Self-assembled nanoporous graphene quantum dot-Mn₃O₄ nanocomposites for surface-enhanced Raman scattering based identification of cancer cells

Abstract

Surface-enhanced Raman scattering (SERS) as an unequivocal surface-sensitive technique has been considered one of the most powerful tools for identifying molecular species. However, the SERS active substrates have mainly been confined to some research on noble metals such as Pd, Au, Ag and Cu. In the present study, we describe the self-assembly of graphene quantum dots (GQDs) with Mn 3 O 4 , and the use of the resulting nanocomposite in the signal enhancement of Raman spectroscopy for nonnoble metal SERS active substrates. GQDs can be used to enhance the Raman signal via an electromagnetic mechanism, but their intrinsic fluorescence overlaps with the Raman signal. Previous studies regarding tuning the energy level and energy gap to change the optical properties of GQDs mainly focused on doping heteroatoms. Assembling Mn 3 O 4 with GQDs in nanocomposites can change the energy level of the material, and quench the fluorescence of the GQDs and adsorbed molecules to improve the Raman signal and noise. The large enhancement factor of 2.06 Â 10 4 , compared to that of graphene and graphene oxide, can be explained using a photon-induced charge transfer resonance model, which means that it not only can be used in small molecule identification but can also be used to discriminate cancer cells and normal cells.

A colorimetric sensing platform based on self-assembled 3D porous CeGONR nanozymes for label-free visual detection of organophosphate pesticides

“…These diffraction peaks can be indexed to the (111), ( 200), ( 220), (311), ( 222), (400), (331), (420), and (422) planes of nanoceria, which are well-matched to the crystal lattice spacings obtained in the HR-TEM image (the 2y value corresponding to the (112) plane obvious in the HR-TEM overlaps with the (111) plane of nanoceria between 25-29 in the XRD pattern). 34,38,39 This observation is concrete evidence of the reaction between the nanoribbons and Ce(III) bound with the O atom containing groups on the GONRs via Ce-O bonds.…”

Research Progress of Biomimetic Self-assembly of Nanomaterials in Morphology and Performance Control

“…与单个金属纳米粒子相比，组装体由于耦合作 用引起电磁场局部增强，形成的拉曼散射强度高达 六个数量级， 具有更高的表面增强拉曼散射 (SERS) [87] ，是强有力的化学和生物传感现象 [88] 。Ma 等 [89] 制备了由金纳米颗粒在环己烷/水界面处自组装形 成的表面增强拉曼平台，用于农药残留量检测。在 环己烷/水双相界面，以亲水性十六烷基三甲基溴化 铵包覆的金纳米棒为自组装基元，形成的二维阵列 能极大地增强 SERS，由此获得的便携式拉曼光谱 仪可以检测人体尿液中极低含量的甲基苯丙胺，为 毒品的快速侦查提供帮助 [90] 。此外还有金纳米粒子 组装胶带，可用于检测鱼表面残留的孔雀石绿 [91] ； 金/银纳米球自组装单分子膜可检测三苯基甲烷染 料 [92] ； 采用银/氧化亚铜自组装纳米复合薄膜制作非 酶电化学 H2O2 传感器 [93] 。 强的 SERS 效应主要集中于 Au [94] 、Ag [95] 和 Cu 等金属 [96][97] ，但这些金属材料成本较高，且稳定性 不理想 [98] ，生物相容性差 [99] ，急需替代 SERS 的材 料 [100] 。 Lan 等 [101] 报道了基于石墨烯量子点和 Mn3O4 的自组装复合材料，具有较好的 SERS 效应。Yi 等 [102] 开发了基于紧密堆积的 SiO2 球形颗粒实现 SERS 的技术，在表面化学、生物学和微电子学等 领域都有潜在的应用。除传统材料外，新型二维层 状材料 MXene [103] 同样可以用于 SERS。Chen 等 [104] 研究了磺胺酸改性 MXene，表明的其潜在 SERS 应 用价值。…”

Advances in surface‐enhanced Raman spectroscopy for cancer diagnosis and staging

“…By identifying specific spectral peaks, discrimination among normal, cancer, and cancer stem cell from breast tissue has been performed using Au nanohexagon‐coated graphene substrates . Moreover, graphene quantum dots (GQDs) has also been incorporated in graphene‐metal composite substrates for detecting cancer cells using label‐free GQD‐Mn 3 O 4 composite substrate . Unlike CM‐based graphene‐enhanced Raman scattering, GQDs exhibits plasmonic property similar to that of noble metals.…”