Abstract
Strong surface (metal) enhanced fluorescence (SEF or MEF) is observed from clusters and single E coli bacteria cells labeled with Carbon nanodots (CDs), which were synthesized from date pits. The enhancement factor (EF) for SEF of the cell clusters were close to 50 for both 533 and 633nm laser excitation wavelength. Those EFs are ratios of emission peak areas from CD labeled cell clusters on gold film to the peak areas of the same batch cell clusters on glass substrate. SEF with 633nm excitation performed better than SEF with 532nm excitation, achieving higher fluorescence intensity and much higher contrast. The contrast as high as 66 for cell clusters on gold film is a ratio of fluorescent emission peak area measured at the CD labeled cell clusters to the fluorescent peak area measured at unlabeled cell clusters (autofluorescence) on the same substrate. The contrast with the background (S/N) or the ratio of fluorescent peak area measured at bacteria cells to area measured at bare substrate was as high as 200. This report may pave a way for the broader application of surface enhanced fluorescence and especially metal enhanced fluorescence imaging of CD labeled cells and other biological objects. Graphical abstract Carbon dots, synthesized from dates, are used for direct staining of E coli cells. Emission fluorescent spectroscopy of those CD labelled cells on gold film and glass, demonstrated enhancement factor about 50 for emission on gold as compared to glass, Excitation at 633nm appears far superior to excitation at 532nm in terms of contrast (up to 67) with unlabeled cells /control due to decrease in auto fluorescence of cells. Maximum Signal to noise ratio is 200.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call