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标题: moving to a Graphene world（石墨烯专题） [打印本页]

作者: sunsong7 时间: 2011-5-18 16:33 标题: moving to a Graphene world（石墨烯专题）

本帖最后由细胞海洋于 2011-8-11 19:46 编辑

法国皇帝拿破仑曾经说过：“笔比剑更有威力”，然而他在200年前说这话的时候绝对不会想到，人类使用的普通铅笔中竟然包含着地球上强度最高的物质！石墨烯被为“完美原子晶体”，作为二维结构单层碳原子材料，强度相当于钢的100倍，导电性能好、导热性能强，这是目前世界上最薄的材料，仅有一个原子厚。/ @- e4 c, r* g8 p1 i; v
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瑞典皇家科学院 2010年10月5日宣布，将诺贝尔物理学奖授予英国曼彻斯特大学科学家安德烈海姆和康斯坦丁诺沃肖洛夫，以表彰他们在石墨烯材料方面的卓越研究。

作者: sunsong7 时间: 2011-5-18 17:20

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扫描隧道显微镜显示一个接近完单层美石墨烯的8nm波浪( |& v" Z ?3 H/ u0 X

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石墨层叠的六角模型. [* B$ X0 P1 g: M: S! m' P; \
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平凡的铅笔蕴涵伟大的科学发现/ F7 c# F) w* b. u, g$ v; j

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两根头发与2百万个碳纳米管

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碳纳米管
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石墨烯中的单个碳原子

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无定形碳3 N2 U, W0 I, t- ?% \6 q6 u

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中子活化石墨放射自显影术:9毫米热(红色)显示较高的活性
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“太空电梯”缆线

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富勒烯与螺旋状星云

作者: sunsong7 时间: 2011-5-18 17:29

石墨烯与干细胞( x) n! R3 H) o, w
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Graphene for Controlled and Accelerated Osteogenic Differentiation of Human Mesenchymal Stem Cells.（石墨烯控制和加速间充质干细胞成骨分化）
Nayak TR, Andersen H, Makam VS, Khaw C, Bae S, Xu X, Ee PL, Ahn JH, Hong BH, Pastorin G, Ozyilmaz B7 y) Y7 b9 ]- i' k' ]( J0 N
Modern tissue engineering strategies combine living cells and scaffold materials to develop biological substitutes that can restore tissue functions. Both natural and synthetic materials have been fabricated for transplantation of stem cells and their specific differentiation into muscles, bones and cartilages. One of the key objectives for bone regeneration therapy to be successful is to direct stem cells' proliferation and to accelerate their differentiation in a controlled manner through the use of growth factors and osteogenic inducers. Here we show that graphene provides a promising biocompatible scaffold that does not hamper the proliferation of human mesenchymal stem cells (hMSCs) and accelerates their specific differentiation into bone cells. The differentiation rate is comparable to the one achieved with common growth factors, demonstrating graphene's great potential for stem cell research.) E* k1 B5 L. ]" V
Published 2 May 2011 in ACS Nano. [attach]27091[/attach]' b; ]! I5 X O+ l: d9 G
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作者: sunsong7 时间: 2011-5-18 17:41

石墨烯减缓细胞毒- g6 J3 d7 v/ F* J' o# W
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Protein Corona-Mediated Mitigation of Cytotoxicity of Graphene Oxide（石墨烯氧化物对蛋白晕状调节细胞毒的减缓） |; v2 n' T* S& o6 I
Wenbing Hu, Cheng Peng, Min Lv, Xiaoming Li, Yujie Zhang, Nan Chen, Chunhai Fan,* and Qing Huan, |' ?! e# a/ G( A+ ~
Laboratory of Physical Biology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, People's Republic of China

ABSTRACT Graphene is a single layer of sp2-bonded carbons that has unique and highly attractive electronic, mechanical, and thermal properties. Consequently, the potential impact of graphene and its derivatives (e.g., graphene oxide, GO) on human and environmental health has raised considerable concerns. In this study, we have carried out a systematic investigation on cellular eﬀects of GO anosheets and identiﬁed the eﬀect of fetal bovine serum (FBS), an often-employed component in cell culture medium, on the cytotoxicity of GO. At low concentrations of FBS (1%), human cells were sensitive to the presence of GO and showed concentration-dependent cytotoxicity. Interestingly, the cytotoxicity of GO was greatly mitigated at 10% FBS, the concentration usually employed in cell medium. Our studies have demonstrated that the cytotoxicity of GO nanosheets arises from direct interactions between the cell membrane and GO nanosheets that result in physical damage to the cell membrane. This eﬀect is largely attenuated when GO is incubated with FBS due to the extremely high protein adsorption ability of GO. The observation of this FBS-mitigated GO cytotoxicity eﬀect may provide an alternative and convenient route to engineer nanomaterials for safe biomedical and environmental applications.[attach]27092[/attach]

作者: sunsong7 时间: 2011-5-18 18:33

本帖最后由 sunsong7 于 2011-5-18 18:43 编辑 " K& W4 E j, o( ?; J: g- B: d

石墨烯带来单个DNA分子测序革命; J9 C) f( d0 g; C; E6 e" J
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Graphene could revolutionize DNA sequencing
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DNA单链穿越石墨烯小孔
Passing through a gap in the wonder material
By feeding individual strands of DNA through nanometre-sized holes, researchers in the Netherlands say they have proved the principle of a revolutionary new DNA sequencing technique. The breakthrough is part of a worldwide race to develop fast and low-cost strategies to analyse these codes that underpin the chemistry of life.
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The genetic profile – or "genome" – of an organism is determined by recording the full sequence of acid base pairs that make up its DNA. In 2003, the Human Genome Project made history by determining the entire human genetic code – 3 billion DNA base pairs that took 13 years to analyse using a technique that has changed very little since the late 1970s. 6 M, i- {$ Z) y

This pioneering project used a "shotgun" approach, which first isolates a DNA strand and forces it to copy itself millions of times over in a chemical reaction. These strands are then "blasted" into tiny fragments because current techniques can only analyse very short sections of DNA. Finally, a supercomputer matches up overlapping base patterns to piece together the full genome.

