Un inventor 100% colombiano

César Sierra, investigador de la U. Nacional, creó una tela que mata bacterias y una bolsa para enviar frutas a Europa, entre otros inventos.

César Sierra, químico e investigador de la Universidad Nacional. / Pablo Correa

El colombiano Juan Pablo Hinestroza, profesor en la Universidad de Cornell y experto en textiles inteligentes, cuenta que llevaba dos años y US$1,2 millones invertidos buscando el método para que pequeñas partículas conocidas como MOF (diminutas estructuras porosas) se adhirieran de forma estable a fibras de ropa, pero todos sus esfuerzos habían fracasado. Entonces alguien le habló de César Sierra, químico de la Universidad Nacional, y la suerte del proyecto cambió.

Sierra viajó a Estados Unidos y en tan sólo un mes de trabajo encontró la solución al problema que tenía desesperado a su colega. Patentaron en Estados Unidos la técnica para que las MOF queden adheridas a las fibras textiles. Hoy, varias multinacionales de ropa han mostrado su interés en la técnica, pues es un nuevo paradigma para crear telas con propiedades muy especiales. Por ejemplo fabricar jeans que no huelan cuando estén sucios o ropa interior que pueda durar hasta 45 días sin lavar.

“César es el químico más recursivo que he conocido. Es brillante. Ahora creo en milagros después de ver cómo trabajan los científicos en Colombia”, dice Hinestroza. Esta semana los dos científicos colombianos, junto a los investigadores Carlos Soto, Haendel Rodríguez y Cristian Ochoa, firman un artículo publicado por la revista Journal of Applied Polymer en el que dan cuenta de otro invento prometedor: telas que matan bacterias.

Desde hace siglos se sabe que metales como la plata matan bacterias al entrar en contacto con ellas. No está muy clara la cadena de eventos celulares que conduce a la muerte de las bacterias, pero el efecto antibacterial de los metales es incuestionable. Bajo ese principio, Sierra y el grupo de colaboradores de ambas universidades lograron fijar nanopartículas de cobre a una tela y demostraron que el 100% de las bacterias Escherichia coli y Staphylococcus aureus, responsables de buen número de infecciones intrahospitalarias, mueren al entrar en contacto con la tela.

“Con telas como estas se podrían fabricar sábanas de hospitales, uniformes de médicos y enfermeras, pijamas para los pacientes, y así reducir el riesgo de infecciones”, explica Sierra. Ahora el reto es lograr extender el efecto bactericida a otras bacterias que pululan en los hospitales. Sierra ya tiene una solución en mente. Cree que si logran que todas las partículas metálicas sean del mismo tamaño, la eficiencia bactericida aumentará y cubrirá un espectro mayor de microorganismos.

Cuando se graduó del colegio que dirigía su abuelo en Barrancabermeja, Sierra tenía dos cosas claras: quería ser militar y por ninguna razón se iba a quedar trabajando en la finca de su familia. Sus planes de ir al ejército se frustraron porque su mamá no lo autorizó. Entonces pensó en estudiar una carrera universitaria y la novia de su hermano, que estudiaba química en la Universidad Industrial de Santander (UIS), se ofreció a ayudarlo. Fue ella la responsable de que se convirtiera en químico, pues compró el formulario de inscripción y sin preguntarle lo anotó en la lista de candidatos a la carrera de química.

“Fue amor a primera vista”, confiesa Sierra. En el colegio ya sentía interés por las matemáticas y la física, así que cuando comenzaron las clases sobre los elementos fundamentales de la materia y sus interacciones se sintió en el lugar correcto.

Cuando estaba entrando al último año de la carrera consiguió un trabajo con la multinacional Dow, que lo obligaba a viajar visitando clientes que tuvieran algún problema. Así se fue desarrollando su talento para solucionar situaciones difíciles. Cuando la empresa decidió irse del país, un colega volvió a señalarle el camino, como ya lo había hecho la novia de su hermano: “Usted debería estudiar un doctorado, usted es bueno para eso”.

Consiguió una beca y viajó a Estados Unidos, donde estudió una maestría y un doctorado en la Universidad de Massachusetts. En 2005 regresó a Colombia y, luego de un breve paso por la UIS, ganó un concurso docente en la Universidad Nacional y comenzó a trabajar en el Departamento de Química. Entre sus primeras creaciones está un material que al entrar en contacto con gases como el metano se ilumina; un desarrollo con potencial en la industria minera, pues podría hacer parte de los sistemas de seguridad para mineros.

