Gold nanotriangles : from atoms to LSPR-based sensing

The presented work guides through a thorny path from gold atoms to nanocrystals in triangular shape and their application as optical transducers in LSPR-based sensing. Gold nanotriangles possess unique physicochemical and optical properties offering a powerful platform for precise and sensitive analyte detection. However, their true potential can be fully realized only through meticulous optimization and understanding of the synthesis techniques for achieving high purity and quality in a productive, preferably automated, and sustainable manner. Starting with the optimization of colloidal synthesis by investigating its critical parameters and employing a microfluidic system, this study develops a highly efficient procedure to manufacture gold nanotriangles of high quality. Next, the surface of manufactured material is functionalized following a rational and versatile strategy, which offers flexibility in adapting it to a wide variety of samples. The performed ligand exchange enables determining the bulk refractive index sensitivity of gold nanotriangles and proves their potential for LSPR-based sensing. Finally, the surface of gold nanospheres is utilized by LSPR-based sensing to investigate the adsorption of proteins in a comparative study with fluorescence spectroscopy, as a well-established method in this field. Comparing both techniques validates the applicability and accuracy of LSPR-based sensing for e.g. nanotoxicological studies. The shown technique is less prone to optical interferences and is more cost-effective, which is expected to promote its wider acceptance in the field of nanomedicine and nanosafety. In conclusion, the future incorporation of novel nanomaterials into the realm of LSPR-based sensing holds tremendous promise for expanding the horizons of molecular detection and biosensing using compact bioanalytical devices in the diversity of applications from point-of-care medical diagnostics to on-site environmental monitoring and beyond.