An efficient chemiluminescent probe based on Ni-doped CsPbBr perovskite nanocrystals embedded in mesoporous SiO for sensitive assay of L-cysteine.

This study presents an efficient chemiluminescence (CL) probe based on perovskite nanocrystals (NCs) for detection of L-cysteine (L-Cys). It consists of nickel-doped CsPbBr NCs embedded in the mesoporous SiO matrix as CL reagent and cerium (IV) as an oxidant in aqueous environment. The probe was designed for the highly selective determination of L-Cys based on its remarkable enhancing effect on the CL intensity.

A novel fluorescent sensor for selective rifampicin detection based on the bio-inspired molecularly imprinted polymer-AgInS/ZnS quantum dots.

A fluorescent sensing material based on the ternary core-shell quantum dots with outstanding optical properties and a bio-inspired molecularly imprinted polymer (MIP) as a recognition element has been prepared for selective detection of rifampicin (RFP). Firstly, AgInS/ZnS core/shell quantum dots (ZAIS QDs) were prepared by a hydrothermal process. Then, the fluorescent sensor was prepared by coating these QDs by a dopamine-based MIP layer.

A smartphone-assisted fluorescent sensing platform for ochratoxin A using Mn-doped CsPbBr perovskite quantum dots embedded in the mesoporous silica as a ratiometric probe.

Food sources are susceptible to contamination with ochratoxin A (OTA), which is a serious threat to human health. Thus, the construction of novel, simple sensing platforms for OTA monitoring is of utmost need. Manganese-doped lead halide perovskite quantum dots encapsulated with mesoporous SiO (Mn-CsPbBr QDs@SiO) were prepared here and used as a ratiometric fluorescent probe for OTA.

A fluorescent magnetic nanosensor for imidacloprid based on the incorporation of polymer dots and Fe O nanoparticles into the covalent organic framework.

A magnetic nanoprobe was designed for imidacloprid by encapsulating nonconjugated polymer dots (NCPDs) and Fe O nanoparticles in the covalent organic framework (COF). The fluorescence intensity of the COF-based nanocomposite is markedly suppressed by imidacloprid. As the absorption spectrum of imidacloprid was close to the band-gap of the NCPDs, and due to the presence of a nitro group (as an electron acceptor), the electrons can be easily transferred from the conduction band of NCPDs to the LUMO of imidacloprid, so fluorescence quenching was more likely to have been caused by the electron transfer process.

A colorimetric assay for HO and glucose based on the morphology transformation of Au/Ag nanocages to nanoboxes.

Herein, we introduced a sensitive colorimetric platform for hydrogen peroxide (HO) assay based on gold/silver (Au/Ag) nanocages with porous structure. In the presence of HO, the morphology of hollow Au/Ag nanocages was converted to closed nanoboxes, altering their localized surface plasmon resonance (LSPR) peak position and the solution color from light blue to deep blue. The morphology transformation and LSPR peak position of Au/Ag nanocages were proportional to HO concentration at the range of 0.

Highly sensitive colorimetric assay for penconazole using gold nanostar-graphene quantum dot composite.

In this study, a simple and sensitive colorimetric method for penconazole sensing is reported. It is based on the etching/anti-etching strategy in which gold nanostar@graphene quantum dot (AuNS@GQD) nanocomposite acts as a sensing nanoprobe and IO as an etching agent. With adding IO to the solution of AuNSs@GQDs, the sharp tips of NSs are etched and they are transformed into nearly spherical nanostructures, and the color of the solution changes from green to violet.

Sonochemically synthesized mesoporous cobalt oxide nanoparticles for luminol-enhanced chemiluminescence sensing.

In recent years, mesoporous cobalt oxides have attracted more attention due to their exceptional physical and chemical properties and their important applications in various fields. The synthesis of cobalt oxides of various sizes, morphologies, and porosity is still a challenging process. In this report, mesoporous CoONPs with different porosity were synthesized through facile, one-step, and cost-effective routes, without using any complicated materials or instruments, via the sonochemical process.

Perovskite quantum dots as a chemiluminescence platform for highly sensitive assay of cefazolin.

This paper reports on a chemiluminescence (CL) probe consist of CsPbBr quantum dots (QDs) in organic phase together with Fe(II) and KSO in aqueous medium for the highly selective and sensitive determination of the antibiotic, cefazolin (CFZ). The CsPbBrperovskite QDs prepared by the ligand assisted reprecipitation method, exhibit a narrow fluorescence at 533 nm under 460 nm excitation with a high quantum yield (42 %). The Fe(II) - SO as an ultra-weak CL system is converted to a rather strong CL sensing platform in the presence of organic-phase CsPbBr QDs.

Eco-friendly nonconjugated polymer dots for chemiluminometric determination of 4-nitrophenol.

