Current interest in melanin films derived from the autoxidation of dopamine stems their use as a universal adhesion layer. Here we report chemical and physical characterization polydopamine deposited on gold surfaces stirred basic solutions at times ranging 2 to 60 min, with focus ≤10 min. Data Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS), electrochemical methods suggest presence starting (dopamine) intermediate (C=N-containing tautomers quinone indole) species...

We present results of a systematic examination functionalized gold nanoparticles (Au-NPs) by electrospray-differential mobility analysis (ES-DMA). Commercially available, citrate-stabilized Au colloid solutions (10-60 nm) were sized using ES-DMA, from which changes in particle size less than 0.3 nm readily discerned. It was found that the formation salt particles and coating Au-NPs during electrospray process can interfere with analysis, required development sample preparation data...

We report the synthesis and evaluation of four Newkome-type dendrons, G1-COOH, G2-COOH, SH-G1-COOH, TA-G1-COOH, their respective gold–dendron conjugates, where GX represents generation number. G1- G2-COOH are two-directional symmetric dendrons that have cystamine cores containing a disulfide group. SH-G1-COOH was prepared by treatment G1-COOH with dithioerythritol to yield free thiol group replace linkage. TA-G1-COOH has thioctic acid moiety, which is five-membered ring cleaves produce two...

Here we present a method to determine the surface coverage or density of biological molecules conjugated nanoparticle surfaces. Electrospray-differential mobility analysis (ES-DMA) is used coating thickness by measuring change in size gold nanoparticles before and after modification with thiol-derivatized single-stranded DNA. The DNA then obtained from through use simple random coil model. requires neither fluorescent tagging nor calibration curves. We believe ES-DMA be broadly applicable...

NISTCHO is a Chinese hamster ovary (CHO) cell line expressing the same amino acid sequences as heavy and light chains of National Institute Standards Technology (NIST) monoclonal antibody [Reference Material (RM) 8671 NISTmAb]. was generated by MilliporeSigma to be developed NIST RM support biomanufacturing research innovation, method development qualification, pre-competitive collaboration. The line, denoted 8675 NISTCHO, Clonal CHO-K1 Cell Line Producing cNISTmAb, interest...

We demonstrate the utility of electrospray gas-phase ion-mobility analysis as a new method to investigate nanoparticle flocculation, or aggregation. Au (Au-NP) solutions were sampled via (ES), followed by differential (DMA) determine particle mobility distribution. Multimodal size distributions obtained with ES-DMA indicated presence single Au-NPs (monomer) well larger Au-NP clusters such dimers, trimers, and tetramers under specific solution conditions. The fraction each aggregate species...

Here we demonstrate a rapid and quantitative means to characterize the size packing structure of small clusters nanoparticles in colloidal suspension. Clustering aggregation play important roles wide variety phenomena both scientific technical importance, yet characterizing within predicting their aerodynamic remains challenging because available techniques can lack adequate resolution sensitivity for smaller than 100 nm (optical techniques), perturb arrangement (electron microscopies), or...

We have developed a simple, fast, and accurate method to measure the absolute number concentration of nanoparticles in solution. The combines electrospray differential mobility analysis (ES-DMA) with statistical droplet-induced oligomer formation. A key feature is that it allows determination particles by knowing only droplet size generated from particular ES source, thereby eliminating need for sample-specific calibration standards or detailed transport losses. approach was validated...

The first characterization of the length distribution single-walled carbon nanotubes (SWCNT) dispersed in a liquid by electrospray differential mobility analysis (ES-DMA) is presented. Although an understanding geometric properties SWCNTs, including length, diameter, aspect ratio, and chirality, essential for commercial applications, rapid nanotube distributions remains challenging. Here use ES-DMA to obtain DNA-wrapped SWCNTs aqueous solutions demonstrated. Lengths measured compare...

Electrospray (ES) sources are commonly used to introduce nonvolatile materials (e.g., nanoparticles, proteins, etc.) the gas phase for characterization by mass spectrometry or ion mobility. Recent studies in our group using ES mobility characterize protein aggregation solution have raised question as whether itself induces and thus corrupts results. In this article, we develop a statistical model determine extent which process formation of dimers higher-order aggregates. The is validated...

