Aptamer- and Fab’- Functionalized Microring Resonators for Aflatoxin M1 Detection

Label-Free and Redox Markers-Based Electrochemical Aptasensors for Aflatoxin M1 Detection

“…Thus, the sensitivity of AFM1 detection by both aptamers does not differ significantly and is close to the values obtained based on the label-free aptasensor presented above using APT1 and the EIS method of detection. We should also mention that the sensitivity of Fc-based detection by APT3 is much higher in comparison with optical detection as reported in [20].…”

“…It can be seen that the sensitivity of aptasensors is comparable with that of immunosensors. The only exception is work by Chalyan et al [20] in which an immunosensor based on an AFM1-selective Fab’ fragment revealed higher sensitivity in comparison with those based on aptamers analyzed by the micro-ring resonator method. However, the LOD of this immunosensor (1641 ng/L) is not sufficient for practical applications.…”

“…Following aptamers were used in experiments: 21-mer DNA aptamer of following sequence: 5′-ACT GCT AGA GAT TTT CCA CAT-3′ (APT1) described by Nguyen et al [25] and modified at the 5′ end by an amino group or by biotin at the 5′ end, but containing a dT 15 spacer: 5′-TTT TTT TTT TTT TTT ACT GCT AGA GAT TTT CCA CAT-3′ (APT2) and 50-mer DNA aptamer modified by biotin at the 5′ end: 5′-GTT GGG CAC GTG TTG TCT CTC TGT GTC TCG TGC CCT TCG CTA GGC CCA CA-3′ (APT3) [20,33] that is characterized by high specificity to AFM1 (dissociation constant K d = 10 nM). Aptamers were purchased from Eurogentec (Seraing, Belgium).…”

“…Later, an electrochemical immunosensor with capture antibodies immobilized on the Au screen-printed electrode and signaling antibodies conjugated with alkaline phosphatase was tested in spiked milk samples with a LOD of 37 ng/L [19]. Chalyan et al developed a sensing device that consisted of four silicon oxynitride (SiON) micro-ring resonators that detected AFM1 with off-chip silicon photodetectors onto which either DNA aptamers or antigen binding fragments (Fab’) were immobilized [20]. The most reproducible signal was obtained for sensors based on a Fab’-functionalized surface with a LOD of 5 nM (1641 ng/L).…”

Aptamer-Based Biosensor for Detection of Mycotoxins

“…The binding of AFM1 on the functionalized microring surface led to the effective refractive index change, and a resonance shift in the MRR transmission was then detected using off-chip silicon photodetectors. In addition, this approach was demonstrated for AFM1 determination specifically with a detection limit of 5 nM (Chalyan et al, 2017). Recently, a new aptamer specific to AFM1 was selected by a traditional SELEX technique with the dissociation constant of 35 nM (Malhotra et al, 2014).…”