Stanislaw Slomkowski

Terminology of polymers and polymerization processes in dispersed systems (IUPAC Recommendations 2011)

A large group of industrially important polymerization processes is carried out in dispersed systems. These processes differ with respect to their physical nature, mechanism of particle formation, particle morphology, size, charge, types of interparticle interactions, and many other aspects. Polymer dispersions, and polymers derived from polymerization in dispersed systems, are used in diverse areas such as paints, adhesives, microelectronics, medicine, cosmetics, biotechnology, and others. Frequently, the same names are used for different processes and products or different names are used for the same processes and products. The document contains a list of recommended terms and definitions necessary for the unambiguous description of processes, products, parameters, and characteristic features relevant to polymers in dispersed systems.

Adsorption of aminopropyltriethoxy silane on quartz: an XPS and contact angle measurements study

Aminopropyltriethoxy silane (APS) adsorption onto quartz has been monitored by XPS and found to be of the Langmuir type. XPS brings evidence for the partial protonation of the coupling agent amino group. It is shown by angular dependent XPS that the ammonium group is in that case oriented towards the quartz substrate. Contact angle measurements of water indicated that the quartz surface wettability has decreased following APS treatment.

Polyacrolein containing microspheres: Synthesis, properties and possible medical applications

Abstract Polymeric microspheres are used in medical diagnostics, therapy, and as supports for enzymes and other proteins in biotechnology. These particles have also found application in fundamental studies in the life-sciences as useful tools for separation of the living cells and subcellular fragments. This article presents comprehensive information on polyacrolein containing microspheres suitable for medical applications. Various synthetic procedures (radical, anionic, and red-ox polymerizations) are described, leading to polyacrolein microspheres, microspheres made of polyacrolein and other polymers, and copolymer microspheres containing polyacrolein segments. These particles can be obtained in a range of diameters from ca . 50 nm to a few micrometers, often with very narrow diameter distributions. Depending on the particular synthetic routes, it is possible to obtain microspheres with a uniform structures, core-shell, and raspberry morphologies. In this review, methods used for the characterization of the chemical structure of the surface layer of microspheres, in particular, methods used for determination of reactive (aldehyde) groups are also discussed. Results of studies on the immobilization of proteins onto polyacrolein containing microspheres, including relationships between the mode of protein binding (covalent immobilization and physical adsorption) and the fraction of polyacrolein in the surface layer of microspheres are reviewed. Methods allowing one to obtain protein-microsphere systems in which the attached proteins retain a substantial part of their biological activity are described. Polyacrolein containing microspheres, after attachment of selected antibodies, can be used as reagents in diagnostic tests. There are examples of using these particles for the fabrication of new materials for hemoperfusion columns and for the formation of two-dimensional particle assemblies on surfaces of polyethylene, quartz, and glass, which are potentially useful for the fabrication of biosensors.

Highly hydrophilic surfaces from polyglycidol grafts with dual antifouling and specific protein recognition properties.

Homopolymer grafts from α-tert-butoxy-ω-vinylbenzyl-polyglycidol (PGL) were prepared on gold and stainless steel (SS) substrates modified by 4-benzoyl-phenyl (BP) moieties derived from the electroreduction of the parent salt 4-benzoyl benzene diazonium tetrafluoroborate. The grafted BP aryl groups efficiently served to surface-initiate photopolymerization (SIPP) of PGL. In similar conditions, SIPP of hydroxyethyl methacrylate (HEMA) permitted the production of PHEMA grafts as model surfaces. Water contact angles were found to be 66°, 15°, and 0° for SS-BP, SS-PHEMA, and SS-PPGL, respectively. The spontaneous spreading of water drops on SS-PPGL was invariably observed with 1.5 μL water drops. PPGL thus appears as a superhydrophilic polymer. Resistance to nonspecific adsorption of proteins of PPGL and PHEMA grafts on gold was evaluated by surface plasmon resonance (SPR) using antibovine serum albumin (anti-BSA). The results conclusively show that PPGL-grafts exhibit enhanced resistance to anti-BSA adsorption compared to the well-known hydrophilic PHEMA. PPGL grafts were further modified with BSA through the carbonyldiimidazole activation of the OH groups providing immunosensing surfaces. The so-prepared PPGL-grafted BSA hybrids specifically interacted with anti-BSA in PBS as compared to antimyoglobin. It is clear that the superhydrophilic character of PPGL grafts opens new avenues for biomedical applications where surfaces with dual functionality, namely, specific protein grafting together with resistance to biofouling, are required.

