Zhiyuan Sun,Gege Zhao,Ming Guan,Huixian Li,Fang Mi,Xiaobo Ma,Yajun Zhao,Han Song
In this work, boric acid affinity magnetic materials and Au nanorods capped by Ag (AuNRs@Ag) core-shell structure were used to construct the sandwich structure to obtain surface-enhanced Raman scattering (SERS) sensor for detecting glucose. The AuNRs@Ag modified with 4-mercaptophenylboronic acid (4-MPBA) as SERS substrate, illustrating the efficient electromagnetic enhancement. Moreover, the boric acid affinity magnetic materials (FMNPs) were further functionalized with knife bean lectin as “capture probe”, which illustrated the high adsorption capacity to glucose. The maximum adsorption amount can reach 33.3 mg/g. The conditions for preparing SERS platform as well as glucose detection were optimized. Under the optimal experimental conditions, the detection linear range for glucose is 1.0×10-11 ~ 1.0×10-3 mol/L with a limit of detection (LOD) 1.8×10-12 mol/L (S/N = 3). In addition, the developed SERS sensor was further applied for determination of glucose in human urine with recoveries in the range from 97.5% to 101.5%. As expected, the prepared sandwich SERS sensor was successfully employed to recognize and detect glucose with high sensitivity.
Jingying Yang,Mingfei Pan,Kaixin Liu,Xiaoqian Xie,Shan Wang,Liping Hong,Shuo Wang
A core-shell AuNRs@Ag-enhanced and magnetic separation-assisted surface-enhanced Raman spectroscopy (SERS) immunosensing platform was developed for rapid, accurate and sensitive detection of amantadine (AMD) contaminant in animal-derived foods. This SERS immunosensing platform works in a competitive strategy, which used the 4-mercaptobenzoic acid (4-MBA) labeled AuNRs@Ag with AMD-BSA immobilized as a signal probe and magnetic beads (MBs) with mAbs covalently attached to the surface as a capture probe. It was found that the synthesized core-shell AuNRs@Ag could significantly enhance the SERS signal of the reporter 4-MBA ( EF : 2.91 × 10 7 ), and the coating of Ag shell effectively avoided the shedding of 4-MBA, thereby improving the sensitivity and stability of SERS analysis. The use of MBs not only overcomes the shortcoming of mAbs inactivation, but also simplifies the detection procedure, improving the detection efficiency. This SERS immunosensing platform was demonstrated to have a linear response in a wide AMD concentration range of 0.01–50 μg/L with high sensitivity (limit of detection (LOD): 0.0038 μg/L) and specificity. For actual animal-derived foods (chicken, milk, egg), acceptable recoveries of AMD (82.0–106.0%) at three spiked levels (0.5, 5, 50 μg/kg) were obtained with relative standard deviation (RSD, n = 5) ranging from 4.7% to 9.6%. The whole detection procedure can be completed within 30 min. These results demonstrated that the proposed SERS immunosensing platform was reliable and sensitive in the quantitative analysis of AMD and could be applied as an effective tool for rapid screening for AMD-contaminated foods.
Photothermal therapy (PTT) has presented its inherent application value in cancer treatment. Nevertheless, single-functional photothermal materials cannot meet the precise diagnosis and treatment of cancer. Therefore, it is important to design a nanocomposite that has both high therapeutic efficiency and multimodal imaging capabilities. In our work, a new nanostructure of gold nanorods (AuNRs) with silver shells decorated by BaGdF 5 :Yb 3+ ,Er 3+ nanoparticle was synthesized by a simple way. The biostability of AuNRs is increased by coating with silver shells, and the AuNR@Ag nanoparticles can be used as excellent surface enhanced Raman scattering (SERS) probe. Moreover, the modification of BaGdF 5 :Yb 3+ ,Er 3+ nanoparticles provides the possibility of real-time optical imaging of the tumor area. Under the irradiation of NIR laser, the AuNR@Ag/BaGdF 5 :Yb 3+ ,Er 3+ nanocomposites (NCs) have strong upconversion emission and excellent photothermal conversion efficiency. Meanwhile, the NCs show low cytotoxicity and good biocompatibility in MTT cytotoxicity test. Moreover, the NCs are also exceptional contrast agents for CT imaging. For in vitro photothermal therapy test, NCs show excellent killing efficiency on tumor cells. Therefore, the multifaceted research of AuNR@Ag/BaGdF 5 :Yb 3+ ,Er 3+ multifunctional nanomaterials provides a break for high-efficiency tumor photothermal therapy and multimodal imaging.
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