Magnetic Cellular ‘Legos’ For Tissue Engineering

By incorporating magnetic nanoparticles in cells and developing a system using miniaturized magnets, researchers from 3 associated universities* in Paris (France) , have succeeded in creating cellular magneticLegos.” They were able to aggregate cells using only magnets and without an external supporting matrix, with the cells then forming a tissue that can be deformed at will. This approach, which is detailed in Nature Communications, could prove to be a powerful tool for biophysical studies, as well as the regenerative medicine of tomorrow.

Nanotechnology has quickly swept across the medical field by proposing sometimes unprecedented solutions at the furthest limits of current treatments, thereby becoming central to diagnosis and therapy, notably for the regeneration of tissue. A current challenge for regenerative medicine is to create a cohesive and organized cellular assembly without using an external supporting matrix. This is a particularly substantial challenge when it involves synthesizing thick and/or large-sized tissue, or when these tissues must be stimulated like their in vivo counterparts (such as cardiac tissue or cartilage) in order to improve their functionality.

The researchers met this challenge by using magnetism to act on the cells at a distance, in order to assemble, organize, and stimulate them. Cells, which are the building blocks of tissue, are thus magnetized in advance through the incorporation of magnetic nanoparticles, thus becoming true cellular magnetic “Legos” that can be moved and stacked using external magnets. In this new system acting as a magnetic tissue stretcher, the magnetized cells are trapped on a first micromagnet, before a second, mobile magnet traps the aggregate formed by the cells. The movement of the two magnets can stretch or compress the resulting tissue at will.

Researchers first used embryonic stem cells to test their system. They began by showing that the incorporation of nanoparticles had no impact on either the functioning of the stem cell or its capacity for differentiation. These functional magnetic stem cells were then tested in the stretcher, in which they remarkably differentiated toward cardiac cell precursors when stimulation imposed “magnetic beating” imitating the contraction of the heart. These results demonstrate the role that purely mechanical factors can play in cell differentiation.

This “all-in-one” approach, which makes it possible to build and manipulate tissue within the same system, could thus prove to be a powerful tool both for biophysical studies and tissue engineering.

* Laboratoire Matière et Systèmes Complexes (CNRS/Université Paris Diderot), in collaboration with the Laboratoire Adaptation Biologique et Vieillissement (CNRS/UPMC) and the Centre de Recherche Cardiovasculaire de Paris (Inserm/Université Paris Descartes)

Source: https://www.nature.com/
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https://eurekalert.org/

Single Molecule LED For NanoComputer

The ultimate challenge in the race to miniaturize light emitting diodes (LED) has now been met: a team led by the Institut de Physique et de Chimie des Matériaux de Strasbourg (IPCMS, France, CNRS/Université de Strasbourg), in collaboration with UPMC and CEA, has developed the first ever single-molecule LED.
The device is formed from a single polythiophene wire placed between the tip of a scanning tunneling microscope and a gold surface. It emits light only when the current passes in a certain direction.
This experimental tour de force sheds light on the interactions between electrons and photons at the smallest scales. Moreover, it represents yet another step towards creating components for a molecular computer or nanocomputer in the future.

ledelectroluminescence in a single polythiophene molecular wire suspended between the tip and the surface of a scanning tunneling microscope

Light emitting diodes are components that emit light when an electric current passes through them and only let light through in one direction. LEDs play an important role in everyday life, as light indicators. They also have a promising future in the field of lighting, where they are progressively taking over the market. A major advantage of LEDs is that it is possible to make them very small, so point light sources can be obtained. With this in mind, one final miniaturization hurdle has recently been overcome by researchers at IPCMS in Strasbourg, in collaboration with a team from the Institut Parisien de Chimie Moléculaire (CNRS/UPMC): they have produced the first ever single-molecule LED! To achieve this, they used a single polythiophene wire. This substance is a good electricity conductor. It is made of hydrogen, carbon and sulfur, and is used to make larger LEDs that are already on the market.
Source; http://www2.cnrs.fr/

3 Times Less Radiation Doses To Cure Cancer

Targeted radiation therapy that is less harmful to healthy cells could see the light of day thanks to a team of French researchers from the Laboratoire de Chimie Physique – Matière et Rayonnement (CNRS/UPMC) – Paris – working in collaboration with German and American scientists. Until now, radiotherapy treatments employed to combat cancer used a wide energy range when irradiating biological tissues. By studying at a fundamental level the behavior of molecules subjected to radiation with a carefully chosen energy, the researchers paved the way for tomorrow’s radiotherapy treatments, which would not affect as much surrounding tissue and whose total radiation dose would be considerably reduced (at least 3 times less).

Radiotherapy_2
With specific molecules sticked to the cancerous cells, we could theoretically reduced up to 3 times the radiation doses” says Marc Simon, Research Director, co-author of the study from Université Pierre et Marie Curie – Paris 6.

This work, which sheds new light on the behavior of matter at the atomic scale and which could have important benefits in medicine, is published on 22 December 2013 on the website of the journal Nature.
Source: http://www2.cnrs.fr/

Color In Brown Your White Hair For Good

A french team led by Philippe Walter from University Pierre et Marie CurieUPMC– in Paris , France explain that gold nanoparticles — 40,000-60,000 of which could fit across the width of a human hair — are a hot topic. Scientists are exploring uses, ranging from electronics and sensors to medical diagnostic tests and cancer treatments. Gold nanoparticles have been deposited on hair for use as electrodes, and gold nanoparticles had been used to dye wool. Walter’s team looked at a new use — dyeing hair, inspired by the ancient Greeks’ and Romans’ use of another metal, lead, to color their hair. In their discovery scientists are reporting the first synthesis of gold nanoparticles inside human hairs. Their study appears in ACS’ journal Nano Letters.

Gold nanoparticles darken hair after treatment for one day, center,
and 16 days, right (untreated hairs, left).

After soaking white hairs in a solution of a gold compound, the hairs turned pale yellow and then darkened to a deep brown. Using an electron microscope, the scientists confirmed that the particles were forming inside the hairs’ central core cortex. The color remained even after repeated washings.
Source: http://portal.acs.org