Qualitative analysis of trace quinolone antibiotics by SERS with fine structure dependent sensitivity

Unveiling Electrostatic Interaction Modulated Sensitive and Selective SERS Detection for Negatively Charged Molecules

Strengthening the interaction between the target and SERS substrate is crucial for sensitive SERS detection; we thereby explored the molecular structure-dependent SERS sensitivity for negatively charged targets on the positively charged SERS substrate. Both experimental and theoretical studies confirm that the SERS sensitivity is determined by the electrostatic interaction between the target and linker. This interaction is not only manipulated by the protonation capacity of the linker and its surface adsorption configuration and geometry but also significantly determined by the target's structure, encompassing electronegativity and the number of interaction sites. The optimized interaction leads to a marked improvement in detection sensitivity of up to 1-3 orders of magnitude. The interaction mechanism revealed in this work not only provides theoretical guidance and technical support for electrostatically driven SERS detection but also offers a conceptual framework that can be extended to various SERS detections based on diverse surface forces.

Au nano-cone array for SERS detection of associated miRNA in lymphoma patients

Based on Au nano-cone array (Au-NCA) and a three-segment hybridization strategy, a novel SERS biosensor is proposed for the ultrasensitive detection of the microRNA miR-21. The uniform, stable, and reproducible Au-NCA was prepared by the single-layer colloidal ball template method. Subsequently, the target was hybridized with sequence 2. The resulting target-sequence 2 complex was then hybridized with sequence 1 anchored on Au-NCA. Thus, a three-segment sequence complex was formed. SERS measurements can be performed without the need for complex purification and amplification steps. Due to the ability of miR-21 to perform specific complementary hybridization with two sequences, SERS biosensors have superior specificity for miR-21 without interference from other miRNAs. Under the optimal conditions, the SERS biosensor was applied and the limit of detection (LOD) was as low as 3.02 aM. This method has been successfully used to the detection of miR-21 in the serum of lymphoma patients and healthy volunteers. The results are consistent with the traditional test methods. Therefore, this novel SERS biosensor shows excellent clinical translational potential in the detection of lymphoma.