Design and investigation of targeting agent orientation and density on nanoparticles for enhancing cellular uptake efficiency

A chemiluminescence immunosensor for biomarker detection based on boronic acid-modified magnetic composite microspheres

High-sensitivity detection of biomarkers in biological samples is crucial for the early diagnosis and treatment of diseases. In this paper, a versatile and flexible immobilization technique based on the specific affinity interaction between boronic acid and cis-diol groups of antibodies was developed for biomarker detection. As a model, the boronic acid-modified immunomagnetic beads were used for facile and quick immobilization of the alpha-fetoprotein (AFP) antibody due to the specific affinity interactions. Based on this new class of immunomagnetic beads, the chemiluminescence immunosensor could efficiently detect the biomarker of AFP. Under optimal conditions, the limit of detection (LOD) is as low as 8 fM (S/N = 3), showcasing superior sensitivity and detection specificity for AFP. Subsequently, the system was successfully applied to the detection of AFP in fetal bovine serum samples, and the average recovery rate is greater than 95%. Its performance surpassed that of commercial immunomagnetic beads, showcasing the potential application of this new strategy for bioanalysis and clinical diagnosis.

Biomineralization-powered integrated immunoprobe and its application in Immunochromatographic assay

Immunochromatographic assay (ICA) has attracted widespread attention owing to its advantages of economy, simplicity, and rapidity. However, the synthesis of immunoprobes is still limited by complicated design ideas and multistep operations from preparing nanoparticles to conjugating monoclonal antibodies (mAb) onto nanoparticles. Inspired by the biomineralization of zeolitic imidazolate framework-8 (ZIF-8), we proposed a strategy for the rapid synthesis of an integrated immunoprobe (ZIF-8@QDs-mAb), achieving a one-step integration with strong fluorescent signal output capability and specific recognition ability. In addition, different fluorescent colors of ZIF-8@QDs-mAb were generated by doping red and green quantum dots (QDs) in various ratios. With a smart detection platform, the developed ZIF-8@QDs-mAb-based multiplex ICA (ZIF-8@QDs-mAb-mICA) achieved the on-site quantitative detection of enrofloxacin, sulfamethazine, and kanamycin in milk within 15 min, with the limit of detection (LOD) of 0.052, 0.186 and 0.216 ng mL-1, which were 5.69, 2.20 and 4.40 times higher than that of gold nanoparticles-based mICA, respectively. The quantitative detection of alpha-fetoprotein and human chorionic gonadotropin was also achieved with LOD of 0.516 ng mL-1 and 0.225 mIU mL-1, respectively, which verified the universality of the strategy. This work provides a novel idea for the design of an efficient integrated immunoprobe and has broad application prospects in ICA.