Effect of surface modification of silica nanoparticles on toxicity and cellular uptake by human peripheral blood lymphocytes in vitro

Abstract Silica nanoparticles have an interesting potential in drug delivery, gene therapy and molecular imaging due to the possibility of tailoring their surface reactivity that can be obtained by surface modification. Despite these potential benefits, there is concern that exposure of humans to certain types of silica nanomaterials may lead to significant adverse health effects. The motivation of this study was to determine the kinetics of cellular binding/uptake of the vinyl- and the aminopropyl/vinyl-modified silica nanoparticles into peripheral blood lymphocytes in vitro, to explore their genotoxic and cytotoxic properties and to compare the biological properties of modified silica nanoparticles with those of the unmodified ones. Size of nanoparticles determined by SEM varied from 10 to 50 nm. The average hydrodynamic diameter and zeta potential also varied from 176.7 nm (+18.16 mV) [aminopropyl/vinyl-modified] and 235.4 nm (−9.49 mV) [vinyl-modified] to 266.3 (−13.32 mV) [unmodified]. Surface-modified silica particles were internalized by lymphocytes with varying efficiency and expressed no cytotoxic nor genotoxic effects, as determined by various methods (cell viability, apoptosis/necrosis, oxidative DNA damage, chromosome aberrations). However, they affected the proliferation of the lymphocytes as indicated by a decrease in mitotic index value and cell cycle progression. In contrast, unmodified silica nanoparticles exhibited cytotoxic and genotoxic properties at high doses as well as interfered with cell cycle.

Polypyrrole core/polyacrolein shell latex for protein immobilization

The redox polymerization of pyrrole, with ferric chloride as oxidant, carried out in the presence of polyvinylpyrrolidone (PVP), yielded polypyrrole latex particles. The polypyrrole latex was used, as seed, for the radical polymerization of acrolein. The resulting polypyrrole core/polyacrolein shell latex (poly(P/A)) was suitable for immobilization of up to 11 mg of human serum albumin (HSA) and/or 33 mg of human gamma globulin (γG) per 1 g of latex particles.

Synthesis of Bioerodible Poly(ε-caprolactone) Latexes and Poly(D, L-lactide) Microspheres by Ring-Opening Polymerization:

Poly(ε-caprolactone) [poly(CL)] latexes and poly(D,L-lactide) [poly(D,L-Lc)] microspheres were prepared directly by ring-opening precipita tion polymerization carried out in heptane-dioxane (4:1 v/v) mixed solvent in the presence of poly(dodecyl acrylate)-g-poly(ε-caprolactone) used as the surface active agent. This designed synthetic method yielded latexes and microspheres with narrow size distribution; poly(CL) latex D v/Dn = 1.038 and for poly(D,L- Lc) microspheres Dv/Dn = 1.15. (Dv and Dn denote the volume and number average diameters of particles.) The poly(CL) latex, synthesized by using CH3CH2OAl(CH2CH3) 2 as initiator, had a narrow polymer polydispersity of 1.11. Poly(D,L-Lc) microspheres, besides polymer with Mw/M n = 1.05 contained some unreacted lactide. Adsorption of human serum albumin and human gamma globulins on both kinds of polyester particles was studied for their potential use as polypeptide and protein delivery systems.