Polymer dots (PDs) are a new family of quantum dots for which their behavior and potential applications have not yet been completely explored. In this study, nonconjugated PDs were synthesized using a simple pyrolysis method and used for the chemiluminescence (CL) assay of 4-nitrophenol (4-NP). PDs increased the CL signal of the Ce(IV)-Na SO reaction 39-fold.

Plasmon-enhanced fluorimetric and colorimetric dual sensor based on fluorescein/Ag nanoprisms for sensitive determination of mancozeb.

A plasmon-enhanced fluorimetric and colorimetric dual sensor was designed to detect mancozeb based on fluorescein (as a fluorimetric reporter) and AgNPRs (as a fluorescence enhancer and colorimetric reporter). The sensing mechanism was based on the shape transformation of AgNPRs due to etching and anti-etching effect of SO and mancozeb. We observed that AgNPRs enhanced the fluorescence intensity of fluorescein around 4-fold.

A sensitive homogeneous enzyme assay for euchromatic histone-lysine-N-methyltransferase 2 (G9a) based on terbium-to-quantum dot time-resolved FRET.

Histone modifying enzymes include several classes of enzymes that are responsible for various post-translational modifications of histones such as methylation and acetylation. They are important epigenetic factors, which may involve several diseases and so their assay, as well as screening of their inhibitors, are of great importance. Herein, a bioassay based on terbium-to-quantum dot (Tb-to-QD) time-resolved Förster resonance energy transfer (TR-FRET) was developed for monitoring the activity of G9a, the euchromatic histone-lysine N-methyltransferase 2.

A chemiluminescence probe enhanced by cobalt and nitrogen-doped carbon dots for the determination of a nitrosative stress biomarker.

A chemiluminometric method is introduced for the determination of the stress biomarker, 3-nitrotyrosine (3-NT) based on the HO-NaIO reaction enhanced by cobalt and nitrogen-doped carbon dots (Co,N-CDs). In this chemiluminescence (CL) system, the emission proved to be originated from the excited-state Co,N-CDs (λ = 504 nm). Comparing the effect of Co,N-CDs with that of some other metal ion-doped CDs and undoped CDs indicated the high efficiency of Co,N-CDs in the CL amplification (about 1980-fold).

A Fatigue Damage Model for Life Prediction of Injection-Molded Short Glass Fiber-Reinforced Thermoplastic Composites.

Short glass fiber-reinforced (SGFR) thermoplastics are used in many industries manufactured by injection molding which is the most common technique for polymeric parts production. Glass fibers are commonly used as the reinforced material with thermoplastics and injection molding. In this paper, a critical plane-based fatigue damage model is proposed for tension-tension or tension-compression fatigue life prediction of SGFR thermoplastics considering fiber orientation and mean stress effects.

Gold nanostar@graphene quantum dot as a new colorimetric sensing platform for detection of cysteine.

We here report on a facile method for preparation of gold nanostar-graphene quantum dot (AuNS@GQD) composite, which produces highly active surfactant-free AuNSs. The etching reaction of this composite with NaSO was studied and used as a new sensing strategy for colorimetric detection of nM levels of cysteine. In the presence of NaSO, the shape of AuNSs changes to sphere-like nanoparticles, leading to a distinct color change of solution from light green to indigo.

A new enhanced chemiluminescence reaction based on polymer dots for the determination of metronidazole.

Polymer dots (PDs) with non-conjugated functional groups are attracting nanomaterials due to their ease of synthesis, the biocompatibility of precursors, and low toxicity. In this work, PDs with non-conjugated groups were synthesized with a simple and straightforward method by Schiff base reaction. Then their possible application in the chemiluminescence (CL) reactions was explored.

A Simple and Novel Sensor for the Determination of Acetamiprid Based on Its Reducing Effect on the Chemiluminescence of S, N-CQDs in CHCN-HO System.

A simple and novel method for the determination of acetamiprid in water samples is suggested. The method is based on the reducing effect of acetamiprid on the chemiluminescence intensity of new sulfur and nitrogen co-doped carbon dots (S, N-CQDs) in an acetonitrile-hydrogen peroxide (CHCN-HO) system. The possible mechanism was investigated, and it was found that S, N-CQDs react with (O)*, produced from the CHCN-HO reaction, leading to excited state S, N-CQDs, which deactivate to the ground state by photon emission.

Doped-carbon dots: Recent advances in their biosensing, bioimaging and therapy applications.

As a fascinating class of fluorescent carbon dots (CDs), doped-CDs are now sparked intense research interest, particularly in the diverse fields of biomedical applications due to their unique advantages, including low toxicity, physicochemical, photostability, excellent biocompatibility, and so on. In this review, we have summarized the most recent developments in the literature regarding the employment of doped-CDs for pharmaceutical and medical applications, which are published over approximately the past five years. Accordingly, we discuss the toxicity and optical properties of these nanomaterials.