Pero uno de los inventos que más lo enorgullecen es el desarrollo de un empaque para gulupa, una fruta de la cual Colombia exporta a Asia, Europa y América 3.000 toneladas cada año. Los exportadores colombianos se quejaban porque el largo viaje de casi 35 días que debe hacer la carga por barco hasta sus destinos terminaba arruinando el 25% de las frutas. Para evitar este desastre, los comerciantes se veían obligados a comprar unas bolsas fabricadas en Israel que conservan mejor la fruta, pero cuyo precio por unidad ronda los $400 pesos.

César y sus colaboradores desarrollaron un empaque a mucho menor precio ($10 pesos por unidad), que prolonga la vida de la fruta por más días y que evita su deshidratación. El problema, dos años después, es que no ha sido posible resolver todos los líos jurídicos en Colombia para patentar el invento.

Sierra no deja que esas cosas hagan mella en su optimismo y parece que no va a claudicar en su intento de acercar la investigación académica a los problemas de la industria en el país.

pcorrea@elespectador.com

@pcorrea78

ORIGINAL: El Espectador

Por: Pablo Correa

14 Mayo 2014

Scientists in US and Japan achieve possible breakthrough on stem cells

A lab treatment can turn a mouse's ordinary cells into stem cells, a surprising study has found. The research hints at a possible new way to grow tissue for treating illnesses such as diabetes and Parkinson's disease.

 

Scientists reported in this week's Nature journal that they had found a way to reprogram mature mouse cells into an embryonic-like state that allows them to generate many types of tissue. The research suggests that scientists could in the future similarly reprogram human cells, offering a simpler way to replace damaged cells or grow new organs for sick and injured people. The experiments, reported in two papers in the journal Nature on Wednesday, involved scientists from the RIKEN Center for Developmental Biology in Japan and Brigham and Women's Hospital and Harvard Medical School in the United States.

"It's very simple to do," said Dr. Charles Vacanti of Brigham and Women's Hospital in Boston. "I think you could do this actually in a college lab."

Vacanti acknowledged that the technique could conceivably provide a new potential route towards cloning people - a subject that remains highly controversial. He has no interest in doing that, he said, but "it is a concern."

'A wide range'

Researchers wrote that they allowed mature adult cells from the mice to multiply and then subjected them to stress "almost to the point of death" by exposing them to various events, including trauma, low oxygen levels and acidic environments. Within days, the scientists found that the cells had survived and recovered from the stressful stimulus by naturally reverting to a state similar to that of embryonic stem cells. The cells created by exposure to stresses - dubbed STAP cells by the researchers - then differentiated and matured into different types of cells and tissue depending on their environments.

Haruko Obokata, a scientist at the RIKEN Center for Developmental Biology in Kobe, Japan, and one of the study's co-authors, said that researchers had begun studying whether the technique might work with humans. By making stem cells from the patients themselves, doctors could get around the problem of transplant rejection.

"If we can work out the mechanisms by which differentiation states are maintained and lost, it could open up a wide range of possibilities for new research and applications using living cells," said Obokata, who led the work at RIKEN.

Many possible uses

Stem cells, the body's master cells, can develop into all other types of bodily cells. Scientists believe that, by helping to regenerate tissue, they could offer ways of tackling diseases for which only limited treatments currently exist - such as strokes, heart disease and Parkinson's. Two primary types of stem cells exist:

• those harvested from embryos and 
• adult or iPS cells, which scientists take from skin or blood and then reprogram back into stem cells.

Chris Mason, chair of regenerative medicine bioprocessing at University College London, called the study's approach "the most simple, lowest-cost and quickest method" to generate "pluripotent" cells - those able to develop into many different types - from mature cells.

"If it works in man, this could be the game changer that ultimately makes a wide range of cell therapies available using the patient's own cells as starting material," Mason said. "The age of personalized medicine would have finally arrived."

Earlier this year, German scientists reported their own research breakthough when looking at how to treat leukemia with stem cells.

mkg/msh (Reuters, AFP, AP)


ORIGINAL: DW

A unique covalent bond in basement membrane is a primordial innovation for tissue evolution

Significance

The evolution of multicellular animals from single-celled ancestors was one of the most significant transitions of life on earth. The emergence of larger, more complex animals able to resist predation and colonize new environments was enabled, in part, by a collagen scaffold, which anchors cells together to form tissues and organs. Here, we show that a unique chemical bond, a link between sulfur and nitrogen atoms called a sulfilimine bond, arose over 500 Mya, binding this scaffold together and enabling tissues to withstand mechanical forces. Peroxidasin forms the bond by generating hypohalous acids as strong oxidants, a form of bleach, which normally function as antimicrobial agents. These understandings may lead to approaches for targeting tumors and treatment of other diseases.

