Subject Number             :S-20-NI-0024

Support Type                : Collaborative research

Proposal Title (English)      : Fabrication of Au nanoneedles

Username (English)         : Yong Yang¹⁾, Masaki Tanemura²⁾

Affiliation (English)             :1) Shanghai Institute of Ceramics, Chinese Academy of Science,

2) Nagoya Institute of Technology (NITech)

1. Summary

The current COVID-19 pandemic urges the extremely sensitive and prompt detection of SARS-CoV-2 virus.  Here, we demonstrated a Human Angiotensin-converting-enzyme 2 (ACE2)- functionalized gold “virus traps” nanostructure as an extremely sensitive SERS (surface enhanced Raman scattering) biosensor, to selectively capture and rapidly detect S-protein expressed coronavirus, such as the current SARS-CoV-2 in the contaminated water, down to the single-virus level.

2. Experimental

The gold nanoneedles array (GNA) were fabricated by an ion-beam sputtering technique to sputter a gold film using a carbon nanofiber (CNF) synthesis system (CSS) [1].  The morphology of the samples thus prepared were observed by a scanning electron microscope (SEM).  CSS and SEM were provided by Nanotechnology platform of NITech.  As-prepared ACE2-functionalized GNAs were immersed in different SARS-CoV-2 (inactivated) in phosphate-buffered saline (PBS)  solution or urine solution for different times, and taken out for washing by PBS-solution and drying.  Then, the SERS measurements were performed.

3. Results and Discussion

Figure 1(a) shows the SEM image of GNAs. The diameter of the nanoneedles in the stem part is around 300 nm, and the density of nanoneedles is approximately 9 μm⁻².  The tips of the nanoneedles exhibit an extremely sharp curvature with an apex diameter of 15 nm.  SARS-CoV-2 virus are covered by S protein (spike glycoprotein) which generates detectable characteristic Raman signals as shown in Fig. 1(b, c).  Combined with machine-learning and identification techniques, single-virus diagnose can be realized in less than 5 min, and lowest detection limit can be down to 80 copies mL⁻¹.

Fig. 1 (a) Typical SEM image of Au-nanoneedles array, (b) schematic drawing of SARS-CoV-2, and (c) SERS spectra of SARS-CoV-2 S protein and nucleocapsid protein, SARS-CoV S protein, and Human ACE2 protein at 100 nM level.

4. Others

[1] Yong Yang, Masaki Tanemura, et al., Nanoscale 6, No. 8 (2012) 2663-2669.

5. Publication/Presentation

(1) Yusi Peng, Yong Yang. et al., “Charge-Transfer Resonance and Electromagnetic Enhancement Synergistically Enabling MXenes with Excellent SERS Sensitivity for SARS-CoV-2 S Protein Detection,” Nano-Micro Lett. 13 (2021) 52-1-17.

(2) Yong Yang, Masaki Tanemura, et al., “Human ACE2‑Functionalized Gold “Virus‑Trap” Nanostructures for Accurate Capture of SARS‑CoV‑2 and Single‑Virus SERS Detection,” Nano-Micro Lett. 13 (2021) 109-1-13.

6. Patent

N/A