Self-Assembled Integrated Nanozyme Cascade Biosensor with Dual Catalytic Activity for Portable Urease Analysis

In this work, a novel nanozyme (Cu@Zr) with all-in-one dual enzyme and fluorescence properties is designed by simple self-assembly. A nanozyme cascade sensor with disodium phenyl phosphate (PPDS) as substrate was first established by exploiting the dual enzymatic activities of phosphatase and laccase. Specifically, phosphatase cleaves the P–O bond of PPDS to produce colorless phenol, which is then oxidized by laccase and complexed with the chromogenic agent 4-aminoantipyrine (4-AP) to produce red quinoneimine (QI). Strikingly, the NH3 produced by the urease hydrolysis of urea can interact with Cu@Zr, accelerating the electron transfer rate and ultimately leading to a significantly improved performance of the cascade reaction. Moreover, the fluorescence at 440 nm of Cu@Zr is further quenched by the inner filter effect (IFE) of QI. Thus, the colorimetric and fluorescence dual-mode strategy for sensitive urease analysis with LODs of 3.56 and 1.83 U/L was established by the proposed cascade sensor. Notably, a portable swab loaded with Cu@Zr was also prepared for in situ urease detection with the aid of a smartphone RGB readout. It also provides a potentially viable analytical avenue for environmental and biological analysis

Highly Sensitive Protein Concentration Assay over a Wide Range via Surface-Enhanced Raman Scattering of Coomassie Brilliant Blue

In the Bradford protein assay, protein concentrations are determined by the absorbance at 595 nm due to the binding of Coomassie brilliant blue G-250 (CBBG) to proteins. In a protein−CBBG liquid mixture, surface-enhanced Raman scattering (SERS) is sensitive to the amount of unbound CBBG molecules adsorbed on silver surfaces, and the bound CBBG amount is directly related to the target protein concentration. Accordingly, a novel method for detecting total protein concentration in a solution has been developed based on SERS of unbound CBBG with an internal standard of silicon. Two obvious advantages of the proposed protein assay over conventional Bradford protein assay are its much wider linear concentration range (10−5−10−9 g/mL) and 200 times lower limit of detection (1 ng/mL), which demonstrates its great potential in rapid, highly sensitive concentration determination of high and low-abundance proteins

Research on the Mechanism of Ultrasound To Enhance the Biodegradation of Profenofos by Lactiplantibacillus plantarum

The effect and mechanism of ultrasound on the biodegradation of profenofos by Lactiplantibacillus plantarum were studied in this work. The results showed that ultrasound applied in the prelogarithmic phase of microbial growth would significantly enhance the biodegradation of profenofos (P < 0.05). The key ultrasonic parameters (ultrasonic intensity, pulse mode, and duration time) were optimized using the response surface methodology. The Holden model was used to describe the growth of L. plantarum and the biodegradation of profenofos. Under the optimal ultrasonic condition, the maximum specific growth rate of L. plantarum and the maximum specific degradation rate of profenofos were 2 and 1.7 times higher than those without sonication, respectively. The promotion of profenofos degradation by ultrasound comes from two aspects: one is the enhancement of phosphatase activity; the second is the improvement of cell membrane permeability, which accelerates the transport of nutrients, profenofos, and other metabolites through the cell membrane

Evaluation of the analgesic potential and safety of <i>Cinnamomum camphora</i> chvar. <i>Borneol</i> essential oil

Cinnamomum camphora chvar. Borneol essential oil (BEO, 18.2% v/v borneol) is a by-product of steam distillation to produce natural crystalline borneol (NCB, 98.4% v/v borneol). Given the known medicinal properties of borneol, the analgesic function and safety were studied. Horn’s method and the Draize test revealed a gender difference in mice regarding acute oral LD50, i.e., low-toxicity to female mice (2749 mg/kg), but practically nontoxic to male mice (5081 mg/kg). There was no acute and skin or eye irritation when BEO was applied directly, if the BEO concentration was less than 50%. The analgesic effect of BEO was evaluated by the glacial acetic acid-induced writhing pain model. Continuous topical application of BEO to the abdomen of mice for 6 d, significantly reduced observed writhing in mice (p 2 (PGE2) and transient receptor potential melastatin-8 (TRPM8) were significantly reduced (p < 0.001), and the latter showed a strong dose-response relationship (r = −0.9427). Therefore, BEO had similar analgesic functions to borneol and was demonstrated to be safe for medicinal use.</p

Quantitative Detection Method of Hydroxyapatite Nanoparticles Based on Eu³⁺ Fluorescent Labeling in Vitro and in Vivo

One major challenge for application of hydroxyapatite nanoparticles (nHAP) in nanomedicine is the quantitative detection method. Herein, we exploited one quantitative detection method for nHAP based on the Eu³⁺ fluorescent labeling via a simple chemical coprecipitation method. The trace amount of nHAP in cells and tissues can be quantitatively detected on the basis of the fluorescent quantitative determination of Eu³⁺ ions in nHAP crystal lattice. The lowest concentration of Eu³⁺ ions that can be quantitatively detected is 0.5 nM using DELFIA enhancement solution. This methodology can be broadly applicable for studying the tissue distribution and metabolization of nHAP in vivo

Inhibition of <i>Candida</i><i> albicans</i> and induced vaginitis by <i>sapindus</i> water extract