However, with the promise of personalized medicine, scientists are working to develop new technologies that could rapidly sequence an individual's genetic make-up. In addition to the human genome there are also slight variations in DNA sequences and processes that give people their phenotypes such as "blue eyes" or "blond hair". 8 _5 H/ d& m3 B- j( c) c( _5 c

Promising idea
In 2008, physicsworld.com reported one promising idea that involves passing DNA through tiny punctures in a sheet of graphene – an extremely strong sheet of carbon just one atom thick. A voltage is applied along the graphene surface as DNA strands are passed slowly through the slit one base at a time. The idea is that each of the four bases – A, C, G and T – will have a unique effect on the conductance of graphene across the gap. / Z- Y8 k2 K4 E" ~) @) v! J

Now, Cees Dekker and his colleagues at the Kavli Institute of Nanoscience are the first team to demonstrate DNA motion through graphene, although their technique cannot yet read the genetic code. : }2 [! }5 a/ H+ m. j( E& }

They create a series of pores ranging from 5 to 25 nm in diameter by placing flakes of graphene over a silicon nitride membrane and drilling nanosized holes in the graphene using an electron beam. By applying a voltage of 200 mV across the graphene membrane, a series of spikes are observed in an electric current that scales the gap. These, say the researchers, correspond to drops in conductance when DNA strands slide across the gap via a biochemical process known as translocation.

The researchers intend to develop their research by identifying which spikes correspond to particular bases. Dekker told physicsworld.com that one area of science that could benefit in particular from ultrafast sequencing is epigenetics – that is, the study of changes in phenotypes that are not related to changes in underlying DNA sequences. / r) n. u8 s+ K% w

Henk Postma, a researcher at California State University, Northridge, who is also developing nanopore sequencing, is excited by the result. "They have demonstrated that DNA does indeed go through little holes in graphene, and that it does so with great speed. Both of these are important advancements towards using graphene for DNA sequencing," he says.
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This research is published in Nano Letters.
About the author：James Dacey is a reporter for physicsworld.com

作者: sunsong7 时间: 2011-5-18 18:47

石墨烯纸张可在常温直接杀菌
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Graphene Kills Bacteria
Graphene could be used to make antibacterial paper, according to new work by researchers at the Chinese Academy of Sciences in Shanghai. The researchers have found that graphene derivatives, like graphene oxide and reduced graphene oxide, inhibit the growth of E. Coli bacteria. This is an important finding, because previous studies showed that graphene, and particularly graphene oxide, is biocompatible and that biological cells can grow well on graphene substrates. While other nanoparticles, like silver, are well known antibacterial materials, they are often cytotoxic.1 W4 o, m- R& }$ }/ m

Transmission electron microscopy showed that the cell membranes of E. Coli bacteria placed on the graphene sheets were severely destroyed. According to the researchers, this occurs because graphene enters the endosome of the cell’s cytoplasm, pushing it out of the cell. Almost 99% of the cells were destroyed after just two hours in contact with a 85 g/mL solution of graphene oxide at 37 °C. In contrast, the nanosheets were not toxic to mammalian cells under the same conditions.
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The team is now further studying why and how graphene oxide is antibacterial. “Ultimately we wish to develop new antibacterial materials from graphene that could be directly applied onto skin to aid in wound healing,” says Chunhai Fan. “However, we are aware that it is still a challenge to mass produce graphene nanomaterials, and particularly to fabricate large-scale graphene paper.” $ P5 r6 J* }( l0 w6 [* g

作者: sunsong7 时间: 2011-5-18 18:55

本帖最后由 sunsong7 于 2011-5-18 19:07 编辑
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石墨烯包裹帮助电子显微镜进行细菌真实大小成像6 q* k9 [: h/ U! }# E9 e* K+ [
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Graphene Cloak Protects Bacteria, Leading to Better Images. }7 {: P% A( R5 }
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ScienceDaily (Mar. 18, 2011) — It's a cloak that surpasses all others: a microscopic carbon cloak made of graphene that could change the way bacteria and other cells are imaged.
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Vikas Berry, assistant professor of chemical engineering at Kansas State University, and his research team are wrapping bacteria with graphene to address current challenges with imaging bacteria under electron microscopes. Berry's method creates a carbon cloak that protects the bacteria, allowing them to be imaged at their natural size and increasing the image's resolution.6 z5 `- N( G4 h- Y* Q

Graphene is a form of carbon that is only one atom thick, giving it several important properties: it's impermeable, it's the strongest nanomaterial, it's optically transparent and it has high thermal conductance.
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"Graphene is the next-generation material," Berry said. "Although only an atom thick, graphene does not allow even the smallest of molecules to pass through. Furthermore, it's strong and highly flexible so it can conform to any shape."* n  X0 U  L& b2 v4 B

