Nanoporous Gold Nanoparticles-Modified Electrode for the Detection of Endotoxins
Abstract
1. Introduction
2. Materials and Methods
2.1. Chemicals
2.2. Synthesis of Nanoporous Gold Nanoparticles (np-AuNPs)
2.3. Scanning Electron Microscopy (SEM) Analysis
2.4. Transmission Electron Microscopy (TEM) Analysis
2.5. Dynamic Light Scattering (DLS) Analysis
2.6. UV-Vis Spectroscopy Analysis
2.7. Modification of Electrode with np-AuNPs
2.8. Modification of Electrode for Biosensing LPS
2.9. Cyclic Voltammetry (CV)
2.10. Electrochemical Impedance Spectroscopy (EIS)
3. Results and Discussion
3.1. Synthesis of np-AuNPs
3.2. SEM/EDS Characterization
3.3. TEM Analysis
3.4. DLS Analysis
3.5. Sizes of np-AuNPs
3.6. Effects of Dealloying Time
3.7. UV-Vis Spectroscopic Analysis and Surface Plasmon Resonance
3.8. Application of np-AuNPs in LPS Biosensing
3.8.1. Proposed Biosensing Platform for LPS Detection
3.8.2. SEM Characterization of Modified Electrode
3.8.3. Electrochemical Characterization of Modified Electrode
Cyclic Voltammetry (CV)
Electrochemical Impedance Spectroscopy (EIS)
3.8.4. Electrochemical Impedance Spectroscopy (EIS) for LPS Detection
Procedure
Calibration Curves for LPS Detection
4. Conclusions
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
Abbreviations
APTES | (3-Aminopropyl)triethoxysilane |
CPE | Constant phase element |
CV | Cyclic voltammetry |
DLS | Dynamic light scattering |
EDC | N-(3-dimethylaminopropyl)-N′-ethylcarbodiimide |
EDS | Energy-dispersive X-ray spectroscopy |
EIS | Electrochemical impedance spectroscopy |
EU | Endotoxin unit |
FCC | Face-centered cubic |
GNB | Gram-negative bacteria |
HAADF | High-angle annular dark field |
ICH | International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use |
ITO | Indium tin oxide |
LOD | Limit of detection |
LOQ | Limit of quantification |
LPS | Lipopolysaccharide |
LSPR | Localized surface plasmon resonance |
NHS | N-hydroxysuccinimide |
NIR | Near infrared |
np-Au | Nanoporous gold |
np-AuNPs | Nanoporous gold nanoparticles |
PEG | Polyethylene glycol |
PVP | Polyvinylpyrrolidone |
SEM | Scanning electron microscopy |
STEM | Scanning transmission electron microscopy |
TEM | Transmission electron microscopy |
References
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np-AuNPs According to Molar Au:Ag (Au% in Alloy Nanoparticles) | Average Size of np-AuNPs (nm ± SD) |
---|---|
7:3 (70% Au) | 89.18 ± 13.31 (pores were not clearly visible) |
np-AuNPs(3:2) (60% Au) | 121.49 ± 9.22 |
np-AuNPs(1:1) (50% Au) | 131.01 ± 11.14 |
np-AuNPs(2:3) (40% Au) | 155.90 ± 15.27 |
np-AuNPs(3:7) (30% Au) | 182.38 ± 13.86 |
np-AuNPs(1:4) (20% Au) | 308.81 ± 25.22 |
np-AuNPs(3:17) (15% Au) | 525.39 ± 71.86 |
1:9 (10% Au) | Ligaments not connected properly to form np-AuNPs |
Time | Elment | Atomic % | Atomic % Error | Weight % | Weight % Error |
---|---|---|---|---|---|
(A) 4 h | Ag | 19.1 | 1.7 | 11.5 | 1.0 |
Au | 80.9 | 0.8 | 88.5 | 0.9 | |
(B) 6 h | Ag | 14.5 | 2.8 | 8.5 | 1.6 |
Au | 85.5 | 1.3 | 91.5 | 1.4 | |
(C) 8 h | Ag | 10.2 | 1.6 | 5.9 | 0.9 |
Au | 89.8 | 0.9 | 94.1 | 1.0 | |
(D) 10 h | Ag | 7.6 | 1.9 | 4.3 | 1.1 |
Au | 92.4 | 1.7 | 95.7 | 1.8 |
Anodic Peak Potential (Ep,a) (V) | Cathodic Peak Potential (Ep,c) (V) | Anodic Peak Current (Ip,a) (mA) | Cathodic Peak Current (Ip,c) (mA) | ∆E = Ep,a − Ep,c | ||
---|---|---|---|---|---|---|
Bare ITO | 0.5422 | −0.1742 | 0.3029 | −0.0337 | 0.7164 | 8.9908 |
np-AuNPs (1:1) | 0.3679 | 0.0209 | 0.6444 | −0.5229 | 0.3470 | 1.2322 |
np-AuNPs (2:3) | 0.3651 | 0.0321 | 0.6616 | −0.5518 | 0.3294 | 1.1990 |
np-AuNPs (3:7) | 0.2944 | 0.1137 | 0.9614 | −0.9329 | 0.1807 | 1.0305 |
np-AuNPs (1:4) | 0.3167 | 0.0849 | 0.9200 | −0.7758 | 0.2319 | 1.1859 |
Analytes on the Electrode Surface | Charge-Transfer Resistance (Rct) (Ω) |
---|---|
Lipid-A LPS Antibody | 176.0 |
BSA and Antibody | 177.5 |
Con-A Only | 208.2 |
1 ng/L LPS | 263.9 |
5 ng/L LPS | 332.6 |
10 ng/L LPS | 420.4 |
50 ng/L LPS | 1112.0 |
100 ng/L LPS | 1574.0 |
500 ng/L LPS | 2261.0 |
1000 ng/L LPS | 3024.3 |
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Lingden, D.; Willis, P.; Bhattarai, J.K.; Stine, K.J. Nanoporous Gold Nanoparticles-Modified Electrode for the Detection of Endotoxins. Micromachines 2025, 16, 1014. https://doi.org/10.3390/mi16091014
Lingden D, Willis P, Bhattarai JK, Stine KJ. Nanoporous Gold Nanoparticles-Modified Electrode for the Detection of Endotoxins. Micromachines. 2025; 16(9):1014. https://doi.org/10.3390/mi16091014
Chicago/Turabian StyleLingden, Dhanbir, Preston Willis, Jay K. Bhattarai, and Keith J. Stine. 2025. "Nanoporous Gold Nanoparticles-Modified Electrode for the Detection of Endotoxins" Micromachines 16, no. 9: 1014. https://doi.org/10.3390/mi16091014
APA StyleLingden, D., Willis, P., Bhattarai, J. K., & Stine, K. J. (2025). Nanoporous Gold Nanoparticles-Modified Electrode for the Detection of Endotoxins. Micromachines, 16(9), 1014. https://doi.org/10.3390/mi16091014