•Adsorption of organophosphorous pesticides using hierarchical sorbents.•New binding behavior in hierarchical, mesoporous organosilicate materials.•Capillary phase-separation of paraoxon from aqueous solution in presence of sorbent.•Target binding shows good agreement with Freundlich–BET isotherm.

The potential for encapsulating RNA within tunable, semi-permeable structures for storage and transportation purposes offers an interesting approach to the reduction of stringent storage requirements that often hamper the field application of genetic analysis methods. In this study, we assessed the potential for application of functionalized, porous silicate sorbents in maintaining nucleic acid integrity. Mesoporous silica nanoparticles (MSNs) with and without incorporated stabilizing reagents were used to encapsulate triosephosphate isomerase mRNA of Arabidopsis thaliana. The absorption, elution, and the long-term stability of the RNA were monitored by using quantitative real-time RT-PCR. The results indicate that adsorbed RNA can be eluted from the sorbents using simple buffers and employed directly for downstream molecular diagnostic assays without any further processing. RNA integrity can be maintained for extended time periods under refrigeration temperatures in the presence of covalently immobilized stabilizing compounds. This study provides initial evidence of the potential for application of MSNs in transportation and storage. They may also have utility in sample collection and processing in restrictive environments.

We examined the adsorption and release of TNT using diethylbenzene-bridged (DEB) periodic mesoporous organosilica sorbents under varying conditions. The sorbents were applied for in-line target pre-concentration in conjunction with an electrochemical flow cell containing a glassy carbon electrode. Square wave voltammetry was employed for TNT detection. TNT sample volumes between 2 and 480mL at concentrations ranging from 0.5 to 500ppb were passed through the DEB sorbents (imprinted or not imprinted for TNT) at pH 6 (sodium acetate) or at pH 7.4 (PBS). Release of target was accomplished using solvent mixtures of methanol/water with sodium acetate as electrolyte or acetonitrile/water with PBS components as electrolyte. Under these conditions, the TNT was released in <200μL of the solvent mixture, and pre-concentration factors of >3000 can be achieved when using large volumes of trace TNT samples. When sample volumes of 2mL were utilized, the sensing system gave a linear response between 20 and 500ppb with an estimated limit of detection of 13ppb. When pre-concentrating 480mL of sample in either buffered solution or seawater, detection of 0.5ppb TNT was achieved with a signal to noise ratio of 20.

Periodic mesoporous organosilicas (PMOs) with diethylbenzene bridging groups (DEB) in the pore walls are promising adsorbents for harmful compounds including nitroenergetics. The hierarchical macropore–mesopore structures developed here are expected to facilitate diffusion for such applications and to offer the potential for application in column formats. DEB-functionalized PMOs were synthesized with triblock copolymer Pluronic®P123 and the swelling additive mesitylene. Many of the materials were prepared through co-condensation of the DEB precursor bis(trimethoxysilylethyl)benzene with 1,2-bis(trimethoxysilyl)ethane (BTE) to improve mesostructure. Conditions were optimized to form micron-scale macropores by polymerization-induced phase separation. PMOs were also produced using only the DEB precursor. These materials exhibited relatively high surface areas (ca. 400 m2/g) and mesopore sizes (ca. 45 Å) as well as isolated macropores. As-synthesized materials were fabricated as centimeter-scale monoliths that became powders after multiple solvent refluxes. Soxhlet extraction could be used to preserve monolithic morphology while removing enough P123 to access mesopores. Nitrogen sorption, powder X-ray diffraction, SEM, TEM, and TGA were applied to characterize the PMOs.

Hierarchical organosilicate sorbents were synthesized which possess structure on two length scales: macropores of approximately 1microm lined by mesopores (35-45A). The incorporation of macropores provides enhanced flow-through characteristics over purely mesoporous materials, thereby reducing back pressure when used in column formats. Materials of this type with varied surface groups were applied to the adsorption of 2,4,6-trinitrotoluene (TNT) and 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX) in both batch and column formats. The results presented here demonstrate the potential of these materials for application as solid phase extraction materials for the pre-concentration of nitroenergetic targets from aqueous solutions. The structural and binding characteristics of the materials have been evaluated and preliminary data on the impact of complex matrices is provided.

Patterning of metal colloids by inkjet printing on paper is demonstrated as a precursor to electroless metallization. The development of the metal pattern is followed in terms of the conductivity and mass of the metal deposited and is shown to have critical phase behavior. The utility of this technique for large-area microscale patterning is demonstrated. Sample patterns of frequency-selective surface designs were manufactured and shown to conform to computationally modeled expectations in the microwave regime.

