Illustration
of the fluorescence "On" process. Credit: WANG Yanfang et al.
Photothermal
therapy (PTT) is a promising alternative method for cancer treatment due to
advantages of non-invasiveness, precise temporal and spatial control, strong
specificity and high tumor destruction efficiency.
At
present, the clinical evaluation of cancer treatment mainly relies on cytology,
histopathology and imaging. Meanwhile, tumor therapy and its therapeutic
efficiency evaluation are conducted separately.
Recently,
a research group led by Prof. Liang Gaolin from University of Science and
Technology of China (USTC) of Chinese Academy of Science, collaborating with
Dr. Wang Longsheng from the Second Affiliated Hospital of Anhui Medical
University, reported an 'intelligent' strategy of using organic nanoparticles
to evaluate PTT efficiency on tumor in real time.
The study
was published online in ACS Nano on July 27.
Via a
CBT-Cys click condensation reaction, the researchers designed a small molecular
near-infrared probe Cys(StBu)-Asp-Glu-Val-Asp-Lys(Cypate)-CBT (Cy-CBT) and
prepared an intelligent nanoparticle Cy-CBT-NP, which is a
fluorescence-quenched photothermal nanoparticle.
After
tumor cells' uptake of Cy-CBT-NP, the tumor was treated with photothermal
therapy under 808 nm laser irradiation. During the PTT, the tumor cell
eventually died and the Caspase 3 (Casp 3) was activated.
Casp 3
specifically recognized and cleaved DEVD substrates in the Cy-CBT-NP to yield
Cy-CBT-NP-Cleaved which was accompanied by near-infrared fluorescence (NIF),
turning the fluorescence 'on.'
Because
the PTT efficiency, Casp3 activity, and the turned-on NIR fluorescence
intensity are positively correlated, this intelligent nanoparticle Cy-CBT-NP
can be used to evaluate the tumor photothermal efficiency in real time.
Compared
with the traditional tumor efficiency evaluation method, the strategy is
real-time and can help doctors adjust the treatment plan in time.
How to
make non-magnetic materials magnetic
A complex
process can modify non-magnetic oxide materials in such a way to make them
magnetic. The basis for this new phenomenon is controlled layer-by-layer growth
of each material. An international research team with researchers from Martin
Luther University Halle-Wittenberg (MLU) reported on their unexpected findings
in the journal Nature Communications.
In
solid-state physics, oxide layers only a few nanometres thick are known to form
a so-called two-dimensional electron gas. These thin layers, separated from one
another, are transparent and electrically insulating materials. However, when
one thin layer grows on top of the other, a conductive area forms under certain
conditions at the interface, which has a metallic shine. "Normally this
system remains non-magnetic," says Professor Ingrid Mertig from the Institute
of Physics at MLU. The research team has succeeded in controlling conditions
during layer growth so that vacancies are created in the atomic layers near the
interface. These are later filled in by other atoms from adjoining atomic
layers.
The
theoretical calculations and explanations for this newly discovered phenomenon
were made by Ingrid Mertig's team of physicists. The method was then
experimentally tested by several research groups throughout Europe—including a
group led by Professor Kathrin Dörr from MLU. They were able to prove the
magnetism in the materials. "This combination of computer simulations and
experiments enabled us to decipher the complex mechanism responsible for the
development of magnetism," explains Mertig.