Gold Nanorod-Based Bio-Barcode Sensor Array for Enzymatic Detection in Biomedical Applications

Abstract

Early diagnosis of disease onset requires sensor systems that detect multiple disease-related processes within the body. However, major obstacles must be surmounted for in vivo sensor use, including size, biocompatibility, sensitivity, and selectivity. As an initial study, here we fabricated a multidimensional gold nanorod (GNR)-based bio-barcode sensing array for sensitive and selective detection of biological events. The sensor comprises an array of gold nanocavities and GNRs that are bound to the array as well as to fluorescein via bio-barcode peptides. Exposure of the sensor to peptide-specific enzymes as inputs led to bio-barcode cleavage, which produced distinct optical-based output, that is, changes in fluorescence lifetime and surface plasmon resonance. The sensor showed sensitivity and selectivity to each biomarker input alone, as well as simultaneous distinguishable responses to their combination. By performing AND, OR, and XOR operations at the sensing system level, the biological events can be simply detected. This GNR-based bio-barcode sensor, incorporating plasmonic and fluorescent-enhancing nanotechnologies, is versatile and adaptable and thus has the potential to enable detection of a wide range of biomarkers to provide complex and advanced detection capabilities that have not been previously possible.

Carbon Dots-Based Logic Gates

“…These molecular logic gates are superior to their semiconductor comparable as they can provide different information available to molecular logic as opposed to voltage information only [ 14 ]. The input can be physical (temperature [ 15 ], pressure [ 16 ], pH [ 17 ], light [ 18 ]), biochemical (enzymes [ 19 , 20 ] nucleotides [ 21 ]), and chemical (atomic [ 12 ], molecular [ 22 ]). For molecular computing, it is essential to design the logic gates using nano regime electronic circuits.…”

Optimization of Gold Nanorod Features for the Enhanced Performance of Plasmonic Nanocavity Arrays

“…The binding of a target analyte to a plasmonic nanocavity array is sensed by spectral variation in the plasmonic resonance observed at either transmission maxima or transmission minima . In particular, gold plasmonic nanocavity arrays of various types have distinct surface plasmon resonance (SPR) and are used for nanoplasmonic biosensing due to their biocompatibility and absorption spectrum in a visible range. , …”

“…Despite the advantages of plasmonic nanocavity arrays over conventional SPR schemes, such as portability and multiplexing capabilities, they generally have a lower bulk sensitivity . The biosensing capabilities of such nanocavity arrays can be improved by enhancing the spectral variations in response to a target molecule binding. , To this end, efforts have focused on varying the thickness as well as the cavity size, structure, and periodicity of the nanocavity array, which affect their transmission spectrum and generate different plasmonic modes. − Another attractive approach for enhancing the spectral variation of nanocavity arrays is by incorporating gold nanorods (GNRs), which have unique optical properties − that enhance spectroscopic processes. ,,, We previously demonstrated that GNRs conjugated to a gold nanocavity array enable biomarker detection for biosensing applications …”

“…9 In particular, gold plasmonic nanocavity arrays of various types have distinct surface plasmon resonance (SPR) and are used for nanoplasmonic biosensing due to their biocompatibility and absorption spectrum in a visible range. 10,11 Despite the advantages of plasmonic nanocavity arrays over conventional SPR schemes, such as portability and multiplexing capabilities, they generally have a lower bulk sensitivity. 12 The biosensing capabilities of such nanocavity arrays can be improved by enhancing the spectral variations in response to a target molecule binding.…”

“…8,10,25,26 We previously demonstrated that GNRs conjugated to a gold nanocavity array enable biomarker detection for biosensing applications. 11 GNRs are straightforward to synthesize and enable simple control over their size and aspect ratio (AR). 10,27,28 GNRs have two plasmonic modes: the transverse mode at ∼520 nm and the longitudinal plasmon mode in the near-infrared (NIR) region.…”