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Nanociencia y nanotecnologías

El limpiador de arterias tipo 2 - Ilustración de

El limpiador de arterias tipo 2 - Ilustración de

En pirmer plano, se observa un robot limpiador de arterias y algo mas arriba, su robot supervisor. Interpretación del artista. Nanomedicine Art Gallery, The Foresight Institute

Microscopía de Fuerza Atómica: de la imagenología a la manipulación molecular

Microscopía de Fuerza Atómica: de la imagenología a la manipulación molecular

Los sistemas biológicos solo pueden ser comprendidos cabalmente si se conoce su estructura. El Microscopio de Fuerza Atómica (AFM) es una de las herramientas más poderosas para determinar la topografía superficial de las biomoléculas nativas con una resolución subnanométrica.

A diferencia de la microscopía electrónica y de la cristalografía de rayos X, el AFM permite, en ciertas circunstancias experimentales, la imagenología de moléculas no solo bajo condiciones relativamente fisiológicas, sino además cuando los procesos biológicos están en acción.

Empleando una punta extremadamente delgada en el extremo de un cantilever que oficia de sonda, el AFM puede explorar la topografía superficial de una gran variedad de  especímenes biológicos.

En la figura acompañante se ilustra esquemáticamente, en la parte superior, coloreada en amarillo, gris y rojo, la estructura molecular de la punta del cantilever, con su extremo inferior rojo  (que contacta la muestra) y bajo esa punta se representa la muestra con la molécula -pentacene- estudiada sobre un fondo azul y verde. Más abajo, sobre fondo negro, se representa la estructura atómica que se logró como conclusión de este estudio. Y mas abajo aún, en tonos de gris, la imagen experimental, obtenida con el AFM.

La obtención de imágenes biológicas se ha enfrentado con algunas dificultades mayores debido a la escasa dureza  y gran dinámica de la mayoría de los materiales biológicos.

El progreso en nuestra comprensión de las interacciones entre la punta de la sonda del AFM y las muestras biológicas ha proporcionado resultados espectaculares en diferentes áreas biológicas. Numerosos ejemplos recientes ilustran las inmensas posibilidades que ofrece el AFM para la imagenología de células intactas, de membranas aisladas, los sistemas modelo de membranas y las moléculas aisladas trabajando.

En los últimos años, este microscopio ha ido ganando gran popularidad entre los biólogos debido al rápido perfeccionamiento de los equipos y las técnicas imagenológicas, y en gran medida por el importante desarrollo de nuevas aplicaciones no-imagenológicas, algunas de las cuales, por ejemplo,  permiten  explorar las propiedades elásticas, o químicas de las moléculas superficiales de la muestra estudiada.

Son relevantes las aplicaciones en las que la punta del AFM se usa como nano-herramienta para manipular biomoléculas y para determinar las fuerzas intra- e intermoleculares de moléculas individuales. Por ejemplo, nos da información sobre las propiedades de binding de los sistemas biológicos.

Silver sputtered nano chips mimic brain synapse


04 March 2010

US researchers aiming to emulate the functionality of a cat’s brain have developed an easily-fabricated, robust nanoscale device that imitates the connectivity between neurons in the brain.

The two-terminal electronic device, known as a memristor (’memory’ + ’resistor’), is similar to a biological synapse in that its conductance can be precisely changed by controlling the charge running through it. The researchers found that changing the way they embedded silver ions in the silicon-based devices improved their performance.

A memristor’s resistance is controlled by its ’memory’ of the currents and voltages it has been exposed to. ’It can be employed to build a computer in the way that nature builds brains,’ explained Wei Lu of the University of Michigan, Ann Arbor. 

The first memristor was made in 2008 from titanium dioxide, which is difficult to integrate with traditional silicon computer chips. Silicon-based devices have since followed, although the resistance change is abrupt. Now Lu’s team has produced silicon memristors that work more smoothly. ’The new design emulates biological systems better because the change is more gradual and can be more precisely controlled,’ he says. 

