Paper Biosensor for the Detection of NT-proBNP Using Silver Nanodisks as Electrochemical Labels

Abstract

We report on the use of silver nanodisks (AgNDs), having a diameter of 50 ± 8 nm and a thickness of 8 ± 2 nm, as electrochemical labels for the detection of a model metalloimmunoassay for the heart failure biomarker NT-proBNP. The detection method is based on an electrochemically activated galvanic exchange (GE) followed by the detection of Ag using anodic stripping voltammetry (ASV). The AgNDs labels are superior to Ag nanocubes and Ag nanospheres in terms of the dynamic range for both the model and NT-proBNP metalloimmunoassays. The linear dynamic range for the model composite is 1.5 to 30.0 pM AgNDs. When AgND labels are used for the NT-proBNP assay, the dynamic range is 0.03–4.0 nM NT-proBNP. The latter range fully overlaps the risk stratification range for heart failure from 53 pM to 590 pM. The performance improvement of the AgNDs is a result of the specific GE mechanism for nanodisks. Specifically, GE is complete across the face of the AgNDs, leaving behind an incompletely exchanged ring structure composed of both Ag and Au.

Advanced Nanomaterial-Based Biosensors for N-Terminal Pro-Brain Natriuretic Peptide Biomarker Detection: Progress and Future Challenges in Cardiovascular Disease Diagnostics

“…By enabling the analysis and interpretation of NT-ProBNP levels through user-friendly mobile applications, these advancements are making cardiovascular monitoring more accessible outside traditional clinical settings. Additionally, the application of artificial intelligence and machine learning algorithms in interpreting biosensor data is enhancing the predictive accuracy of NT-ProBNP measurements, offering potential for personalized treatment regimens and improved patient outcomes in cardiovascular care [ 17 , 54 , 55 ]. A comparative analysis of various nanomaterial-based biosensors for NT-ProBNP detection is given in Table 1 .…”

Silver nanoparticles in electrochemical immunosensing and the emergence of silver–gold galvanic exchange detection

“…Then, the group developed several immunosensors, where a GE/ASV electrochemical method was utilized to detect different shapes of AgNP labels. 104,[115][116][117][118][119][120][121][122] It was demonstrated that the shape of the AgNP played a crucial role in determining the detection efficiency of metalloimmunoassay based on GE/ASV process. Specifically, it was shown that the LOD and analyte detection range could be tuned by simply altering the shape of the silver nanoparticle.…”

“…8). 119 AgNDs were employed because they have a large surface area and contain minimal interior Ag atoms that can be shielded by Au skin. This leads to higher GE efficiency and better assay performance.…”

“…After optimizing the AgND labels, the final sensor configuration detected NT-proBNP in human serum samples. 119 The final result of the AgND-based immunosensors is reported in Fig. 9.…”

Ultrasensitive and Rapid Detection of N-Terminal Pro-B-Type Natriuretic Peptide (NT-proBNP) Using Fiber Optic Nanogold-Linked Immunosorbent Assay

“…Thus far, a number of analytical methods in the literature have been reported for the analysis of NT-proBNP, including radioimmunoassay (RIA) [ 11 ], colorimetry [ 12 ], fluorescent bead-based immunoassay [ 13 ], chemiluminescent immunoassay [ 14 ], dynamic light scattering [ 15 , 16 ], surface-enhanced Raman scattering [ 17 ], amperometric immunosensors based on enzyme label [ 18 ], silver nanoparticle label method [ 19 ], silver nanodisk label method [ 20 ], photoelectrochemical immunosensor method [ 21 ], electrochemiluminescent (ECL) immunosensor method [ 22 ], field-effect transistor biosensor method [ 23 ], giant magnetoresistance assay [ 24 ], and fluorescence-based lateral flow immunoassay [ 25 ]. While very sensitive electrochemical biosensors for the detection of NT-proBNP have been reported [ 18 , 19 , 20 , 21 , 22 , 23 ], the requirement of a reference electrode in electrochemical biosensors may be a weak point, as liquid junction error often exists in practical situations [ 26 ]. Optical sensors do not require a so-called reference optrode, and also have the advantages of immunity to electromagnetic interference.…”