Lipid bilayer membranes supported on polyelectrolyte multilayers are widely used as a new biomembrane model that connects biological and artificial materials since these ultrathin polyelectrolyte supports may mimic the role of the extracellular matrix and cell skeleton in living systems. Polyelectrolyte multilayers were fabricated by a layer-by-layer self-assembly technique. A quartz crystal mi...

Lanthanide-doped upconversion nanoparticles (UCNPs) have attracted widespread interests in bioapplications due to their unique optical properties by converting near infrared excitation to visible emission. However, relatively low quantum yield prompts a need for developing methods for fluorescence enhancement. Plasmon nanostructures are known to efficiently enhance fluorescence of the surroundi...

Membrane-spanning phospholipid bolaamphiphiles either alone or as a constituent of a multicomponent lipid membrane may prove to be facile building blocks for generating robust bioactive membrane-mimetic assemblies. We have previously reported the synthesis of asymmetric dialkyl phospholipid bolaamphiphiles that contain ester linked phosphatidylcholine and amine functionalities at opposite chain...

Polynucleotide adsorption to negatively charged surfaces via divalent ions is extensively used in the study of biological systems. We analyze here the adsorption mechanism via a self-consistent mean-field model that includes the pH effect on the surface-charge density and the interactions between divalent ions and surface groups. The adsorption is driven by the cooperative effect of divalent me...

We report that user-defined DNA nanostructures, such as two-dimensional (2D) origamis and nanogrids, undergo a rapid higher-order folding transition, referred to supra-folding, into three-dimensional (3D) compact structures (origamis) or well-defined μm-long ribbons (nanogrids), when they adsorb on soft cationic substrate prepared by layer-by-layer deposition of polyelectrolytes. Once supra-fol...

Cooperative interactions between RNA and vesicle membranes on the prebiotic earth may have led to the emergence of primitive cells. The membrane surface offers a potential platform for the catalysis of reactions involving RNA, but this scenario relies upon the existence of a simple mechanism by which RNA could become associated with protocell membranes. Here, we show that electrostatic interact...

Gold nanorods (AuNRs) have attracted a great deal of attention due to their potential for use in wide range biomedical applications. However, production typically requires the relatively toxic cationic surfactant cetyltrimethylammonium bromide (CTAB) leading continued demand protocols detoxify them vivo In this study, robust and facile protocol displacement CTAB from surface AuNRs using phospho...

Polyelectrolytes have been at the center of interdisciplinary research for many decades. In field polymer science and soft matter, they provided dimensions electrostatic interactions, which opens a vast variety opportunities new physical properties applications. biological polyelectrolytes are present in forms, from extracellular polysaccharides to complex DNA molecules proteins. This review di...

We demonstrate a methodology to prepare Au-core-Ag-shell nanoparticles displaying both SERS and surface-enhanced fluorescence (SEF) activities simultaneously by embedding dye molecules between the core and the shell. Polyelectrolytes are used to adjust the spacing and the dye position between the core and the shell. Layer-by-layer polyelectrolyte deposition can serve as an effective and flexibl...