Label-Free Colorimetric Protein Assay and Logic Gates Design Based on the Self-assembly of Hemin-Graphene Hybrid Nanosheet

Abstract

Here we report a label-free colorimetric method for protein assay based on the intrinsic peroxidase-like catalytic activity of DNA-hemin-graphene (DNA-GH) composite. By using aptamers as protein recognition elements, protein-mediated aggregation of the DNA-GH composite leads to the decrease or increase of the colorimetric signal depending on the sandwich or competitive design strategy. Thrombin and PDGF-BB were chosen as model analytes and the detection limits (LOD) by this method were estimated to be 0.5 nM and 5 nM, respectively. Compared to traditional ELISA method for protein detection, this method possesses the advantages of high sensitivity, simplicity, and low cost. In addition, by designing different DNA-modified hemin-graphene (GH) constructs, using proteins as inputs, the "OR" and "INHIBIT" logic gates were built. This procedure does not require chemical modification on the aptamer probes or analytes and circumvents the limitation associated with the number of target binding sites. Given the attractive analytical characteristics and distinct advantages of DNA-GH composite, the universal approach can be widely applied for the detection of diverse proteins and for the design of versatile logic gates.

ATP-responsive DNA-graphene hybrid nanoaggregates for anticancer drug delivery

“…To explore the DNA-mediated assembly and ATP-triggered dissociation of DNA-GA, the particle size was determined using the dynamic laser scanning (DLS) measurement [35, 45–47] (Fig. 2).…”

“…Upon mixing DNA12-GC with the control aptamer, no significant changes were determined in the particle size of the mixture when varying the concentrations of the control aptamer. The mixture remained the particle size at 200 nm as the concentration of the control aptamer increased, suggesting that the ATP aptamer with the specific sequence could hybridize with DNA1 and DNA2, which associatively acted as a bridge to connect DNA-GC together for the formation of DNA-GA. We further applied DLS to monitor the DNA-mediated GO assembly process, which showed close association with the relative physical sizes of GA [35, 45–47]. …”

A highly sensitive fluorescence turn-on platform with silver nanoparticles aptasening for human platelet-derived growth factor-BB

“…Besides, the one with AgNPs had a lower detection limit of 7 ng mL -1 estimated by three times standard deviation rule. The result was a rather low detection limit among assays that without using the amplification [46,47], such as PCR, RCA or MEF.…”

A survey of advancements in nucleic acid-based logic gates and computing for applications in biotechnology and biomedicine

“…For that reason, many researchers have focused on making detection methods simple and effective including, for example, strip platforms, 72 photoinduced electron transfer (PET), 73 nanomaterials, 74, 75 and electrochemiluminescent devices. 76 …”