On cellulose sheets

Hawlisch, H., Muller, M., Frank, R., Bautsch, W., Klos, A., and Kohl, J. (2001) Sitespecific anti-C3a receptor single-chain antibodies selected by differential panning on cellulose sheets. Anal. Biochem. 293, 142-145. 

A different way to produce chemical microarrays in situ is spot synthesis of combinatorial libraries on cellulose sheets [56]. Spot synthesis is configured as an open system to be operated at room temperature. Despite attempts to replace cellulose with polypropylene as a synthesis support [57], cellulose is still the support of choice for spot synthesis, and reaction conditions have to be compatible with the restricted chemical stability of cellulose. Due to the acid labihty of such membranes, the diversity content of these arrays was initially restricted to the synthesis of peptides. Recently, a method was described that could widen the scope of spot synthesis arrays. Germeroth and coworkers [57] succeeded in the assembly of a library of 8000 cellulose-bound 1,3,5-triazines under mild reaction conditions. They employed a strategy that took advantage of a temperature-dependent, successive displacement of cyanuric chlorides by different nucleophiles in a first report of the synthesis of smaU organic compounds on ceUulose sheets. 

Figure 12.33. (b) Shielding effectiveness (SE) obtained using multilayer polyaniline grafted on cellulose sheet using the ASTM-7 coaxial test method. 

Lesser et al (75) used cellulose sheets with fluorescent indicator, acetic acid/0.01M aqueous disodium edetate (3 97), and observed an Rf value of O.78 for hydralazine. On silica gel with fluorescent indicator, the Rf value was less than 0.05 with (a) chloroform/n-heptane/ acetic acid (6 4 1), and (b) cyclohexane/chloroform/ acetonitrile (1 2 1). 

Figure 11.22 represents a paper electrophoresis apparatus. The soaked cellulose sheet is sandwiched between two horizontal glass plates with the ends dipped into vessels containing more electrolyte solution. The electrodes are also dipped into these vessels, as shown. The sample is spotted in the center of the sheet, and the oppositely charged ions then have room to migrate in opposite directions on the sheet. Qualitative analysis is performed much as with paper chromatography, by comparing the distances the... 

Mark the start with a pencil on a PEI Cellulose sheet (dimensions as in Protocol 3.1.2) and apply the samples with a microliter syringe or a pipet. 

The decorative plastic laminates widely used for countertops and cabinets are based on melamine—formaldehyde resin (see Laminates). Several layers of phenolic-saturated kraft paper are placed in a press and a sheet of CC-cellulose paper printed with the desired design and impregnated with melamine—formaldehyde resin is placed over them. Then a clear CC-cellulose sheet, similarly impregnated with the resin, is placed on top to form a clear, protective surface over the decorative sheet. The assembly is cured under heat and pressure up to 138°C and 10 MPa (1450 psi). A similar process is used to make wall paneling, but because the surfaces need not be as resistant to abrasion and wear, laminates for wall panels are cured under lower pressure, about 2 MPa (290 psi). 

Shoaf and Lium [103] used thin layer chromatography to separate algal chlorophylls from their degradation products. Chlorophyll is extracted from the algae with dimethyl sulphide and chromatographed on commercially available thin layer cellulose sheets, using 2% methanol and 98% petroleum ether as solvents, before determination by either spectrophotometry or fluorometry. 

Application of Additives to Silk. Deacidifying Agent. This material is ethoxymagnesium ethyl carbonate dissolved in trichlorotrifluoroethane (Wei To Associates). It has been extensively used as an alkaline buffering agent to protect paper and cellulosic textiles from aging (7,8,21). Samples were dipped one at a time in the solution for 30 s and then dried flat on a sheet of poly(methyl methacrylate). The treated samples had an add-on of approximately 3% and were relatively stiff. 

A solution of the adenosine derivative (2 mmol) in 1,0-1.6 M aq chloroacetaldchyde (20 mL) at pH 4.0 4.5 was stirred at 24-37 C for 12-72 h until no starting material was detectable by TLC (on Easterman chromatogram cellulose sheets using i-PrCOjH/NH OH/HjO, 71 1 24, v/v/v) and until the peak ratios 265/275 run became constant in the UV absorption spectra. The etheno product was decolorized with charcoal and evaporated to dryness in vacuo, Recrystallization of the residue by dissolving in a minimum amount of HjO, followed by addition of EtOH and EtjO to the cloud point or reprecipitation from aq EtOH followed by an EtOH wash yielded pure product (yield 90-95%). 

A chromatographic bed the stationary phase may be packed into a glass or metal column, spread as a thin layer on a sheet of glass or plastic, or adsorbed on cellulose fibres (paper). 

Non-woven media in the form of felts and compressed cellulose pulps, are used for clarification by depth filtration. Unless carefully prepared, they have the disadvantage of losing fibrous material from the downstream side of the filter. The application of sheet media has been discussed earlier. High wet strength is conferred on paper sheets by resin impregnation. An alternative technique employs asbestos fibers supported in a cellulose framework. 

Another modification in which form thin sheet electrophoresis is employed is known as ionophoresis. In this method, devised by Sanger and his co-workers, high voltage electrophoresis is carried out on ion-exchange paper. It is a rapid method of great resolution and sensitivity and is used in Biochemistry for the separation of constituents of a highly complex mixture e.g. a mixture of oligoribonucleotides produced by partial enzymic hydrolysis of RNA. For separation of the constituents of this hydrolysate mixture, a two-dimensional technique is used in which the mixture is subjected to electrophoresis on cellulose acetate and then the partially separated mixture is transferred to a DEAE-cellulose... 

The freeze-dried peptide is hydrolyzed in 6 N HCl at 110°C for 1 h, HCl is removed by evaporation, and the residue is dissolved in H2O, mixed with unlabeled phosphoamino acid markers, and electrophoresed on the Kodak cellulose sheets (Erdodi et al., 1987). The phosphoamino acids are identified by ninhydrin staining and autoradiography (Rg. 2). The procedure is only qualitative, because of the incomplete hydrolysis of the phosphopeptide and the partial destruction of the liberated phosphoserine and phosphothreonine. 

Cellulose dissolves in Schweitzer s reagent, which is prepared by dissolving carefully washed precipitated copper hydroxide in ammonia. From this solution it is precipitated iii an amorphous condition by acids and salts. Advantage is taken of the effect of this reagent on cellulose in the preparation of waterproof paper. A sheet of paper left for a short time in contact with Schweitzer s reagent is superficially attacked, and when passed through rollers and dried is rendered impervious to water. 

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