A research team in Asia has developed a method for tracking, or etracingf, cells that overcomes the limitations of existing methods. The teamfs fluorescent organic tracers will provide researchers with a non-invasive tool to continually track biological processes for long periods. Applications for the tracers include following carcinogenesis or the progress of interventions such as stem cell therapies.
Bin Liu and Ben Zhong Tang of the A*STAR Institute of Materials Research and Engineering in Singapore and their co-workers developed probes composed of a small number of molecules that aggregate. The aggregation means that the probes have more detectable fluorescence and less leakage than that provided by single-molecule probes. Importantly, rather than eblinkf, the teamfs tracers show steady fluorescence, and do not contain heavy metal ions that can be toxic for living systems.
Compared with their existing inorganic counterparts, the teamfs carbon-based tracers show greater chemical stability and improved biocompatibility with cell biochemistry. They are also more resistant to bleaching by light and do not interfere with normal biochemical processes. Furthermore, the fluorescent signals emitted by the probes do not overlap with the signal naturally emitted by cells.
The tracers developed by Liu, Tang and their colleagues are examples of fquantum dotsf, as they are composed of a small number of molecules with optical characteristics that rely on quantum-mechanical effects. Technically, they are referred to as aggregation-induced emission dots (AIE dots) as they become photostable and highly efficient fluorescent emitters when their component molecules aggregate.
The assembly of the AIE dots began with the synthesis of organic molecules, specifically 2,3-bis(4-(phenyl(4-(1,2,2-triphenylvinyl)phenyl)amino)phenyl)fumaronitrile (TPETPAFN), which the researchers then encapsulated in an insoluble lipid-based matrix. Next, the researchers attached small peptide molecules derived from the human immunodeficiency virus (HIV) to exploit the ability of these peptides to promote efficient uptake of AIE dots into living cells.
gOur AIE dots could track isolated human breast cancer cells in vitro for 10 to 12 generations and glioma tumor cells in vivo in mice for 21 days,h says Liu. gThey outperform existing commercial inorganic quantum dots, and open a new avenue in the development of advanced fluorescent probes for following biological processes such as carcinogenesis, stem cell transplantation and other cell-based therapies.h
Future work by Liu, Tang and co-workers will aim to broaden the application of the organic tracers for their use in conjunction with magnetic resonance and nuclear imaging techniques.The A*STAR]affiliated researchers contributing to this research are from the Institute of Materials Research and Engineering
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Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
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Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
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Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
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