We describe the use of nanoporous organosilicas for rapid preconcentration and extraction of trinitrotoluene (TNT) for electrochemical analysis and demonstrate the effect of template-directed molecular imprinting on TNT adsorption. The relative effects of the benzene (BENZ)- and diethylbenzene (DEB)-bridged organic-inorganic polymers, having narrow or broad pore size distributions, respectively, on electrochemical response and desorption behavior were examined. Sample volumes of 0.5-10 mL containing 5-1000 ppb TNT in a phosphate-buffered saline buffer were preconcentrated in-line before the detector using a microcolumn containing 10 mg of imprinted BENZ or DEB. Square-wave voltammetry was used to detect the first reduction peak of TNT in an electrochemical flow cell using a carbon working electrode and a Ag/AgCl reference electrode. Imprinted BENZ released TNT faster than imprinted DEB with considerably less peak tailing and displayed enhanced sensitivity and an improvement in the limit of detection (LOD) owing to more rapid elution of TNT from that material with increasing signal amplitude. For imprinted BENZ, the slope of signal versus concentration scaled linearly with increasing preconcentration volume, and for preconcentrating 10 mL of sample, the LOD for TNT was estimated to be 5 ppb. Template-directed molecularly imprinted DEB (TDMI-DEB) was 7-fold more efficient in adsorption of TNT from aqueous contaminated soil extract than nonimprinted DEB.

The anti-adhesive effects of cranberry have been attributed to both interactions of its components with the surface of bacterial cells and to inhibition of p-fimbriae expression. Previous reports also suggested that the presence of cranberry juice changed the Gram stain characteristics of Escherichia coli. Here, we show that the morphology of E. coli is changed when grown in the presence of juice or extract from Vaccinium macrocarpon (cranberry). Gene expression analysis indicates the down regulation of flagellar basal body rod and motor proteins. Consistent with this finding and previous reports, the SEM images indicate a decrease in the visible p-fimbriae. The iodine used in Gram-staining protocols was found to interact differently with the bacterial membrane when cells were cultured in spiked media. Slight alterations in the Gram stain protocol demonstrated that culturing in the presence of cranberry juice does not change the Gram stain characteristics contradicting other reports.

We describe a nanoscale gating effect by an atypical tether-containing polythiophene, [poly(thiophene-3-carboxylic acid 2-(2-(2-(2-ethoxy-ethoxymethyl sulfonate)-ethoxy)-ethoxy)-amide], referred to as poly(TP-OEG-SO4). Cyclic voltammetry data permitted us to calculate liquid-phase ion diffusivities in the polymer as a function of its oxidation state. Diffusivities are more than 350 times higher in the oxidized state versus the reduced state. As a control, poly 3′,4′-dimethyl-[2,2′;5′,2″] terthiophene (DMPT) was synthesized and characterized. On comparing both polymers in the reduced state, we find diffusivities in poly(TP-OEG-SO4) to be more than 4500 times lower than in poly(DMPT). To explain this behavior, we propose a model that features a charge-balancing mechanism by the sulfonate tethers in poly(TP-OEG-SO4), which causes nanoporous regions around the polymer main chains to be opened and closed, leading to the large observed differences in diffusivities. These data suggest that the polymer poly(TP-OEG-SO4) is evidently able to act as a reversible “nanogate” with an open pore structure when oxidized, and a closed one when reduced.

Periodic mesoporous organosilicas incorporating diethylbenzene bridges in their pore walls were applied for the adsorption of nitroenegetic targets from aqueous solution. The materials were synthesized by co-condensing 1,4-bis(trimethoxysilylethyl)benzene (DEB) with 1,2-bis(trimethoxysilyl)ethane to improve structural characteristics. Molecular imprinting of the pore surfaces was employed through the use of a novel target-like surfactant to further enhance selectivity for targets of interest (tri- and dinitrotoluenes) over targets of similar structure ( p-cresol and p-nitrophenol). The headgroup of the commonly used alkylene oxide surfactant Brij76 was modified by esterification with 3,5-dinitrobenzoyl chloride. This provided a target analogue which was readily miscible with the Brij76 surfactant micelles used to direct material mesopore structures. The impact of variations in precursor ratios and amounts of imprint molecule was evaluated. The use of 12.5% of the modified Brij surfactant with a co-condensate employing 30% DEB was found to provide the best compromise between total capacity and selectivity for nitroenergetic targets.

Porphyrin-embedded periodic mesoporous organosilica (PMO) materials were developed for sunlight-stimulated degradation of cyclic organics. The binding affinity and selectivity of the PMOs act to bring porphyrin and target into close proximity, provide extensive surface area, and a stable substrate for porphyrin immobilization. Aqueous samples incubated with these PMO materials showed a decrease in analyte concentration greater than that expected based on adsorption and uncatalyzed photoconversion during 5 h of sunlight illumination. Both materials show selective binding of TNT over structurally similar compounds such as p-nitrophenol. Template directed molecular imprinting was used in an attempt to increase the selectivity of the catalyst.

We describe a new electroless iron bath capable of depositing a ferromagnetic FeB coating onto Pd/Sn-catalyzed substrates at room temperature without the need for an accompanying galvanic couple and illustrate its use for the fabrication of magnetic cellulose microfibers. The new electroless iron bath contains Fe2+ as the metal source, citrate as the metal chelator, boric acid buffer as the pH controller, and borohydride as the reductant. Surface analysis following plating confirms the deposition of an amorphous FeB coating of composition ∼Fe10B onto the microfiber surface. Through the use of two-level factorial design statistical methods, we characterize the effects of plating variables (i.e., bath pH and concentrations of each bath component) on bath behavior, identifying pH as the sole factor influencing the mass of plated Fe and establishing optimal, reproducible conditions for electroless Fe deposition.