We report a glycoanalysis method in which lectins are used to probe the glycans of therapeutic glycoproteins that adsorbed on gold nanoparticles. A model mannose-presenting glycoprotein, ribonuclease B (RNase B), and monoclonal antibody (mAb) rituximab, were found adsorb spontaneously non-specifically bare nanoparticles such accessible for lectin binding. Addition multivalent binding lectin, as concanavalin (Con A), solution modified resulted cross-linking This phenomenon was evidenced...

Biosensors based on electrochemical transduction mechanisms have recently made advances into the field of glycan analysis. These glyco-biosensors offer simple, rapid, sensitive, and economical approaches to measurement need for rapid analysis biomarker detection, cancer disease diagnostics, bioprocess monitoring therapeutic glycoproteins. Although prevalent methods (high-performance liquid chromatography, mass spectrometry, nuclear magnetic resonance spectroscopy) provide detailed...

This paper describes the development of a unique fluorescence-based DNA diagnostic microfluidic assay that does not require labeling target sequence prior to analysis. The is based on displacement short sacrificial fluorescent-tagged indicator oligomer by longer untagged as it electrophoresed through DNA-containing hydrogel plug immobilized in channel. distinct advantages this are sensing times, result directed electrophoretic transport element, combined with ability detect nonlabeled DNA.

We present here a study of the effects surface modification on efficiency transfer ultrathin Langmuir−Blodgett films rodlike aggregates phthalocyanine (Pc) (2,3,9,10,16,17,23,24-octakis((2-benzyloxy)ethoxy)phthalocyaninato)copper (1) to gold and silicon substrates. These modifications impact (i) molecular orientation individual Pcs within aggregates, (ii) coherence (providing for lengths some Pc rods over 100 nm), (iii) optical anisotropy overall uniformity lack pinholes in bilayer films, μm...

It has been recently demonstrated that single-stranded DNA, modified on the 5' end with an acrylic acid functionality, can be incorporated into a polyacrylamide hydrogel matrix. These types of DNA-containing gels have spatially immobilized in plastic microfluidic channels by photopolymerization, creating selective DNA three-dimensional capture elements. The oligomers retain activity and are able to bind complementary target strands as they migrate through gel plug under electrophoretic...

We have examined the adsorption of DNA-wrapped single-walled carbon nanotubes (DNA-SWNTs) on hydrophobic, hydrophilic, and charged surfaces alkylthiol self-assembled monolayers (SAMs) gold. Our goal is to understand how DNA-SWNTs interact with varying chemical functionality. These samples were characterized using reflection absorption FTIR (RAIRS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy. found that preferentially adsorb positively amine-terminated SAMs bare gold versus...

The physical behavior of polyelectrolytes at solid−liquid interfaces presents challenges both in measurement and interpretation. An informative, yet often overlooked, property that characterizes the equilibrium organization these systems is their membrane or rest potential. Here a general classification scheme presented relationship between potential structural response polyelectrolyte films to salt concentration. A numerical lattice theory, adapted from polymer community, used analyze...

We report here the synthesis, characterization, and thin film formation of a polymerizable octa-substituted phthalocyanine (Pc) with styryl-terminated side chains, CuPc(OCH2CH2OCH2CHCHPh)8, 2,3,9,10,16,17,23,24-octakis(2-cinnamyloxyethoxy) phthalocyaninato copper(II) (1). compare this Pc previously discussed phthalocyanine, also possessing styryl groups at termini but one alkoxy group in chain removed, CuPc(OCH2CH2CHCHPh)8 (2) (J. Am. Chem. Soc. 2001, 123, 3595). Both 1 2 are related to...

Conducting polymer diffraction gratings on Au substrates have been created using microcontact printing of C18-alkanethiols, followed by electropolymerization either poly(aniline) (PANI) or poly(3,4-ethylenedioxythiophene) (PEDOT). Soft-polymer replicas simple grating masters (1200 lines/mm) were used to define the alkanethiol template for growth. Growth PANI and PEDOT was in real time, through situ tapping-mode atomic force microscopy, monitoring efficiency (DE) as a function depth. DE...

Patterned thin films of a unique phthalocyanine (Pc), (2,3,9,10,16,17,23,24-oktakis((2-benzyloxy)ethoxy)phthalocyaninato) copper (1), are created by means capillary flow chloroform solutions into micrometer-dimension hydrophobic/hydrophilic channels. These channels combination microcontact printing octadecylmercaptan (C18-SH) layers on gold, creating hydrophobic channel bottom, and oxidative electropolymerization m-aminophenol (at pH 4), hydrophilic walls (microcontact...