Fig. 1.  The sulfilimine bond stabilizes collagen IV scaffolds by the cross-linking of triple helical building block protomers.
(A) The sulfilimine bond cross-links Met93 and Hyl211 at the interface between the trimeric NC1 domains of two adjoining protomers, forming a globular hexamer structure.
(B) Dimeric subunits reflect the presence of the sulfilimine bond in human collagen IV by immunoblot (JK2 Ab) and protein stain.
(C) MS analysis of tryptic peptides derived from dimeric subunits verified the presence of the bond by a mass difference of 2.0299 between theoretical mass of uncross-linked and observed mass of cross-linked peptides and subsequent multistep CID fragmentation (MS2/MS3) analyses.

Fig. 2. Multiple sequence alignment of collagen IV NC1 domains encompassing Met93 and Hyl211 amino acid residues and Pxdn among 11 metazoan and 1 protozoan phyla.
(A) Met93 and Lys/Hyl211 (yellow) are conserved in all eumetazoans, except for the cnidarian H. magnipapillata, and they are absent in the phyla of Placozoa and Porifera and the protozoan phylum Choanozoa. All sequences belong to the collagen IV α1-like subfamily of chains, except for Drosophila (viking) and Ascaris (α2 chain).
(B) Schematic representations of Pxdn. Pxdn sequence was incomplete on both ends for Mytilus, Clytia, Trichoplax, and Monosiga and short on one end for Saccoglossus, which is indicated here by a shortened schematic representation. Sequence data were gathered from *National Center for Biotechnology Information Reference Sequence, †gathered from whole-genome shotgun/transcriptome shotgun assembly, §generated by RNA-Seq analysis of animal tissues, or ¶assembled from cDNA libraries. All National Center for Biotechnology Information GenBank accession numbers are listed in Table S1.

Fig. 3. NC1 hexamers were excised from animal basement membranes and analyzed by SDS/PAGE as shown in Fig. 1 A and B. The dimeric subunits, which indicate the presence of the bond, were found in nine major eumetazoan phyla. Among eight cnidarians investigated, only Hydra NC1 lacked dimeric subunits. All NC1s were immunoblotted against the rat monoclonal antibody, JK2, except for C. elegans (rabbit polyclonal; NW-154) and Drosophila (mouse monoclonal; 6G7). Black outlines indicate the locations of cropping for blot images. 

Fig. 4. Expression of collagen IV and Pxdn during development in zebrafish and morpholino (MO) knockdown of peroxidasin in zebrafish embryos. (A) Pxdn and collagen IV expression during zebrafish embryonic development. Real-time qPCR studies were conducted to examine expression levels of Pxdn, collagen4α1, and collagen4α2. *Student t test P value < 0.03 compared with expression at 1,000 cells. Error bars = SEM. Blue, pxdn; red, col4a; black, col4a2. (B) Control and (C) Pxdn MO groups. MO-injected embryos displayed (D) general severe defects that include cardiac edema, smaller eyes, and gross trunk patterning defects (4/45), (E) partial curved trunk (21/45), or (F) normal development (20/45). (G) SDS/PAGE analysis of Pxdn MO embryonic phenotypes at 24 hpf by Western blot. Collagenase digests were normalized for total protein load by protein stain with SYPRO-Ruby (Fig. S8).


Abstract

Basement membrane, a specialized ECM that underlies polarized epithelium of eumetazoans, provides signaling cues that regulate cell behavior and function in tissue genesis and homeostasis. A collagen IV scaffold, a major component, is essential for tissues and dysfunctional in several diseases. Studies of bovine and Drosophila tissues reveal that the scaffold is stabilized by sulfilimine chemical bonds (S = N) that covalently cross-link methionine and hydroxylysine residues at the interface of adjoining triple helical protomers. Peroxidasin, a heme peroxidase embedded in the basement membrane, produces hypohalous acid intermediates that oxidize methionine, forming the sulfilimine cross-link. We explored whether the sulfilimine cross-link is a fundamental requirement in the genesis and evolution of epithelial tissues by determining its occurrence and evolutionary origin in Eumetazoa and its essentiality in zebrafish development; 31 species, spanning 11 major phyla, were investigated for the occurrence of the sulfilimine cross-link by electrophoresis, MS, and multiple sequence alignment of de novo transcriptome and available genomic data for collagen IV and peroxidasin. The results show that the cross-link is conserved throughout Eumetazoa and arose at the divergence of Porifera and Cnidaria over 500 Mya. Also, peroxidasin, the enzyme that forms the bond, is evolutionarily conserved throughout Metazoa. Morpholino knockdown of peroxidasin in zebrafish revealed that the cross-link is essential for organogenesis. Collectively, our findings establish that the triad—a collagen IV scaffold with sulfilimine cross-links, peroxidasin, and hypohalous acids—is a primordial innovation of the ECM essential for organogenesis and tissue evolution.