Inorganic–organic systems with tailored properties controlled on molecular, macromolecular and microscopic level

Abstract Methods suitable for modification of quartz and glass (plates and beads) on molecular, macromolecular and microscopic levels are described in this paper. The modifications led to composite materials with the core containing quartz (fused silica) or glass and outer shells composed of layers of γ-aminopropyltriethoxysilane (small molecules), dendrimers with aldehyde groups (G5) and/or Starburst PAMAM dendrimers with amino groups (macromolecules), and with one particle thick assemblies of poly(styrene–divinylbenzene–acrolein) microspheres with aldehyde groups at their surface (microscopic objects). Monitoring by AFM quartz plates with immobilized dendrimers revealed that their surfaces are relatively smooth with roughness parameter R g close to 2 nm and with diameters and maximal height of objects covering surface in form of bumps close to 4 nm, i.e. to diameters of single macromolecules of dendrimers. XPS studies of surfaces of modified quartz plates and glass beads unequivocally confirmed attachment of γ-aminopropyltriethoxysilane, dendrimers, and microspheres. Quantitative analysis revealed that dendrimer layers are 3.7 and 3.2 nm thick, for G5 and PAMAM dendrimers, respectively, indicating that these macromolecules form monolayer structures. XPS and SEM studies of quartz surface covered with layers of γ-aminopropyltriethoxysilane, G5 and PAMAM denrimers and subsequently with poly(styrene–divinylbenzene–acrolein) microspheres indicated that saturation of the surface coverage with these particles is achieved at the degree of coverage close to 0.60, i.e. to the maximal value attainable in the case of rapid covalent immobilization of spherical particles. Surfaces of quartz plates and glass beads, with outer layers containing G5 dendrimers and/or poly(styrene–divinylbenzene–acrolein) microspheres and thus, equipped with aldehyde groups, were used for covalent immobilization of human serum albumin (HSA). AFM studies revealed that macromolecules of HSA from dilute protein solution are attached onto surface of G5 dendrimers in such a way that they form clusters composed of not less than 50 protein macromolecules each. X-ray photoelectron spectroscopy used for monitoring of surfaces with immobilized poly(styrene–divinylbenzene–acrolein) microspheres which were subsequently exposed to contact with solution of HSA revealed that macromolecules of HSA are readily attached onto immobilized microspheres.

Kinetics of the anionic polymerization of β-propiolactone in dimethylformamide

Abstract Dissociation constants and thermodynamic parameters of the dissociation of poly(β-propiolactone) macroion pairs (carboxylate anions with K + ·dibenzo-18-crown-6 ether counterions) and CH 3 COO − K + ·dibenzo-18-crown-6 ether were determined in isodielectric β-propiolactone (β PL ) dimethylformamide (DMF) and ϵ-caprolactone (ϵ CL ) DMF systems. Stabilization of ion pairs by DMF, due to the (CH 3 ) 2 N + δ = CHO − δ resonance DMF form was proposed. Rate constants of propagation on macroions, k − p , and on macroion pairs, k ∓ p , were measured. The ratio k − p k ∓ p decreases with decreasing temperature, and at 20°C ([ β PL] 0 = 1 mol l −1 ) macroion pairs become more reactive than macroions ( k − p / k ∓ p = 7.5 × 10 −1 ). This results from a greater enthalpy of activation for propagation on macroions due to the fact that they are more strongly solvated than macroion pairs. Even in practically isodielectric mixtures, activation parameters for propagation on macroions depend on the monomer concentration. The explanation assumes that macroions are strongly solvated with β-propiolactone due to the very high dipole moment ( μ = 4.18) of monomer molecules.

The direct determination of protein concentration for proteins immobilized on polystyrene microspheres

In this paper we show how the Lowry method, designed for the determination of proteins in solution, can be used for the determination of proteins immobilized on the surface of microspheres (for protein concentrations higher than 10 micrograms/ml). Measurements were made for human serum albumin (HSA) and for immunoglobulins [rabbit immunoglobulins--antibodies against human fibrinogen (IgGF) and against fragment D of human fibrinogen (IgGFgD)] immobilized on the surface of polystyrene microspheres.