Latest ArticlesTraditional colorimetric glucose biosensor generally involves complex assay procedures. Free labile enzymes and peroxidase substrates are used separately for triggering a chromogenic reaction. These limits result in inferior enzyme stability and defective enzymatic catalytic efficiency, making it hard to routinely utilize them for the direct and fast test of glucose. In this work, we provide an all-inclusive substrates/enzymes nanoparticle employed 3, 3'5, 5'-tetramethylbenzidine (TMB) as chromogenic substrates and glucose oxidase (GOx)/horseradish peroxidase (HRP) as signal amplifier enzymes (TMB-GH NPs) by the molecule self-assembly technique. The "all-inclusive" nanoparticles can realize the tandem colorimetric reactions, and the oxidation product of TMB (ox-TMB) exhibits a strong NIR laser-driven photothermal effect, thus allowing quantitative photothermal detection of glucose. Owing to the restriction of the molecular motion of GOx, HRP, and TMB, the distance of mass transfer between substrates was shortened largely, leading to improved catalytic activity for glucose. Overall, our strategy will simplify the analysis procedure, furthermore, these integrated nanoparticles not only display higher stability and activity than that of the free GOx/HRP system and possesses an excellent performance for colorimetric and photothermal bioassay of glucose simultaneously. We believe that this unique technique will give good inspirations to develop simple and precise methods for bioassay.
The increasing incidence of osteoarthritis (OA) seriously affects life quality, posing a huge socioeconomic burden. Tissue engineering technology has become a hot topic in articular cartilage repair as one of the key treatment methods to alleviate OA. Hydrogel, one of the most commonly used scaffold materials, can provide a good extracellular matrix microenvironment for seed cells such as bone marrow mesenchymal stem cells (BMSCs), which can promote cartilage regeneration. However, the low homing rate of stem cells severely limits their role in promoting articular cartilage regeneration. Stromal cell-derived factor- 1α (SDF-1α) plays a crucial role in the activation, mobilization, homing, and migration of MSCs. Herein, a novel injectable chemotaxis hydrogel, composed of chitosan-based injectable hydrogel and embedding SDF-1α-loaded nanodroplets (PFP@NDs-PEG-SDF-1α) was designed and fabricated. The ultrasound was then used to augment the injectable chemotaxis hydrogel and promote the homing migration of BMSCs for OA cartilage repair. The effect of ultrasound augmenting injectable PFP@NDs-PEG-SDF-1α/hydrogel on the migration of BMSCs was verified in vitro and in vivo, which remarkably promotes stem cell homing and the repair of cartilage in the OA model. Therefore, the treatment strategy of ultrasound augmenting injectable chemotaxis hydrogel has a bright potential for OA articular cartilage repair.
Fragrances are frequently added to a variety of products, including food, cosmetics and health products. However, the high volatility and instability of essence limit its application in some fields. In this study, mesoporous silica nanoparticles (MSNs) were prepared to encapsulate eugenol, which could reduce the volatilization of the fragrance molecules. A facile approach was presented to synthesize MSNs with three different pore diameters for encapsulating eugenol. In addition, the properties of MSNs including mean particle size, morphology, encapsulating efficiency and release tendency were characterized. Results showed that the larger the pore diameters of MSNs, the more aromatic molecules were adsorbed. Furthermore, the release mechanism was described as the smaller the pore diameters of MSNs, the slower the release of eugenol.
Understanding the physical mechanisms governing aggregation-induced-emission (AIE) and aggregation-caused-quenching plays a vital role in developing functional AIE materials. In this work, tetraphenylethene (TPE, a classical AIEgen) and naphthalimide (NI, a popular fluorophore with ACQ characteristics) were connected through non-conjugated linkages and conjugated linkages. We showed that the nonconjugated-linkage of TPE to NI fragments leads to substantial PET in molecular aggregates and ACQ. In contrast, the conjugated connection between TPE and NI moieties results in the AIE phenomenon by suppressing twisted intramolecular charge transfer. This work provides an important guideline for the rational design of AIE materials.
