Impact of secondary salts, temperature, and pH on the colloidal stability of graphene oxide in water

Fluorescence 'turn-on' sensing of glial fibrillary acidic protein using graphene oxide-quenched copper nanoclusters

This study introduces a fluorescence based sensing platform made to detect glial fibrillary acidic protein (GFAP), a critical biomarker associated with glioblastoma and other astrocytic malignancies. Leveraging the unique optical properties of copper nanoclusters (CuNCs) functionalized with GFAP antibodies (GFAP Ab), the platform incorporates graphene oxide (GO) as a fluorescence quencher to create a highly sensitive turn on sensor responsive to GFAP antigens. The detection mechanism relies on Förster resonance energy transfer (FRET), wherein the binding of GFAP antigens disrupts the GFAP Ab@CuNCs-GO interaction, effectively restoring fluorescence. The CuNCs stabilized with l-cysteine to enhance biocompatibility and stability, exhibited strong green fluorescence with a quantum yield of 1.0%. Graphene oxide efficiently quenched the fluorescence of GFAP Ab@CuNCs therefore enhancing the platform's sensitivity. The sensor displayed a linear fluorescence response across a GFAP concentration range 0-46 ng/mL, with a detection limit of 32 pg/mL, demonstrating its capability to detect GFAP at clinically relevant levels. Validation of the sensor in biological fluids, including saliva, serum and urine, confirmed its applicability for minimally invasive diagnostics. Situated at the intersection of biosensing and clinical relevance, this study aims to address the need for cost effective and accessible diagnostic and screening tools for glioblastoma.

Facile Access to High Solid Content Monodispersed Microspheres via Dual-Component Surfactants Regulation toward High-Performance Colloidal Photonic Crystals

Monodispersed microspheres play a major role in optical science and engineering, providing ideal building blocks for structural color materials. However, the method toward high solid content (HSC) monodispersed microspheres has remained a key hurdle. Herein, a facile access to harvest monodispersed microspheres based on the emulsion polymerization mechanism is demonstrated, where anionic and nonionic surfactants are employed to achieve the electrostatic and steric dual-stabilization balance in a synergistic manner. Monodispersed poly(styrene-butyl acrylate-methacrylic acid) colloidal latex with 55 wt% HSC is achieved, which shows an enhanced self-assembly efficiency of 280% compared with the low solid content (10 wt%) latex. In addition, Ag-coated colloidal photonic crystal (Ag@CPC) coating with near-zero refractive index is achieved, presenting the characteristics of metamaterials. And an 11-fold photoluminescence emission enhancement of CdSe@ZnS quantum dots is realized by the Ag@CPC metamaterial coating. Taking advantage of high assembly efficiency, easily large-scale film-forming of the 55 wt% HSC microspheres latex, robust Ag@CPC metamaterial coatings could be easily produced for passive cooling. The coating demonstrates excellent thermal insulation performance with theoretical cooling power of 30.4 W m-2, providing practical significance for scalable CPC architecture coatings in passive cooling.