Hydrophilic glasses

Figure 9.5 AFM images of CdTe QDs (3.3 nm) on a hydrophilic glass substrate after drying the D2O solution without (a) and with (b) a trapping laser beam. Incident average laser power is 120 mW.

The motion of droplets in solution was used to manipulate micro-partides on surfaces. The didiloromethane droplet pushed aside hydrophilic glass beads of about... 

Figure 16.12 Transportation of glass-beads by the droplet, (a) Hydrophilic glass beads were pushed by the oil droplet. The droplet moved from the upper right of the figure. A magnified image of the region within the square is shown in the inset. Hydrophobic beads in the droplet (b) were carried with the motion of the oil droplet (c). The droplet shown in (c) was moved for several mm in the direction shown by the arrow in (b).

By preparing planar lipid monolayers or bilayers on hydrophobically derivatized or native hydrophilic glass, respectively, the adsorption equilibrium constants of a blood coagulation cascade protein, prothrombin, have been examined by TIRF on a surface that more closely models actual cell surfaces and is amenable to alterations of surface charge. It was found that membranes of phosphatidylcholine (PC) that contain some phosphatidyl-serine (PS) bind prothrombin more strongly than pure PC membranes/83... 

Obviously, the above example involved the use of higher loading capacity pins. In addihon, we printed onto a hydrophobic plastic substrate. While the profile shown in Figure 4.18 applies to more hydrophilic glass slides, we expect that the number of preprints could be greatly reduced as explained in the following discussion. 

One assembly example is polyethylenamine (PEI)-mediated self-assembly of FePt nanoparticles [56]. PEI is an all -NH-based polymer that can replace oleate/oleylamine molecules around FePt nanoparticles and attach to hydrophilic glass or silicon oxide surface through ionic interactions [52], A PEI/FePt assembly is readily fabricated by dipping the substrate alternately into PEI solution and FePt nanoparticle dispersion. Figure 10 shows the assembly process and TEM images of the 4 nm Fes8Pt42 nanoparticle self-assemblies on silicon oxide surfaces. Characterizations of the layered structures with X-ray reflectivity and AFM indicate that PEI-mediated FePt assemblies have controlled thickness and the surfaces of the assemblies are smooth with root mean square roughness less than 2 nm. 

Preliminary studies showed that it was possible to transfer monolayers composed of the fifth generation dendrimer to hydrophilic glass substrates. A Z-type deposition (deposition takes place during upstroke dipping) was observed with remarkably high transfer ratios in the range 0.8-1.0 (five layers were deposited). 

Fig. 14 Typical flow curves for a concentrated emulsion sheared between two rough surfaces closed circles the line is a fit to the Herschel-Bulkley equation), and between rough and smooth surfaces open circles hydrophilic glass surface open squares hydrophobic polymer surface). 7a denotes the apparent shear rate, and is the value of the apparent shear rate at the yield point (cr = CJy). CJs is the sticking yield stress below which the emulsion adheres to the surface...

Hydration Limit of Small Molecule Hydrophilic Glasses.304... 

Care must be taken to ensure the slide is properly prepared to accept the continuous phase. Water-wet solids suspended in an oil phase can interact differently when prepared on a hydrophilic glass surface compared with a hydrophobic sample holder. Careful observation and comparison of suspension morphology using both hydrophilic and oleophilic sample holders are sometimes required to confidently characterize a suspension. The transmitted light technique is limited by the opaque nature of most oil samples, and in cases where the sample cannot be made thin enough, an alternative technique using reflected light is available. 

The polyurethane in the phase-separated state (ANN), however, behaved in a manner similar to certain other hydrophobic surfaces (3), including siliconized glass, in that platelet adhesion was independent of the time of exposure to plasma, that is, no difference between 3 s and 3 min existed. The hydrophobic SBS block copolymer, on the other hand, attached significantly (P < 0.025) less platelets at 3 min of plasma exposure. The effect was relatively more predominant in the mixed state as the percent decrease in platelets attached at 3 min (conversion) was 56 compared with 34 for the phase-separated state (Table II). The conversion, however, was far less than the 99% observed on the hydrophilic glass. 

Optical fibers without cladding can be used to monitor the adsorption of chemical species such as proteins on an optical Hber core [87]. Fluorescence is induced by the evanescent wave field of the light propagating in the core. For example, the intrinsic fluorescence of the amino acid tryptophan in immunoglobulin (IgG) and the fluorescence of fluorescein-labelled IgG were detected and used to calculate the amount of protein adsorbed on hydrophilic glass and quartz surfaces. Fluorescent, nonadsorbing dextran was used as a calibration molecule which approximates the diffusion properties of the protein. Remote spectroscopic sensing of the adsorption of Rhodamine B-labelled IgG at the tip of a 600-pm fiber optic has also been described [88, 89]. 

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