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Biomedical subjects

A Baszkin

Publications and source records attributed to A Baszkin.

26 records · Page 2Linked to original sources
PubMed1987

Collagen at interfaces. II: Competitive adsorption of collagen against albumin and fibrinogen.

Adsorption of chemically radiolabeled [14C] collagen from binary mixtures with albumin or fibrinogen was studied on the solution/air and solution/polyethylene interfaces and revealed the preferential adsorption of albumin. This phenomenon is confirmed by the data of surface tension measurements of single protein, collagen-albumin, and collagen-fibrinogen solutions. Desorption experiments clearly show that more irreversibly adsorbed collagen was found on polyethylene surfaces when adsorption was performed from collagen-fibrinogen than from collagen-albumin solutions. The combined adsorption-desorption and the surface tension data show that competitive adsorption of collagen at the hydrophobic surfaces is strongly influenced by the surface tension properties of the proteins in solution.

Adsorption↗
PubMed1987

Surface characterization of heparin-complexing poly(amido amine) chains grafted on polyurethane and glass surfaces.

Poly(amido-amine) chains grafted onto polyurethanes and glass form stable complexes with heparin yielding potential nonthrombogenic surfaces. The characterization of the surfaces, and the product of each chemical reaction including final heparinized surfaces, has been studied by contact angle data and scanning electron microscopy (SEM). Air in water, octane in water, and drop-on-plate contact angle data were used to estimate surface (gamma sv) and interfacial (gamma sw) free energies. Solid-water work of adhesion (Wa) and its dispersive (Wda) and polar (Ipsw) components were calculated for all studied surfaces. It has been found that the viscosity of polyurethane solution used for film casting influences wetting properties of these films. It has also been found that a direct correlation exists between the Ipsw/Wda values and the degree of coverage of the surfaces by cellular deposits after their exposure to platelet-rich plasma. Final heparinized polyurethane and glass materials are hydrophilic, their Ipsw/Wda ratio is high, and little or no cellular deposit is observed on their surfaces.

Biocompatible Materials↗
PubMed1987

Monolayer studies on poly(isobutylcyanoacrylate)-ampicillin association.

Surface pressure-area isotherms (pi-A) of poly(isobutylcyanoacrylate) monolayers with or without glucose and dextran as polymerization adjuvants used in the preparation of nanoparticles have been derived from measurements made at the air-water interface with the subphase pH at 2.7, 5.5 or 8.8. The isotherms were characteristic of the expanded type of polymer monolayer curves, yielding unusually low limiting area values compared with those of other known poly(acrylate) derivatives. This behaviour may be explained by the folding of polar moieties of the polymer groups in the water subphase. Ampicillin incorporated during preparation of nanoparticles had a negligible effect on the general behaviour of adjuvant-free monolayers, but a significant one on the adjuvant-loaded polymer monolayer system which showed an increase in surface area throughout the compression cycle, as compared with the surface area of the adjuvant-free polymer system although the collapse pressure was practically the same at 67 mN m-1.

Ampicillin↗
PubMed1986

Collagen at interfaces. I. In situ collagen adsorption at solution/air and solution/polymer interfaces.

Collagen was isolated from rat tail tendons and acetylated with 1-14C acetic anhydride. In situ adsorption of this collagen from a buffer solution (pH = 2.7) was measured at the interfaces to air, polyethylene and polyethylene grafted with poly(maleic acid), respectively. The kinetics of adsorption were recorded for all surfaces studied and the corresponding diffusion coefficients for collagen in solution with various protein concentrations were calculated. The desorption of collagen from polymer surfaces was also studied. These experiments reveal the existence of both a reversibly and an irreversibly adsorbed collagen layer on the polymers tested. The desorption/adsorption ratio for the polyethylene is higher than that for the grafted polyethylene indicating stronger interactions of collagen with the grafted surface than with the non-modified polyethylene.

Adsorption↗
PubMed1985

The effect of the surface free energy of pharmaceutical tablets on liquid penetration.

The surface free energies (gamma SV) of the integral and partial tablet formulations of an antiarrhythmic drug--cibenzoline succinate, have been assessed by contact angle measurements using high-viscosity polyols and Neumann's equation of state. Independent measurements of penetration for these liquids into the tablets yielded pore size values through the use of the Washburn equation. The role of different constituents of the formulations are analysed in terms of their influence upon the free surface energy of the tablets and penetration rates. The relation between (gamma SV) and penetration rates yields for a series of liquids two threshold values: (gamma SV)s 'start' and (gamma SV)r, 'rapid', which define respectively the beginning of the measurable penetration and the rapid penetration.

Anti-Arrhythmia Agents↗
PubMed1984

Adsorption of bovine submaxillary mucin on silicone contact lenses grafted with poly(vinyl pyrrolidone).

Bovine submaxillary mucin is considered to be an analogue of the high molecular protein present in the conjunctival mucus. This mucin was isolated from fresh salivary glands and acetylated with [1-14C]acetic anhydride. In situ adsorption of the bovine submaxillary mucin on silicone contact lenses ungrafted and grafted with poly(vinyl pyrrolidone) was performed for the first time using an original radiotracer technique. The results show that the adsorbed amounts of mucin are higher on grafted samples and that thick layers are adsorbed when mucin concentration in the bulk solution is increased. Desorption experiments reveal that in addition to the tightly adsorbed protein layer, a loosely bound mucin layer of the same thickness exists on grafted and ungrafted silicones.

Adsorption↗
PubMed1980

The interaction of plasma proteins with polymers. I. Relationship between polymer surface energy and protein adsorption/desorption.

Adsorption of bovine albumin, gamma-globulin and fibrinogen from phosphate buffer solution (pH = 7.5) onto several polymer films was studied using the radioiodinated proteins (125I). The kinetics of desorption of the proteinated polymer films in bovine plasma was determined. Contact angle measurements on these same polymers allowed the calculation of dispersive (WA d) and polar (Ip) components of the polymer-protein solution system. Results from these measurements show that the nondispersive-dispersive force balance at the polymer-protein solution interface, expressed by the Ip/WA d ratio, is an important factor for binding of proteins on polymer surfaces. The purity of fibrinogen and the cleaning procedures for the polymer surfaces influence the absolute values of proteins adsorbed on polymer surfaces.

Adsorption↗