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Cardiomyocytes, differentiated from induced pluripotent stem cells (iPSCs), have the potential to produce patient- and disease-specific pharmacological and toxicological platforms, in addition to their cardiac cell therapy applications. However, the lack of both a robust and a simple procedure for scalable cell substrate production is one of the major limitations in this area. Mimicking the natural healthy myocardium extracellular matrix (ECM) properties by altering the cell substrate properties, such as stiffness and chemical/biochemical composition, can significantly affect cell substrate interfacial characteristics and potentially influence cellular behavior and differentiation of iPSCs to cardiomyocytes. Here, we propose a systematic and biomimetic approach, based on the preparation of poly(dimethylsiloxane) (PDMS) substrates having the similar stiffness as healthy heart tissue and a well-defined surface chemistry obtained by conventional [(3-aminopropyl)triethoxysilane (APTES) and octadecyltrimethoxysilane (OTS)] and amino acid (histidine and leucine)-conjugated self-assembled monolayers (SAMs). Among a wide range of different concentrations, the 50:1 prepolymer cross-linker ratio of PDMS allowed adaptation of the myocardium stiffness with a Young's modulus of 23.79 +/- 0.61 kPa. Compared with conventional SAM modification, amino acidconjugated SAMs greatly improved iPSC adhesion, viability, and cardiac marker expression by increasing surface biomimetic properties, whereas all SAMs enhanced cell behavior, with respect to native PDMS. Furthermore, leucine-conjugated SAM modification provided the best environment for cardiac differentiation of iPSCs. This optimized approach can be easily adapted for cardiac differentiation of iPSCs in vitro, rendering a very promising tool for microfluidics, drug screening, and organ-on-chip platforms.

Molecular imprinting is a powerful, generic, and cost-effective technique; however, challenges still remain related to the fabrication and development of these systems involving nonhomogeneous binding sites, insufficient template removing, incompatibility with aqueous media, low rebinding capacity, and slow mass transfer. The vapor-phase deposition of polymers is a unique technique because of the conformal nature of coating and offers new possibilities in a number of applications including sensors, microfluidics, coating, and bioaffinity platforms. Herein, we demonstrated a simple but versatile concept to generate one-dimensional surface-imprinted polymeric nanotubes within anodic aluminum oxide (AAO) membranes based on initiated chemical vapor deposition (iCVD) technique for biorecognition of immunoglobulin G (IgG). It is reported that the fabricated surface-imprinted nanotubes showed high binding capacity and significant specific recognition ability toward target molecules compared with the nonimprinted forms. Given its simplicity and universality, the iCVD method can offer new possibilities in the field of molecular imprinting.

In the present study, we have focused our attention to prepare molecular imprinted composite cryogel membranes for purification of hepatitis B surface antibody (anti-HBs) by fast protein liquid chromatography. Before the preparation of the molecular imprinted composite cryogel membranes (MI-CMs) by free radical polymerization at sub-zero temperature, we have synthesized and characterized the anti-HBs imprinted particles. Then, the cryogel membranes (CMs) were characterized by swelling test, scanning electron microscopy and Fourier transform infrared spectroscopy. Prior to chromatographic purification studies, the effective parameters on the anti-HBs adsorption process were evaluated by investigating the dependency of the adsorption capacity on flow-rate, anti-HBs concentration, contact time and ionic strength. The maximum anti-HBs adsorption capacity was calculated as 701.4 mIU/g CM. The selectivity of the MI-CMs was shown by competitive adsorption of anti-HBs, total anti-hepatitis A antibody (anti-HAV) and total immunoglobulin E (IgE) adsorption studies. The MI-CMs have relative selectivity coefficients as 5.45 for anti-HBs/total anti-HAV and 9.05 for anti-HBs/total IgE, respectively. The phosphate buffer solution (pH 7.4) containing 1.0 M NaCl was used for elution, almost completely, of adsorbed anti-HBs molecules. The MI-CMs could be used many times without any significant decrease in the adsorption capacity. The chromatographic purification performances of the MI-CMs were also investigated. The chromatographic parameters such as capacity and separation factors, the theoretical plate number and resolution of the MI-CMs were calculated as 5.48, 6.02, 1153.9, and 1.72 for anti-HBs molecules, respectively. As a conclusion, we can say that the MI-CMs could be used for specific purification of anti-HBs from anti-HBs positive human plasma. (C) 2012 Elsevier B.V. All rights reserved.