In this study, water extract of Sapindus mukorossi Gaertn. pericarps against Candida albicans was evaluated through in vitro and in vivo studies. The most abundant active ingredient was triterpenoid saponins determined by UPLC-TOF-MS analysis. The minimum inhibitory concentration (MIC) was 0.039 mg/mL by using agar double dilution methods. The percentage of inhibition was 93.07% when C. albicans was treated for 4 h using a 1 mg/mL in vitro dose. A vaginitis model was developed by infecting mice with C. albicans. The fungal burden was tracked, which indicated that 10 mg/mL triterpenoid saponins reduced fungal quantity ranging from 3.0 to 1.84 Log CFU/100 μL. Moreover, the subsequent studies regarding four biomarkers with an enzyme-linked immunosorbent assay were conducted. It was confirmed that interleukin IL-1β, IL-6, IL-8, and lactate dehydrogenase (LDH) were lower than untreated group, and vaginal pathology was significantly improved in tissue sections.</p

An electrolyte-rich nano-organic cathode constructs an ultra-high voltage Zinc-ion battery

To realize green and sustainable energy storage systems, it is urgent to propose emerging strategies to construct and understand the relationship between electrode materials and electrolytes. Based on the strategy of storing the electrolyte in an organic cathode, we prepare a Zn2+-doped polyaniline (PAZ) nano-organic cathode with a re-doping method, which possesses high crystallinity in the (0 1 0) plane and high conductivity compared with conventional H+-doped polyaniline (PA). The resultant Zn//PAZ battery exhibits outstanding electrochemical performance for 3000 cycles at an ultra-high voltage of 2.4 V, attributed to the enhancement of electrolyte concentration and reduction of free water stemming from the dedoping of PAZ. A hybrid charge storage mechanism including Zn2+ and multi-anions insertion/extraction is also demonstrated for the Zn//PAZ batteries during the charge/discharge process. To further expand the practical applications of the strategy, we manufacture an electrolyte-free Zn//PAZ battery, which achieves acceptable performance for 400 cycles. This research provides insight into the relationship between the electrolyte and re-doped polyaniline organic cathode and opens a new avenue for emerging Zinc batteries

DNA-Hairpin-Templated Silver Nanoclusters: A Study on Stem Sequence

DNA hairpins are widely used to synthesize silver nanoclusters (AgNCs) with excellent optical properties due to their specific secondary structure. Hairpin-AgNCs have been popularly employed for sensoring applications, while no systematic study has been done about the effect of stem sequence on the fluorescence property of hairpin-AgNCs. In this presented work, the synthesizing conditions of hairpin-AgNCs were fully examined first. Then, the effect of percentage content and distribution of GC base pairs as well as stem length on the fluorescence property of hairpin-AgNCs were studied. Intriguing phenomena were observed and basic conclusions were drawn, which would be helpful to understand the hairpin-AgNCs comprehensively and instructional for the applications using hairpin-AgNC probes

Simultaneous Determination of Antibiotics, Mycotoxins, and Hormones in Milk by an 8–17 DNAzyme-Based Enzyme-Linked Immunosorbent Assay

The simultaneous detection of three kinds of small-molecule contaminants (antibiotics, mycotoxins, and hormones) in milk was realized by using an 8–17 DNAzyme-based fluorescent enzyme-linked immunosorbent assay (ELISA), in which 8–17 DNAzyme was utilized as the catalytic enzyme for amplifying the signal. Compared with the conventional ELISA in which horseradish peroxidase is used as the catalyzing factor, this 8–17 DNAzyme-based ELISA could achieve multicolor signal output with lower detection limits. The linearities for chloramphenicol, 17β-estradiol, and aflatoxin M1 were in the range of 0.3 ng/mL–3 μg/mL, 3 ng/mL–3 μg/mL, and 3 pg/mL–3 ng/mL with quantitation limits of 0.3, 3, and 0.003 ng/mL, respectively. This proposed scheme demonstrated that the 8–17 DNAzyme might be an effective substitute for horseradish peroxidase in ELISA for the development of ultrasensitive and multicolor fluorescence immunoassay, which would stimulate the development of ELISA in a new orientation

Luminescence Enhanced Eu³⁺/Gd³⁺ Co-Doped Hydroxyapatite Nanocrystals as Imaging Agents In Vitro and In Vivo

Biocompatible, biodegradable, and luminescent nano material can be used as an alternative bioimaging agent for early cancer diagnosis, which is crucial to achieve successful treatment. Hydroxyapatite (HAP) nanocyrstals have good biocompatibility and biodegradability, and can be used as an excellent host for luminescent rare earth elements. In this study, based on the energy transfer from Gd³⁺ to Eu³⁺, the luminescence enhanced imaging agent of Eu/Gd codoping HAP (HAP:Eu/Gd) nanocrystals are obtained via coprecipitation with plate-like shape and no change in crystal phase composition. The luminescence can be much elevated (up to about 120%) with a nonlinear increase versus Gd doping content, which is due to the energy transfer (⁶P_J of Gd³⁺ → ⁵H_J of Eu³⁺) under 273 nm and the possible combination effect of the cooperative upconversion and the successive energy transfer under 394 nm, respectively. Results demonstrate that the biocompatible HAP:Eu/Gd nanocrystals can successfully perform cell labeling and in vivo imaging. The intracellular HAP:Eu/Gd nanocrystals display good biodegradability with a cumulative degradation of about 65% after 72 h. This biocompatible, biodegradable, and luminescence enhanced HAP:Eu/Gd nanocrystal has the potential to act as a fluorescent imaging agent in vitro and in vivo