Molecularly imprinted stationary phase prepared by reverse micro-emulsion polymerization for selective recognition of gatifloxacin in aqueous media.
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Molecularly imprinted microspheres for bisphenol a prepared using a microfluidic device.
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Spherical molecularly imprinted polymer particles for bisphenol A (BPA-MIP) were easily prepared by using a Y-junction microfluidic device. The sizes of the obtained BPA-MIP particles were found to be 86 microm with a narrow size distribution. The binding characteristics were investigated by drawing a binding isotherm to estimate the binding constant and by switching the polarity of solvents to examine the feasibility of use as a medium for affinity chromatography. When dichloromethane was used as a solvent, BPA was strongly bound to the spherical BPA-MIP particles based on hydrogen bond formation; after switching the solvent to methanol, BPA was eluted quantitatively due to the weakening of the hydrogen bonding, suggesting that the spherical BPA-MIP particles can be applied to affinity-type solid-phase extraction for BPA. As the present method can provide a diverse range of spherical MIPs without tedious procedures, MIP-based affinity media will be able to be more readily used as pretreatment and/or purification for various fields. (+info)
Fabrication of a hybrid microfluidic system incorporating both lithographically patterned microchannels and a 3D fiber-formed microfluidic network.
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A device containing a 3D microchannel network (fabricated using sacrificial melt-spun microfibers) sandwiched between lithographically patterned microfluidic channels offers improved delivery of soluble compounds to a large volume compared to a simple stack of two microfluidic channel layers. With this improved delivery ability comes an increased fluidic resistance due to the tortuous network of small-diameter channels. (+info)
Ordered arrays of native chromatin molecules for high-resolution imaging and analysis.
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Individual chromatin molecules contain valuable genetic and epigenetic information. To date, there have not been reliable techniques available for the controlled stretching and manipulation of individual chromatin fragments for high-resolution imaging and analysis of these molecules. We report the controlled stretching of single chromatin fragments extracted from two different cancerous cell types (M091 and HeLa) characterized through fluorescence microscopy and atomic force microscopy (AFM). Our method combines soft lithography with molecular stretching to form ordered arrays of more than 250,000 individual chromatin fragments immobilized into a beads-on-a-string structure on a solid transparent support. Using fluorescence microscopy and AFM, we verified the presence of histone proteins after the stretching and transfer process. (+info)
DNA origami with double-stranded DNA as a unified scaffold.
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Scaffolded DNA origami is a widely used technology for self-assembling precisely structured nanoscale objects that contain a large number of addressable features. Typical scaffolds are long, single strands of DNA (ssDNA) that are folded into distinct shapes through the action of many, short ssDNA staples that are complementary to several different domains of the scaffold. However, sources of long single-stranded DNA are scarce, limiting the size and complexity of structures that can be assembled. Here we demonstrated that dsDNA (double-stranded DNA) scaffolds can be directly used to fabricate integrated DNA origami structures that incorporate both of the constituent ssDNA molecules. Two basic principles were employed in the design of scaffold folding paths: folding path asymmetry and periodic convergence of the two ssDNA scaffold strands. Asymmetry in the folding path minimizes unwanted complementarity between staples, and incorporating an offset between the folding paths of each ssDNA scaffold strand reduces the number of times that complementary portions of the strands are brought into close proximity with one another, both of which decrease the likelihood of dsDNA scaffold recovery. Meanwhile, the folding paths of the two ssDNA scaffold strands were designed to periodically converge to promote the assembly of a single, unified structure rather than two individual ones. Our results reveal that this basic strategy can be used to reliably assemble integrated DNA nanostructures from dsDNA scaffolds. (+info)
Cell-adhesive and cell-repulsive zwitterionic oligopeptides for micropatterning and rapid electrochemical detachment of cells.
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