Poly(styrene/acrolein) and poly(styrene/α-tert-butoxy-ω- vinylbenzyl-polyglycidol) microspheres. Similarities and differences

Abstract

Properties of two types of polystyrene microspheres with polyacrolein and polyglycidol components in their surface layers are compared. Microspheres were prepared in batch radical emulsifier-free emulsion copolymerizations of styrene with acrolein and/or α-tert-butoxy-ω-vinylbenzyl-polyglycidol macromonomer (M n = 2700). Polymerizations were initiated with potassium peroxodisulfate, and the ratio of initial concentrations of styrene and initiator was constant. Number average diameters of poly(styrene/acrolein) (P(S/A)) and of poly(styrene/polyglycidol) (P(S/PGL)) particles were in the range of 200 -650 nm and decreased with increasing concentration of acrolein and/or polyglycidol in the polymerizing mixtures. The diameter polydispersity of synthesized particles (D /D w n ) was usually lower than 1.02. X-ray photoelectron spectroscopy for P(S/A) and P(S/PGL) microspheres showed that surface layers of particles were significantly enriched in polyacrolein or polyglycidol segments, surface fractions of which increased with increasing concentration of the more hydrophilic comonomer in the polymerizing mixture. In the case of P(S/A) particles, the maximal fraction of polyacrolein approached 80 mol-%, whereas for P(S/PGL) particles the maximal surface fraction of PGL was 42 mol-%. Human serum albumin was used as a model protein for studies of attachment onto P(S/A) and P(S/PGL) microspheres. It has been found that for both kinds of particles, the maximal surface concentration of attached (adsorbed and/or covalently immobilized) protein decreased with increasing fraction of hydrophilic component in the particle surface layer (polyacrolein or polyglycidol units). In the case of P(S/A) particles, adsorption always accompanied covalent immobilization of proteins. To the contrary, covalent immobilization of proteins onto the P(S/PGL) microspheres proceeded without adsorption of proteins.

Principle of a New Immunoassay Based on Electrophoretic Mobility of Poly(styrene/α‐tert‐butoxy‐ω‐vinylbenzyl‐polyglycidol) Microspheres: Application for the Determination of Helicobacter pylori IgG in Blood Serum

“…four times the amount of protein being eventually immobilized. [7,25] The above-mentioned observation is in agreement with the results of our present studies on the immobilization of H. pylori. Indeed, in all experiments with concentration of P(S/PGL) microspheres equal to 3 Â 10 À3 g ml À1 and the initial concentration of H. pylori antigen higher than 3 Â 10 À4 g ml À1 , the surface concentration of immobilized protein did not exceed (1.6 AE 0.3) Á 10 À3 g m À2 .…”

Cytologic features of the nested variant of urothelial carcinoma

“…Usually, such compounds could be bound only to the end groups of hydrophilic blocks of copolymers 2. However, there are known microspheres (obtained by emulsion and/or dispersion copolymerizations) with surface‐layer‐containing hydrophilic polymer segments with functional groups along the chains 24, 25…”

Hydrophilic Core‐Shell Microspheres: A Suitable Support for Controlled Attachment of Proteins and Biomedical Diagnostics

“…The process of protein immobilization consists of the following steps: diffusion towards the surface of a microsphere; adsorption (on hydrophilic surfaces this is very weak and thus reversible); formation of covalent bonds with adjacent reactive groups at a surface 73. The results of many studies suggest that the surface of some microspheres composed from hydrophilic and hydrophobic polymers is not homogeneous and contains hydrophobic and hydrophilic patches 53,73,74. For particles with an interfacial layer containing hydrophobic patches without reactive groups parallel to covalent immobilization in hydrophilic domains, a reversible adsorption on hydrophobic patches may also occur.…”

“…Studies on the immobilization of human serum albumin (HSA) onto poly(styrene/acrolein) microspheres revealed that the fraction of covalently bound protein increased gradually with increasing fraction of polyacrolein in the surface layer of the particles 73…”

“…Extensive studies have been carried out on the covalent immobilization of human serum albumin, gamma globulins and fibrinogen onto poly(styrene/polyglycidol) (P(S/PGL)) microspheres activated with 1,3,5‐trichlorotriazine (TCT) 73. It was noticed that the maximal surface concentration of HSA, gamma globulins and fibrinogen decreased with increasing surface fraction of polyglycidol.…”