期刊
NANOMATERIALS
卷 12, 期 9, 页码 -出版社
MDPI
DOI: 10.3390/nano12091505
关键词
electrolyte-insulator-semiconductor sensor; aptamer; PAMAM dendrimer; saxitoxin; marine toxins
类别
资金
- National Natural Science Foundation of China [51861145307, 32071370, 31700859]
This study presents a label-free EIS sensor for the detection of Saxitoxin (STX), a highly toxic shellfish toxin. The sensor is convenient, desirable, and affordable, and demonstrates high selectivity and stability. It enables rapid and label-free detection of marine toxins.
Saxitoxin (STX) is a highly toxic and widely distributed paralytic shellfish toxin (PSP), posing a serious hazard to the environment and human health. Thus, it is highly required to develop new STX detection approaches that are convenient, desirable, and affordable. This study presented a label-free electrolyte-insulator-semiconductor (EIS) sensor covered with a layer-by-layer developed positively charged Poly (amidoamine) (PAMAM) dendrimer. An aptamer (Apt), which is sensitive to STX was electrostatically immobilized onto the PAMAM dendrimer layer. This results in an Apt that is preferably flat inside a Debye length, resulting in less charge-screening effect and a higher sensor signal. Capacitance-voltage and constant-capacitance measurements were utilized to monitor each step of a sensor surface variation, namely, the immobilization of PAMAM dendrimers, Apt, and STX. Additionally, the surface morphology of PAMAM dendrimer layers was studied by using atomic force microscopy and scanning electron microscopy. Fluorescence microscopy was utilized to confirm that Apt was successfully immobilized on a PAMAM dendrimer-modified EIS sensor. The results presented an aptasensor with a detection range of 0.5-100 nM for STX detection and a limit of detection was 0.09 nM. Additionally, the aptasensor demonstrated high selectivity and 9-day stability. The extraction of mussel tissue indicated that an aptasensor may be applied to the detection of STX in real samples. An aptasensor enables marine toxin detection in a rapid and label-free manner.
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