Combing of Molecules in Microchannels (COMMIC):  A Method for Micropatterning and Orienting Stretched Molecules of DNA on a Surface

Petit, Cécilia A. P.; Carbeck, Jeffrey D.

doi:10.1021/nl034341x

Cited by 65 publications

(77 citation statements)

References 26 publications

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“…Once one end of SWNTs is pinned by van der Walls force or chemical bonding between -COOH on carbon nanotubes and -NH 2 on the functionalized surface of silicon dioxide, the capillary force is exerted by the contact line on nanotubes which can be stretched and aligned perpendicular to the liquid front edge. Similar mechanism has been reported to assemble high aspect ratio structures of single DNA molecules [19].…”

Section: Resultssupporting

confidence: 73%

Alignment of Nanoscale Single-Walled Carbon Nanotubes Strands

et al. 2011

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Abstract:Depositing single-walled carbon nanotubes (SWNTs) with controllable density, pattern and orientation on electrodes presents a challenge in today's research. Here, we report a novel solvent evaporation method to align SWNTs in patterns having nanoscale width and micronscale length. SWNTs suspension has been introduced dropwise onto photoresist resin microchannels; and the capillary force can stretch and align SWNTs into strands with nanoscale width in the microchannels. Then these narrow and long aligned SWNTs patterns were successfully transferred to a pair of gold electrodes with different gaps to fabricate carbon nanotube field-effect transistor (CNTFET). Moreover, the electrical performance of the CNTFET show that the SWNTs strands can bridge different gaps and fabricate good electrical performance CNTFET with ON/OFF ratio around 106 . This result suggests a promising and simple strategy for assembling well-aligned SWNTs into CNTFET device with good electrical performance.

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Section: Resultssupporting

confidence: 73%

Alignment of Nanoscale Single-Walled Carbon Nanotubes Strands

et al. 2011

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“…One such example consists of coating carboxylated FNDs with polyL-lysines (PLs) to facilitate binding of the particles nonspecifically with DNA through electrostatic interactions (27,29,30). In this experiment, a single T4 DNA molecule fluorescently labeled with TOTO-1 dye molecules was stretched on an amine-terminated glass substrate with a channel-combing method (31). How the positively charged FND particles interact with the negatively charged DNA molecules was observed directly by a wide-field epifluorescence microscope equipped with a dual-view system.…”

Section: Resultsmentioning

confidence: 99%

Characterization and application of single fluorescent nanodiamonds as cellular biomarkers

Lee

Chen

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

804

455

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Type Ib diamonds emit bright fluorescence at 550 -800 nm from nitrogen-vacancy point defects, (N-V) 0 and (N-V) ؊ , produced by high-energy ion beam irradiation and subsequent thermal annealing. The emission, together with noncytotoxicity and easiness of surface functionalization, makes nano-sized diamonds a promising fluorescent probe for single-particle tracking in heterogeneous environments. We present the result of our characterization and application of single fluorescent nanodiamonds as cellular biomarkers. We found that, under the same excitation conditions, the fluorescence of a single 35-nm diamond is significantly brighter than that of a single dye molecule such as Alexa Fluor 546. The latter photobleached in the range of 10 s at a laser power density of 10 4 W/cm 2 , whereas the nanodiamond particle showed no sign of photobleaching even after 5 min of continuous excitation. Furthermore, no fluorescence blinking was detected within a time resolution of 1 ms. The photophysical properties of the particles do not deteriorate even after surface functionalization with carboxyl groups, which form covalent bonding with polyL-lysines that interact with DNA molecules through electrostatic forces. The feasibility of using surface-functionalized fluorescent nanodiamonds as single-particle biomarkers is demonstrated with both fixed and live HeLa cells.blinking ͉ photobleaching ͉ single-molecule detection ͉ single-particle tracking ͉ live cell O ne of the key avenues to understanding how biological systems function at the molecular level is to probe biomolecules individually and observe how they interact with each other directly in vivo. Laser-induced fluorescence is a technique widely adopted for this purpose owing to its ultrahigh sensitivity and capabilities of performing multiple-probe detection (1-3). However, in applying this technique to imaging and tracking a single molecule or particle in a biological cell, progress is often hampered by the presence of ubiquitous endogenous components such as flavins, nicotinamide adenine dinucleotides, collagens, and porphyrins that produce high fluorescence background signals (4-6). These biomolecules typically absorb light at wavelengths in the range of 300-500 nm and fluoresce at 400-550 nm (Fig. 1). To avoid such interference, a good biological fluorescent probe should absorb light at a wavelength longer than 500 nm and emit light at a wavelength longer than 600 nm, at which the emission has a long penetration depth through cells and tissues (5, 7). Organic dyes and fluorescent proteins are two types of molecules often used to meet such a requirement (1,8,9); however, the detrimental photophysical properties of these molecules, such as photobleaching and blinking, inevitably restrict their applications for long-term in vitro or in vivo observations. Fluorescent semiconductor nanocrystals (or quantum dots), on the other hand, have gained considerable attention in recent years because they hold a number of advantageous features including high photobleaching thresholds a...

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“…The molecules are aligned parallel to the microfluidic walls (Figure 2, inset), indicating the low curvature of the air-water interface as it passes through the channel. 43 The extension length distribution of λ-DNA combed in a microfluidic channel with a cross sectional area of 100 × 100 µm 2 is shown in Figure 3. The majority of the combed DNA molecules had an extension length between 7 and 11 µm, whereas the mean extension was ∼9 µm, corresponding to an extension ratio of <x>/L ≈ 0.45, where L is the contour length.…”

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confidence: 99%

Microfluidic Assays for DNA Manipulation Based on a Block Copolymer Immobilization Strategy

2010

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Methods to manipulate and visualize isolated DNA and oligonucleotide strands are important for investigation of their biophysics as well as their interactions with proteins. Herein, we report such a method by combining a block copolymer surface functionalization strategy with microfluidics. The copolymer poly(L-lysine-graftpolyethylene glycol) (PLL-g-PEG) coated one surface of the microfluidic channels, rendering it passive to adsorption and thus minimizing any noise arising from nontargeted adsorbed molecules. Single λ-phage DNA molecules were immobilized and were extended by molecular combing. Their extension did not exceed their contour length, which we attribute to the low surface tension of the coated surface. To demonstrate further the applicability of our method, the anchored DNA was extended by hydrodynamic flow. We propose this method for exploring DNA-protein interactions due to the copolymer's enhanced capacity for single-molecule detection, stability under wet or dry conditions, hydrophilicity, full compatibility with microfluidics and simplicity being a one-step process.

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Combing of Molecules in Microchannels (COMMIC): A Method for Micropatterning and Orienting Stretched Molecules of DNA on a Surface

Cited by 65 publications

References 26 publications

Alignment of Nanoscale Single-Walled Carbon Nanotubes Strands

Alignment of Nanoscale Single-Walled Carbon Nanotubes Strands

Characterization and application of single fluorescent nanodiamonds as cellular biomarkers

Microfluidic Assays for DNA Manipulation Based on a Block Copolymer Immobilization Strategy

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