Carboxylated latex spheres

Figure 2. Two-dimensional agarose gel electrophoresis of car-boxylated latex spheres. The following mixture was made 24 pi of 2.5% carboxylated latex spheres with an R of 30 nm (purchased from Polysciences, Inc.) 6.0 pi containing 4 pg each of bacteriophages T3 and (j)II (R = 30.1 nm), 2 pg of bacteriophage P22 (R = 31.4 nm) 1.0 pi containing 3 pg of tomato bushy stunt virus (TBSV R = 17.0 nm) (20) and 28 pi of 6% sucrose, 400 pg/ml bromphenol blue in 0.025 M sodium phosphate, pH 7.4,...

A droplet of the latex suspension in water (solid content 0.1-1 %) was placed onto the patterned substrate, covered to prevent evaporation, and incubated for >3 h (preferably over night) at 4 °C (refridgerator). Excessive liquid was then slowly removed with a pipet and some patterns (when stable enough, e.g. carboxylated latex spheres on NR4 ) were carefully rinsed with water and ethanol. We refer to this procedure as drop coating . The assembly structures were investigated immediately after preparation with the optical microscope (Axioskop, Zeiss) in reflection mode. 

Carhodiimide Method. In this reaction, a water-soluble carhodiimide derivative is used to couple carboxyl groups on the latex spheres to amino groups on the antibody molecules via a peptide bond.i The reaction mechanism is shown in Figure k. 

Figure 3.14 Reduced viscosity jj/jjo ( ) of 1 MDa polyacrylamide, and reduced microviscosity fiO/p, encountered by 55 (O), 140 (0), and 215 ( ) nm fluorescent carboxylate-modifled polystyrene latex spheres in these solutions. Original measurements by Radko and Chrambach(7).

Advancing to larger matrix chains, Radko and Chrambach compare the concentration dependences of p and rj for human serum albumin and for carboxylate and sulfate-modified polystyrene latex spheres, radii between 7 and 1085 nm, in solutions of 5 MDa polyacrylamide(36). Polyacrylamide chains had a nominal c ... 

Fig. 11. Site selection by different spin probes in an aqueous polymer dispersion (latex). Spin-labeled surfactants insert into the surfactant layer and may probe insertion of the surfactant tail into the polymer (16-DOXYL-stearate) or order of the surfactant layer (5-DOXYL-stearate). The weakly polar prohe TEMPO diffuses (dotted arrow) from the aqueous serum into the polymer sphere (gray). More polar prohes such as 4-hydroxy-TEMPO and TEMPO-4-carboxylate reside in the aqueous serum.

---