Footnotes

1A.L.F., R.M.V., and S.V.C. contributed equally to this work.

2A list of The Aspirnaut coauthors can be found in Table S2. Aspirnaut is a K--20 Science, Technology, Engineering, and Math (STEM) pipeline program for diversity that partners the experiential and content expertise of Vanderbilt University with rural kindergarten through 12th grade schools and diverse high school, undergraduate, and graduate students.

3To whom correspondence should be addressed. E-mail: billy.hudson@vanderbilt.edu.

Author contributions: R.M.V., S.V.C., V.K.P., V.P.Y., M.T.I., J.K.H., and B.G.H. designed research; A.L.F., S.V.C., G.B., V.P.Y., C.L.S., K.L.R., W.H.M., T.A.C., D.-B.B., R.E.S., and T.A. performed research; G.B. contributed new reagents/analytic tools; A.L.F., R.M.V., S.V.C., V.K.P., V.P.Y., D.-B.B., and R.E.S. analyzed data; and A.L.F. and B.G.H. wrote the paper.

The authors declare no conflict of interest.

*This Direct Submission article had a prearranged editor.

Data deposition: The sequences reported in this paper have been deposited in the GenBank database (accession nos. GAMX01000001, GAMX01000002, GAND01000001, GAND01000002, GANB01000001, GANB01000002,GAMY01000001, GAMY01000002, GANA01000001, GANA01000002, GAMZ01000002, and GANC01000002).

This article contains supporting information online at 

www.pnas.org/lookup/suppl/doi:10.1073/pnas.1318499111/-/DCSupplemental.

Freely available online through the PNAS open access option. (Full Text)

ORIGINAL: PNAS

Aaron L. Fidlera,1, 

Roberto M. Vanacorea,b,1, 

Sergei V. Chetyrkina,b,1, 

Vadim K. Pedchenkoa,b,

Gautam Bhavea,b, 

Viravuth P. Yinc, 

Cody L. Stothersa, 

Kristie Lindsey Rosed,e, 

W. Hayes McDonaldd,e,f,

Travis A. Clarkg, 

Dorin-Bogdan Borzaa,b, 

Robert E. Steeleh, 

Michael T. Ivyi, 

The Aspirnautsb,2,

Julie K. Hudsonj, and 

Billy G. Hudsona,b,c,d,f,k,l,3

Author Affiliations

Edited* by Mina J. Bissell, E. O. Lawrence Berkeley National Laboratory, Berkeley, CA, and approved November 22, 2013 (received for review September 30, 2013)

Getting CLARITY: Hydrogel process developed at Stanford creates transparent brain

Stanford bioengineers have transformed an intact, post-mortem mouse brain into a transparent three-dimensional structure that keeps all the fine wiring and molecular structures in place. Known as CLARITY, the technique stands to transform our understanding of the brain and indeed of any biological tissue.
Combining neuroscience and chemical engineering, researchers at Stanford University have developed a process that renders a mouse brain transparent. The postmortem brain remains whole — not sliced or sectioned in any way — with its three-dimensional complexity of fine wiring and molecular structures completely intact and able to be measured and probed with visible light and chemicals.

The process, called CLARITY, ushers in an entirely new era of whole-organ imaging that stands to fundamentally change our scientific understanding of the most important, but least understood of organs, the brain, and potentially other organs, as well.

The process is described in a paper to be published online April 10 in Nature by bioengineer and psychiatrist Karl Deisseroth leading a multidisciplinary team, including postdoctoral scholar Kwanghun Chung.

“Studying intact systems with this sort of molecular resolution and global scope — to be able to see the fine detail and the big picture at the same time — has been a major unmet goal in biology, and a goal that CLARITY begins to address,” Deisseroth said.

CLARITY provides the ability to do a fly-through of an intact mouse brain using a fluorescent imaging technique on a complete brain that previously could only be performed on a brain sectioned into thin slices. (Video: Karl Deisseroth and Kwanghun Chung, Stanford University)

“This feat of chemical engineering promises to transform the way we study the brain’s anatomy and how disease changes it,” said Thomas Insel, MD, director of the National Institute of Mental Health. “No longer will the in-depth study of our most important three-dimensional organ be constrained by two-dimensional methods.”

The research in this study was performed primarily on a mouse brain, but the researchers have used CLARITY on zebrafish and on preserved human brain samples with similar results, establishing a path for future studies of human samples and other organisms.

