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- An, Rong, et al.
(författare)
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Ti–Si–Zr–Zn Nanometallic Glass Substrate with a Tunable Zinc Composition for Surface-Enhanced Raman Scattering of Cytochrome c
- 2023
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 15:21, s. 25275-25284
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Tidskriftsartikel (refereegranskat)abstract
- As a remarkably powerful analytical technique, surface-enhanced Raman scattering (SERS) continues to find applications from molecular biology and chemistry to environmental and food sciences. In search of reliable and affordable SERS substrates, the development has moved from noble metals to other diverse types of structures, e.g., nano-engineered semiconductor materials, but the cost of the enhancement factors (EF) substantially decreasing. In this work, we employ biocompatible thin films of Ti–Si–Zr–Zn nanometallic glasses as the SERS substrates, while tuning the Zn composition. Aided by quartz crystal microbalance, we find that the composition of 4.3% Zn (Ti–Si–Zr–Zn4.3) gives an ultrasensitive detection of Cytochrome c (Cyt c) with an EF of 1.38 × 104, 10-fold higher than the previously reported EF in the semiconducting metal oxide nanomaterials, such as TiO2, and even comparable to the reported noble-metal-assisted semiconducting tungsten oxide hydrate. Ti–Si–Zr–Zn4.3 exhibits a stronger adhesion force toward Cyt c, which ensures the strong binding of Cyt c to the surface, facilitating the Cyt c adsorption onto the surface and thus enhancing the SERS signal. The high separation efficiency of photoinduced electrons and holes in Ti–Si–Zr–Zn4.3 is also acknowledged for promoting the SERS activity.
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- Dong, Yihui, et al.
(författare)
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AFM Study of pH-Dependent Adhesion of Single Protein to TiO2 Surface
- 2019
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Ingår i: Advanced Materials Interfaces. - : John Wiley & Sons. - 2196-7350. ; 6:14
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Tidskriftsartikel (refereegranskat)abstract
- The effect of pH-induced electrostatic conditions on the molecular interaction force of a single lysozyme molecule with TiO2 is investigated using atomic force microscopy (AFM). The force between the charged or neutral lysozyme molecule and the TiO2 surface is measured at different pH from 3.6 to 10.8. It is found to be directly proportional to the contact area, given by an effective diameter of the lysozyme molecule, and is further qualitatively verified by the AFM-measured friction coefficients. The results of the Derjaguin–Landau–Verwey–Overbeek theory show that the pH can change the surface charge densities of both lysozyme and TiO2, but the molecular interaction force at different pH is only dependent on the pH-induced effective diameter of lysozyme. The molecular interaction forces, quantified at the nanoscale, can be directly used to design high-performance liquid chromatography measurements at macroscale by tuning the retention time of a protein under varied pH conditions. They can also be applied to develop a model for predicting and controlling the chromatographic separations of proteins.
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- Dong, Yihui, et al.
(författare)
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Complementary Powerful Techniques for Investigating the Interactions of Proteins with Porous TiO2 and Its Hybrid Materials: A Tutorial Review
- 2022
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Ingår i: Membranes. - : MDPI. - 2077-0375. ; 12:4
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Forskningsöversikt (refereegranskat)abstract
- Understanding the adsorption and interaction between porous materials and protein is of great importance in biomedical and interface sciences. Among the studied porous materials, TiO2 and its hybrid materials, featuring distinct, well-defined pore sizes, structural stability and excellent biocompatibility, are widely used. In this review, the use of four powerful, synergetic and complementary techniques to study protein-TiO2-based porous materials interactions at different scales is summarized, including high-performance liquid chromatography (HPLC), atomic force microscopy (AFM), surface-enhanced Raman scattering (SERS), and Molecular Dynamics (MD) simulations. We expect that this review could be helpful in optimizing the commonly used techniques to characterize the interfacial behavior of protein on porous TiO2 materials in different applications.
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- Dong, Yihui, et al.
(författare)
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Determination of the small amount of proteins interacting with TiO2 nanotubes by AFM-measurement
- 2019
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Ingår i: Biomaterials. - : Elsevier. - 0142-9612 .- 1878-5905. ; 192, s. 368-376
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Tidskriftsartikel (refereegranskat)abstract
- Detecting the small amounts of proteins interacting effectively with the solid film electrodes surface still remains a challenge. To address this, in this work, a new approach was proposed by the combination of the adhesion forces and the molecular interaction measured with AFM. Cytochrome c (Cyt C) interacting effectively with TiO2 nanotube arrays (TNAs) was chosen as a probe. The amounts of Cyt C molecules interacting effectively on TNAs surface (CTNA) range from 5.5×10-12 to 7.0×10-12 mol/cm2 (68.2-86.8 ng/cm2) and they are comparable with the values obtained by the electrochemistry method in the literature, in evidence of the accuracy of this AFM-based approach. The reliability of the proposed approach was further verified by conducting Surface Enhanced Raman Scattering (SERS) measurements and estimating the enhancement factor (EF). This interaction-based AFM approach can be used to accurately obtain the small amounts of adsorbed substances on the solid film electrodes surface in the applications such as biosensors, biocatalysis, and drug delivery, etc.
