Superior Sensitivity of Copper-Based Plasmonic Biosensors

Area of Science:

• Materials Science
• Nanotechnology
• Biosensing

Background:

• Plasmonic biosensors, typically using gold or silver, are powerful for molecular analysis but limited by industrial production incompatibility.
• Noble metal-based biosensors face challenges in scalability and cost-effectiveness for widespread industrial applications.

Purpose of the Study:

• To develop and investigate copper-based biosensor chips compatible with standard complementary metal-oxide-semiconductor (CMOS) fabrication processes.
• To enhance the sensitivity and stability of plasmonic biosensors through novel dielectric coatings on copper films.

Main Methods:

• Fabrication of copper biosensor chips using a standard CMOS process.
• Protection of copper films against oxidation using deposited SiO2 and Al2O3 dielectric layers.
• Surface Plasmon Resonance (SPR) measurements to evaluate sensitivity to refractive index changes and biomolecule immobilization using graphene oxide.

Main Results:

• Copper biosensor chips coated with SiO2 (25 nm) and Al2O3 (15 nm) exhibited 55% and 75% higher sensitivity, respectively, compared to gold sensor chips.
• Dielectric film deposition improved electromagnetic field localization, enhancing biosensing sensitivity.
• Successful selective analysis of oligonucleotide hybridization demonstrated the functionalization capability of copper-dielectric biosensor chips.

Conclusions:

• Copper-based plasmonic biosensors fabricated with CMOS technology offer a scalable and affordable alternative to traditional noble metal sensors.
• The developed dielectric coating strategy enhances sensitivity and protects the copper surface, enabling robust biosensing.
• These findings provide a foundation for integrating advanced plasmonic biosensing capabilities into compact electronic devices for diverse applications.