“CLARITY promises to revolutionize our understanding of how local and global changes in brain structure and activity translate into behavior,” said Paul Frankland, PhD, a senior scientist in neurosciences and mental health at the Hospital for Sick Children Research Institute in Toronto, who was not involved in the research. Frankland’s colleague, senior scientist Sheena Josselyn, PhD, added that the process could turn the brain from “a mysterious black box” into something essentially transparent. 

An inscrutable place

The mound of convoluted grey matter and wiring that is the brain is a complex and inscrutable place. Neuroscientists have struggled to fully understand its circuitry in their quest to comprehend how the brain works, and why, sometimes, it doesn’t.

CLARITY is the result of a research effort in Deisseroth’s lab to extract the opaque elements — in particular the lipids — from a brain and yet keep the important features fully intact. Lipids are fatty molecules found throughout the brain and body. In the brain, especially, they help form cell membranes and give the brain much of its structure. Lipids pose a double challenge for biological study, however, because they make the brain largely impermeable both to chemicals and to light.

Neuroscientists would have liked to extract the lipids to reveal the brain’s fine structure without slicing or sectioning, but for one major hitch: removing these structurally important molecules causes the remaining tissue to fall apart.

Prior investigations have focused instead on automating the slicing/sectioning approach, or in treating the brain with organic molecules that facilitate the penetration of light only, but not macromolecular probes. With CLARITY, Deisseroth’s team has taken a fundamentally different approach.

“We drew upon chemical engineering to transform biological tissue into a new state that is intact but optically transparent and permeable to macromolecules,” said Chung, the paper’s first author.

This new form is created by replacing the brain’s lipids with a hydrogel. The hydrogel is built from within the brain itself in a process conceptually similar to petrification, using what is initially a watery suspension of short, individual molecules known as hydrogel monomers. The intact, postmortem brain is immersed in the hydrogel solution and the monomers infuse the tissue. Then, when “thermally triggered,” or heated slightly to about body temperature, the monomers begin to congeal into long molecular chains known as polymers, forming a mesh throughout the brain. This mesh holds everything together, but, importantly, it does not bind to the lipids.

With the tissue shored up in this way, the team is able to vigorously and rapidly extract lipids through a process called electrophoresis. What remains is a 3-D, transparent brain with all of its important structures — neurons, axons, dendrites, synapses, proteins, nucleic acids and so forth — intact and in place.

Going things one better

CLARITY then goes one better. In preserving the full continuity of neuronal structures, CLARITY not only allows tracing of individual neural connections over long distances through the brain, but also provides a way to gather rich, molecular information describing a cell’s function is that is not possible with other methods.

“We thought that if we could remove the lipids nondestructively, we might be able to get both light and macromolecules to penetrate deep into tissue, allowing not only 3-D imaging, but also 3-D molecular analysis of the intact brain,” said Deisseroth, who holds the D.H. Chen Professorship.

Using fluorescent antibodies that are known to seek out and attach themselves only to specific proteins, Deisseroth’s team showed that 

• it can target specific structures within the CLARITY-modified — or “clarified” — mouse brain and 
• make those structures and only those structures light up under illumination. The researchers 
• can trace neural circuits through the entire brain or 
• explore deeply into the nuances of local circuit wiring. They 
• can see the relationships between cells and 
• investigate subcellular structures. They
• can even look at chemical relationships of protein complexes, nucleic acids and neurotransmitters.

“Being able to determine the molecular structure of various cells and their contacts through antibody staining is a core capability of CLARITY, separate from the optical transparency, which enables us to visualize relationships among brain components in fundamentally new ways,” said Deisseroth, who is one of 15 experts on the “dream team” that will map out goals for the $100 million brain research initiative announced April 2 by President Obama.

A three-dimensional rendering of clarified brain imaged from below (ventral half). (Image: Courtesy of the Deisseroth lab)

And in yet another significant capability from a research standpoint, researchers are now able to destain the clarified brain, flushing out the fluorescent antibodies and repeating the staining process anew using different antibodies to explore different molecular targets in the same brain. This staining/destaining process can be repeated multiple times, the authors showed, and the different data sets aligned with one another.

Opening the door

CLARITY has accordingly made it possible to perform highly detailed, fine-structural analysis on intact brains — even human tissues that have been preserved for many years, the team showed. Transforming human brains into transparent-but-stable specimens with accessible wiring and molecular detail may yield improved understanding of the structural underpinnings of brain function and disease.

Beyond the immediate and apparent benefit to neuroscience, Deisseroth cautioned that CLARITY has leapfrogged our ability to deal with the data. “Turning massive amounts of data into useful insight poses immense computational challenges that will have to be addressed. We will have to develop improved computational approaches to image segmentation, 3-D image registration, automated tracing and image acquisition,” he said.

