We synthesized multimetal microrods intrinsically encoded with submicrometer stripes. Complex striping patterns are readily prepared by sequential electrochemical deposition of metal ions into templates uniformly sized pores. The differential reflectivity adjacent stripes enables identification the conventional light microscopy. This readout mechanism does not interfere use fluorescence for detection analytes bound to particles affinity capture, as demonstrated DNA and protein bioassays.

A new approach to ultrasensitive detection of DNA hybridization based on nanoparticle-amplified surface plasmon resonance (SPR) is described. Use the Au nanoparticle tags leads a greater than 10-fold increase in angle shift, corresponding more 1000-fold improvement sensitivity for target oligonucleotide as compared unamplified binding event. This enhanced shift SPR reflectivity combined result greatly increased mass, high dielectric constant particles, and electromagnetic coupling between...

Glass-coated, analyte-tagged nanoparticles (GANs) are core−shell particles where a nanometer-scale Au or Ag core is functionalized with Raman active molecules and encapsulated in glass shell. The shell provides the particle mechanical chemical stability. Specifically, coating renders amenable to use many solvents without altering spectral response makes agglomeration nonfactor. density thickness of controllable through synthetic conditions; thus, rate diffusion silica network can be tuned...

Covalent attachment of nanometer-scale colloidal Au particles to organosilane-coated substrates is a flexible and general approach formation macroscopic surfaces that have well-defined nanostructure. Variations in substrate (glass, metal, Al2O3), geometry (planar, cylindrical), functional group (−SH, −P(C6H5)2, −NH2, −CN), particle diameter (2.5−120 nm) demonstrate each component these assemblies can be changed without adverse consequences. Information about coverage interparticle spacing...

How could the incredible complexity of modern cells evolve from something simple enough to have appeared in a primordial soup? This enduring question has sparked interest researchers since Darwin first considered his theory natural selection. Organic molecules, even potentially functional molecules including peptides and nucleotides, can be produced abiotically. Amphiphiles such as surfactants lipids display remarkable self-assembly processes spontaneous formation vesicles resembling...

Liquid-liquid phase separation is responsible for formation of P granules, nucleoli, and other membraneless subcellular organelles composed RNA proteins. Efforts to understand the physical basis liquid organelle have thus far focused on intrinsically disordered proteins (IDPs) as major components that dictate occurrence properties. Here, we show complex coacervates low complexity (polyuridylic acid, polyU) short polyamines (spermine spermidine) share many features IDP-based coacervates....

Membraneless compartments, such as complex coacervates, have been hypothesized plausible prebiotic micro-compartments due to their ability sequester RNA; however, compatibility with essential RNA World chemistries is unclear. We show that compartments can enhance key prebiotically-relevant chemistries. demonstrate template-directed polymerization sensitive polycation identity, polydiallyldimethylammonium chloride (PDAC) outperforming poly(allylamine), poly(lysine), and poly(arginine) in...

Liquid-liquid phase separation (LLPS) in biology is a recently appreciated means of intracellular compartmentalization. Because the mechanisms driving separations are grounded physical interactions, they can be recreated within less complex systems consisting only few simple components, to serve as artificial microcompartments. Within these systems, effect compartmentalization and microenvironments upon biological reactions processes studied. This review will explore several approaches...

Biological systems employ liquid–liquid phase separation to localize macromolecules and processes. The properties of intracellular condensates that allow for multiple, distinct liquid compartments the impact their coexistence on composition solute partitioning are not well understood. Here, we generate two three coexisting macromolecule-rich by complex coacervation based ion pairing in mixtures contain or polyanions together with one, two, polycations. While some polyelectrolyte...

The coverage of Au surfaces with nanowires by linking them DNA offers great prospects for the assembly wire structures particular connectivity. This work presents first example using hybridization to control micrometer-size inorganic particles on surfaces. Figure shows optical microscopy image modified DNA.

This manuscript describes the stepwise, ligand-directed assembly, characterization, and prospective applications of three-dimensional Au Ag nanoparticle, multlilayered films. Films were prepared by successive treatments a nanoparticle monolayer with bifunctional cross-linker colloidal or solutions. Changes in film electrical optical properties are reported for series cross-linkers varying molecular lengths. Interestingly, these films exhibit Beer's law behavior despite presence strong...

Very highly conductive Au films on glass substrates have been prepared by stepwise, layer-by-layer immobilization of 11-nm diameter colloidal particles and a short organic cross-linker. Particle coverage, optical spectra, nanometer-scale topography, electrical resistance measured as function the number layers reveal rapid transition from insulating to metallic behavior.

An experimental model for cytoplasmic organization is presented. We demonstrate dynamic control over protein distribution within synthetic cells comprising a lipid bilayer membrane surrounding an aqueous polymer solution. This solution generally exists as two immiscible phases. Protein partitioning between these phases leads to microcompartmentation, or heterogeneous the "cell" interior. cytoplasm can be reversibly converted single phase by slight changes in temperature osmolarity, such that...

Atomic force microscopy (AFM), field emission scanning electron (FE-SEM), transmission (TEM), and near-field optical (NSOM) have been used to characterize the nanostructure of Au colloid-based surfaces. Because these substrates are composed particles whose dimensions known prior assembly, they well-suited for a critical comparison capabilities limitations each nanoscale imaging technique. The three criteria this comparison, which relevant nanoparticle assemblies in general, (i) accuracy...

Abstract Sequential electrodeposition within a porous template can be used to prepare striped nanowires with tailorable dimensions and composition. Variations in composition along the length of wire incorporate electrical functionality, optical contrast, and/or desired surface chemistry. Nanowires functionalized chemical or biochemical reagents appropriate for assembly biosensing. Therefore, these particles are interesting as building blocks nanoscale electronics “barcodes” both biological...

Conjugates between cytochrome c (Cc) and colloidal Au particles have been prepared. These conjugates, purified by centrifugation/resuspension, provide a reproducible means of positioning biomolecule analyte two metal surfaces: the nanoparticle to which is bound an aggregated Ag sol used as substrate for surface enhanced Raman scattering (SERS). SERS spectra Ag:Cc:Au sandwiches made addition Cc:Au conjugates show that protein retains its native conformation. Conjugation Cc nanoparticles prior...

Asymmetric cell division is common in biology and plays critical roles differentiation development. Unicellular organisms are often used as model systems for understanding the origins consequences of asymmetry during division. Although basic compared to mammalian cells, these already quite complex. We report complete budding asymmetric fission very simple nonliving cells produce daughter vesicles that chemically distinct both interior membrane compositions. Our based on giant lipid (GVs,...