An efficient approach to sulfur-bridged imidazopyridines has been developed under metal-free conditions using inexpensive sulfur powder as the sulfur source. Most appealingly, the reaction can proceed smoothly without addition of any additives, ultimately decreasing the production of chemical waste. The inexpensive and green method should provide a useful strategy for constructing a library of novel and biological interesting heteroaromatic sulfides.
In this paper, we demonstrate that modification of anion-transport active 1, 3-bis(benzimidazol-2-yl) benzene with strongly electron-withdrawing trifluoromethyl and nitro groups leads to a dramatic increase in the anionophoric activity, and the activity may be greatly regulated by the curvatures of the liposomes used.
Acetaminophen (ACE) is commonly used in analgesic and antipyretic drug, which is hardly removed by traditional wastewater treatment processes. Herein, amorphous Co(OH)2 nanocages were explored as peroxymonosulfate (PMS) activator for efficient degradation of ACE. In the presence of amorphous Co(OH)2 nanocages, 100% of ACE removal was reached within 2 min with a reaction rate constant k1 = 3.68 min-1 at optimum pH 5, which was much better than that of crystalline β-Co(OH)2 and Co3O4. Amorphous materials (disorder atom arrangement) with hollow structures possess large specific surface area, more reactive sites, and abundant vacancies structures, which could efficiently facilitate the catalytic redox reactions. The radicals quenching experiment demonstrated that SO4·- radicals dominated the ACE degradation rather than ·OH radicals. The mechanism of ACE degradation was elucidated by the analysis of degradation intermediates and theoretical calculation, indicating that the electrophilic SO4·- and ·OH tend to attack the atoms of ACE with high Fukui index (f-). Our finding highlights the remarkable advantages of amorphous materials as heterogeneous catalysts in sulfate radicals-based AOPs and sheds new lights on water treatment for the degradation of emerging organic contaminants.
Based on 4-bromo-1, 8-naphthalic anhydride, one novel ratiometric fluorescence H2S-probe (IDNA) was designed and synthesized. Further studies indicate that IDNA can sensitively recognize H2S (detection limit of 7 μmol/L) with good selectivity and anti-interference ability. In addition, IDNA has satisfactory photostability in HeLa cells, ability of mitochondrial co-localization, and can be utilized in fluorescence imaging of H2S.
A convenient synthetic protocol for the hexasubstituted benzene derivatives was successfully developed by DABCO promoted domino reaction of arylidene malononitrile with two molecules of dialkyl but-2-ynedioates. The domino reaction resulted in tetraalkyl 6-cyano-[1, 1'-biphenyl]-2, 3, 4, 5-tetracarboxylates in good to high yields. This formal [2 + 2 + 2] cycloaddition was believed to proceed with sequential nucleophilic addition, Michael addition, annulation and aromatization processes.
We constructed a reaction-based near-infrared fluorescent probe (Niap) to specifically identify alkaline phosphatase (ALP) with fast red fluorescence enhancement. Based on the positive concentration-dependent manner between the fluorescent intensity of the Niap and ALP, probe Niap was used to study the ALP enrichment and variation in golden apple snails (Pomacea canaliculata) exposed to the molluscicide candidate PPU06. After treatment with different concentrations of PPU06 over various times, three organs of the surviving snails, liver, stomach and plantaris, were frozen and sectioned for fluorescent imaging experiments. With increased PPU06 concentration, red fluorescence substantially increased in the liver and reached a maximum within 24 h when the PPU06 concentration was 0.75 mg/L. No obvious changes in the stomach or foot plantaris were found. It showed PPU06 caused liver injury and stimulated the increase of ALP in the liver of P. canaliculata. This study demonstrates a rapid ALP fluorescent identification method that can be used to study the effects of PPU06 on P. canaliculata. It also provides optical evidence that may aid in the discovery of new chemistry for snail control.
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