Magnetic multi-enzyme nanosystems have been prepared via co-precipitation of enzymes and metal–organic framework HKUST-1 precursors in the presence of magnetic Fe3O4 nanoparticles. The spatial co-localization of two enzymes was achieved using a layer-by-layer positional assembly strategy. Glucose oxidase (GOx) and horseradish peroxidase (HRP) were used as the model enzymes for cascade biocatalysis. By controlling the spatial positions of enzymes, three bienzyme nanosystems GOx@HRP@HKUST-1@Fe3O4, GOx–HRP@HKUST-1@Fe3O4 and HRP@GOx@HKUST-1@Fe3O4 were prepared in which GOx and HRP containing layers were in close proximity, either encapsulated in the HKUST-1 inner layer, or immobilized on the HKUST-1 outer shell, or randomly distributed in the two MOF layers. Their properties were characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, thermal gravimetric analysis, and zeta potential measurements. The highest activity was observed at pH = 6 and a temperature of 20 °C. Thanks to the favorable positioning of enzymes, the GOx@HRP@HKUST-1@Fe3O4 nanosystem revealed superior kinetics with a Michaelis constant Km = 0.8 mmol L−1 and the maximum reaction rate Vmax = 11.3 μmol L−1 min−1. The enzyme–HKUST-1 conjugates exhibited remarkably high operational stability compared to the free enzymes. This work provides a facile and versatile approach to spatially organized multienzyme systems with well-defined nanostructures and greatly enhanced the overall biocatalytic efficiency.

Fabrication of metal–organic frameworks (MOFs) with large apertures triggers a brand-new research area for selective encapsulation of biomolecules within MOF nanopores. The underlying inclusion mechanism is yet to be clarified however. Here we report a molecular dynamics study on the mechanism of protein encapsulation in MOFs. Evaluation for the binding of amino acid side chain analogues reveals that van der Waals interaction is the main driving force for the binding and that guest size acts as a key factor predicting protein binding with MOFs. Analysis on the conformation and thermodynamic stability of the miniprotein Trp-cage encapsulated in a series of MOFs with varying pore apertures and surface chemistries indicates that protein encapsulation can be achieved via maintaining a polar/nonpolar balance in the MOF surface through tunable modification of organic linkers and Mg–O chelating moieties. Such modifications endow MOFs with a more biocompatible confinement. This work provides guidelines for selective inclusion of biomolecules within MOFs and facilitates MOF functions as a new class of host materials and molecular chaperones.

•Large-area SERS-active substrates with high uniformity and reproducibility have been prepared.•The substrates exhibited preferential adsorption of living bacteria Escherichia coli from a very dilute solution.•The substrates also enabled immediate detection of the captured microorganisms using the SERS spectrum.For the first time, large-area surface-enhanced Raman scattering sensing active substrates using porous polymer monolithic layers have been successfully prepared. Our approach includes a simple photoinitiated polymerization process using glycidyl methacrylate and ethylene dimethacrylate in a glass mold, followed by a chemical reaction of the epoxy functionalities leading to thiols, and the attachment of preformed gold nanoparticles. We demonstrated that this very simple process produced uniform and reproducible large area surfaces that significantly enhance sensitivity of Raman spectroscopy. Experiments were also carried out that confirmed preferential adsorption of living bacteria Escherichia coli from a very dilute solution on the surface of the monolithic layer, and immediate detection of the captured microorganisms using the SERS spectrum.

pH-responsive surface layers consisting of porous polymer monoliths containing thiol groups have been prepared via a “thiol-ene” click reaction using a mixture of hydrophobic and ionizable unsaturated “ene” compounds. A proportion of these two “ene” reagents controlled the wettability of the surface that varied with pH, and enabled reversible switching between superhydrophilic and superhydrophobic properties.

•Simple monolithic adsorption devices for chelating of metal ions were prepared in syringe barrels.•Poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith modified with ethylenediamine exhibited the best adsorption properties.•Large enrichment factor was achieved for metal ions adsorbed from very dilute solutions.Simple devices for the adsorption and preconcentration of metal ions comprising various monolithic polymers have been prepared by in situ polymerization within the 5.5 cm long and 5.6 mm i.d. polypropylene syringes. Poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith was modified with ethylenediamine to obtain the chelating material. The poly(butyl methacrylate-co-ethylene dimethacrylate) and poly(lauryl methacrylate-co-ethylene dimethacrylate) monoliths were first photografted with glycidyl methacrylate prior to functionalization with ethylenediamine. Alternatively, other chelating functionalities including poly(ethylene imines) varying in molecular weight and shape (linear and branched) as well as lysozyme were also attached to the monolithic supports. We found that the poly(glycidyl methacrylate-co-ethylene dimethacrylate) monolith functionalized with ethylenediamine exhibited the best chelating properties characterized with rapid adsorption and a capacity of 111.2 mg/g (537 μmol/g) for Pb2+, 38.1 mg/g (649 μmol/g) for Ni2+, 69.9 mg/g (1100 μmol/g) for Cu2+, and 188.9 mg/g (3633 μmol/g) for Cr3+. The very fast desorption was then achieved using 1.0 mol/L HNO3 as the eluent. An enrichment factor of 300 was observed for metal ions adsorbed from solutions containing 2 ppb of the metal.

Thermal energy storage (TES) transfers heat to storage media during the charging period, and releases it at a later stage during the discharging step. It can be usefully applied in solar plants, or in industrial processes, such as metallurgical transformations. Sensible, latent and thermo-chemical media store heat in materials which change temperature, phase or chemical composition, respectively. Sensible heat storage is well-documented. Latent heat storage, using phase change materials (PCMs), mainly using liquid–solid transition to store latent heat, allows a more compact, efficient and therefore economical system to operate. Thermo-chemical heat storage (TCS) is still at an early stage of laboratory and pilot research despite its attractive application for long term energy storage.The present review will assess previous research, while also adding novel treatments of the subject. TES systems are of growing importance within the energy awareness: TES can reduce the LCOE (levelized cost of electricity) of renewable energy processes, with the temperature of the storage medium being the most important parameter. Sensible heat storage is well-documented in literature and applied at large scale, hence limited in the content of the present review paper. Latent heat storage using PCMs is dealt with, specifically towards high temperature applications, where inorganic substances offer a high potential. Finally, the use of energy storage through reversible chemical reactions (thermo-chemical storage, TCS) is assessed. Since PCM and TCS storage media need to be contained in a capsule (sphere, tube, sandwich plates) of appropriate materials, potential containment materials are examined. A heat transfer fluid (HTF) is required to convey the heat from capture, to storage and ultimate re-use. Particle suspensions offer a valid alternative to common HTF, and a preliminary assessment confirms the advantages of the upflow bubbling fluidized bed and demonstrates that particulate suspensions enable major savings in investment and operating costs.Novel treatments of the TES subject in the review involve the required encapsulation of the latent and chemical storage media, the novel development of powder circulation loops as heat transfer media, the conductivity enhancement of PCMs, the use of lithium salts, among others.

pH-responsive surface layers consisting of porous polymer monoliths containing thiol groups have been prepared via a “thiol-ene” click reaction using a mixture of hydrophobic and ionizable unsaturated “ene” compounds. A proportion of these two “ene” reagents controlled the wettability of the surface that varied with pH, and enabled reversible switching between superhydrophilic and superhydrophobic properties.