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Natural amino acids possess side chains with different functional groups (R groups), which make them excellent precursors for programmable synthesis of biomolecule-derived nanodots (biodots) with desired properties. Herein, we report the first systematic study to uncover the material design rules of biodot synthesis from 20 natural α-amino acids via a green hydrothermal approach. The as-synthesized amino acid biodots (AA dots) are comprehensively characterized to establish a structure-property relationship between the amino acid precursors and the corresponding photoluminescent properties of AA dots. It was found that the amino acids with reactive R groups, including amine, hydroxyl, and carboxyl functional groups form unique C-O-C/C-OH and N-H bonds in the AA dots which stabilize the surface defects, giving rise to brightly luminescent AA dots. Furthermore, the AA dots were found to be amorphous and the length of the R group was observed to affect the final morphology (e.g., disclike nanostructure, nanowire, or nanomesh) of the AA dots, which in turn influence their photoluminescent properties. It is noteworthy to highlight that the hydroxyl-containing amino acids, that is, Ser and Thr, form the brightest AA dots with a quantum yield of 30.44% and 23.07%, respectively, and possess high photostability with negligible photobleaching upon continuous UV exposure for 3 h. Intriguingly, by selective mixing of Ser or Thr with another amino acid precursor, the resulting mixed AA dots could inherit unique properties such as improved photostability and significant red shift in their emission wavelength, producing enhanced green and red fluorescent intensity. Moreover, our cellular studies demonstrate that the as-synthesized AA dots display outstanding biocompatibility and excellent intracellular uptake, which are highly desirable for imaging applications. We envision that the material design rules discovered in this study will be broadly applicable for the rational selection of amino acid precursors in the tailored synthesis of biodots.

Foodborne nanostructures have gained more and more attention in recent years. In this paper, the presence and physicochemical properties of carbonaceous nanostructures (CNSs) from roasted pike eel ( Muraenesox cinereus) were reported. The monodispersed CNSs are strongly photoluminescent under the illustration of ultraviolet (UV) light, with a fluorescent quantum yield of 80.16%, and display excitation-dependent emission behavior. The formation of CNSs is believed to go through a process of morphology evolution, including polymerization, pyrolysis, nucleation, growth, emergence, and blossom. The optical properties of the CNSs were shown to be affected by the roasting temperature. Furthermore, cellular uptake of the CNSs was investigated, and it is shown that the CNSs were clearly absorbed into live cells and were mainly distributed within the cell cytoplasm and not in the cell nucleus. This work is among the very first reports on CNSs present in roasted fish, providing valuable insights into the formation mechanism of such nanostructures and showcasing the biodistribution of these food-originated CNSs in live cells.

In this paper, MAl 2 Si x O 2x+4 :Eu 2+ /Eu 3+ (Eu 2+ + Eu 3+ = 2%, molar ratio; M = Mg, Ca, Sr, Ba; x = 0, 0.5, 1, 1.5, 2) phosphors with different SiO 2 concentrations (the ratio of SiO 2 to MAl 2 O 4 is n%, n = 0, 50, 100, 150, 200, respectively) were prepared by high-temperature solid-state reaction under atmospheric air conditions. Their structures and photoluminescent properties were systematically researched. The results indicate that Eu 3+ ions have been reduced and Eu 2+ ions are obtained in air through the self-reduction mechanism. The alkaline earth metal ions and doping SiO 2 strongly affect the crystalline phase and photoluminescent properties of samples, including microstructures, relative intensity of Eu 2+ to Eu 3+ , location of emission lines/bands. It is interesting and important that the emission color and intensities of europium-doped various phosphors which consist of aluminosilicate matrices prepared under atmospheric air conditions could be modulated by changing the kinds of alkaline earth metal and the content of SiO 2 ., (Copyright © 2017 John Wiley & Sons, Ltd.)

