Tandem femto- and nanomolar analysis of two protein biomarkers in plasma on a single mixed antibody monolayer surface using surface plasmon resonance

The multiplexed detection of protein biomarkers in plasma present over a range of clinically relevant concentrations continues to be difficult for surface-based bioaffinity detection platforms such as surface plasmon resonance (SPR). As well as nonspecific adsorption, challenges include quantitative comparison between targets whose concentrations differ by orders of magnitude, regenerating SPR chips after plasma exposure, and the two- or four-channel limitation of many commercial SPR instruments limiting sample throughput. In this article, we explore an approach where two protein biomarkers alpha-1 antitrypsin (AAT) and Tau 381 are detected in tandem within a single SPR channel at micromolar and femtomolar concentrations, respectively. This was achieved by creating a mixed antibody (antiAAT and antiTau) monolayer on the chip surface. After the adsorption of AAT and/or Tau, further specificity was obtained via the adsorption of a DNA aptamer specific to each target. The detection range for each target was controlled via the relative surface density ratio of each antibody type as well as each aptamer concentration. Calibration measurements were performed in both buffer and spiked plasma with the detection of native concentrations of ∼39 fM (Tau) and ∼65 μM (AAT) in a human plasma sample. Finally, tandem measurements of both targets within the same SPR signal channel were demonstrated at these very different concentrations

Facile Method To Disperse Nonporous Metal Organic Frameworks: Composite Formation with a Porous Metal Organic Framework and Application in Adsorptive Desulfurization

It is generally not easy to utilize nonporous metal organic frameworks (MOFs) with a large crystal size (especially for catalysis or adsorption) because their surface area is low and the majority of the active sites exist inside the MOFs. Composing with porous materials may be one way to disperse the nonporous materials. In this study, a nonporous/nonsoluble MOF (in which the particle size was much larger than the cavity size of the porous MOFs) containing Cu­(I) ((Cu₂(pyz)₂(SO₄)­(H₂O)₂)_<i>n</i>, denoted as CP) was composed with typical porous MOFs such as MIL100­(Fe) (iron-benzenetricarboxylate) and CuBTC (cupper-benzenetricarboxylate). The Cu­(I) species of the nonporous MOF was effectively utilized for the adsorptive desulfurization (ADS) of model fuel. Even though the porosities of the composed MOFs decreased as the content of CP increased, the adsorption capacity increased as the content of CP increased (up to a certain content). Considering the negligible capacity of CP for ADS, the enhanced adsorption capacity may be a result of the well-dispersed Cu­(I), which is known to be beneficial for ADS via π-complexation. The dispersed CP was also observed by transmission electron microscopy mapping. Therefore, composing a nonporous MOF with porous MOF is a new and facile way to disperse/utilize the active sites of a nonporous MOF

Scandium-Triflate/Metal–Organic Frameworks: Remarkable Adsorbents for Desulfurization and Denitrogenation

Scandium-triflate (Sc­(OTf)₃) was introduced for the first time on metal–organic frameworks (MOFs), to utilize acidic Sc­(OTf)₃ for adsorptive desulfurization and denitrogenation of fuel containing benzothiophene (BT), dibenzothiophene (DBT), quinoline (QUI), and indole (IND). A remarkable improvement in the adsorption capacity (about 65% based on the weight of adsorbents; 90% based on the surface area of the adsorbents) was observed with the Sc­(OTf)₃/MOFs as compared to the virgin MOFs for the adsorption of BT from liquid fuel. The basic QUI was also adsorbed preferentially onto the acidic Sc­(OTf)₃/MOFs. However, nonsupported Sc­(OTf)₃ showed negligible adsorption capacities. The improved adsorptive performance for BT, DBT, and QUI might be derived from acid–base interactions between the acidic Sc­(OTf)₃ and basic adsorbates. On the other hand, the Sc­(OTf)₃, loaded on MOFs, reduced the adsorption capacity for neutral IND due to lack of interaction between the neutral adsorbate and acidic adsorbent and the reduced porosities of the modified adsorbents. The reusability of the adsorbents was found satisfactory up to the fourth run. On the basis of the result, it is suggested that metal-triflates, such as Sc­(OTf)₃, can be prospective materials for adsorptive desulfurization/denitrogenation of fuels when supported on porous materials such as MOFs

Adsorptive Removal of Indole and Quinoline from Model Fuel over Various UiO-66s: Quantitative Contributions of H‑Bonding and Acid–Base Interactions to Adsorption

