Recyclable aptamer-derived aqueous two-phase flotation for high-efficiency separation of mercury(II) ions modulated by aggregation states

Covalently Immobilizable Tris(Pyridino)-Crown Ether for Separation of Amines Based on Their Degree of Substitution

A great number of biologically active compounds contain at least one amine function. Appropriate selectivity can only be accomplished in a few cases upon the substitution of these groups, thus functionalization of amines generally results in a mixture of them. The separation of these derivatives with very similar characteristics can only be performed on a preparative scale or by applying pre-optimized HPLC methods. A tris(pyridino)-crown ether was designed and synthetized for overcoming these limitations at a molecular level. It is demonstrated, that this selector molecule is able to distinguish protonated primary, secondary and tertiary amines by the formation of reversible complexes with different stabilities. This degree of substitution-specific molecular recognition of amines opens the door to develop separation processes primarily focusing on the purification of biologically active compounds in a nanomolar scale.

Selective preconcentration separation of Hg(ii) and Cd(ii) from water, fish muscles, and cucumber samples using recycled aluminum adsorbents

Modified aluminum scrap waste was used in the selective extraction of Hg(ii), and Cd(ii) ions. The aluminum scraps were modified with dibenzoylmethane, or isatoic anhydride, or 5-(2-chloroacetamide)-2-hydroxybenzoic acid. The modified aluminum sorbents were characterized by FT-IR, SEM, XRD, XPS, TGA, and elemental analysis. Modes of chelation between adsorbents and target metal ions were deduced via DFT. The highest adsorption capacity was observed for benzo-amino aluminum (BAA) toward Hg(ii), which reached 234.56 mg g⁻¹, while other modified sorbents ranged from 135.28 mg g⁻¹ to 229.3 mg g⁻¹. Under the optimized conditions, the BAA adsorbent showed a lower limit of detection (1.1 mg L⁻¹) and limit of quantification (3.66 mg L⁻¹) for mercury ions than other sorbents. The prepared aluminum adsorbents also exhibited significant selectivities for Hg(ii) and Cd(ii) ions in the presence of competing metal ions.

Modified aluminum scrap waste was used in the selective extraction of Hg(ii), and Cd(ii) ions.

Rational design of hydrogen bonds for driving thermo-responsive phase transition and assembly behavior of block copolymer in water

Hydrogen bonding interactions were intensified in the present study by adjusting the chain architectures, which provided a sufficient driving force for UCST phase transition in pure water.

Modulating the biofunctionality of enzyme-MOF nanobiocatalyst through structure-switching aptamer for continuous degradation of BPA

Encapsulating enzyme within MOF (enzyme-MOF) gives rise to new opportunity to improve the fragility of enzyme, but practical application of enzyme-MOF composite is far from being realized. The development of a novel enzyme-MOF composite system should simultaneously guarantee the enhanced activity and controllably complete recycling, and only in this way can we efficiently and economically utilize the enzyme-MOF composite. Herein, we addressed all these fundamental limitations of current enzyme-MOF composite by establishing aptamer-functionalized enzyme-MOF composite (HRP-ZIF-8@P1). HRP-ZIF-8@P1 relied on automatic structure switch of aptamer-target binding and aptamer-cDNA (complementary DNA) hybridization, achieving effectiveness in self-enriching substrate around HRP-ZIF-8@P1 to boost enzymatic activity first, subsequently hybridizing spontaneously with magnetically controllable cDNA sequence (Fe₃O₄@P3) to completely recover the HRP-ZIF-8@P1, where preferentially capturing substrate could further induce the release of the hybridized HRP-ZIF-8@P1 for automatically starting the cyclic enzyme catalysis. A 5.6-fold enhancement in the catalytic efficiency for BPA degradation was endowed, and 94.7% catalytic activity was retained for 8 consecutive degradations of BPA, both of which were even more significant than HRP-ZIF-8. Additionally, remarkable stability of HRP-ZIF-8@P1 was afforded by dual-layer protection of ZIF-8 and P1 in denaturing conditions. Taking the possibility of discovering an aptamer for any target into account, the aptamer-functionalized enzyme-MOF composites provide a generic and simple guide for simultaneously boosting enzymatic activity and controllably full recycling the enzyme-MOF systems, accelerating their commercial utilizations.