Indeed, such pressures will increase as CLARITY could begin to support a deeper understanding of large-scale intact biological systems and organs, perhaps even entire organisms.

“Of particular interest for future study are intrasystem relationships, not only in the mammalian brain but also in other tissues or diseases for which full understanding is only possible when thorough analysis of single, intact systems can be conducted,” Deisseroth said. “CLARITY may be applicable to any biological system, and it will be interesting to see how other branches of biology may put it to use.”

Other co-authors include undergraduate student Jenelle Wallace; graduate students Sung-Yon Kim, Kelly Zalocusky, Joanna Mattis, Aleksandra Denisin and Logan Grosenick; research assistants Sandhiya Kalyanasundaram, Julie Mirzabekov, Sally Pak and Charu Ramakrishnan; postdoctoral scholars Aaron Andalman, PhD, and Tom Davidson, PhD; former undergraduate student Hannah Bernstein; and former staff scientist Viviana Gradinaru.

The research is supported by the National Institute of Mental Health (grant MH099647); the National Science Foundation; the Simons Foundation; the President and Provost of Stanford University; the Wiegers, Snyder, Reeves, Gatsby and Yu foundations; the DARPA REPAIR program; and the Burroughs Wellcome Fund.

Information about Stanford’s Department of Bioengineering, which also supported the work, is available at http://bioengineering.stanford.edu. The department is jointly operated by the School of Engineering and the School of Medicine.

Andrew Myers is associate director of communications for the Stanford University School of Engineering.


ORIGINAL: Stanford U
Andrew Myers | Stanford Engineering 

 Tom Abate
tabate@stanford.edu
Jamie Beckett
jbeckett@stanford.edu
April 10, 2013

Organovo Announces Plans to Create World's First 3D-Printed Human Liver tissue in 2014

2014 could be a landmark year for medical technology, as researchers just announced that they are close to creating the world’s first 3D printed organ tissue. San Diego-based biotech firm Organovo plans to use its bioprinting technology to successfully 3D print a liver by the end of 2014. In an interview with ComputerWorld, the bioprinting company said it has overcome a big obstacle to creating the vascular system needed to provide man-made organs with life-sustaining oxygen and nutrients.

Just like your everyday MakerBot, Organovo’s organic 3D printer lays down layers of material to form a solid entity. The major issue with fabricating human tissue thus far has been cells would literally die before the tissue made it off the printer table.

Organovo’s researchers were able to overcome this obstacle by bringing together fibroblasts and endothelial cells, which create a tiny vascular network of blood vessels. This microscopic addition allowed Organovo to build up an organ thicker than 500 microns (0.019 inches). It might seem insignificantly small, but the man-made tissue was fully functional for at least 40 days while it sat in a petri dish.

Although the liver won’t be suitable for transplants in human beings, it could be extremely effective for scientific research and drug testing. The drug testing field still uses controversialanimal testing, and fabricating 3D printed organs could be a much more humane alternative. Organovo also hopes its 3D printing technology will help reduce the exorbitant costs of drug testing.

+ Organnovo
Via ComputerWorld
Images © Organnovo

ORIGINAL: Inhabitat
by Kevin Lee,
12/27/13

Behold, the Human Brain

ORIGINAL: Serious Wonder

Gabriel Sistare

13. Dec '13

Research scientists at The Institute of Molecular Biotechnology at the Austrian Academy of Sciences derived segments of a human brain from stem cells. The study was published in Nature, and it is an early opportunity to experiment using actual human brain tissue cells instead of mice or rat brains.

Juergen Knoblich, an author of the study, calls the tissue “cerebral organoids,” and they can be cultured for months, eventually growing into whole sections of the brain like the cerebral cortex or portions of the hindbrain.

Although the brain cells can and will be used for diverse experiments, Knoblich and his team are focusing on replicating the causes and consequences of brain diseases or disorders like microcephaly, a condition of the head having a smaller circumference than the mean.

A segment of the organoids cultured by Knoblich and his team

These cerebral organoids are a huge advantage for neuroscience researchers. Many experiments with the brain are done using mice or rats, but these animals are not a perfect simulation of how a human brain reacts to disease or disorder. With the organoids, scientists can achieve a simulation of a human brain and eliminate animal testing all together.

FUTURE IMPLICATIONS 
Growth of human tissue from stem cells is, in general, a tremendous leap for research science and healthcare. The ability to understand the behavior of human cells without experimentation on actual human beings is crucial. We can leave animals well enough alone now, and we can understand our personal biology without having to make assumptions about how a cancerous rat’s brain relates to an affected human brain. With experimentation on human tissue-derived organs, the time it takes researchers to clarify hypotheses and produce valuable material will be dramatically shortened.