In the memristor, current flow is associated with ion motion, changing its resistance as they move. Previous memristors introduced silver ions to perform this function into the silicon from an electrode deposited on top. However, this process carves localised conduction channels responsible for the abrupt changes. 

How the memristors work

How memristors can act as synapses between neurons, with schematics of the memristor structure and the two-terminal device in the insets.

© Nano Letters, American Chemical Society

Instead, Lu’s students Sung-Hyun Jo and Ting Chang introduced silicon and silver simultaneously via co-sputtering. Using an argon plasma, they ejected atoms from pure elemental targets into a vacuum chamber containing the partially-fabricated memristors. The atoms deposit onto the device in a 20-30nm thick film, allowing easy control over the ratio between the two components. ’The device can endure at least 150 million write and erase cycles,’ Lu told Chemistry World. ’When you write and erase other systems a few thousand times, performance typically starts to degrade.’ 

Memristors can simulate synapses because electrical synaptic connections between two neurons can seemingly strengthen or weaken depending on when the neurons fire. Lu and colleagues demonstrated that their memristor performs an equivalent function with a conventional silicon-based circuit acting as neurons, raising and lowering the memristor’s resistance. The team is part of a US Defense Advanced Research Projects Agency programme that aims to create computers that mimic biological neural systems. ’These will be the components we will use to make the hardware version of a cat brain,’ Lu said. 

Nadine Gergel-Hackett, who researches memristor technology at the US National Institute of Standards and Technology, acknowledges the Michigan team’s successful creation of a brain synapse analogue. ’This work is a large step towards the realisation of biology-inspired computing,’ she says. 

Andy Extance 

 

La nanomedicina es promisoria en el tratamiento de las lesiones de la médula espinal

La nanomedicina es promisoria en el tratamiento de las lesiones de la médula espinal

En la parte superior de la Fig. se representan cuatro micelas de co-polímero

 

Un grupo de investigadores de la Universidad de Purdue descubrieron una nueva forma de reparar las fibras nerviosas dañadas en las lesiones de la médula espinal. Usan nano-esferas  que pueden ser inyectadas por vía sanguína casi enseguida de un accidente.

Las micelas sintéticas de copolímero son esferas de unos 60 nm de diametro, que están resultando muy útiles para llevar drogas o fármacos a determninados lugares del organismo.  Con esas dimensiones, son unas 100 veces mas pequeñas que el diametro de un glóbulo rojo.

Los investigadores de Purdue han comprobado que las mismas micelas reparan axones dañados. "Fue un descubrimiento sorprendente", dijo el científico  Ji-Xin Cheng, ya que las micelas  han sido usadas por 30 años como "drug-delivery vehicles" en investigación" y, sin embargo, estas propiedades de reparar axones que poseen las micelas de copolímero habían pasado desapercibidas.

Nuevo Chip Detecta Tipo y Severidad de Cáncer

Nuevo Chip Detecta Tipo y Severidad de Cáncer

Noticia original en inglés. Fuente: Physorg.com

Investigadores de la Universidad de Toronto, usando nanomateriales, desarrollaron un microchip con la sensibilidad necesaria como para detectar el tipo y la severidad de la  enfermedad en pacientes con cáncer, de modo que la enfermedad puede ser detectada antes y así ser sometida a un tratamiento mas efectivo.

Their groundbreaking work, reported Sept. 27 in Nature Nanotechnology heralds an era when sophisticated molecular diagnostics will become commonplace.

"This remarkable innovation is an indication that the age of nanomedicine is dawning," says Professor David Naylor, president of the University of Toronto and a professor of medicine. "Thanks to the breadth of expertise here at U of T, cross-disciplinary collaborations of this nature make such landmark advances possible."