Berry's team has been researching graphene for three years, and Berry recently saw a connection between graphene and cell imaging research. Because graphene is impermeable, he decided to use the material to preserve the size of bacterial cells imaged under high-vacuum electron microscopes.
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The research results appear in the paper "Impermeable Graphenic Encasement of Bacteria," which was published in a recent issue of Nano Letters, a monthly scientific journal published by the American Chemical Society. The team's preliminary research appeared in Nature News in 2010.
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The current challenge with cell imaging occurs when scientists use electron microscopes to image bacterial cells. Because these microscopes require a high vacuum, they remove water from the cells. Biological cells contain 70 to 80 percent water, and the result is a severely shrunk cell. As a result, it is challenging to obtain an accurate image of the cells and their components in their natural state.
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But Berry and his team created a solution to the imaging challenge by applying graphene. The graphene acts as an impermeable cloak around the bacteria so that the cells retain water and don't shrink under the high vacuum of electron microscopes. This provides a microscopic image of the cell at its natural size.3 I) C9 o: n: t) n. }7 y

The carbon cloaks can be wrapped around the bacteria using two methods. The first method involves putting a sheet of graphene on top of the bacteria, much like covering up with a bed sheet. The other method involves wrapping the bacteria with a graphene solution, where the graphene sheets swaddle the bacteria. In both cases the graphene sheets were functionalized with a protein to enhance binding with the bacterial cell wall.
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Under the high vacuum of an electron microscope, the wrapped bacteria did not change in size for 30 minutes, giving scientists enough time to observe them. This is a direct result of the high strength and impermeability of the graphene cloak, Berry said.* B& I+ ]9 X1 n3 J
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Graphene's other extraordinary properties enhance the imaging resolution in microscopy. Its electron-transparency enables a clean imaging of the cells. Since graphene is a good conductor of heat and electricity, the local electronic-charging and heating is conducted off the graphene cloak, giving a clear view of the bacterial cell well. Unwrapped bacterial cells appear dark with an indistinguishable cell wall.* ~6 |; E" g- j" o4 s
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"Uniquely, graphene has all the properties needed to image bacteria at high resolutions," Berry said. "The project provides a very simple route to image samples in their native wet state."

The process has potential to influence future research. Scientists have always had trouble observing liquid samples under electron microscopes, but using carbon cloaks could allow them to image wet samples in a vacuum. Graphene's strong and impermeable characteristics ensure that wrapped cells can be easily imaged without degrading them. Berry said it might be possible in the future to use graphene to keep bacterium alive in a vacuum while observing its biochemistry under a microscope.
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The research also paves the way for enhanced protein microscopy. Proteins act differently when they are dry and when they are in an aqueous solution. So far most protein studies have been conducted in dry phases, but Berry's research may allow proteins to be observed more in aqueous environments.

"This research could be the point of evolution for processing of sensitive samples with graphene to achieve enhanced imaging," Berry said.

Other researchers involved in the project include Daniel Boyle, research assistant professor in biology; Nihar Mohanty, doctoral student in chemical engineering, India; Ashvin Nagaraja, former master's student in electrical engineering; and Monica Fahrenholtz, a May 2010 chemical engineering graduate from Clearwater.; ^4 Y5 q9 C: \2 P8 T

作者: sunsong7 时间: 2011-5-18 19:04

本帖最后由 sunsong7 于 2011-5-18 19:06 编辑 - G8 B5 ^- c( q% r3 m

细菌呼吸作用将石墨烯氧化物还原
Reduction of Graphene Oxide via Bacterial Respiration4 [' D3 C) s3 P5 G' D, q
Everett C. Salas†, Zhengzong Sun‡, Andreas L
ACS Nano, 2010, 4 (8), pp 4852–4856 DOI: 10.1021/nn101081t Publication Date (Web): July 21, 2010+ d2 e+ S3 R: f" | ~
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Here we present that graphene oxide (GO) can act as a terminal electron acceptor for heterotrophic, metal-reducing, and environmental bacteria. The conductance and physical characteristics of bacterially converted graphene (BCG) are comparable to other forms of chemically converted graphene (CCG). Electron transfer to GO is mediated by cytochromes MtrA, MtrB, and MtrC/OmcA, while mutants lacking CymA, another cytochrome associated with extracellular electron transfer, retain the ability to reduce GO. Our results demonstrate that biodegradation of GO can occur under ambient conditions and at rapid time scales. The capacity of microbes to degrade GO, restoring it to the naturally occurring ubiquitous graphite mineral form, presents a positive prospect for its bioremediation. This capability also provides an opportunity for further investigation into the application of environmental bacteria in the area of green nanochemistries.

