Accurate thermometry at micro- and nanoscales is essential in many nanobiotechnological applications. The nanothermometers introduced in this paper are composed of labeled molecular beacons (MBs) comprising gold nanoparticles (AuNPs) on which, depending on application, many MBs of one or more types are immobilized. In this design, three differently labeled MBs with different thermostabilities function as the sensing elements, and AuNPs act as carriers of the MBs and also quenchers of their fluorophores. This flexible design results in a number of nanothermometers with various temperature-sensing ranges. At the lowest temperature, the MBs are in the closed form, where they are quenched. By increasing the temperature, the MBs start to open with respect to their melting points (Tm), and as a result, the fluorescence emission will increase. The temperature resolution of the nanoprobes over a range of 15-60 °C is less than 0.50 °C, which indicates their high sensitivity. Such a good temperature resolution is a result of the specific design of the unusual less stable MBs and also presence of many MBs on AuNPs. The reproducibility and precision of the probes are also satisfactory. The multiplex MB nanoprobe is suitable for thermal imaging by fluorescence microscopy.

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The electrochemical water-oxidation reaction usually requires a catalyst to reduce the overpotential and Earth-abundant catalysts, like MnO2, are attracting much attention. Here we use chemometric analysis, EPR and UV-Vis spectroscopies to track Mn(II) and MnO4(-) byproducts to the reaction of a MnO2 film in the presence of cerium(IV) ammonium nitrate. Permanganate ion is involved in at least two key reactions: it may oxidize water to O2 or can combine with Mn(II) to remake MnO2 solid. We propose mechanisms for water oxidation and present a self-healing process for this reaction.

In this report, Fe3O4 nanoparticles are modified for the first time with graphene quantum dots (GQD) and used for the stabilization of PdCu bimetallic nanoparticles. The new magnetic compound, PdCu@GQD@Fe3O4, is characterized by different methods such as SEM, high‐resolution (HR)‐TEM, energy‐dispersive X‐ray spectroscopy (EDS) mapping, XRD, and X‐ray photoelectron spectroscopy (XPS). This material is applied as an efficient catalyst for the Sonogashira reaction of aryl iodides, bromides, and chlorides in toluene or N,N‐dimethylacetamide at 60–110 °C in very high yields with 0.3 mol % of Pd loading. According to different tests, such as polyvinylpyridine poisoning, hot filtration, and kinetic studies, this catalyst works under heterogeneous conditions. By magnetic separation of the catalyst, it can be recycled for six consecutive runs with only a small decrease in activity without appreciable structural modification of the reused catalyst, which is characterized by TEM and XPS.

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Magnetic Fe3O4 nanoparticles (NPs) functionalized with carbon dots (C‐dots) that contain carboxylic acid and hydroxyl groups were synthesized successfully and used for the reduction of PdII and the formation of Pd NPs. The new material was characterized by SEM, TEM, energy‐dispersive spectroscopy, solid UV spectroscopy, vibrating sample magnetometry, XRD, and X‐ray photoelectron spectroscopy and was used as a very efficient catalyst in the Suzuki–Miyaura cross‐coupling reaction of aryl bromides and chlorides with arylboronic acids in aqueous media. Design of experiments indicates that the use of 0.22 mol % of Pd, K2CO3 as the base, and aqueous ethanol are the best reaction conditions. The reactions of aryl bromides take place at room temperature, and aryl chlorides react at 80 °C. The easily synthesized and air‐stable catalyst Pd@C‐dots@Fe3O4 NPs could be separated from the reaction mixture by using an external magnet and reused in eight consecutive runs with no significant loss of catalytic activity.

The single stranded DNA can be adsorbed on the negatively charged surface of gold nanoparticles (AuNPs), but the rigid structure of double stranded DNA prevents it from adsorption. Signal of a tagged single stranded DNA will be quenched by the plasmon effect of the AuNP surface after its adsorption. This phenomenon has been used to study the DNA hybridization and interactions of two complementary 21mer oligonucleotides each tagged with a different fluorescent dye in the presence of 13 nm gold nanoparticles. The DNA strands used in this study belong to the genome of HIV. The obtained rank deficient three-way fluorescence data sets were resolved by both PARAFAC and restricted Tucker3 models. This is the first successful application of a multiway chemometric technique to analyze multidimensional nanobiological data. The restricted Tucker3 showed a better performance compared to PARAFAC in resolving the data sets. The advantages of restricted Tucker3 analysis over the unrestricted one, i.e., the limited rotational freedom (more unique results) and better interpretability of the obtained results, were experienced in this study. The resolved excitation, emission, and concentration profiles and specially fluorescence resonance energy transfer (FRET) profiles obtained by restricted Tucker3 were chemically more meaningful than those obtained from PARAFAC.