Nitrogen-containing compounds (NCCs) such as indole (IND) and quinolone (QUI) in a model fuel were adsorbed over pristine and variously functionalized metal–organic frameworks (MOFs) (here, UiO-66 and −NH₂, −NH₃⁺, −COOH, −COONa, −OH, −SO₃H functionalized UiO-66s) to quantitatively understand the interactions between the adsorbates (IND and QUI) and UiO-66s. The adsorbed quantity of IND and QUI increased linearly with increasing number of H-acceptors and H-donors (for H-bond), respectively, on UiO-66s (excluding one MOF for each adsorption), confirming the importance of H-bonding in the adsorption. UiO-66-NH₃⁺ and UiO-66-NH₂ showed a deviated trend in the IND and QUI adsorption, respectively; this might be explained by cation−π interactions and base–base repulsion, respectively. Moreover, the QUI adsorption increased linearly with increasing number of acidic sites on the MOFs (excluding basic ones), also suggesting the importance of acid–base interactions. Finally, UiO-66-NH₃⁺ showed the highest adsorption for both IND and QUI among the studied MOFs, suggesting that introducing an ammonium group on MOFs can be one way to develop a competitive adsorbent for the adsorptive denitrogenation of fuels

A shape-selective catalyst for epoxidation of cyclic olefins: The nanoporous nickel phosphate VSB-5

27 FIELD Section Title:Heterocyclic Compounds (One Hetero Atom) Catalysis Center for Molecular Engineering,Korea Research Institute of Chemical Technology,Daejeon,S. Korea. FIELD URL: written in English.Nickel in the form of porous nickel phosphate VSB-5 has been used as a shape-selective catalyst for epoxidn. of cyclic olefins such as cyclohexene and cyclooctene using hydrogen peroxide. The VSB-5 showed high selectivity to cyclohexene oxide and cyclohexane diol, much higher productivity per catalyst wt. in the epoxidn. of cyclohexene, and high selectivity to cyclooctene oxide in the epoxidn. of cyclooctene. The VSB-5 behaved as a heterogeneous catalyst in the epoxidn. and can be used many times without structure degrdn., leaching of active nickel species, or significant activity loss. It has been concluded that the epoxidn. reaction with VSB-5 proceeds via a free-radical mechanism by taking into consideration a sharp activity loss in the presence of a radical scavenger, hydroquinone. The effect of radical scavengers with different mol. dimension on the catalytic activity also indicates the shape selectivity in the pores of VSB-5. [on SciFinder (R)

Synthesis of a Metal–Organic Framework, Iron-Benezenetricarboxylate, from Dry Gels in the Absence of Acid and Salt

A nanoporous metal–organic framework (MIL-100­(Fe)) has been synthesized by dry gel conversion for the first time from metallic iron and trimesic acid in the absence of any acid (excluding organic linker), salt, or fluoride

Adsorption of phenol on mesoporous carbon CMK-3: effect of textural properties

Mesoporous carbon CMK-3s with different textural properties have been used for the adsorption of phenol to understand the necessary physicochemical properties of carbon for the efficient removal of phenol from contaminated water. The kinetic constants (both pseudo-second order and pseudo-first-order kinetics) increase with increasing pore size of carbons. The maximum adsorption capacities correlate well with micropore volume compared with surface area or total pore volume even though large pore (meso or macropore) may contribute partly to the adsorption. The pore occupancies also explain the importance of micropore for the phenol adsorption. For efficient removal of phenol, carbon adsorbents should have large micropore volume and wide pore size for high uptake and rapid adsorption, respectively

UiO-66-Type Metal–Organic Framework with Free Carboxylic Acid: Versatile Adsorbents via H‑bond for Both Aqueous and Nonaqueous Phases

The metal–organic framework (MOF) UiO-66 was synthesized in one step from zirconium chloride and isophthalic acid (IPA), together with the usual link material, terephthalic acid (TPA). UiO-66 with free −COOH can be obtained in a facile way by replacing up to 30% of the TPA with IPA. However, the chemical and thermal stability of the synthesized MOFs decreased with increasing IPA content used in the syntheses, suggesting an increase in the population of imperfect bonds in the MOFs because of the asymmetrical structure of IPA. The obtained MOFs with free −COOH were applied in liquid-phase adsorptions from both water and model fuel to not only estimate the potential applications but also confirm the presence of −COOH in the MOFs. The adsorbed amounts of several organics (triclosan and oxybenzone from water and indole and pyrrole from fuel) increased monotonously with increasing IPA content applied in MOF synthesis (or −COOH in the MOFs). The favorable contribution of free −COOH to adsorption can be explained by H-bonding, and the direction of H-bonds (adsorbates: H donor; MOFs: H acceptor) was confirmed by the adsorption of oxybenzone in a wide pH range. The versatile applications of the MOFs with −COOH in adsorptions from both polar and nonpolar phases are remarkable considering that hydrophobic and hydrophilic adsorbents are generally required for water and fuel purification, respectively. Finally, the presence of free −COOH in the MOFs was confirmed by liquid-phase adsorptions together with general Fourier transform infrared analyses and decreased chemical and thermal stability