作者: sunsong7 时间: 2011-5-18 19:19

石墨烯生物传感器用于疾病诊断+ d( U0 p' ]5 r" k& f3 z' u; l) H. A' v! E
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A flash of light turns graphene into a biosensor' A0 l, n# M! h; ]$ m3 e$ {3 k0 ~' |
Disease diagnosis, toxin detection and more are possible with DNA-graphene nanostructure
Biomedical researchers suspect graphene, a novel nanomaterial made of sheets of single carbon atoms, would be useful in a variety of applications. But no one had studied the interaction between graphene and DNA, the building block of all living things. To learn more, PNNL's Zhiwen Tang, Yuehe Lin and colleagues from both PNNL and Princeton University built nanostructures of graphene and DNA. They attached a fluorescent molecule to the DNA to track the interaction. Tests showed that the fluorescence dimmed significantly when single-stranded DNA rested on graphene, but that double-stranded DNA only darkened slightly – an indication that single-stranded DNA had a stronger interaction with graphene than its double-stranded cousin. The researchers then examined whether they could take advantage of the difference in fluorescence and binding. When they added complementary DNA to single-stranded DNA-graphene structures, they found the fluorescence glowed anew. This suggested the two DNAs intertwined and left the graphene surface as a new molecule.
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DNA's ability to turns its fluorescent light switch on and off when near graphene could be used to create a biosensor, the researchers propose. Possible applications for a DNA-graphene biosensor include diagnosing diseases like cancer, detecting toxins in tainted food and detecting pathogens from biological weapons. Other tests also revealed that single-stranded DNA attached to graphene was less prone to being broken down by enzymes, which makes graphene-DNA structures especially stable. This could lead to drug delivery for gene therapy. Tang will discuss this research and some of its possible applications in medicine, food safety and biodefense.
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Reference: Zhiwen Tang, Biofunctionalization of Graphene for Biosensing and Imaging, Tuesday, September 22, 3:30 – 5:30 p.m. in Ross Island/Morrison at the Doubletree Lloyd Center, Portland, Ore.8 ?) \! u7 v1 ^6 t1 Q

作者: sunsong7 时间: 2011-5-18 19:25

石墨烯形成心肌轴突用于细胞电生理信号的高灵敏度、非侵入式检测0 {$ z B" V, c6 P, ?7 u! |
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Graphene and Nanowire Transistors for Cellular Interfaces and Electrical Recording
AbstractFull Text HTMLHi-Res PDF[2442 KB]PDF w/ Links[315 KB]Supporting InfoFiguresCiting ArticlesTzahi Cohen-Karni†, Quan Qing‡, Qiang Li§, Ying Fang*§ and Charles M. Lieber*†‡ 4 b; r/ n' r2 s7 h' W- T$ i
Nano Lett., 2010, 10 (3), pp 1098–1102* S- l, m* H" w. N. `
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Nanowire field-effect transistors (NW-FETs) have been shown to be powerful building blocks for nanoscale bioelectronic interfaces with cells and tissue due to their excellent sensitivity and their capability to form strongly coupled interfaces with cell membranes. Graphene has also been shown to be an attractive building block for nanoscale electronic devices, although little is known about its interfaces with cells and tissue. Here we report the first studies of graphene field effect transistors (Gra-FETs) as well as combined Gra- and NW-FETs interfaced to electrogenic cells. Gra-FET conductance signals recorded from spontaneously beating embryonic chicken cardiomyocytes yield well-defined extracellular signals with signal-to-noise ratio routinely >4. The conductance signal amplitude was tuned by varying the Gra-FET working region through changes in water gate potential, Vwg. Signals recorded from cardiomyocytes for different Vwg result in constant calibrated extracellular voltage, indicating a robust graphene/cell interface. Significantly, variations in Vwg across the Dirac point demonstrate the expected signal polarity flip, thus allowing, for the first time, both n- and p-type recording to be achieved from the same Gra-FET simply by offsetting Vwg. In addition, comparisons of peak-to-peak recorded signal widths made as a function of Gra-FET device sizes and versus NW-FETs allowed an assessment of relative resolution in extracellular recording. Specifically, peak-to-peak widths increased with the area of Gra-FET devices, indicating an averaged signal from different points across the outer membrane of the beating cells. One-dimensional silicon NW- FETs incorporated side by side with the two-dimensional Gra-FET devices further highlighted limits in both temporal resolution and multiplexed measurements from the same cell for the different types of devices. The distinct and complementary capabilities of Gra- and NW-FETs could open up unique opportunities in the field of bioelectronics in the future.6 P: _; @6 h: T3 A* J0 Z* q

作者: sunsong7 时间: 2011-5-18 19:41

本帖最后由 sunsong7 于 2011-5-18 19:45 编辑 1 |% w  x' @) p9 p& g

石墨烯与肿瘤治疗4 s" `' t! A( f+ N. {2 q! w
Graphene in Mice: Ultrahigh In Vivo Tumor Uptake and Efficient Photothermal Therapy.
Nano letters  ISSN: 1530-6992
Although biomedical applications of carbon nanotubes have been intensively studied in recent years, its sister, graphene, has been rarely explored in biomedicine. In this work, for the first time we study the in vivo behaviors of nanographene sheets (NGS) with polyethylene glycol (PEG) coating by a fluorescent labeling method. In vivo fluorescence imaging reveals surprisingly high tumor uptake of NGS in several xenograft tumor mouse models. Distinctive from PEGylated carbon nanotubes, PEGylated NGS shows several interesting in vivo behaviors including highly efficient tumor passive targeting and relatively low retention in reticuloendothelial systems. We then utilize the strong optical absorbance of NGS in the near-infrared (NIR) region for in vivo photothermal therapy, achieving ultraefficient tumor ablation after intravenous administration of NGS and low-power NIR laser irradiation on the tumor. Furthermore, no obvious side effect of PEGylated NGS is noted for the injected mice by histology, blood chemistry, and complete blood panel analysis in our pilot toxicity study. Although a lot more efforts are required to further understand the in vivo behaviors and the long-term toxicology of this new type of nanomaterials, our work is the first success of using carbon nanomaterials for efficient in vivo photothermal therapy by intravenous administration and suggests the great promise of graphene in biomedical applications, such as cancer treatment.
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Targeting tumours with graphene oxide: I9 T, C+ v: P, Z3 U  P5 S5 `+ r
19 November 2010

