Tip-enhanced Raman scattering of glucose molecules

Glucose molecules are of great significance being one of the most important molecules in metabolic chain. However, due to the small Raman scattering cross-section and weak/non-adsorption on bare metals, accurately obtaining their "fingerprint information" remains a huge obstacle. Herein, we developed a tip-enhanced Raman scattering (TERS) technique to address this challenge. Adopting an optical fiber radial vector mode internally illuminates the plasmonic fiber tip to effectively suppress the background noise while generating a strong electric-field enhanced tip hotspot. Furthermore, the tip hotspot approaching the glucose molecules was manipulated via the shear-force feedback to provide more freedom for selecting substrates. Consequently, our TERS technique achieves the visualization of all Raman modes of glucose molecules within spectral window of 400–3200 cm−1, which is not achievable through the far-field/surface-enhanced Raman, or the existing TERS techniques. Our TERS technique offers a powerful tool for accurately identifying Raman scattering of molecules, paving the way for biomolecular analysis.