N-(4-Aminobutyl)-N-ethylisopropanol and Co²⁺ Dual-Functionalized Core–Shell Fe₃O₄@Au/Ag Magnetic Nanomaterials with Strong and Stable Chemiluminescence for a Label-Free Exosome Immunosensor

Abstract

Recently, magnetic beads (MBs) are moving toward chemiluminescence (CL) functional magnetic nanomaterials with a great potential for constructing label-free immunosensors. However, most of the CL-functionalized MBs suffer from scarce binding sites, easy aggregation, and leakage of CL reagents, which will ultimately affect the analytical performance of immunosensors. Herein, by using core–shell Fe3O4@Au/Ag magnetic nanomaterials as a nanoplatform, a novel N-(4-aminobutyl)-N-ethylisopropanol (ABEI) and Co2+ dual-functionalized magnetic nanomaterial, namely, Fe3O4@Au/Ag/ABEI/Co2+, with strong and stable CL emission was successfully synthesized. Its CL intensity was 36 and 3.5 times higher than that of MB@ABEI-Au/Co2+ and ABEI and Co2+ dual-functionalized chemiluminescent MBs previously reported by our group, respectively. It was found that the excellent CL performance of Fe3O4@Au/Ag/ABEI/Co2+ could be attributed to the enrichment effect of the Au/Ag shell and the synergistic enhance effect of the Au/Ag shell and Co2+. A related CL mechanism has been proposed. Afterward, based on the intense and stable CL emission of Fe3O4@Au/Ag/ABEI/Co2+, a sensitive and effective label-free CL immunosensor for exosome detection was established. It exhibited excellent analytical performance with a wide detection range of 3.1 × 103 to 3.1 × 108 particles/mL and a low detection limit of 2.1 × 103 particles/mL, which were better than the vast majority of the reported CL immunosensors. Moreover, the proposed label-free CL immunosensor was successfully used to detect exosomes in human serum samples and enabled us to distinguish healthy persons and lung cancer patients. It has the potential to be a powerful tool for exosome study and early cancer diagnosis.

Ultrasensitive PD-L1-Expressing Exosome Immunosensors Based on a Chemiluminescent Nickel–Cobalt Hydroxide Nanoflower for Diagnosis and Classification of Lung Adenocarcinoma

“…As shown in Figure A, the green curve showed that NiCo-DH-AA exhibited a significant CL emission. Compared to the ABEI and Co 2+ -functionalized nanomaterials previously reported by our group, the CL intensity of NiCo-DH-AA was 130 times higher than that of MB@ABEI-Au/Co 2+ (MAA/Co 2+ ) (black curve), 19 times higher than that of dfCL-MB(red curve), and 3 times higher than that of Fe 3 O 4 @Au/Ag/ABEI/Co 2+ (blue curve) . To clarify the origin of the superior CL emission of NiCo-DH-AA, a series of control experiments were carried out.…”

“…CL-functionalized nanomaterials with good biocompatibility and high CL emission have been widely used as analytical nanoprobes. To date, various types of CL-functionalized nanomaterials have been synthesized, including metal nanoparticles, metal nanoclusters, carbon nanomaterials, metal–organic frameworks, magnetic nanomaterials, and hydrogels. − Depending on whether these nanomaterials can catalyze the CL reaction or not, these CL-functionalized nanomaterials can be classified into two categories. The first category of CL-functionalized nanomaterials is using nanomaterials without CL catalytic activity as carriers, such as polydopamine, Fe 3 O 4 magnetic beads, silicon dioxide, and covalent organic frameworks .…”

“…To date, various types of CL-functionalized nanomaterials have been synthesized, including metal nanoparticles, metal nanoclusters, carbon nanomaterials, metal–organic frameworks, magnetic nanomaterials, and hydrogels. − Depending on whether these nanomaterials can catalyze the CL reaction or not, these CL-functionalized nanomaterials can be classified into two categories. The first category of CL-functionalized nanomaterials is using nanomaterials without CL catalytic activity as carriers, such as polydopamine, Fe 3 O 4 magnetic beads, silicon dioxide, and covalent organic frameworks . They usually require further modification of the catalyst on their surface to achieve higher CL intensity, but this may not only affect the stability of the CL-functionalized nanomaterial but also affect the construction of the immunosensor due to the highly occupied surface binding sites.…”

Importance of DNA nanotechnology for DNA methyltransferases in biosensing assays

“…Various analytical methods have been developed to overcome these limitations, including fluorescence, 23–25 electrochemical, 26,27 surface-enhanced Raman spectroscopy (SERS), 28,29 electrochemiluminescence, 30–32 chemiluminescence, 33 photoelectrochemical biosensing assays (PEC), 34,35 and colorimetric assays. 36,37 These methods not only enhance the sensitivity of DNMT detection, are easy to operate, and are low cost, but also provide certain advantages in the detection of other molecular biomarkers in the biological field, such as exosomes, 38–40 nucleic acids, 41–43 proteins, 44,45 antibodies, 46,47 cells, 48,49 enzymes, 50,51 and other important biological target assays.…”