Figure 2.

(A) Schematic of magnetic and fluorescent bio-probes (MFBP) constructing process and sensing principle of MFBP-based quantification of exosomes. Reprinted with permission from Wu M, Chen Z, Xie Q, et al. One-step quantification of salivary exosomes based on combined aptamer recognition and quantum dot signal amplification. Biosens Bioelectron. 2021;171:112733–112742. Copyright 2021 Elsevier B.V.⁹⁵ (B) Schematic of photonic crystals-assisted signal amplification for measurement of tumor-derived exosomes. Reprinted with permission from Zhang J, Zhu Y, Shi J, et al. Sensitive signal amplifying a diagnostic biochip based on a biomimetic periodic nanostructure for detecting cancer exosomes. ACS Appl Mater Interfaces. 2020;12:33473–33482. Copyright 2020 American Chemical Society.⁹⁶ (C) Schematic of the proposed method for exosome detection based on a copper-mediated signal amplification strategy. Reprinted with permission from He F, Wang J, Yin BC, Ye BC. Quantification of exosome based on a copper-mediated signal amplification strategy. Anal Chem. 2018;90:8072–8079. Copyright 2018 American Chemical Society.⁹⁸ (D) Schematic of design and sensing mechanism of ASPNC. (a) Synthetic route of ASP. Reagents and conditions: i) tris(dibenzylideneacetone)dipalladium(0) [Pd₂(dba)₃], tri(p-tolyl)phosphine (TPTP), chlorobenzene, 100°C, 24 h; ii) trimethylamine, tetrahydrofuran (THF), methanol, 24 h. (b) Illustration of the formation of ASPNC and the afterglow detection of exosomes. Reprinted with permission from Lyu Y, Cui D, Huang J, Fan W, Miao Y, Pu K. Near-infrared afterglow semiconducting nano-polycomplexes for the multiplex differentiation of cancer exosomes. Angew Chem Int Ed. 2019;58:4983–4987. Copyright 2019 Wiley-VCH.⁶⁹