Nanodiamond (ND) is a versatile and promising material for bioapplications. Despite many efforts, agglomeration of nanodiamond and the nonspecific adsorption of proteins on the ND surface when exposed to biofluids remains a major obstacle for biomedical applications. Here, the functionalization of detonation nanodiamond with zwitterionic moieties in combination with tetraethylene glycol (TEG) moieties immobilized by click chemistry to improve the colloidal dispersion in physiological media with strong ion background and for the simultaneous prevention of nonspecific interactions with proteins is reported. Based on five building blocks, a series of ND conjugates is synthesized and their performance is compared in biofluids, such as fetal bovine serum (FBS) and Dulbecco's modified Eagle medium (DMEM). The adsorption of proteins is investigated via dynamic light scattering (DLS) and thermogravimetric analysis. The colloidal stability is tested with DLS monitoring over prolonged periods of time in various ratios of water/FBS/DMEM and at different pH values. The results show that zwitterions efficiently promote the anti‐fouling properties, whereas the TEG linker is essential for the enhanced colloidal stability of the particles.

Detection of metals in different environments with high selectivity and specificity is one of the prerequisites of the fight against environmental pollution with these elements. Pyrenes are well suited for the fluorescence sensing in different media. The applied sensing principle typically relies on the formation of intra-and intermolecular excimers, which is however limiting the sensitivity range due to masking of e. g. quenching effects by the excimer emission. Herein we report a highly selective, structurally rigid chemical sensor based on the monomer fluorescence of pyrene moieties bearing triazole groups. This sensor can quantitatively detect Cu 2 + , Pb 2 + and Hg 2 + in organic solvents over a broad concentrations range, even in the presence of ubiquitous ions such as Na + , K + , Ca 2 + and Mg 2 + . The strongly emissive sensor's fluorescence with a long lifetime of 165 ns is quenched by a 1 : 1 complex formation upon addition of metal ions in acetonitrile. Upon addition of a tenfold excess of the metal ion to the sensor, agglomerates with a diameter of about 3 nm are formed. Due to complex interactions in the system, conventional linear correlations are not observed for all concentrations. Therefore, a critical comparison between the conventional Job plot interpretation, the method of Benesi-Hildebrand, and a non-linear fit is presented. The reported system enables the specific and robust sensing of medically and environmentally relevant ions in the healthrelevant nM range and could be used e. g. for the monitoring of the respective ions in waste streams.

Fluorescent nanodiamonds are versatile tools, which can be employed as perfectly photostable labels as well as for intracellular sensing of a wide array of properties and chemical products due to...

Sensing of metal contaminants in different environments is crucial for the control of pollution. A highly specific sensor for mercury, lead, and copper based on the interaction of pyrene‐based moieties functionalized at their 2‐position has been synthesized and characterized. The detection of fluorescence quenching of the monomer emission allows for a broad dynamic range and sensing is possible in organic solvents and in the presence of other cations such as Na+, K+, Ca2+, or Mg2+. More information can be found in the Full Paper by A. Krueger et al. (DOI: 10.1002/chem.202100594).

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