Supramolecular encapsulation of nanocrystalline Schiff bases into β-cyclodextrin for multifold enrichment of bio-potency

Construction of molecular enrichment accelerators via assembly of enzyme surface grafted polymer and cyclodextrin achieving rapid and stable ester catalysis for biodiesel synthesis

Efficient and stable catalysis has always been the core concept of enzyme catalysis in industrial processes for manufacturing. Here, we constructed molecular enrichment accelerators to synergistically enhance enzyme activity and stability by assembling enzyme surface grafted polymer and cyclodextrin. At 40 °C, the enzyme activity of CalB-PNIPAM212/β-CD was 2.9 times that of CalB-PNIPAM212. The enzyme activity of CalB-PNIPAM428/γ-CD had reached 1.61 times that of CalB. At the same time, the stability of CalB-PNIPAM212/β-CD and CalB-PNIPAM428/γ-CD are slightly better than that of CalB under high temperature, organic solution and extreme pH conditions. The synergistic increase in activity and stability of the lipase-polymer assembly was achieved due to the structure of assembly, in which the role of cyclodextrin could enrich substrate affecting molecular diffusion. In addition, the lipase-polymer assembly proved to be an efficient catalyst for biodiesel synthesis, with a biodiesel conversion 1.4 times that of CalB at 60 °C. Therefore, this simple and low-cost lipase-polymer assembly provides new possibilities for the construction of high-efficiency industrial biocatalytic catalysts.

Reactive Oxygen Species-Responsive Sequentially Targeted AIE Fluorescent Probe for Precisely Identifying the Atherosclerotic Plaques

The formation of atherosclerosis is the root cause of various cardiovascular diseases (CVDs). Therefore, effective CVD interventions call for precise identification of the plaques to aid in clinical treatment of such diseases. Herein, a reactive oxygen species (ROS)-responsive sequentially targeted fluorescent probe is developed for atherosclerotic plaque recognition. An aggregation-induced emission active fluorophore is linked to maleimide (polyethylene glycol) hydroxyl with a ROS-responsive cleavable bond, which is further functionalized with CLIKKPF peptide (TPAMCF) for specifically binding to phosphatidylserine of the foam cells. After being assembled in aqueous medium, TPAMCF nanoparticles can efficiently accumulate in the plaques through the high affinity of CLIKKPF to the externalized phosphatidylserine of the foam cells. Activated by the locally accumulated ROS in foam cells, the nanoparticles are interrupted, and then TPA can be released and subsequently identify the lipid droplets inside the foam cells to achieve fluorescence imaging of the plaques. Such nanoprobes have the favorable ROS response performance and exhibit a special target binding to the foam cells in vitro. In addition, nanoprobe-based fluorescence imaging permitted the high-contrast and precise detection of atherosclerosis specimens ex vivo. Therefore, as a promising fluorescent probe, TPAMCF is capable of being a potential candidate for the detection of atherosclerotic plaque.

Fabrication of Pickering emulsions stabilized by citrus pectin modified with β-cyclodextrin and its application in 3D printing

Pickering emulsions stabilized by polysaccharide particles have received increasing attention because of their potential applications in three-dimensional (3D) printing. In this study, the citrus pectins (citrus tachibana, shaddock, lemon, orange) modified with β-cyclodextrin (β-CD) were used to stabilize Pickering emulsions reaching the requirements of 3D printing. In terms of pectin chemical structure, the steric hindrance provided by the RG I regions was more conducive to the stability of the complex particles. The modification of pectin by β-CD provided the complexes a better double wettability (91.14 ± 0.14°-109.43 ± 0.22°) and a more negative ζ-potential, which was more beneficial for complexes to anchor at oil-water interface. In addition, the rheological properties, texture properties and stability of the emulsions were more responsive to the ratios of pectin/β-CD (R_β/C). The results showed that the emulsions stabilized at a φ = 65 % and a R_β/C = 2:2 achieved the requirements (shear thinning behavior, self-supporting ability, and stability) of 3D printing. Furthermore, the application in 3D printing demonstrated that the emulsions under the optimal condition (φ = 65 % and R_β/C = 2:2) displayed excellent printing appearance, especially for the emulsions stabilized by β-CD/LP particles. This study provides a basis for the selection of polysaccharide-based particles to prepare 3D printing inks which may be utilized in food manufacturing.

Promising Schiff bases in antiviral drug design and discovery

Emerging and re-emerging illnesses will probably present a new hazard of infectious diseases and have fostered the urge to research new antiviral agents. Most of the antiviral agents are analogs of nucleosides and only a few are non-nucleoside antiviral agents. There is quite a less percentage of marketed/clinically approved non-nucleoside antiviral medications. Schiff bases are organic compounds that possess a well-demonstrated profile against cancer, viruses, fungus, and bacteria, as well as in the management of diabetes, chemotherapy-resistant cases, and malarial infections. Schiff bases resemble aldehydes or ketones with an imine/azomethine group instead of a carbonyl ring. Schiff bases have a broad application profile not only in therapeutics/medicine but also in industrial applications. Researchers have synthesized and screened various Schiff base analogs for their antiviral potential. Some of the important heterocyclic compounds like istatin, thiosemicarbazide, quinazoline, quinoyl acetohydrazide, etc. have been used to derive novel Schiff base analogs. Keeping in view the outbreak of viral pandemics and epidemics, this manuscript compiles a review of Schiff base analogs concerning their antiviral properties and structural-activity relationship analysis.