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A graphene oxide anticancer drug carrier that combines different targeting mechanisms has been designed by scientists from China. * {+ J) n9 V- g" U2 d9 O5 S
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Many anticancer drugs are toxic or cause harmful side effects because they target healthy cells as well as tumour cells. Yongsheng Chen from Nankai University, China, and colleagues have developed a delivery system using functionalised graphene oxide as the drug carrier. Graphene oxide has a very high surface area, enabling it to transport a large amount of the drug. As cancer cells are typically more acidic than normal cells, the team developed the system to increase drug release as pH decreases. This confines the drug to the tumour site and limits uptake by healthy cells. This could allow doctors to use higher doses and improve the effectiveness of treatments, or reduce side-effects for patients.

Chen's team attached superparamagnetic Fe3O4 nanoparticles to the graphene oxide. 'Using Fe3O4 nanoparticles linked to the graphene oxide allows the carrier to be targeted to the tumour site by an external magnetic field,' explains Chen. Many cancer cells have high numbers of folate receptors on their surface so the team attached folic acid to the nanoparticles as a second targeting mechanism. This makes it more likely that the drug carrier will enter tumour cells rather than healthy cells. The team then loaded doxorubicin, a potent anticancer drug, onto the graphene oxide via pi-pi stacking. 7 U4 i% c# `9 z2 R3 q
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Preparation of the multi-functionalised graphene oxide anticancer drug carrier

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They tested the carrier in cell uptake and toxicity studies in human breast cancer cells in vitro. These tests confirmed that the carrier can transport and release doxorubicin into tumour cells.

Michael Sailor, an expert in designing nanoparticles for biomedical applications at the University of California, San Diego, US, cautions that further work is needed to test the safety and biological life cycle of any graphene-based drug delivery system.  'One of the major challenges in nano-enabled drug delivery is degradability of the device once it has performed its function. Although many nanoparticles are safely excreted by the body, many others are not. Future patients will be concerned about a nanodevice sticking around after it has delivered its drug or performed its diagnostic test.' 1 `' w  M0 a, I1 B+ o

'Nanomaterial-based targeting drug delivery systems are still at an early stage for commercial applications,' agrees Chen. 'Some reports suggest that modified graphene can be excreted safely from the body, but the digestion or downgrading of nano-delivery vehicles needs more research. This is the focus of our future studies.'

Russell Johnson

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作者: sunsong7 时间: 2011-5-18 19:47

本帖最后由 sunsong7 于 2011-5-18 19:47 编辑

用石墨烯氧化物传输药物4 Q8 g" _5 j& V$ e4 K1 h
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Graphene Oxide Seen as Drug Delivery Vehicle
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New process makes production practical
Bulk production of graphene oxide, an insulating material with potential for use as a drug delivery vehicle, should be easy and inexpensive with a process recently described by researchers at Rice University. The material breaks down into graphite in ambient conditions, making it an appropriate material for “green” nanochemical applications, the researchers reported.
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“Graphene oxide has a number of potential advantages over other nanotechnology-based methods of drug delivery: It can carry a larger cargo, there is no need to modify the drugs, it can be targeted with associated proteins, and it has low toxicity,” said James M. Tour, PhD, a professor of mechanical engineering and materials science and of computer science at Rice, in Houston.

Dr. Tour is senior author of papers describing the improved synthesis of graphene oxide and its breakdown by common bacteria (Marcano DC, Kosynkin DV, Berlin JM, et al. [Published online ahead of print July 22, 2010.] ACS Nano. Salas EC, Sun Z, Lüttge A, et al. [Published online ahead of print July 21, 2010.] ACS Nano).
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The researchers describe making graphene oxide by processing flakes of graphite with common, inexpensive materials, including potassium permanganate, sulfuric acid, and phosphoric acid. Existing production methods use compounds that release toxic chemicals, Dr. Tour explained in an e-mail to PFQ. Manufacturers will be “hard pressed to come up with a cheaper procedure [for graphene oxide production] that is this efficient and as safe and environmentally friendly,” he said.

The material should find widespread application, Dr. Tour added. “Just mix and treat with a host of drug types through non-covalent sequestration of drug.” The vehicle is broken down by environmental bacteria, he said.
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作者: sunsong7 时间: 2011-5-18 20:29

石墨烯在生物医学领域的应用 5 E& Z) o2 C' m! A
作为sp2碳原子组成的一种新型二维纳米材料,石墨烯独特优良的电学、光学和力学性质,以及由此产生的广泛应用前景,已成为备受瞩目的研究热点.目前有关石墨烯及其衍生物的研究,主要集中在其物理学研究领域,石墨烯的化学和材料学研究也发展迅速,而石墨烯在生物医学领域的研究工作才刚刚开始.本文简述石墨烯尤其是氧化石墨烯,在生物和医学领域,包括靶向药物输运、细胞成像、生物检测、肿瘤治疗以及石墨烯生物安全性研究的最新进展.[attach]27108[/attach]
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作者：沈贺张立明张智军
作者单位：中国科学院,苏州纳米技术与纳米仿生研究所,纳米生物医学与安全研究部,江苏,苏州,215123
期刊：东南大学学报（医学版） ISTIC
Journal： JOURNAL OF SOUTHEAST UNIVERSITY(MEDICAL SCIENCE EDITION)  2011, 30(1)