A novel family of π-extended viologens has been synthesized by a concise 3-step route from simple and readily available chemicals. The π-enlargement gives the system new photophysical and electrochemical properties such as photoluminescence and changed redox potentials., (© 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

The fabrication of photoluminescent Ti 3 C 2 MXene quantum dots (MQDs) by a facile hydrothermal method is reported, which may greatly extend the applications of MXene-based materials. Interestingly, the as-prepared MQDs show excitation-dependent photoluminescence spectra with quantum yields of up to ≈10% due to strong quantum confinement. The applications of MQDs as biocompatible multicolor cellular imaging probes and zinc ion sensors are demonstrated., (© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Combined with the features of electrospun nanofibers and the nature of hydrogel, a novel choreographed poly(acrylic acid)-silica hydrogel nanofibers (PAA-S HNFs) scaffold with excellent rare earth elements (REEs) recovery performance was fabricated by a facile route consisting of colloid-electrospinning of PAA/SiO2 precursor solution, moderate thermal cross-linking of PAA-S nanofiber matrix, and full swelling in water. The resultant PAA-S HNFs with a loose and spongy porous network structure exhibited a remarkable adsorption capacity of lanthanide ions (Ln(3+)) triggered by the penetration of Ln(3+) from the nanofiber surface to interior through the abundant water channels, which took full advantage of the internal adsorption sites of nanofibers. The effects of initial solution pH, concentration, and contact time on adsorption of Ln(3+) have been investigated comprehensively. The maximum equilibrium adsorption capacities for La(3+), Eu(3+), and Tb(3+) were 232.6, 268.8, and 250.0 mg/g, respectively, at pH 6, and the adsorption data were well-fitted to the Langmuir isotherm and pseudo-second-order models. The resultant PAA-S HNFs scaffolds could be regenerated successfully. Furthermore, the proposed adsorption mechanism of Ln(3+) on PAA-S HNFs scaffolds was the formation of bidentate carboxylates between carboxyl groups and Ln(3+) confirmed by FT-IR and XPS analysis. The well-designed PAA-S HNFs scaffold can be used as a promising alternative for effective REEs recovery. Moreover, benefiting from the unique features of Ln(3+), the Ln-PAA-S HNFs simultaneously exhibited versatile advantages including good photoluminescent performance, tunable emission color, and excellent flexibility and processability, which also hold great potential for applications in luminescent patterning, underwater fluorescent devices, sensors, and biomaterials, among others.

Bandgaps of photoluminescent graphene quantum dots (GQDs) synthesized from anthracite have been engineered by controlling the size of GQDs in two ways: either chemical oxidative treatment and separation by cross-flow ultrafiltration, or by a facile one-step chemical synthesis using successively higher temperatures to render smaller GQDs. Using these methods, GQDs were synthesized with tailored sizes and bandgaps. The GQDs emit light from blue-green (2.9 eV) to orange-red (2.05 eV), depending on size, functionalities and defects. These findings provide a deeper insight into the nature of coal-derived GQDs and demonstrate a scalable method for production of GQDs with the desired bandgaps.

The important photoluminescence enhancement found in Carbon Dots (CDs) obtained from carbonaceous nanomaterials when passivating with acetone is shown in this paper, in which this type of passivation has not been reported previously. Analytical fluorescent assays were performed with the selected CDs using two different pollutants as target analytes. The results show that the optimal conditions for detecting 2,4-dinitrophenol (DNP) were at pH 3.5 while in case of 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline (4,8-DiMeIQx) were found at physiological pH. The fascinating ability of CDs to interact with certain molecules under certain conditions gave rise to explore some useful applications for a quick detection of contaminants by simply monitoring the photoluminescence of CDs as shown in this article., (Copyright © 2013 Elsevier B.V. All rights reserved.)

A very efficient protocol for synthesizing highly fluorescent, protein-templated silver nanoclusters (Ag/NCs) has been discussed. Two types of Ag/NCs (Ag9/HSA and Ag14/HSA), although showing significant differences in their photophysical properties, can be interconverted at will, which makes this study unique. The Ag/HSA NCs have been quantified by several spectroscopic techniques, and they find tremendous applications as photoluminescent markers. Besides their rather easy synthetic methodology, our Ag/HSA NCs show two-photon excitation properties that enable them to be used in bioimaging.