A sensitive turn-off-on fluorometric sensor based on S,N co-doped carbon dots for environmental analysis of Hg(II) ion.

A simple and sensitive fluorescence turn-off-on sensor was established by means of S,N co-doped carbon dots (S,N-CDs) and Ag nanoparticles (AgNPs) for the determination of Hg . For this purpose, blue emissive S,N-CDs were hydrothermally synthesized and characterized using transmission electron microscopy, Fourier transform infrared spectroscopy, and energy dispersive X-ray spectroscopy. We observed that the fluorescence intensity of the as-prepared S,N-CDs was impressively quenched by AgNPs.

A ratiometric fluorescence sensor for triticonazole based on the encapsulated boron-doped and phosphorous-doped carbon dots in the metal organic framework.

In this work, boron-doped carbon dots (B-CDs) with blue fluorescence and phosphorous-doped green emitting CDs (P-CDs) were encapsulated into zeolitic imidazolate framework-8 (ZIF-8) to prepare a dual-emission ratiometric fluorescence sensor for triticonazole. The B-CDs/P-CDs@ZIF-8 composite exhibited two emission peaks at 440 nm and 510 nm under a single wavelength excitation of 385 nm that respectively belong to B-CDs and P-CDs. In the presence of triticonazole, the fluorescence intensity of B-CDs remarkably declined while that of P-CDs remained unchanged.

Tensile Behavior of High-Density Polyethylene Including the Effects of Processing Technique, Thickness, Temperature, and Strain Rate.

The primary goal of this study was to investigate the monotonic tensile behavior of high-density polyethylene (HDPE) in its virgin, regrind, and laminated forms. HDPE is the most commonly used polymer in many industries. A variety of tensile tests were performed using plate-type specimens made of rectangular plaques.

An ultrasensitive chemiluminescence assay for 4-nitrophenol by using luminol-NaIO reaction catalyzed by copper, nitrogen co-doped carbon dots.

A chemiluminescence (CL) assay on the basis of the tremendous enhancing effect of copper and nitrogen co-doped carbon dots (Cu,N-CDs) on the luminol-NaIO reaction was introduced for the determination of nanomolar levels of 4-nitrophenol (4-NP). Cu,N-CDs were synthesized by a hydrothermal approach and characterized by TEM, XRD, EDX, and FTIR analysis. The potential CL mechanism was elucidated by recording the CL spectrum and by evaluating the influence of reactive oxygen species.

Terbium-to-quantum dot Förster resonance energy transfer for homogeneous and sensitive detection of histone methyltransferase activity.

The development of rapid, simple, and versatile biosensors for monitoring the activity of histone modifying enzymes (HMEs) is needed for the improvement of diagnostic assays, screening of HME inhibitors, and a better understanding of HME kinetics in different environments. Nanoparticles can play an important role in this regard by improving or complementing currently available enzyme detection technologies. Here, we present the development and application of a homogeneous methyltransferase (SET7/9) assay based on time-gated Förster resonance energy transfer (TG-FRET) between terbium complexes (Tb) and luminescent semiconductor quantum dots (QDs).

A chemiluminescence reaction consisting of manganese(IV), sodium sulfite, and sulfur- and nitrogen-doped carbon quantum dots, and its application for the determination of oxytetracycline.

Sulfur- and nitrogen-doped carbon quantum dots (S,N-CQDs) were prepared by a solid-phase hydrothermal method from cysteine and citric acid and characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and FTIR spectroscopy. These QDs were exploited as enhancers to amplify the chemiluminescence (CL) of manganese(IV)-sodium sulfite reaction. S,N-CQDs exceptionally enhanced the CL intensity of this system, around 900-fold.

SPR signals enhancement by gold nanorods for cell surface marker detection.

The detection of micrometer-sized particles like cells is limited by surface plasmon resonance (SPR) biosensors because of having a depth of evanescent wave <500 nm. In this study, for the first time, we exhibited the use of streptavidin-functionalized gold nanorods (GNRs) as intensification labels for detection of cell surface markers in SPR-based biosensors. The GNRs (ʎ max: 735 nm) were modified with streptavidin using EDC/NHS coupling method and human umbilical vein endothelial cells (HUVECs) were selected as the cell model for detecting VE-cadherin on cell surface using real-time SPR device in the 785 nm wavelength of the laser source.

Exploring the behavior of gold nanostar@reduced graphene oxide composite in chemiluminescence: Application to highly sensitive detection of glutathione.

Gold nanostar@reduced graphene oxide (GNS@rGO) nanocomposite was used as a catalyst in a chemiluminescence (CL) reaction. Composites with different sizes of gold nanostars were prepared without any surfactant, and characterized by transmission electron microscopy, UV-visible, FT-IR and Raman spectroscopy. We showed that GNS@rGO can strongly enhance the intensity of luminol‑sodium periodate CL system and the larger the GNS size, the greater the enhancing effect.