A fluorescent nanoprobe could become a universal, noninvasive method to identify and monitor tumors
A*STAR researchers have developed a hybrid metal–polymer nanoparticle that lights up in the acidic environment surrounding tumor cells. Nonspecific probes that can identify any kind of tumor are extremely useful for monitoring the location and spread of cancer and the effects of treatment, as well as aiding initial diagnosis.
Cancerous tumors typically have lower than normal pH levels, which correspond to increased acidity both inside the cells and within the extracellular microenvironment surrounding the cells. This simple difference between tumor cells and normal cells has led several research groups to develop probes that can detect the low pH of tumors using optical imaging, magnetic resonance and positron emission tomography.
Most of these probes, however, target the intracellular pH, which requires the probes to enter the cells in order to work. A greater challenge has been to detect the difference in extracellular pH between healthy tissue and tumor tissue as the pH difference is smaller. Success would mean that the probes are not required to enter the cells.
“Our aim is to address the challenge of illuminating tumors universally,” says Bin Liu from the A*STAR Institute of Materials Research and Engineering. Liu’s team, together with colleagues from the National University of Singapore, based their new probe on polymers that self-assemble on gold nanoparticles. The resulting hybrid structure is not fluorescent at normal physiological pH values: instead acidic conditions similar to those around tumor cells of approximately pH 6.5 alter chemical groups on the surface of the probes and switch on their fluorescence.
After validating the switching mechanism in pH-controlled solutions, the researchers tested the probes using cultured cells and also in tumor-bearing mice illuminated under bright light. Twenty-four hours after injection into the mice, obvious and clear fluorescence was seen only from tumor-bearing tissue, using either whole-body imaging or examination of removed organs (see image). The ability to observe the fluorescence of tumors using noninvasive whole-body examination of living mice indicates the potential of the nanoprobes for use in clinical situations with human patients.
“Our probes have so far proved to be biocompatible, which will be crucial for biomedical applications,” says Liu. “We now plan to check further for any toxicity issues and assess the biological distribution and pharmacological profile of the probes before hopefully moving on to clinical trials,” she adds. This is the latest of several recent advances in nanoscale medical technology from Liu’s group.
 Yuan, Y., Ding, D., Li, K., Liu, J. & Liu, B. Tumor-responsive fluorescent light-up probe based on a gold nanoparticle/conjugated polyelectrolyte hybrid. Small 10, 1967–1975 (2014).
A*STAR Research | ResearchSEA
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences