Direct Immobilization of Fab‘ in Nanocapillaries for Manipulating Mass-Limited Samples

Kim, Bo Young; Swearingen, Carla B.; Ho, Ja‐an Annie; Romanova, Elena V.; Bohn, Paul W.; Sweedler, Jonathan V.

doi:10.1021/ja070041w

Cited by 47 publications

(44 citation statements)

References 47 publications

(113 reference statements)

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“…Insulin has been selectively preconcentrated by microfluidic patterning of immobilized Fab′ on a nanopore membrane, followed by MALDI MS analysis. 13 Although the actual concentration and detection steps were not performed on-chip, microfluidic patterning of nanopore membranes could be scaled up to create arrays of immobilized antibodies for multiplexed sensing. In addition to antibodies, a wide range of chemical functionalities can be grafted onto track-etch membranes and their inner pore surfaces for use in preconcentration, protein digestion, or labeling reactions.…”

Section: Sample Preparationmentioning

confidence: 99%

Nanofluidics in Lab-on-a-Chip Devices

2009

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As the field of nanofluidics matures, fundamental discoveries are being applied to lab-on-a-chip analyses. The unique behavior of matter at the nanoscale is adding new functionality to devices that integrate nanopores or nanochannels. (To listen to a podcast about this feature, please go to the Analytical Chemistry website at pubs. acs.org/journal/ancham.)Advances in microfabrication and miniaturized analysis have resulted in increasingly sophisticated microfluidic systems that are fulfilling the promise of true "labs-on-a-chip" or "micro total analysis systems" by integrating multiple processing steps on a single device.1 Furthermore, improved fabrication techniques have placed the nanoscale regime within reach, even for laboratories with limited fabrication facilities. 2 These advances are allowing scientists to explore fluidic systems containing conduits that approach molecular-length scales. Incorporation of biological and synthetic nanochannels in fluidic devices holds great promise for new analytical applications because there are forces and phenomena at this scale that are absent or negligible in larger microchannels.3 Critical considerations in designing these devices include double-layer overlap (DLO) and the resulting ion permselectivity; localized enhancement of electric fields; and the increased influence of diffusion, surface-to-volume ratio, surface charge, and entropy. Through these effects, nanoscale components can improve routine processing and add new functionality to microfluidic devices. The goals of this article are to highlight progress in integrated micro-and nanofluidic devices, to demonstrate how nanofluidic components may benefit each function performed during chemical analysis (sample preparation, fluid handling and injection, separation, and detection), and to encourage creative thinking about future applications as this technology matures. This article focuses on devices containing one or more nanochannels or nanoporess fluidic features with at least one dimension typically e100 nm. We will discuss discrete features e0.5 µm, as opposed to nanoporous monoliths 4 or membranes with tortuous paths, 5 which are reviewed elsewhere.Some of the earliest work in nanofluidics used native and engineered protein pores in lipid bilayers to characterize a range of molecules, including polymers, nucleic acids, metal ions, and organic molecules, by resistive-pulse sensing. 10Protein pores provide excellent reproducibility with respect to their dimensions and internal chemistry and readily self-insert into a bilayer from solution. However, lipid bilayers on-chip are relatively fragile compared to the glass, polymer, and semiconductor substrates typical for microfluidic applications. As a result, many groups are pursuing emerging nanofabrication methods to produce nanochannels in hard and soft materials. Figure 1 shows integrated micro-and nanofluidic devices in which nanopores or channels are formed by a variety of methods, including track-etching polymer membranes, 6 sacrificial layer deposition, 7 ...

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Section: Sample Preparationmentioning

confidence: 99%

Nanofluidics in Lab-on-a-Chip Devices

2009

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“…[1][2][3][4][5][6][7] A recent step further towards this goal is to incorporate stimuli-responsive molecules and functional chemical groups into nanoporous substrates constructing smart materials and novel nanodevices, [8][9][10][11][12] such as the molecular-recognition nanoporpous membranes [13][14][15][16] and the tunable nanofluidic diodes, [17][18][19] etc. On the one hand, these smart systems can be switched between high and low conducting states by changing conformations of the attached functional molecules in response to the environmental stimuli, including pH, [20] light, [21] ionic strength, [22] and temperature, [23] to control the amount of the fluid transport.…”

Section: Introductionmentioning

confidence: 99%

Current Rectification in Temperature‐Responsive Single Nanopores

et al. 2010

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Herein we demonstrate a fully abiotic smart single-nanopore device that rectifies ionic current in response to the temperature. The temperature-responsive nanopore ionic rectifier can be switched between a rectifying state below 34 degrees C and a non-rectifying state above 38 degrees C actuated by the phase transition of the poly(N-isopropylacrylamide) [PNIPAM] brushes. On the rectifying state, the rectifying efficiency can be enhanced by the dehydration of the attached PNIPAM brushes below the LCST. When the PNIPAM brushes have sufficiently collapsed, the nanopore switches to the non-rectifying state. The concept of the temperature-responsive current rectification in chemically-modified nanopores paves a new way for controlling the preferential direction of the ion transport in nanofluidics by modulating the temperature, which has the potential to build novel nanomachines with smart fluidic communication functions for future lab-on-chip devices.

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“…The large surface-to-volume ratio maximizes analyte separations based on physical size. Multilayer devices with membranes have great potential for removing impurities and pre-concentrating samples before further analysis in microfluidic devices 12–14 , dramatically reducing offline process time and increasing sensitivity when coupled with mass spectrometry 15 or capillary isoelectric focusing (CIEF) 16 . Membranes have also been used in cell-related research 17, 18 , protein digests 19, 20 and bioreactors 20, 21 .…”

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confidence: 99%