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Adsorption of proteins and adhesion of bacteria to a surface is affected by chemical and physical interactions. In this study, polymer coatings and their ability to adsorb avidin and Staphylococcus aureus were investigated. The surface chemistry and topography of the polymer coatings was modified by changing the weight ratio of the hydrophobic polystyrene (PS) and the hydrophilic acrylonitrile butadiene styrene (ABS) components in the polymer blend. Avidin adsorbed less to the ABS phase compared with the PS phase. The side-on orientation of avidin on the ABS surface, however, resulted in a higher specific binding of biotinylated bovine serum albumin. Steric effects and hydrophobic protein-surface interactions decreased the activity of avidin on the PS phase. The increased hydrophobicity and roughness of the polymer coatings enhanced the adhesion of S. aureus. The avidin-coated latex surface with 55% relative surface coverage of the PS phase showed anti-microbial behavior., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Specific interactions of extracellular matrix proteins with cells and their adhesion to the substrate are important for cell growth. A nanopatterned latex-coated paper substrate previously shown to be an excellent substrate for cell adhesion and 2D growth was studied for directed immobilization of proteins. The nanostructured latex surface was formed by short-wavelength IR irradiation of a two-component latex coating consisting of a hydrophilic film-forming styrene butadiene acrylonitrile copolymer and hydrophobic polystyrene particles. The hydrophobic regions of the IR-treated latex coating showed strong adhesion of bovine serum albumin (cell repelling protein), fibronectin (cell adhesive protein) and streptavidin. Opposite to the IR-treated surface, fibronectin and streptavidin had a poor affinity toward the untreated pristine latex coating. Detailed characterization of the physicochemical surface properties of the latex-coated substrates revealed that the observed differences in protein affinity were mainly due to the presence or absence of the protein repelling polar and charged surface groups. The protein adsorption was assisted by hydrophobic (dehydration) interactions., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The use of paper-based test platforms in cell culture experiments is demonstrated. The arrays used for two-dimensional cell cultures were prepared by printing patterned structures on a paper substrate using a hydrophobic polydimethylsiloxane (PDMS) ink. The non-printed, PDMS-free areas formed the array for the cell growth experiments. Cell imaging was enabled by using a lipophilic staining agent. A set of coated paper substrates was prepared to study the effect of the physicochemical properties of the substrate (topography, roughness and surface energetics) on cell attachment and growth. The studied paper substrates were found to be cell-repellent or cell-supporting. Cell growth was supported by substrates with a large bearing area, low surface area ratio (Sdr), high total surface free energy and an intermediate electron donor surface energy component. The cells were grown to full confluency within 72 h., (Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

Control of blood-glucose levels was monitored for 12 wk after withdrawal of biguanides in a group of 118 diabetic patients treated with biguanides (alone or in combination with sulphonylurea) from a population of 39,200. The mean fasting blood-glucose level rose during the first 2 wk from 9.2 +/- 0.3 to 11.3 +/- 0.4 mmol/l (p less than 0.001) and the mean urinary-glucose excretion from 11.7 +/- 3.7 g/24 h to 36.5 +/- 5.5 g/24 h (p less than 0.001), respectively. The change in blood-glucose concentration did not depend on age, sex, bodyweight, or duration of diabetes or biguanide treatment. The mean increase in blood-glucose was similar (2.1-3.1 mmol/l) in subjects with their initial blood-glucose level less than or equal to 6.0 mmol/l, 6.1-11.0 mmol/l, and greater than or equal to 11.1 mmol/l. There were no changes in blood-lipids or bodyweight during the observation period. Biguanides reduced blood-glucose levels in most patients with maturity-onset diabetes. The hypoglycaemic effect was similar in subjects with normal and increased bodyweight and did not depend on the duration or severity of diabetes.