Particle type

Radio-iso tope 1/2 Primary y-ray keV % Decay energy, keV Particle type Average energy, keV Average e y-ray energy, keV... 

The DEP of numerous particle types has been studied, and many apphcations have been developed. Particles studied have included aerosols, glass, minerals, polymer molecules, hving cells, and cell organelles. Apphcations developed include filtration, orientation, sorting or separation, characterization, and levitation and materials handhng. Effects of DEP are easily exhibited, especially by large particles, and can be apphed in many useful and desirable ways. DEP effects can, however, be observed on particles ranging in size even down to the molecular level in special cases. Since thermal effects tend to disrupt DEP with molecular-sized particles, they can be controlled only under special conditions such as in molecular beams. 

Particle Diameter (mm) Particle Type Time to Settle One Foot... 

Particle packings (random) are usually (not alwa) ) less efficient than the pre-packaged/preformed assemblies however, particle types are generally more flexible in loading and the ability to handle dirty fluids. 

Both large-pore and nonporous sorbents have been successfully applied for large biomolecule separations. The fundamental distinction between these two particle types is the balance between efficiency of mass transfer and loading capacity. Porous... 

If the bed material is a mixture of different particle types, abrasion of one component can be reduced by the decrease of its surface in relation to the entire material surface in the bed (cf. Sec. 2). A potential field of application is the coal combustion process with the three components coal, ash and limestone. 

Particle types Specific charge (pC/kg) Method Source... 

The reactions used for coupling affinity ligands to nanoparticles or microparticles basically are the same as those used for bioconjugation of molecules or for immobilization of ligands onto surfaces or chromatography supports. However, with particles, size can be a major factor in how a reaction is performed and in its resultant reaction kinetics. Since particle types can vary from the low nanometer diameter to the micron size, there are dramatic differences in how such particles behave in solution and how the density of reactive groups or functional groups affects reactions. 

The following sections discuss many of the major particle types and provide bioconjugation options for the coupling of ligands to the surface of functionalized particles. Some additional nanoparticle constructs, including gold particles, dendrimers, carbon nanotubes, Buckyballs and fullerenes, and quantum dots are discussed more fully elsewhere (see Chapter 7 Chapter 9, Section 10 Chapter 15 and Chapter 24). 

Perhaps the most common particle type used for bioapplications is the polymeric microsphere or nanosphere, which consists basically of a spherical, nonporous, hard particle made up of long, entwined linear or crosslinked polymers. Creation of these particles typically involves an emulsion polymerization process that uses vinyl monomers, sometimes in the presence of... 

The following protocol for passive adsorption is based on methods reported for use with hydrophobic polymeric particles, such as polystyrene latex beads or copolymers of the same. Other polymer particle types also may be used in this process, provided they have the necessary hydrophobic character to promote adsorption. For particular proteins, conditions may need to be optimized to take into consideration maximal protein stability and activity after adsorption. Some proteins may undergo extensive denaturation after immobilization onto hydrophobic surfaces therefore, covalent methods of coupling onto more hydrophilic particle surfaces may be a better choice for maintaining native protein structure and long-term stability. 

Many particle types contain functional groups that are built into the polymer backbone and displayed on their surface. The quantity of these groups can vary widely depending on the type and ratios of monomers used in the polymerization process or the degree of secondary surface modifications that have been done. Some common particle functionalities are shown in Figure 14.6. Many of these functionalized particles can be used to couple covalently biomolecules through the appropriate reaction conditions (Ilium and Jones, 1985 Arshady, 1993). For each type of particle, manufacturers may offer several different densities of functional groups for different applications. 

Primary amine-containing polymeric particles are available from a number of manufacturers and have either aliphatic or aryl amine groups on their surface. Occasionally, a particle type may have secondary or tertiary amines present, but these should be avoided for covalent coupling, as primary amines typically give better reaction yields than secondary amines and tertiary amines are unreactive. 

Dissolve SPDP in dimethylformamide (DMF) at a concentration of 6.2 mg/ml (makes a 20 mM stock solution). Add 50 pi of the SPDP solution to the 1 ml particle suspension and mix to dissolve. Note The small quantity of DMF in a polymeric particle suspension should not affect particle stability, even if the polymer type is susceptible to swelling in pure DMF. Other particle types, such as metallic or silica based, usually are not affected by organic solvent addition, unless their surfaces are non-covalently coated with a dissolvable polymer. 

After the final wash, resuspend the particles at a concentration of 10 mg/ml in coupling buffer and add an appropriate amount of the solution from step 6, which contains the purified, oxidized antibody. The amount of oxidized antibody to add to the particles should be about 1-10 X over the amount of the calculated monolayer for the particle type used. (Note For 100 mg of 1 pm hydrazide particles, a monolayer equivalent of antibody will be about 1.5 mg, so the total amount added should be in the range of 1.5-15 mg for a 1-10 X excess). 

Wave-particle duality The description of matter as a wave or a particle is possible and neither is preferred. Particle-type questions get particle-type answers and wave-type questions get wave-type answers. 

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