Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Bio-imaging: Probing for deeper diagnostics

01.08.2013
Multi-armed polymers with dual fluorescent and magnetic imaging capabilities boost the resolution of cancer detection tools

Molecular probes that selectively latch onto tumor cells and emit imaging signals can detect cancer without invasive procedures. These tools, however, have specific deficiencies. Fluorescent probes that image individual molecules have poor depth penetration into cells.

The alternative, magnetic resonance imaging (MRI) probes, resolves cells in three dimensions but with low resolution. Bin Liu at the A*STAR Institute of Materials Research and Engineering, Singapore, and co-workers have now solved this problem with a biocompatible polymer that combines MRI and fluorescence imaging in a single molecular probe1.

According to Liu, designing a probe with joint imaging capabilities is challenging because fluorescent and MRI-active materials display different biological behaviors. Substances that emit fluorescent light are often lethal to cells at low concentrations. In contrast, to produce sufficient imaging signals, MRI probes require substantial injections of substances called chelated gadolinium (Gd(III)) agents.

Liu and her team devised a strategy to overcome the dissimilar dosage requirements with polymers known as ‘hyperbranched’ polyglycerols (HPGs). These materials have a tree-like structure of repeating molecular units that radiate from a core. HPGs also have a promising biomedical track record because of their water solubility and low cytotoxicity. Liu and co-workers envisaged using HPGs to encapsulate fluorescent organic molecules as their core. Then, they reasoned, high densities of Gd(III) agents could attach to the numerous hydroxyl attachment points present on the HPG surfaces.

After synthesizing a fluorescent molecule consisting of fused aromatic rings, the researchers attached eight of them to a rigid polysilicate cage, known as polyhedral oligomeric silsesquioxane. With the stable core in place, they initiated growth and outward branching of the HPG into a spherical protective shell — a tricky procedure, notes Liu, as it required carefully controlling the reagents and polymerization conditions. The new nanospherical probe converted over 50% of light photons into fluorescent emissions, a remarkably high quantum yield arising from the water-repellent nature of the dense HPG shell.

Next, the team attached Gd(III) agents to the probe’s exterior and tested its dual detection capabilities inside MCF-7 breast cancer cells. Both MRI and fluorescence imaging revealed that the nanoprobe was well integrated into cell structures with no obvious changes to cell viability. The probe demonstrated high photostability when exposed to laser light — a key attribute for fluorescence imaging — and had promising magnetic properties that compared favorably with commercial MRI probes. “Combining both imaging techniques in one probe simultaneously boosts resolution and penetration depth,” says Liu. “The different signals can also validate each other to improve detection accuracy.”

The A*STAR-affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering

References

Liu, J., Li, K., Geng, J., Zhou, L., Chandrasekharan, P., Yang, C.-T. & Liu, B. Single molecular hyperbranched nanoprobes for fluorescence and magnetic resonance dual modal imaging. Polymer Chemistry 4, 1517–1524 (2013). | article

Associated links
http://www.research.a-star.edu.sg/research/6707

A*STAR Research | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6707
http://www.researchsea.com

More articles from Medical Engineering:

nachricht PET identifies which prostate cancer patients can benefit from salvage radiation treatment
05.12.2017 | Society of Nuclear Medicine and Molecular Imaging

nachricht Designing a golden nanopill
01.12.2017 | University of Texas at Austin, Texas Advanced Computing Center

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>