TY - JOUR

T1 - Design and Fabrication of a Silver Nanocluster-Based Aptasensor for Lysozyme Detection

AU - Ardekani, Leila Safaee

AU - Moghadam, Tahereh Tohidi

AU - Thulstrup, Peter Waaben

AU - Ranjbar, Bijan

PY - 2019

Y1 - 2019

N2 - Lysozyme is a universal part of the innate immune system and is present in various bodily fluids. It is also vastly studied as a biomarker for a variety of diseases and is used in the food industry as a preservative. However, due to lack of a universal and precise detection method, new techniques are highly sought after for this purpose. Here, we introduce a silver nanocluster-based aptasensor to detect lysozyme with high sensitivity. The sensor consists of an RNA aptamer and a complementary DNA sequence with a silver nanocluster template. Silver nanoclusters were synthesized by reduction of silver nitrate in the presence of complementary DNA sequence and characterized by transmission electron microscopy, UV-Visible, fluorescence, and circular dichroism spectroscopy. Emission of the silver nanoclusters switched between low and high intensity based on the quenching ability of the aptamer for DNA-silver nanoclusters and the binding affinity of the aptamer for lysozyme. In the presence of the aptamer, DNA-silver nanoclusters show low fluorescence due to the hybridization of the aptamer, and hence disruption in the formation of DNA-silver nanoclusters. Upon addition of lysozyme, aptamer binding to the DNA-templated silver nanoclusters will be inhibited due to the stronger interaction between the aptamer and lysozyme. Presence of the free DNA template leads to a restored fluorescence signal of DNA-silver nanoclusters which is dependent upon the lysozyme concentration. By utilizing this strategy, the complementary DNA-templated silver nanoclusters sensor can detect concentrations of lysozyme lower than 10 nM via a signal in the visible spectral region. The proposed sensor presents valuable features such as low-cost, high sensitivity, easy fabrication, and convenient operation for detection of lysozyme.

AB - Lysozyme is a universal part of the innate immune system and is present in various bodily fluids. It is also vastly studied as a biomarker for a variety of diseases and is used in the food industry as a preservative. However, due to lack of a universal and precise detection method, new techniques are highly sought after for this purpose. Here, we introduce a silver nanocluster-based aptasensor to detect lysozyme with high sensitivity. The sensor consists of an RNA aptamer and a complementary DNA sequence with a silver nanocluster template. Silver nanoclusters were synthesized by reduction of silver nitrate in the presence of complementary DNA sequence and characterized by transmission electron microscopy, UV-Visible, fluorescence, and circular dichroism spectroscopy. Emission of the silver nanoclusters switched between low and high intensity based on the quenching ability of the aptamer for DNA-silver nanoclusters and the binding affinity of the aptamer for lysozyme. In the presence of the aptamer, DNA-silver nanoclusters show low fluorescence due to the hybridization of the aptamer, and hence disruption in the formation of DNA-silver nanoclusters. Upon addition of lysozyme, aptamer binding to the DNA-templated silver nanoclusters will be inhibited due to the stronger interaction between the aptamer and lysozyme. Presence of the free DNA template leads to a restored fluorescence signal of DNA-silver nanoclusters which is dependent upon the lysozyme concentration. By utilizing this strategy, the complementary DNA-templated silver nanoclusters sensor can detect concentrations of lysozyme lower than 10 nM via a signal in the visible spectral region. The proposed sensor presents valuable features such as low-cost, high sensitivity, easy fabrication, and convenient operation for detection of lysozyme.

KW - Aptamer

KW - Biosensor

KW - Lysozyme

KW - Silver nanocluster

U2 - 10.1007/s11468-019-00954-5

DO - 10.1007/s11468-019-00954-5

M3 - Journal article

AN - SCOPUS:85067309771

VL - 14

SP - 1765

EP - 1774

JO - Plasmonics

JF - Plasmonics

SN - 1557-1955

IS - 6

ER -