Molecular imprinting is a powerful, generic, and cost-effective technique; however, challenges still remain related to the fabrication and development of these systems involving nonhomogeneous binding sites, insufficient template removing, incompatibility with aqueous media, low rebinding capacity, and slow mass transfer. The vapor-phase deposition of polymers is a unique technique because of the conformal nature of coating and offers new possibilities in a number of applications including sensors, microfluidics, coating, and bioaffinity platforms. Herein, we demonstrated a simple but versatile concept to generate one-dimensional surface-imprinted polymeric nanotubes within anodic aluminum oxide (AAO) membranes based on initiated chemical vapor deposition (iCVD) technique for biorecognition of immunoglobulin G (IgG). It is reported that the fabricated surface-imprinted nanotubes showed high binding capacity and significant specific recognition ability toward target molecules compared with the nonimprinted forms. Given its simplicity and universality, the iCVD method can offer new possibilities in the field of molecular imprinting.

In the present study, we have focused our attention to prepare molecular imprinted composite cryogel membranes for purification of hepatitis B surface antibody (anti-HBs) by fast protein liquid chromatography. Before the preparation of the molecular imprinted composite cryogel membranes (MI-CMs) by free radical polymerization at sub-zero temperature, we have synthesized and characterized the anti-HBs imprinted particles. Then, the cryogel membranes (CMs) were characterized by swelling test, scanning electron microscopy and Fourier transform infrared spectroscopy. Prior to chromatographic purification studies, the effective parameters on the anti-HBs adsorption process were evaluated by investigating the dependency of the adsorption capacity on flow-rate, anti-HBs concentration, contact time and ionic strength. The maximum anti-HBs adsorption capacity was calculated as 701.4 mIU/g CM. The selectivity of the MI-CMs was shown by competitive adsorption of anti-HBs, total anti-hepatitis A antibody (anti-HAV) and total immunoglobulin E (IgE) adsorption studies. The MI-CMs have relative selectivity coefficients as 5.45 for anti-HBs/total anti-HAV and 9.05 for anti-HBs/total IgE, respectively. The phosphate buffer solution (pH 7.4) containing 1.0 M NaCl was used for elution, almost completely, of adsorbed anti-HBs molecules. The MI-CMs could be used many times without any significant decrease in the adsorption capacity. The chromatographic purification performances of the MI-CMs were also investigated. The chromatographic parameters such as capacity and separation factors, the theoretical plate number and resolution of the MI-CMs were calculated as 5.48, 6.02, 1153.9, and 1.72 for anti-HBs molecules, respectively. As a conclusion, we can say that the MI-CMs could be used for specific purification of anti-HBs from anti-HBs positive human plasma. (C) 2012 Elsevier B.V. All rights reserved.

Polymerizable terbium(III) complex-based fluorescent molecular imprinted smart nanoparticles were synthesized for the quantitative determination of potential metabolic destitution biomarkers. Melatonin has been reported to be one of the key factors in seasonal affective disorder (SAD) and was chosen as a model metabolite to demonstrate a novel molecularly imprinted polymer (MIP) nanoparticle sensor. We exploited lanthanide ion complexes in our biosensing platforms due to their deeper penetration ability, negligible autofluorescence, lack of photobleaching and photoblinking, and their sharp absorption and emission bands, extreme photostability, and long lifetime. Given the high affinity of lanthanide ions for carboxylic acid groups, we used two amino acid-based functional monomers, N-methacryloyl-L-tryptophan and N-methacryloyl-L-aspartic acid, to coordinate terbium-(III) ions and melatonin, respectively. The fluorescent MIP nanoparticles were synthesized using a miniemulsion polymerization technique after forming complexes between terbium(III):MA-Asp and melatonin:MATrp molecules. Due to the polymerizability of lanthanide complexes, they were readily inserted into the polymeric chain, which enabled homogeneous distribution as well as closer orientation to the imprinted cavities for selective melatonin recognition., Funding Agencies|Scientific and Technological Research Council (TUBITAK) of the Republic of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [113 M 919]