Three-dimensionally assembled gold nanostructures for plasmonic biosensors

Area of Science:

• Nanotechnology
• Materials Science
• Biosensing

Background:

• Plasmonic biosensors are crucial for sensitive biomolecule detection.
• Improving the surface area and accessibility of biosensor chips enhances sensitivity.
• Conventional two-dimensional sensor designs often face limitations in sensitivity and binding capacity.

Purpose of the Study:

• To fabricate a three-dimensional gold nanoarchitecture for enhanced plasmonic biosensing.
• To investigate the performance of the 3D nanoarchitecture compared to traditional 2D designs.
• To demonstrate the improved sensitivity and detection limits for biomolecular binding.

Main Methods:

• Layer-by-layer (LbL) deposition of gold nanoparticles (AuNPs) and functionalized multiwalled carbon nanotubes (MWCNTs) on a glass substrate.
• Functionalization of MWCNTs with thiol groups using 3-mercaptopropyltriethoxysilane (MPTES).
• Fabrication of a self-assembled monolayer (SAM) of AuNPs, followed by sequential dipping into MWCNT-Si-SH and AuNPs to create multilayers.

Main Results:

• The 3D gold nanoarchitecture exhibited a 5.6 times higher bulk refractive index (RI) sensitivity than 2D monolayer chips.
• Detection limits for streptavidin and anti-human serum albumin (HSA) were as low as 0.5 nM and 3.33 nM, respectively.
• The 3D chips demonstrated approximately 20 times higher sensitivity for biomolecular detection compared to 2D chips.

Conclusions:

• The developed 3D gold nanoarchitecture significantly enhances plasmonic biosensor performance.
• The LbL fabrication method provides a large surface area and improved accessibility for target molecules.
• This approach offers a promising platform for highly sensitive and efficient biosensing applications.