This paper presents a novel strategy for ultrasensitive detection of human immunodeficiency virus (HIV) DNA by an electrochemical biosensor. By the shearing cycle of the target DNA (T-DNA), a large amount of complimentary sequence probes (CS probe DNA) are obtained. Then, the Zr 4+ functional probe DNA containing many branched DNAs is captured. Next, the initiator α-bromophenylacetic acid is connected to the branched chains of probe DNA by esterification reaction. Numerous electroactive monomers, namely, ferrocenylmethyl methacrylate (FMMA), are produced at the end of the branched chains by electrochemically mediated atomic transfer radical polymerization reaction. The signal of FMMA is greatly enhanced due to a large number of branched chain-loaded probe clusters containing numerous FMMA. T-DNA can be detected with a linear range of 0.1 fM–10 nM with a detection limit of 0.037 fM. The sensor is highly sensitive and selective. It has been applied to the detection of HIV DNA in human serum samples, and it has potential application prospects in the early clinical diagnosis of AIDS.
Ultrahigh molecular weight polymers display outstanding properties and have great application potential. However, the traditional polymerization methods have inevitable disadvantages that challenge the green synthesis of ultrahigh molecular weight polymers. The paper achieved an ultrahigh molecular weight poly (trifluoroethyl methacrylate) via a novel polymerization and discussed the mechanistic, kinetic, and experimental aspects. The combination of palladium nanoparticles with ethyl 2-bromopropionate has been identified as an exceedingly efficient system for initiating the polymerization of trifluoroethyl methacrylate. An ultrahigh molecular weight poly (trifluoroethyl methacrylate) with a number-average molecular weight up to 3.03 × 106Da has been synthesized at a feeding molar ratio of [poly (trifluoroethyl methacrylate)]/[ethyl 2-bromopropionate]/[palladium nanoparticles] = 3.95 × 104:756:1 at 70 °C. The reaction orders concerning palladium nanoparticles, ethyl 2-bromopropionate, and poly (trifluoroethyl methacrylate) were determined to be 0.59, 0.34, and 1.38, respectively. By analyzing a series of characterizations, we verified that the polymerization of poly (trifluoroethyl methacrylate) was initiated by the ethyl 2-bromopropionate residue radicals, which were generated from the interaction between palladium nanoparticles and ethyl 2-bromopropionate. The comparatively large size of the palladium nanoparticles provided a barrier to chain-growing radicals, promoting the synthesis of ultrahigh molecular weight polymers.
危险品化学品经营许可证（带存储）