Poly Sodium 4-styrenesulphonate Research Articles

Preparation and investigation of core-shell nanoparticles containing human interferon-α.

Sustained release of active interferon-α (IFN-α) has been achieved from core-shell nanoparticles (NPs) prepared by aqueous precipitation of IFN-α-enriched human serum albumin (HSA-IFN-α) and layer-by-layer (L-b-L) by coating of the IFN-α NPs with poly(sodium-4-styrene) sulphonate (PSS) and chitosan (Chit). The concentration and the pH of HSA solution were optimized during the development of this method. Dynamic light scattering (DLS), zeta-potential, thermal analysis (differential scanning calorimetry (DSC) and termogravimetry (TG)), X-ray diffraction (XRD), IFN-α activity and morphology (transmission electron microscope (TEM)) studies were used to control the preparation and analyse the products. The dissolution kinetics of NPs was measured in vitro over 7 days in Hanson dissolution tester with Millex membrane. In vivo studies in Pannon white rabbit detected steady IFN-α plasma level for 10 days after subcutaneous injection administration of the HSA-IFN-α NPs. The IFN-α plasma concentration was detected by using the enzyme-linked immunosorbent assay (ELISA) method. In the present paper we discuss the preparation method, the optimization steps and the results of in vitro and in vivo release studies. It was established that 76.13% HSA-IFN-α are encapsulated in the core-shell NPs.

BSA/polyelectrolyte core–shell nanoparticles for controlled release of encapsulated ibuprofen

Bovine serum albumin (BSA) based core–shell nanoparticles were developed as carrier systems for drug transportation. At pH=3, the oppositely charged polyelectrolytes: poly(sodium-4-styrene)sulphonate (PSS) and the chitosan (Chit) bind to the positively charged protein via electrostatic interactions. We applied ibuprofen (IBU) as model molecule which has low solubility. The changes in the BSA's secondary structure during the steps of the synthesis were inspected by FT-IR measurements. The size and the zeta potential were determined by dynamic light scattering (DLS). The changes in the structure and in the size were investigated by small angle X-ray scattering (SAXS) too, for each composite. The release of the ibuprofen was studied by vertical diffusion cell (Franz cell) at pH 7.4 at 25 and 37.5°C. The structure of the core–shell nanoparticles have significantly changed as the pH has risen from 3.0 to 7.4. Kinetic models were used to describe the release mechanism. The experimental results demonstrated that the BSA has an ordered structure at pH=3 which will become random coil by adding ibuprofen. The first shell restores the ordered structure of the protein. The controlled release was carried out; the IBU release decreased by 40% in the case of two-layered composites compared with the “naked” BSA.

Facile bench-top fabrication of enclosed circular microchannels provides 3D confined structure for growth of prostate epithelial cells.

We present a simple bench-top method to fabricate enclosed circular channels for biological experiments. Fabricating the channels takes less than 2 hours by using glass capillaries of various diameters (from 100 µm up to 400 µm) as a mould in PDMS. The inner surface of microchannels prepared in this way was coated with a thin membrane of either Matrigel or a layer-by-layer polyelectrolyte to control cellular adhesion. The microchannels were then used as scaffolds for 3D-confined epithelial cell culture. To show that our device can be used with several epithelial cell types from exocrine glandular tissues, we performed our biological studies on adherent epithelial prostate cells (non-malignant RWPE-1 and invasive PC3) and also on breast (non-malignant MCF10A) cells We observed that in static conditions cells adhere and proliferate to form a confluent layer in channels of 150 µm in diameter and larger, whereas cellular viability decreases with decreasing diameter of the channel. Matrigel and PSS (poly (sodium 4-styrenesulphonate)) promote cell adhesion, whereas the cell proliferation rate was reduced on the PAH (poly (allylamine hydrochloride))-terminated surface. Moreover infusing channels with a continuous flow did not induce any cellular detachment. Our system is designed to simply grow cells in a microchannel structure and could be easily fabricated in any biological laboratory. It offers opportunities to grow epithelial cells that support the formation of a light. This system could be eventually used, for example, to collect cellular secretions, or study cell responses to graduated hypoxia conditions, to chemicals (drugs, siRNA, …) and/or physiological shear stress.

The modulation of attachment, growth and morphology of cancerous prostate cells by polyelectrolyte nanofilms

The behaviour of cancerous epithelial prostatic cells (PC3) growing on polyelectrolytes (PE) coatings was compared to the behaviour of immortalized normal prostatic cells (PNT-2). The cell behaviour was evaluated and quantified in terms of initial cell attachment, growth, metabolic activity, morphometry, adhesion, apoptosis and stress related gene expression. Both the anionic PSS (poly(sodium 4-styrenesulphonate))-terminated surface and cationic PAH (poly(allylamine hydrochloride))-terminated surfaces were not cytotoxic. The initial attachment of cells was better on the PAH-terminated surface compared to fibronectin. However, the proliferation rate of PC3 cells was reduced on the PAH-terminated surface and slightly increased on the PSS coatings. Only PAH prevented the clustering phenotype of PC3 and reduced the number of focal adhesion points as compared to fibronectin or PSS coatings. In contrast, none of the PE surfaces significantly affected the biological responses of PNT-2 cells. PAH-terminating films provide a tool to preferentially modulate the growth of some cancerous phenotypes, in this case as a micro-environment that reduces the growth of metastatic PC3 cells.