Gray Scott - Digital Immortality - Serious Wonder

Gray Scott, futurist philosopher talks about DIGITAL IMMORTALITY for www.SeriousWonder.com More at www.GrayScott.com
Photo Credit: Discovery News

Breakthrough Could Lead to 'Artificial Skin' That Senses Touch, Humidity and Temperature

ORIGINAL: ScienceDaily

Closeup of fingertip (stock image). Researchers have discovered how to make a new kind of flexible sensor that one day could be integrated into electronic skin. (Credit: iStockphoto)

July 8, 2013 — Using tiny gold particles and a kind of resin, a team of scientists at the Technion-Israel Institute of Technology has discovered how to make a new kind of flexible sensor that one day could be integrated into electronic skin, or e-skin. If scientists learn how to attach e-skin to prosthetic limbs, people with amputations might once again be able to feel changes in their environments.

The findings appear in the June issue of ACS Applied Materials & Interfaces.

The secret lies in the sensor's ability to detect three kinds of data simultaneously. While current kinds of e-skin detect only touch, the Technion team's invention "can simultaneously sense touch, humidity, and temperature, as real skin can do," says research team leader Professor Hossam Haick. Additionally, the new system "is at least 10 times more sensitive in touch than the currently existing touch-based e-skin systems."

Researchers have long been interested in flexible sensors, but have had trouble adapting them for real-world use. To make its way into mainstream society, a flexible sensor would have to run on low voltage (so it would be compatible with the batteries in today's portable devices), measure a wide range of pressures, and make more than one measurement at a time, including humidity, temperature, pressure, and the presence of chemicals. In addition, these sensors would also have to be able to be made quickly, easily, and cheaply.

The Technion team's sensor has all of these qualities. The secret is the use of monolayer-capped nanoparticles that are only 5-8 nanometers in diameter. They are made of gold and surrounded by connector molecules called ligands. In fact, "monolayer-capped nanoparticles can be thought of as flowers, where the center of the flower is the gold or metal nanoparticle and the petals are the monolayer of organic ligands that generally protect it," says Haick.

The team discovered that when these nanoparticles are laid on top of a substrate -- in this case, made of PET (flexible polyethylene terephthalate), the same plastic found in soda bottles -- the resulting compound conducted electricity differently depending on how the substrate was bent. (The bending motion brings some particles closer to others, increasing how quickly electrons can pass between them.) This electrical property means that the sensor can detect a large range of pressures, from tens of milligrams to tens of grams. "The sensor is very stable and can be attached to any surface shape while keeping the function stable," says Dr. Nir Peled, Head of the Thoracic Cancer Research and Detection Center at Israel's Sheba Medical Center, who was not involved in the research.

And by varying how thick the substrate is, as well as what it is made of, scientists can modify how sensitive the sensor is. Because these sensors can be customized, they could in the future perform a variety of other tasks, including monitoring strain on bridges and detecting cracks in engines.

"Indeed," says Dr. Peled, "the development of the artificial skin as biosensor by Professor Haick and his team is another breakthrough that puts nanotechnology at the front of the diagnostic era."

The research team also included Meital Segev-Bar and Gregory Shuster, graduate students in the Technion's Russell Berrie Nanotechnology Institute, as well as Avigail Landman and Maayan Nir-Shapira, undergraduate students in the Technion's Chemical Engineering Department.

Worms regrow their decapitated heads, along with the memories inside

ORIGINAL: The Verge
By Jacob Kastrenakes
July 10, 2013

Some memories just won't die — and some can even be transferred to a whole new brain. Researchers at Tufts University have determined that a small, yellow worm known as a planarian, which has long been studied for its regenerative properties, is able to grow back a lot more than just its body parts: after the worm's small, snake-like head and neck are removed, its body will even regrow a brain that's capable of quickly relearning its lost skills.

A little training makes it all come back
The researchers tested the memory of planarians by measuring how long it took for them to reach food in a controlled setting. The small worms dislike open spaces and bright lights — but they had been trained to ignore it so that they could find their meals. Even after decapitation, worms that had gone through training were able to overcome their fears and start eating much faster than worms that hadn't been trained. However, the memories didn't come back immediately. Each worm still had to be reminded of its earlier knowledge, though it only took a single lesson for it to all come back.

Why this happens is still unclear. Planarians' brains control their behavior, but the researchers suggest that some of their memories might be stored elsewhere in their body. Alternatively, they suggest that the worms' original brain may have modified their nervous systems, and their nervous systems may have then altered how the new brains formed during regrowth.

