| Over the past few decades,the characteristics and properties of fluorescent metal nanoclusters have attracted a lot of special attentions.The usually contain several to hundreds of atoms and the size of them are equivalent to the Fermi wavelength of the electron.They show significantly different optical,electrical and chemical properties,including strong fluorescence,excellent light resistance,good biocompatibility and so on.These kind of properties make the fluorescent metal nanoclusters an ideal nanomaterial,which have potential applications in bioanalysis,biological imaging,environmental monitoring,industrial catalysis and electronic equipment.In this paper,the fluorescent gold nanoclusters and gold and silver alloy nanoclusters were successfully prepared by using cheap egg white as both the reductant and stabilizing agent,and their multifunctional applications were also studied.The main works were divided into the following three sections:1.An easy,green,and economic route for synthesizing red fluorescence AuNCs@ew was demonstrated in this work via a one-step microwave-assisted method,the AuNCs@ew was obtained according to the optimal conditions(30 min,90 ℃,pH 11 and the volume ratio of 1∶2 for tetrachloroauric acid and diluted egg white).The optical properties of AuNCs@ew were investigated by UV-vis and fluorescence spectroscopy.One can see that there was absorption from 200 nm to 450 nm.Under the 320 nm excitation,the sample generated the maximum fluorescence emission peak at about 650 nm.Then,the morphological characteristics of AuNCs@ew were studied by transmission electron microscopy(TEM)and Malvern particle size analyzer,the TEM image indicates that the AuNCs@ew were spherical and based on DLS results,the average size of the AuNCs@ew is about 4-6 nm.Finally,the structural properties were characterized by FTIR,X-ray photoelectron spectroscopy and X-ray diffraction.2.The prepared gold nanoclusters have strong red fluorescence,so we have developed its versatile applications.It shows good selectivity and sensing toward Cu2+ and Hg2+.Based on the quenching effect of the AuNCs@ew-Hg(II),a design was established to probe “switch-on” sensor for GSH detection with the detection limit being 91.9 nM.In addition,the AuNCs@ew-Hg(II)system was applied to markedly recognize tumor cells in the light of the difference in the level of GSH between tumor and normal cells.It may contribute to the early prevention of cancer.Moreover,the nanomaterials can as well be used for temperature sensing.The AuNCs@ew was used as fluorescent inks,fluorescent dyes,which may exploit the wide-ranging anti-counterfeit applications.3.An easy,green,and economic method for synthesizing strong orange fluorescent bimetallic alloying GSNCs was demonstrated in this work by using a new facile one-pot route via adjusting the molar ratios of Au/Ag precursors in the cheap egg white protein matrix based microwave-assisted method.When the as-prepared alloying GSNCs was employed to probe representative anions,only CN-ions could share a significant quenching in the fluorescence of GSNCs.Herein,the “gold and silver synergies” could endow the GSNCs probes the new ability to specifically enhance the response to CN-ions compared to that of only AuNCs,and the sensor could be used effectively for the detection of CN-in real water samples.These features make the GSNCs a promising candidate as a sensor for CN-.In addition,it demonstrates that GSNCs can act as the biolabeling of cells and temperature sensing as well. |
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