The researchers’ new device can easily sense the signature biomarkers that indicate the presence of cancer at the cellular level, even though these biomolecules - genes that indicate aggressive or benign forms of the disease and differentiate subtypes of the cancer - are generally present only at low levels in biological samples. Analysis can be completed in 30 minutes, a vast improvement over the existing diagnostic procedures that generally take days.

"Today, it takes a room filled with computers to evaluate a clinically relevant sample of cancer biomarkers and the results aren’t quickly available," says Shana Kelley, a professor in the Leslie Dan Faculty of Pharmacy and the Faculty of Medicine, who was a lead investigator on the project and a co-author on the publication.

"Our team was able to measure biomolecules on an electronic chip the size of your fingertip and analyse the sample within half an hour. The instrumentation required for this analysis can be contained within a unit the size of a BlackBerry."

Kelley, along with engineering professor Ted Sargent - a fellow lead investigator and U of T’s Canada Research Chair in Nanotechnology - and an interdisciplinary team from Princess Margaret Hospital and Queen’s University, found that conventional, flat metal electrical sensors were inadequate to sense cancer’s particular biomarkers. Instead, they designed and fabricated a chip and decorated it with nanometre-sized wires and molecular "bait."

"Uniting DNA - the molecule of life - with speedy, miniaturized electronic chips is an example of cross-disciplinary convergence," says Sargent. "By working with outstanding researchers in nanomaterials, pharmaceutical sciences, and electrical engineering, we were able to demonstrate that controlled integration of nanomaterials provides a major advantage in disease detection and analysis."

The speed and accuracy provided by their device is welcome news to cancer researchers.

"We rely on the measurement of biomarkers to detect cancer and to know if treatments are working," says Dr. Tom Hudson, president and scientific director of the Ontario Institute for Cancer Research. "The discovery by Dr. Kelley and her team offers the possibility of a faster, more cost-effective technology that could be used anywhere, speeding up diagnosis and helping to deliver a more targeted treatment to the patient."

The team’s microchip platform has been tested on prostate cancer, as described in a paper published in ACS Nano, and head and neck cancer models. It could potentially be used to diagnose and assess other cancers, as well as infectious diseases such as HIV, MRSA and H1N1 flu.

"The system developed by the Kelley/Sargent team is a revolutionary technology that could allow us to track biomarkers that might have significant relevance to cancer, with a combination of speed, sensitivity, and accuracy not available with any current technology," says Dr. Fei-Fei Liu, a radiation oncologist at Princess Margaret Hospital and Head of Applied Molecular Oncology Division, Ontario Cancer Institute. "This type of approach could have a profound impact on the future management for our cancer patients."

Source: University of Toronto

EuroNanoMedicine 2009, Sept 28-30, Bled, Slovenia

EuroNanoMedicine 2009, Sept 28-30, Bled, Slovenia

Mankind is still fighting against a high number of serious and complex illnesses like cancer, cardiovascular diseases, multiple sclerosis, Alzheimer’s and Parkinson’s disease, and diabetes as well as different kinds of serious inflammatory or infectious diseases (e.g. HIV). Nanomedicine, the application of nanotechnology to health, raises high expectations for millions of patients for better, more efficient and affordable healthcare and has the potential of delivering promising solutions to many illnesses.

Several areas of medical care are already benefiting from the advantages that nanotechnology can offer. I.e., the first nanotechnology-based targeted drug delivery systems are already on the market, others are in clinical trials or, by far the largest part, are under development. The promising possibilities that nanomedicine might offer in the future have to be counterweighted against possible risks of this new technology. It is of utmost importance to examine upfront with care and responsibility its possible side effects to human beings and the environment.

The programme of this conference will cover current topics and recent progress in this highly challenging field. In detail all aspects of targeted nanomedicine and therapeutic concepts, overcoming biological barriers, medical diagnostics and sensor devices, nanomedicine and regenerative medicine, nanomedicine for gene delivery, and safety aspects of nanomaterials for medical applications will be addressed.