The researchers' findings appears in The Journal of Experimental Biology. They say that more work needs to be done to nail down the specifics of how planarians recover their memory, but the hope is that the worms can be used as a way to study how memory and learning work. That may sound complicated for a seemingly basic creature, but existing studies are already using them to research drug addiction and withdrawal.

Via Inkfish (Field of Science)
Source The Experimental Journal of Biology
Image Credit Chun Xing Wong (Flickr)
Related Items memorytufts universitybrainwormregrowthplanarianflatwormdecapitation

The origins of the first immortal human cells

ORIGINAL: ScienceDump

by Jur on

11/14/2012

In 1951, a scientist at Johns Hopkins Hospital in Baltimore, Maryland, created the first immortal human cell line with a tissue sample taken from a young black woman with cervical cancer. Those cells, called HeLa cells, quickly became invaluable to medical research—though their donor remained a mystery for decades.

The first immortal human cells grown in culture, they are still alive today, though the donor has been dead for more than sixty years. If you could pile all HeLa cells ever grown onto a scale, they’d weigh more than 50 million metric tons—as much as a hundred Empire State Buildings.

HeLa cells were vital for developing the polio vaccine; uncovered secrets of cancer, viruses, and the atom bomb’s effects; helped lead to important advances like in vitro fertilization, cloning, and gene mapping; and have been bought and sold by the billions.

Photo of the donor: Henrietta Lacks and her husband

Scientists develop 2-component polymer scaffolds for controlled 3-D cell culture

ORIGINAL: Phys.org
April 6, 2011

This is a cell in the two-component polymer scaffold. The photo composition is based on a scanning electron microscopy and laser scanning microscopy. Credit: Image: CFN

At Karlsruhe Institute of Technology (KIT), researchers of the DFG Center for Functional Nanostructures (CFN) succeeded in specifically cultivating cells on three-dimensional structures. The fascinating thing is that the cells are offered small "holds" in the micrometer range on the scaffold, to which they can adhere. Adhesion is possible to these holds only, not to the remaining structure. For the first time, cell adhesion and, hence, cell shape are influenced precisely in three dimensions. The team headed by Professor Martin Bastmeyer thus has achieved big progress in the field of biomaterial engineering.

So far, several approaches have been used to cell culture in three-dimensional environments which are mostly produced from agarose, collagen fibers or matrigel. They are to simulate the flexible three-dimensional reality in which the cells act normally and, hence, allow for more realistic experiments than those using cell cultures in "two-dimensional Petri dishes". All approaches used so far have one common feature: They are mostly heterogeneous with random pore sizes. They have hardly been characterized structurally and biochemically.

It was the objective of the group under the direction of Bastmeyer to develop defined three-dimensional growth substrates for the cell culture. The cells are to adhere at certain points only rather than randomly. In this way, parameters, such as the cell shape, cell volume, intercellular force development, or cellular differentiation can be determined systematically as a function of the external geometry of the surroundings. These findings are needed for the later specific larger-scale production of three-dimensional growth environments for tissue cultures required in regenerative medicine, for instance.

This image shows laser-scanning microscopy (LSM) of the cell in the two-component polymer scaffold. The cytoskeleton of the cell is colored green, parts of the two-component polymer scaffold are colored white, the "cell holds" are colored red. Credit: Image: CFN

This objective was reached by means of a special polymer scaffold. The scaffold consists of a flexible, protein-repellent polymer with small box-shaped holds made of a protein-binding material. For scaffold construction, the scientists used the Direct Laser Writing Method (DLS) developed by the physicists Professor Martin Wegener and Professor Georg von Freymann at CFN. By means of this process, the protein-repellent structure was fabricated. It consists of 25 µm high pillars that are connected by thin bars at various heights. In a second lithography step, the holds were placed exactly in the middle of the bars. With the help of a solution of adhesion proteins, the proteins only bind to these small holds. Within two hours, individual cells colonize the scaffolds and adhere to the given adhesion points only.

For the first time, the scientists of CFN, Karlsruhe, succeeded in producing suitable materials, in which the growth of individual cells can be controlled and manipulated specifically in three dimensions. This is an important step towards the general understanding of how the natural three-dimensional environment in the tissue influences the behavior of cells.

More information: Klein, F., Richter, B., Striebel, T., Franz, C. M., Freymann, G. v., Wegener, M., and Bastmeyer, M., Two-Component Polymer Scaffolds for Controlled Three-dimensional Cell Culture. Advanced Materials, Volume 23, Issue 11, pages 1341, March 18, 2011, DOI:10.1002/adma.201004060

Provided by Helmholtz Association of German Research Centres (news : web)