Figure 2.

(A) Schematic representation of the graphene foam (GF) modified carbon-doped titanium dioxide nanofibers microfluidic immunosensor. Re-used with permission from Ref. [16]. (Copyright 2016 American Chemical Society) (B) Overall representation of the Fe₃O₄@GO work. Re-used with permission from Ref. [17]. (Copyright, 2017 Elsevier, reproduced with permission from Elsevier Ltd.) (C) Scheme of the design of electrochemical Mn₃O₄/Pd@Pt/HRP dual-aptamer biosensor. Re-used with permission from Ref. [18] (Copyright, 2019 Royal society of chemistry, reproduced with permission from Royal society of chemistry Ltd.) and (D) schematic steps involved in the preparation of AuNPs/3DGH sandwich–type aptasensor. Re-used with permission from Ref. [20]. (Copyright, 2021 Elsevier, reproduced with permission from Elsevier Ltd.).