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Herein, we prepared PEI-immobilized core-shell particles possessing various types of polymer cores via a visible light-induced surfactant-free emulsion polymerization (SFEP) of three vinyl monomers: styrene (St), methyl methacrylate (MMA), and 2-hydroxyethyl methacrylate (HEMA). An effect of monomers on the polymerization and characteristics of resulting products was investigated. Monomers with high polarity can provide high monomer conversion, high percentage of grafted PEI, stable particles with uniform size distribution but less amino groups per particles. All prepared nanoparticles exhibited a core-shell nanostructure, containing PEI on the shell with hydrodynamic size around 140-230nm. For in-vitro study in Caco-2 cells, we found that the incorporation of PEI into these core-shell nanoparticles can significantly reduce its cytotoxic effect and also be able to internalized within the cells. Accordingly, these biocompatible particles would be useful for various biomedical applications, including gene transfection and intracellular drug delivery., (© 2013.)

Water-soluble β-cyclodextrin grafted with chitosan (CD-g-CS) was carried out by quaternizing the CD-g-CS with glycidyltrimethyl ammonium chloride (GTMAC) under mild acidic condition, corresponding to the quaternized CD-g-CS (QCD-g-CS). The degrees of substitution (DS) and quaternization (DQ), ranging from 5% to 23% and 66% to 80%, respectively, were determined by (1)H NMR spectroscopy. Self-aggregates formation of all QCD-g-CSs were investigated in water using dynamic light scattering (DLS), atomic force microscopy (AFM), and transmission electron microscopy (TEM) techniques. The result revealed that all QCD-g-CSs are able to form self-aggregates in water. Large particle sizes ranged from 800 to 3000nm were obtained by DLS while zeta-potentials were ranging from 25 to 40mV. AFM and TEM depicted a spherical shape with particle sizes ranging from 100 to 900nm. Mucoadhesive and cytotoxic properties of all QCD-g-CSs were evaluated using a mucin particle method and MTT assay compared to quaternized chitosan (QCS). It was found that the mucoadhesive property increased with decreasing DS due to less quaternary ammonium moiety into the chitosan backbone. On the other hand, the cytotoxicity increased with increasing DS even though the DQ is decreased., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Novel immunomagnetic particles have been prepared for separation of CD4(+) lymphocytes. The magnetic nanoparticles with a diameter of approximately 5-6 nm were first synthesized by co-precipitation from ferrous and ferric iron solutions and subsequently encapsulated with poly(glycidyl methacrylate) (PGMA) by precipitation polymerization. Monoclonal antibody specific to CD4 molecules expressed on CD4(+) lymphocytes was conjugated to the surface of magnetic PGMA particles through covalent bonding between epoxide functional groups on the particle surface and primary amine groups of the antibodies. The generated immunomagnetic particles have successfully separated CD4(+) lymphocytes from whole blood with over 95% purity. The results indicated that these particles can be employed for cell separation and provide a strong potential to be applied in various biomedical applications including diagnosis, and monitoring of human diseases., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The core-shell nanoparticles possessing poly(methyl methacrylate) (PMMA) core coated with chitosan (CS), polyethyleneimine (PEI), and chitosan-mixed-polyethyleneimine (CS/PEI) shells were synthesized in this work. The emulsifier-free emulsion polymerization triggered by a redox initiating system from t-butylhydroperoxide (TBHP) and amine groups on CS and/or PEI was used as a synthetic method. In the CS/PEI systems, the amount of CS was kept constant (0.5g), while the amount of PEI was varied from 0.1 to 0.5g. The surface and physico-chemical properties of prepared nanoparticles were then examined. FTIR spectra indicated the presence of grafted PMMA on CS and/or PEI, and the weight fraction of incorporated PEI in the CS/PEI nanoparticles. All nanoparticles were spherical in shape with uniform size distribution illustrated by scanning electron microscopy (SEM). The introduction of PEI to CS nanoparticles yielded the higher monomer conversion, grafting efficiency, and grafting percentage compared with the CS nanoparticles. The size of CS/PEI nanoparticles was smaller than the original CS and PEI nanoparticles, and tended to decrease with increasing amount of PEI introduced. The introduction of PEI also brought the higher colloidal stability to the nanoparticles as indicated by zeta-potential measurement and isoelectric point analysis. The nanoparticles exhibited a promising antibacterial activity against Staphylococcus aureus and Escherichia coli. The nanoparticle-bacteria interaction was studied via SEM. The results suggested that they would be useful as effective antibacterial agents., (Copyright 2010 Elsevier B.V. All rights reserved.)

Objective: The urine pregnancy test is an easily available diagnostic test in the present day and is routinely performed. The test is based on an immunochromatography technique. Here, we used an advanced nanomedicine technique for modification of the urine pregnancy test., Materials and Methods: The preparation of gold nanoparticle solution in this study followed the standard method. We performed an experiment on both pregnancy-positive and -negative urine samples. First, a mixture with an equal amount (500 microliters) of gold nanoparticle solution and urine sample was prepared. Then, it was further tested for pregnancy by the urine pregnancy test strip., Results: The pregnancy-positive mixture became pink, while the pregnancy-negative mixture became gray. The urine pregnancy test strip for a positive mixture had two lines, while the negative mixture had one line., Conclusion: This application can help the diagnosis of pregnancy and can be an alternative method for a urine pregnancy test. To our knowledge, this is the first report on this application.