Biocompatible transition metal complexes dyes emitting in the near-infrared (NIR) region, are highly desirable in fluorescence imaging techniques. However, a high-performance mitochondria-specific labeling NIR probe with high photostability is still lacking. Herein we reported two NIR-emitting cationic iridium(iii) complexes [Ir(pbq-g)(N^N)]Cl (pbq-g = phenylbenzo[g]-quinoline; N^N = 2-(1-benzyl-1H-pyrazol-3-yl) pyridine (Ir1) and 2-(1-(naphthalen-1-ylmethyl)-1H-pyrazol-3-yl) pyridine (Ir2)). These two novel Ir(iii) complexes with different N^N ligands exhibited similar NIR emission with λ at 751 nm for Ir1 and 750 nm for Ir2 in PBS solution, with luminescence quantum yields of around 0.62 for Ir1 and 0.85 for Ir2. These two complexes showed high mitochondrial specificity, superior photostability, high resistance to the loss of the mitochondrial membrane potential and appreciable tolerance to environmental changes, allowing NIR imaging of mitochondrial morphological changes over long periods of time. These excellent photophysical and imaging properties made them promising NIR luminescent tags for applications in bioimaging.
In this study, mesoporous silica SBA‐15 is modified by imidazole based ionic liquids (IL) with three different side‐chain length of cations and two different anions. Prepared supports (IL‐SBA‐15) are characterized by small‐angle powder X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS) as well as Fourier transform infrared (FT‐IR), and then used to immobilize Candida antarctica lipase B (CALB). The enzymatic properties of the obtained IL‐SBA‐15‐CALB are evaluated, and the catalytic selectivity toward diacylglycerols (DAG) production in glycerolysis of triacylglycerols (TAG) reaction is also studied. Compared with the parent SBA‐15 immobilized CALB (SBA‐15‐CALB), the IL modification gives a maximum improvement of enzymatic activity from 1855 to 5044 U g−1; in addition, the selectivity toward the diacylglycerols (DAG) production also increases, with the DAG/MAG ratio increasing from 3.72 to 11.99, and the DAG content increasing from 53.6 to 67.2 wt%.
Practical applications: Immobilization of lipases facilitates the separation of products and the recovery of lipases for reuse. The present study shows that CALB immobilized on the IL modified SBA‐15 is potential for DAG production through glycerolysis, due to its considerable reusability as well as its high glycerolysis activity and selectivity toward DAG production, it could be considered for practical applications.
Glycerolysis of corn oil catalyzed by ionic liquids modified SBA‐15 supports CALB to produce diacylglycerols. SBA‐15 is modified by ionic liquids, and then employed as carrier for Candida antarctica lipase B (CALB) immobilization. The obtained solid lipases are used to catalyze glycerolysis for diacylglycerols (DAG) production. Compared with the parent SBA‐15 immobilized CALB (SBA‐15‐CALB), ionic liquids modification gives a maximum improvement of enzymatic activity from 1855 to 5044 U g−1; in addition, the selectivity toward the DAG production is also increased, with the DAG/MAG ratio increasing from 3.72 to 11.99, and the DAG content increasing from 53.6 to 67.2 wt%.
A new method has
been developed for the high-value utilization
of larch bark, which is regarded as a low-value byproduct of the logging
industry. Polymeric proanthocyanidins (PPCs) were extracted from the Larix gmelinii bark and depolymerized by catalytic
hydrogenolysis, using ruthenium/carbon (Ru/C) as the catalyst. The
method has been found that although the molecular weight of the depolymerized
product was significantly lower, the basic structural units were not
destroyed, and the product retained a condensed flavanol polyphenol
structure; the depolymerized product contains very little Ru metal
and thus complies with food safety standards; the antioxidant properties
of both the depolymerized products and PPCs were better than those
of the commonly used antioxidant 2,6-di-tert-butyl-4-methylphenol.
The relative molecular weight and steric hindrance of the depolymerized
products were lower than those of the PPCs, leading to better antioxidant
performance. A new technical route for the depolymerization of PPCs
from the L. gmelinii bark is provided.
The route offers practical and commercial advantages, and the product
could have many applications as an antioxidant.
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