imaging, bio-sensing and nanomedicine, due to their intense fluorescence, high stability under exposure to light and low cytotoxicity. Their spectroscopic properties are tunable by tweaking the polymer structures. This makes it essential to consider their design at the molecular level.

Bio-imaging applications require nanoparticles small enough to be eliminated from the body and strongly emit light in the far-red to near-infrared range. However, current design and fabrication of Pdots have mostly relied on empirical approaches, hindering attempts to manufacture these ultrasmall nanoparticles.

To meet this challenge, Dr. Hubert Piwoski and Associate Professor Satoshi Habuchi came up with a systematic method that enhances the performance of Pdots. Habuchi explained that his team aimed to create Pdots of a smaller size and brighter fluorescence by using conjugated polymers, whose backbone of alternating single and multiple bonds enables so-called π electrons to move freely throughout the structure.

For the first time, the researchers opted for twisted, instead of planar, conjugated polymers as building blocks to generate their Pdots. Existing Pdots usually exhibit lower fluorescence intensity than their precursors as result of complex inter- and intra-chain photophysical interactions within particles.

According to Habuchi, this trial was a shot in the dark -- his team initiated the project without really knowing what would eventuate -- but they were still surprised by the fluorescence behaviors of these Pdots compared to their previously investigated analogues.

Preliminary results suggest that the newly synthesized nanoparticles were the smallest and brightest Pdots reported to date. "Therefore, we hypothesized that the twisted shape of the molecules is responsible for the very bright fluorescence due to the suppression of π-π interactions inside the particles," explained Habuchi.

The researchers validated their hypothesis by comprehensive photophysical and structural characterizations. "That was the most exciting moment of our project," added Habuchi, noting that this demonstration has opened a new door for the correct prediction of the fluorescence properties of Pdots.

"We are now trying to introduce functional groups into these Pdots for bioconjugation," Habuchi continued. The team is also designing and fabricating near-infrared-emitting nanoparticles.

King Abdullah University of Science & Technology (KAUST)

Related Particles Articles:

Sound waves direct particles to self-assemble, self-heal
Berkeley Lab scientists have demonstrated how floating particles will assemble and synchronize in response to acoustic waves.
'Immunoswitch' particles may be key to more-effective cancer immunotherapy
Scientists at Johns Hopkins have created a nanoparticle that carries two different antibodies capable of simultaneously switching off cancer cells' defensive properties while switching on a robust anticancer immune response in mice.
Heavy particles get caught up in the flow
By teasing out signatures of particles that decay just tenths of a millimeter from the center of a trillion-degree fireball that mimics the early universe, nuclear physicists smashing atoms at the Relativistic Heavy Ion Collider (RHIC) are revealing new details about the fundamental particles that make up our world.
Finding the 'ghost particles' might be more challenging than what we thought
Results from the NEOS experiment on sterile neutrinos differ partly from the theoretical expectations.
'Ghost particles' could improve understanding the universe
New measurements of neutrino oscillations, observed at the IceCube Neutrino Observatory at the South Pole, have shed light on outstanding questions regarding fundamental properties of neutrinos.
New microscope chemically identifies micron-sized particles
A team from MIT Lincoln Labs have developed a microscope that can chemically identify individual micron-sized particles.
Calculating 1 billion plasma particles in a supercomputer
At the National Institutes of Natural Sciences National Institute for Fusion Science (NIFS) a research group using the NIFS 'Plasma Simulator' supercomputer succeeded for the first time in the world in calculating the movements of one billion plasma particles and the electrical field constructed by those particles.
Quantum particles form droplets
In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: the atoms form a new type of quantum liquid or quantum droplet state.
Clarifying the plasma oscillation by high-energy particles
The National Institute for Fusion Science has developed a new code that can simulate the movement of plasma and, simultaneously, the movement of particles circulating at high speeds.
An Archimedes' screw for groups of quantum particles
A scheme proposed by researchers from the Centre for Quantum Technologies at the National University of Singapore and their international collaborators that uses 'topological pumping' could move information about inside future quantum computers.

Related Particles Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Climate Crisis
There's no greater threat to humanity than climate change. What can we do to stop the worst consequences? This hour, TED speakers explore how we can save our planet and whether we can do it in time. Guests include climate activist Greta Thunberg, chemical engineer Jennifer Wilcox, research scientist Sean Davis, food innovator Bruce Friedrich, and psychologist Per Espen Stoknes.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...