Significant metal enhanced fluorescence of Ag₂S quantum dots in the second near-infrared window

Gold Nanostar Substrates for Metal-Enhanced Fluorescence through the First and Second Near-Infrared Windows

“…24 In our own work, arrays of Ag or Au nanotriangles with tunable optical features, obtained by nanosphere lithography, allowed fluorescence enhancement of up to two orders of magnitude, in both the NIR, 32 and NIR-II regions. 38 Bottom-up approaches for the fabrication of MEF substrates represent a lower cost alternative, that would allow the Page 3 of 37…”

“…32,38 First, to form monolayers of bBSA on the substrates, 26 µL of a 100 µg/mL bBSA solution in PBS (pH 7.2) were added to their surface, and incubated for 1 h in a humidified chamber. bBSA is known to bind, involving different binding mechanisms, 46 to both glass and Au surfaces, forming a complete monolayer.…”

“…1 Ag 2 S QDs were selected as the NIR-II fluorophore to test because, among the limited number of probes reported to date, these benefit from high biocompatibility and tunability of their emission to discrete wavelengths. 38,75 However, their low fluorescence quantum yield (<10%), limits their exploitation in imaging applications.…”

“…38 The Ag Table 2, were calculated using Equation 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 and silver sulfide quantum dots (Ag 2 S QDs). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 …”

“…38 They were rendered hydrophilic with a carboxylic acid group capping by ligand exchange, and conjugated with streptavidin via carbodiimide cross-linker chemistry.…”