Aluminum foil as a substrate for metal enhanced fluorescence of bacteria labelled with quantum dots, shows very large enhancement and high contrast

Review: Applications of surface-enhanced fluorescence (SEF) spectroscopy in bio-detection and biosensing

“…The next trend arises from analyte nature, and demonstrates that the increase in complexity of analytes requires more complicated substrates and procedures. This can be traced from the simple metal films and nanoparticles used for small organic molecules and proteins [ 18 , 22 , 34 , 39 , 58 , 60 ] to the complicated plasmonic chips, platforms, nanostructures, and quantum dots used for DNA sensing and detection of antibodies, toxins, and bacteria [ 77 , 82 , 94 , 97 , 99 , 101 ]. Furthermore, the last trend, arising from the differences between substrates and their increasing level of sophistication, states the following: the increase in the complexity of the substrate leads to better sensitivity and consequently, a lower limit of detection.…”

“…Despite this, the applicability of both metals is limited due to the contamination by S-containing and C-containing compounds [ 104 , 105 ]. This disadvantage opens an opportunity for the development of non-noble nanostructures, like Al and Si, which are more robust and cost-efficient [ 101 , 106 ]. One such fresh example is shown by our research group, in which we applied organic carbon dots for bacteria labeling on Al foil and Al film substrates [ 107 ].…”

“… Authors et al Analytes Concentration range LODs Substrate and exc. λ Other analytical parameters Anatoliy I. Dragan [ 95 ] anthrax toxin (protective antigen) 0,01 pg/ml - 10 ng/ml 0,1 pg/ml SIFs, 473 nm LLoQ - 1 pg/ml, 40 min TTD, EF 200–400 Yun Li [ 96 ] microcystin-LR 0.02–16 ng/mL 7 pg/ml Au nano-crosses, 646 nm Rsq = 0.9981, EF 2.3–35 Francesco Todescato [ 97 ] Ochratoxin A (OTA) NA LOQ 3.6 pg/g Ag–FON, 647 nm EFs of 0.9 ± 1 × 10 4 14 ± 6 × 10 4 , I. Abdulhalim [ 98 ] E. coli (TV1061) 3.6 × 10 8 cfu/ml NA STFs made of Ag, Al, Au, Cu, 546 nm EFs > 15 Chun-Jen Huang [ 99 ] E. coli O157:H7 10–10^6 cfu/ml 10 cfu/ml Plasmonic chip, 633 nm 40 min TTD, Rsq = 0.993 Syed Rahin Ahmed [ 22 ] Influenza A virus targeting hemagglutinin (HA) 50–10,000 PFU/mL 50 PFU/mL QDs and NPGL, 380 nm EF – 2-9 Rostislav Bukasov [ 100 ] E. coli (DH5α) NA NA CDs made from date pits on Au film, 633 nm and 532 nm S/N – 200, contrast – 66, EF - 50 Alisher Sultangaziyev [ 101 ] E. coli (DH5α) NA NA CdSeS/ZnS and CdTe alloyed QDs, 633 nm and 532 nm EF – 450-480, contrast 360 Rostislav Bukasov [ 107 ] E. coli (DH5α) NA NA CDs made from date pits on Al foil and Al film EF -35 contrast up to 200 …”

“…Moreover, it was found that the excitation wavelength has a considerable effect on the fluorescence signal, with 633 nm excitation wavelength producing higher contrast than 532 nm laser. Next, we performed another experiment on the detection of E. coli (DH5α) bacteria, in which we used CdSe/ZnS alloyed quantum dots and CdTe core-type QDs on Al foil, Au film, Al film, silver and glass substrates [ 101 ]. Here, a significant increase in both signal enhancement and contrast was achieved, with values up to 450–480 and 360, respectively.…”

Portable Plasmonic Paper-Based Biosensor for Simple and Rapid Indirect Detection of CEACAM5 Biomarker via Metal-Enhanced Fluorescence

“…While organic dyes are mostly used in conventional MEF biosensors as traditional signal transducers, they quench quickly and possess a very narrow Stokes shift. On the other hand, semiconductor inorganic particles, such as quantum dots (QD), represent a better candidate in practical biological applications, such as multiplexed labelling or biological immunoassays, due to their sensing capacity, high quantum yield, great photostability, larger emission–absorption spectra, and improved fluorescent properties [ 20 , 21 , 22 , 23 ]. Several studies have shown the use of QD as fluorescent labels in combination with nanohole arrays for substrate-enhanced luminescence in the detection of relevant biomarkers and diagnosis [ 24 , 25 ].…”