作者: sunsong7 时间: 2011-8-11 16:54

本帖最后由 sunsong7 于 2011-8-11 17:15 编辑 6 y0 P9 U% n# m
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石墨烯可以形成高度柔韧的膜，具有生物相容性，可转化，可植入等优异的特质，有望成为未来干细胞技术的新平台....- V" X; t8 D6 G# g( g6 ~) A- w

Origin of Enhanced Stem Cell Growth and Differentiation on Graphene and Graphene Oxide
引自：http://pubs.acs.org/doi/pdf/10.1021/nn202190c
Wong Cheng Lee†§, Candy Haley Y. X. Lim†‡, Hui Shi, Lena A. L. Tang‡, Yu Wang‡, Chwee Teck Lim†§*, and Kian Ping Loh‡*
NUS Graduate School for Integrative Sciences and Engineering, Centre for Life Sciences #05-01, National University of Singapore, 28 Medical Drive, 117456, Singapore
Department of Chemistry, National University of Singapore, Science Drive 3, 117543, Singapore
Division of Bioengineering and Department of Mechanical Engineering, National University of Singapore, 7 Engineering Drive 1, 117574, Singapore
Mechanobiology Institute, National University of Singapore, T-Lab, #05-01, 5A Engineering Drive 1, 117411, Singapore.; f! w1 R3 X; \5 O7 g
ACS Nano, Article ASAP
DOI: 10.1021/nn202190c
Publication Date (Web): July 27, 20110 }, `# ?5 k2 \4 H/ i
Copyright © 2011 American Chemical Society1 c: ]2 d% r: f9 H" _" O

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The culture of bone marrow derived mesenchymal stem cells (MSCs), as well as the control of its differentiation toward different tissue lineage, is a very important part of tissue engineering, where cells are combined with artificial scaffold to regenerate tissues. Graphene (G) and graphene oxide (GO) sheets are soft membranes with high in-plane stiffness and can potentially serve as a biocompatible, transferable, and implantable platform for stem cell culture. While the healthy proliferation of stem cells on various carbon platforms has been demonstrated, the chemical role of G and GO, if any, in guiding uncommitted stem cells toward differentiated cells is not known. Herein, we report that the strong noncovalent binding abilities of G allow it to act as a preconcentration platform for osteogenic inducers, which accelerate MSCs growing on it toward the osteogenic lineage. The molecular origin of accelerated differentation is investigated by studying the binding abilities of G and GO toward different growth agents. Interestingly, differentiation to adipocytes is greatly suppressed on G because insulin, which is a key regulator for the synthesis of fatty acids, is denatured upon π–π adsorption on G; in contrast, GO does not interfere with adipogenesis due to electrostatic binding with insulin. The different binding interactions and their subsequent influence on stem cell growth and differentiation are ascribed to different degrees of π–π stacking and electrostatic and hydrogen bonding mediated by G and GO.

作者: sunsong7 时间: 2011-8-11 17:05

不同性质的表面对干细胞的增殖、分化能力有很大的干扰作用，纳米材料做为非侵入式表面可为干细胞研究提供niche条件，研究表明，间充质干细胞可以在纳米表面生长8周表型和生长特征不发生改变....

Nanoscale surfaces for the long-term maintenance of mesenchymal stem cell phenotype and multipotency
Rebecca J. McMurray,1 Nikolaj Gadegaard,2 P. Monica Tsimbouri,1 Karl V. Burgess,3 Laura E. McNamara,1 Rahul Tare,4 Kate Murawski,4 Emmajayne Kingham,4 Richard O. C. Oreffo4, 5 & Matthew J. Dalby1 6 b3 b4 f8 [0 b# q! P' j X: q0 D7 j' g
Affiliations Contributions Corresponding authors Journal name: u! K2 \! a& J* W
Nature Materials Volume: 10, Pages: 637–644 Year published: (2011) DOI: doi:10.1038/nmat3058 ' Q" T" Y. s: W9 y+ s+ a( g
Received 27 September 2010 Accepted 31 May 2011 Published online 17 July 2011 ! k. \" `4 m7 b' u' }
Abstract
There is currently an unmet need for the supply of autologous, patient-specific stem cells for regenerative therapies in the clinic. Mesenchymal stem cell differentiation can be driven by the material/cell interface suggesting a unique strategy to manipulate stem cells in the absence of complex soluble chemistries or cellular reprogramming. However, so far the derivation and identification of surfaces that allow retention of multipotency of this key regenerative cell type have remained elusive. Adult stem cells spontaneously differentiate in culture, resulting in a rapid diminution of the multipotent cell population and their regenerative capacity. Here we identify a nanostructured surface that retains stem-cell phenotype and maintains stem-cell growth over eight weeks. Furthermore, the study implicates a role for small RNAs in repressing key cell signalling and metabolomic pathways, demonstrating the potential of surfaces as non-invasive tools with which to address the stem cell niche
http://www.nature.com/nmat/journal/v10/n8/abs/nmat3058.html

作者: sunsong7 时间: 2011-10-10 15:22

本帖最后由 sunsong7 于 2011-10-10 15:24 编辑 * |% J9 i; J1 d* a- F* r6 C
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石墨烯：干细胞生长的明智选择