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- Dong, Yihui, et al.
(författare)
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Excellent Protein Immobilization and Stability on Heterogeneous C–TiO2 Hybrid Nanostructures : A Single Protein AFM Study
- 2020
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 36:31, s. 9323-9332
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Tidskriftsartikel (refereegranskat)abstract
- Enhancing molecular interaction is critical for improving the immobilization and stability of proteins on TiO2 surfaces. In this work, mesoporous TiO2 materials with varied pore geometries were decorated with phenyl phosphoric acid (PPA), followed by a thermal treatment to obtain chemically heterogeneous C–TiO2 samples without changing the geometry and crystalline structure, which can keep the advantages of both carbon and TiO2. The molecular interaction force between the protein and the surfaces was measured using atomic force microscopy by decomposing from the total adhesion forces, showing that the surface chemistry determines the interaction strength and depends on the amount of partial carbon coverage on the TiO2 surface (∼40–80%). Samples with 58.3% carbon coverage provide the strongest molecular interaction force, consistent with the observation from the detected friction force. Surface-enhanced Raman scattering and electrochemical biosensor measurements for these C–TiO2 materials were further conducted to illustrate their practical implications, implying their promising applications such as in protein detection and biosensing.
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- Dong, Yihui, et al.
(författare)
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Excellent Trace Detection of Proteins on TiO2Nanotube Substrates through Novel Topography Optimization
- 2020
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Ingår i: The Journal of Physical Chemistry C. - : American Chemical Society (ACS). - 1932-7447 .- 1932-7455. ; 124:50, s. 27790-27800
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Tidskriftsartikel (refereegranskat)abstract
- For improving the surface-enhanced Raman scattering (SERS) performance of nanomaterials to achieve trace detection of proteins and complex biological systems, structural and topographical control is one of the important strategies. In this work, a facial and effective method to optimize the topography of TiO2 nanotube arrays (TNAs) is demonstrated, together with a significant enhancement of the SERS performance of cytochrome C (Cyt C) on TNAs. An enhancement factor (EF) up to 104, which is obtained with the newly developed method on the basis of the quantification of atomic force microscopy (AFM)-measured interaction force, is achieved, corresponding to a superior detection limit of Cyt C down to 10-7 M. The main reason is that adjusting the fluoride contents in an electrolyte (from 0.4 to 0.1 wt %) can reduce the content and sizes of cracks, as well as the tube ruptures of TNAs, where the fluoride content at 0.2 wt % can successfully provide the excellent and optimized topography of TNAs. The TNAs with the optimized topography, especially those with larger tube diameters, demonstrated the importance of structural integrity on a remarkably excellent SERS performance in the trace detection of proteins. The proposed method will stimulate the development and optimization of the active substrate on the SERS applications in biology, bioanalysis, and nanoscience. © 2020 American Chemical Society.
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- Dong, Yihui, et al.
(författare)
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Hydrated Ionic Liquids Boost the Trace Detection Capacity of Proteins on TiO2 Support
- 2021
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Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 37:16, s. 5012-5021
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Tidskriftsartikel (refereegranskat)abstract
- Trace detection based on surface-enhanced Raman scattering (SERS) has attracted considerable attention, and exploiting efficient strategies to stretch the limit of detection and understanding the mechanisms on molecular level are of utmost importance. In this work, we use ionic liquids (ILs) as trace additives in a protein-TiO2 system, allowing us to obtain an exceptionally low limit of detection down to 10(-9) M. The enhancement factors (EFs) were determined to 2.30 x 10(4), 6.17 x 10(4), and 1.19 x 10(5), for the three systems: one without ILs, one with ILs in solutions, and one with ILs immobilized on the TiO2 substrate, respectively, corresponding to the molecular forces of 1.65, 1.32, and 1.16 nN quantified by the atomic force microscopy. The dissociation and following hydration of ILs, occurring in the SERS system, weakened the molecular forces but instead improved the electron transfer ability of ILs, which is the major contribution for the observed excellent detection. The weaker diffusion of the hydrated IL ions immobilized on the TiO2 substrate did provide a considerably greater EF value, compared to the ILs in the solution. This work clearly demonstrates the importance of the hydration of ions, causing an improved electron transfer ability of ILs and leading to an exceptional SERS performance in the field of trace detection. Our results should stimulate further development to use ILs in SERS and related applications in bioanalysis, medical diagnosis, and environmental science.
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