Label-Free and Highly Sensitive Detection of Native Proteins by Ag IANPs via Surface-Enhanced Raman Spectroscopy.
Ying BaoYang LiLing LingXiaoxuan XiangXiao-Xia HanBing ZhaoXinhua GuoPublished in: Analytical chemistry (2020)
The use of silver nanoparticles (Ag NPs) as substrates to obtain satisfactory Raman spectra of native proteins is a simple and valuable but challenging process. Herein, the Ag NPs modified with aluminum and iodide ions (Ag IANPs) were introduced for Raman detection of proteins, including acidic BSA (PI 4.7), catalase (PI 5.4), β-casein (PI 4.5), α-casein (PI 4.0), insulin (PI 5.35), basic myoglobin (PI 6.99), and lysozyme (PI 11.2). The Raman signals of all the detected proteins were significantly improved in comparison with the reported spectra obtained by using Ag NPs containing Na2SO4, I-, and Mg2+. Specifically, detection sensitivities of the acidic proteins were drastically increased. The limit of detection (LOD) of bovine serum albumin (BSA), α-casein, and β-casein was 0.03 ng/mL. The LOD of insulin and catalase were 0.3 and 3 ng/mL, respectively. As the bands corresponding to disulfide bonds, α-helices, residues of Phe, Trp, and Tyr, and carboxyl groups were also greatly enhanced, it was easy to monitor the folding of native protein and the denaturation of protein under acidic and heated conditions. Thus, Ag IANPs as substrates open a way for surface-enhanced Raman spectroscopy (SERS) detection of proteins. Hence, the method can provide more valuable information about protein and, therefore, has the potential for wide applications.
Keyphrases
- label free
- raman spectroscopy
- quantum dots
- type diabetes
- loop mediated isothermal amplification
- real time pcr
- silver nanoparticles
- highly efficient
- sensitive detection
- ionic liquid
- amino acid
- protein protein
- metabolic syndrome
- gold nanoparticles
- mass spectrometry
- climate change
- skeletal muscle
- small molecule
- weight loss
- binding protein
- density functional theory