撰稿：刘颖昳5 z& g5 w& D3 k( W# M H. \$ C

韩国的研究人员报道：神经干细胞在石墨烯表面生长比在玻璃表面生长时，分化成的神经元（neurons）与神经胶质细胞（glial cells）的比例更大。
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干细胞在医学上的应用越来越为公众所接受，他们往往认为这是一个神奇的治疗方法，虽然目前为止，科学界还并没能完全理解和控制它。科学家利用人类神经干细胞（human neural stem cells , hNSCs），以帮助进行脑组织的修复和神经通路的再生。hNSCs一般以两种方式生长；分化为神经元或者胶质细胞。控制这些细胞生长分化的种类是至关重要的，但是hNSCs 在实验室培养中，不受生化因子（biochemical directors）或者其他细胞诱导的情况下，一般倾向于形成胶质细胞。然而，如果用于修复和再生，人们更希望它能够生长分化为神经元。8 g' H) F" t1 c* p' Y/ R* ~- t4 c

来自韩国汉城国立大学（Seoul National University）和成均馆大学（Sungkyunkwan University）的科学家们发现，通过使用一种特殊的细胞生长基底，他们可以诱导hNSCs 生成神经元而不是胶质细胞。这种特殊基底就是石墨烯，研究人员尝试在其表面上进行神经细胞培养。由于石墨烯独特的物理和光学特性，这种原子厚度的碳层结构深受物理学家们的关注；由于其良好的生物相容性，导电性和透明度（在使用显微镜研究细胞时十分有优势），它也被用于细胞培养。但是，目前使用它进行干细胞生长相关的研究并不多见。

研究人员经过一个月的培养和观察，发现在没有其他任何生化因子诱导的条件下，石墨烯表面培养的神经干细胞分化成神经元的比例相对于玻璃表面要更大。细胞在石墨烯表面生长和粘附都非常好。他们还发现，石墨烯可以向神经细胞传递电流，用于神经刺激；这离最终实现脑组织修复的目标又前进了一个台阶。

研究人员认为，石墨烯可以作为优良的纳米支架用于长期地增强神经干细胞分化。他们还希望这可以广泛应用于神经修复（neural prosthetics）和神经再生医学（neural regenerative medicine）。这些可以帮助脑损伤患者重新获得自主行动能力，以及达到一些其他重要目标。

S. Y. Park et al., Adv. Mater. 2011, DOI: 10.1002/adma.201101503.
http://www.materialsviewschina.c ... growing-stem-cells/! G) u+ V- e" b$ v
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作者: sunsong7 时间: 2012-1-29 14:29

本帖最后由 sunsong7 于 2012-1-29 14:30 编辑 5 _& e2 g2 m" z8 E. r! q' n( x3 X

iPS细胞培养与分化研究用石墨烯平台
A graphene-based platform for induced pluripotent stem cells culture and differentiation

G.-Y. Chena, 1,
D.W.-P. Panga, 1,
S.-M. Hwangb,
H.-Y. Tuana, ,
Y.-C. Hua, , , * S+ ^) S& h0 a5 q$ c0 S0 `

a Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan
b Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu 300, Taiwan; x1 W6 E/ P8 Q7 {0 w2 U

Received 9 September 2011. Accepted 27 September 2011. Available online 18 October 2011.
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http://dx.doi.org/10.1016/j.biomaterials.2011.09.071, How to Cite or Link Using DOI$ I: Z4 \. v. ?' P5 a

Abstract

Induced pluripotent stem cells (iPSCs) hold great promise as a cell source for regenerative medicine yet its culture, maintenance of pluripotency and induction of differentiation remain challenging. Conversely, graphene (G) and graphene oxide (GO) have captured tremendous interests in the fields of materials science, physics, chemistry and nanotechnology. Here we report on that G and GO can support the mouse iPSCs culture and allow for spontaneous differentiation. Intriguingly, G and GO surfaces led to distinct cell proliferation and differentiation characteristics. In comparison with the glass surface, iPSCs cultured on the G surface exhibited similar degrees of cell adhesion and proliferation while iPSCs on the GO surface adhered and proliferated at a faster rate. Moreover, G favorably maintained the iPSCs in the undifferentiated state while GO expedited the differentiation. The iPSCs cultured on both G and GO surfaces spontaneously differentiated into ectodermal and mesodermal lineages without significant disparity, but G suppressed the iPSCs differentiation towards the endodermal lineage whereas GO augmented the endodermal differentiation. These data collectively demonstrated that the different surface properties of G and GO governed the iPSCs behavior and implicate the potentials of graphene-based materials as a platform for iPSCs culture and diverse applications.

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Keywords

Graphene;
Graphene oxide;
Induced pluripotent stem cells;
Differentiation;
Proliferation;
Stem cells+ M$ J, }; R& S/ W6 D5 N

Fig. 1. FTIR spectra (1000–3750 cm−1) and XPS spectra of GO and G. (a) FTIR spectra. (b) XPS spectra of GO, (c) XPS spectra of G. The FTIR absorption bands at 1042 cm−1 and 1730 cm−1 demonstrated C–O and CO stretching of COOH group, respectively; the 1620 cm−1 band indicated the absorptions of O–H bending vibration, epoxide groups and skeletal ring vibrations; C–O vibration band of epoxide groups was shown at 1170 cm−1. In the G spectrum, a new band of 1560 cm−1 was attributed to the skeletal vibration of G sheets, indicating the higher degree of graphitic domain. The GO spectrum showed a more prominent broad peak than G spectrum near 3380 cm−1 due to the O-H stretching vibration and the resultant adsorbed water molecules on the GO surface. The deconvolution spectrum of GO showed four different peaks centered at 285 eV, 286.4 eV, 287.1 eV and 289 eV, which corresponded to C–C/CC, C–OH, CO and O=C–OH, respectively. Except the aromatic C–C/CC at 285 eV, peaks were diminished in the case of G, confirming the reduction of GO to G.

