Exploiting stokes and anti-stokes type emission profiles of aptamer-functionalized luminescent nanoprobes for multiplex sensing applications

WOS: 000434412700016Multiplex biosensing of four types of bacterial food pathogens in one pot is described. Stokes and anti-Stokes type photoluminescence (PL) of two quantum dots (QD) and two upconverting nanoparticles (UCNP) were utilised for realisation of the multiplex detection. The biosensing system was composed of aptamer-functionalized QD and UCNP nanoprobes that were conjugated with partially complementary DNA-modified magnetic beads for separation. PL signals of the conjugates were collected before and after incubation with target pathogens in one pot through the sequential excitations at 335nm for QD probes and 980nm for UCNP probes. The limit of detection values achieved were 28, 15, 12 and 25 cfu center dot mL(-1) for Listeria monocytogenes, Staphylococcus aureus, Salmonella typhimurium and Pseudomonas aeruginosa, respectively. Efforts for extending the multiplex detection up to five pathogens were also presented even though the PL signal cross-talk of a third QD nanoprobe hindered the detection. This work empowers co-deployment of QDs and UCNPs and paves the way for future studies in multiplex sensing, labelling, and bioimaging fields.Scientific and Technological Research Council of Turkey (TUBITAK) [114Z379]; TUBITAK [2215]The authors acknowledge the Scientific and Technological Research Council of Turkey (TUBITAK), Grant ID: 114Z379 for the financial support. B.H. acknowledges TUBITAK 2215 Graduate Scholarship Program. The authors would like to thank PhD candidates, Tug. dem Muslu (Sabanci University) and Kadriye Kahraman (Sabanci University) for maintenance of the bacterial cultures and Assist. Prof. Hayriye Unal (Sabanci University) for providing access to the PMT-integrated fluorescence spectrometer. M.Y. owes special thanks to Assist. Prof. Tolga Sutlu (Sabanci University) for the administrative support