Chemical-Driven Assembly Synthesis of Self-Stabilizing Massage Ball-Type QD Microspheres for High-Performance...

It remains a formidable challenge to fabricate highly stable quantum dot (QD) microspheres for the field of high-sensitivity quantitative detection, in that the enhancement of fluorescent material stability in current fabrication techniques inevitably entails sophisticated operational processes and severe fluorescence attenuation. In this paper, the self-stabilizing QD microspheres were fabricated by loading silicon-coated QDs onto silica sphere substrates through the chemical bond-driven assembly method and used as the highly luminescent label of the fluorescence sensor system to ensure the high-sensitivity and selectivity for the detection of dopamine (DA). The developed simple chemical bond-driven method enabled the combination of numerous silica-coated QDs anchored by functional groups with SiO₂ substrates, forming QD microspheres with a massage-ball type structure. This method not only significantly reduced the coating treatment required to improve stability but also allowed for the acquisition of microspheres with different surface groups by altering chemical bond-driven methods, thereby enriching the application scenarios of the microspheres. The massage ball-type microspheres possessed excellent stability and superior fluorescence signal as well as a larger surface area that facilitated the adsorption of target molecules, which were constructed into fluorescent sensors for the detection of DA. The fluorescence quenching of massage-ball type microspheres had good linearity (R² = 0.994 and 0.995), with the concentration of dopamine ranging from 0.013 to 2.611 μM and 1 to 1024 μM, and the limit of detection was 5.36 nM, enabling the determination of dopamine at varying levels. The fluorescent sensor with high sensitivity and selectivity was successfully applied to the detection of DA in real serum and urine with recovery rates of 93.18% to 104.74%. This microsphere construction technology provided a new way for improving the properties of QDs in disease diagnosis and treatment.