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Fig. 2. AFM analyses of GO. (a) Images of as-prepared GO on a silicon substrate. (b) Height profile of the square area shown in (a). The lateral size of GO was ≈2–6 μm. Height difference between the GO sheet and substrate (the cursor pair in (b)) was 1.319 nm, consistent with the thickness of the single layer GO sheet. The crumpled silk wave observed under the AFM was characteristic of very thin sheets of GO layer covered on the substrate.

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Fig. 3. SEM images of GO and G. (a, d) Silicon wafer, (b, e) GO and (c, f) G on the silicon substrate. Dense coverage of GO and G on the substrate is revealed in (b, c). The thin sheet morphology of GO and G is clearly observed in (e, f).

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Fig. 4. AFM images of (a) GO and (b) G sheets immobilized on silicon substrates. Surface roughness parameters, including the average deviation from mean (Ra), the root–mean-square deviation (Rq) and the peak-to-peak distance (Rz), are shown in Table S2.

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Fig. 5. G and GO enabled iPSCs attachment and proliferation. (a) Photograph of blank, G- and GO-coated glass coverslips, (b) cell growth, (c) cell morphology. The cells were seeded at the same density (1 × 104 cells/cm2) onto the unmodified, G-coated and GO-coated coverslips and cultured in the LIF-containing medium to facilitate the maintenance of undifferentiated state. Bar, 100 μm.

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Fig. 6. G and GO led to differences in the iPSCs differentiation state. (a) Confocal microscopic observation of GFP expression. (b) mRNA levels of pluripotency markers Nanog and Oct4. (c) Immunohistochemical staining against Oct4. iPSCs were cultured on the 3 different substrates and analyzed at days 5 and 9. For confocal microscopy, the cells were counterstained by DAPI. Bar, 100 μm.

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Fig. 7. G and GO resulted in discrepancies in the iPSCs propensity of differentiation. iPSCs were cultured on the 3 different substrates and analyzed for the expression levels of lineage-specific marker genes: (a) endodermal markers (Gata4 and Ihh), (b) ectodermal markers (Fgf5 and Nestin) and (c) mesodermal markers (T and Bmp4). The expression levels were measured by qRT-PCR and normalized against those at day 1.

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Fig. 8. iPSCs cultured on the G- or GO-coated substrates remained amenable to gene transfer. (a) Microscopic observation. (b) Quantitative analyses of gene expression. The iPSCs cultured on the 3 substrates were transduced with a recombinant baculovirus expressing DsRed and continued to be cultured. Mock-transduced cells were cultured in parallel and served as the negative control. The cells were observed under the phase contrast microscope (upper panel in (a)) or the confocal microscope (lower panel in (a)), or measured by flow cytometry for the total fluorescence intensities (FI) at 1 day post-transduction. The total FI represent the averages of 3 independent culture experiments and are expressed in arbitrary units (a.u.). The total FI are similar for the 3 groups (glass, G and GO) without statistical difference.

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http://www.sciencedirect.com/science/article/pii/S0142961211011471

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作者: sunsong7 时间: 2012-1-29 14:33

本帖最后由 sunsong7 于 2012-1-29 14:48 编辑 1 N _; f P0 S% s
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石墨烯做为细胞界面:与细胞的机电耦合 Graphene as Cellular Interface: Electromechanical Coupling with Cells
Ravindra Kempaiah, Alfred Chung, and Vivek Maheshwari*
The Nanotechnology Engineering Program, Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Canada N2L 3G1
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ACS Nano, 2011, 5 (7), pp 6025–6031
DOI: 10.1021/nn201791k
Publication Date (Web): June 15, 20111 g( Z' o3 u6 @7 E' X9 W% P- v
Copyright © 2011 American Chemical Society
Address correspondence to vmaheshw@uwaterloo.ca.8 E, n% D! E! q. N+ @
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Section:4 W! j/ |& \+ p2 ]
Biochemical Methods6 E# K, Z: l5 y) H* @: P
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Abstract

Interfacing cells with nanomaterials such as graphene, nanowires, and carbon nanotubes is useful for the integration of cellular physiology with electrical read outs. Here we show the interfacing of graphene sheets on the surface of yeast cells, leading to electromechanical coupling between the sheets and the cells. The cells are viable after the interfacing. The response caused by physiologically stressing the cells by exposure to alcohols, which causes a change in cell volume, can be observed in the electrical signal through graphene. The change in the cell volume leads to straining of the sheets, forming wrinkles which reduce the electrical conductivity. As the dynamic response of the cell can be observed, it is possible to differentiate between ethanol, 2-propanol, and water. We believe this will lead to further development of cell-based electrical devices and sensors.

Keywords: cell; nano-bioelectronics; electromechanical coupling; dynamic cell response; graphene& r8 k* Y+ U5 V8 k

http://pubs.acs.org/doi/abs/10.1021/nn201791k

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