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Plasmonic nanostructures, functioning as nano-antenna reactors to highly focus light and efficiently convert it into thermal/chemical energy, have a significant potential for sustainable solar water disinfection (SODIS). A high-density plasmonic nanogap-based reactor array opens a way of maximizing the photothermal effect, but achieving uniformity and large density in such a technology while scaling up remains challenging. In this study, we provide an integrative plasmonic dimer array (hPDA) that is uniform and has high density ensuring significantly enhanced SODIS performance. The hPDA is constructed by a combined fabrication of the self-assembled monolayer and block copolymer lithography approaches. This combination leads to a two-dimensional hexagonal array of the Au dimer structures consisting of a 1.3 nm nanogap. The uniformity and high density of nanogaps of the hPDA result in the physically and optically stabilized dimer array, which allows strong light focusing and a rapid and highly efficient harvesting of photothermal energy in the visible region. Finally, the integrated hPDA with an optofluidic reactor enables 5-fold enhanced Escherichia coli (E. coli) disinfection. We anticipate that the hPDA will be useful in the scalable sustainable energy and environmental process that converts solar energy. [ABSTRACT FROM AUTHOR]

DNA walkers have shown superior performance in biosensing due to their programmability to design molecular walking behaviors with specific responses to different biological targets. However, it is still challenging to make DNA walkers capable of distinguishing DNA targets with single-base differences, so that DNA walkers that can be used for circulating tumor DNA sensing are rarely reported. Herein, a flap endonuclease 1 (FEN 1)-assisted DNA walker has been proposed to achieve mutant biosensing. The target DNA is captured on a gold nanoparticle (AuNP) as a walking strand to walk by hybridizing to the track strands on the surface of the AuNP. FEN 1 is employed to report the walking events by cleaving the track strands that must form a three-base overlapping structure recognized by FEN 1 after hybridizing with the captured target DNA. Owing to the high specificity of FEN 1 for structure recognition, the one-base mutant DNA target can be discriminated from wild-type DNA. By constructing a sensitivity-enhanced DNA walker system, as low as 1 fM DNA targets and 0.1% mutation abundance can be sensed, and the theoretical detection limits for detecting the DNA target and mutation abundance achieve 0.22 fM and 0.01%, respectively. The results of epidermal growth factor receptor (EGFR) L858R mutation detection on cell-free DNA samples from 15 patients with nonsmall cell lung cancer were completely consistent with that of next-generation sequencing, indicating that our DNA walker has potential for liquid biopsy.

The loop-mediated isothermal amplification (LAMP) is a well-developed method for replicating a targeted DNA sequence with a high specificity, but multiplex LAMP detection is difficult because LAMP amplicons are very complicated in structure. To allow simultaneous detection of multiple LAMP products, a series of target-specific barcodes were designed and tagged in LAMP amplicons by FIP primers. The targeted barcodes were decoded by pyrosequencing on nicked LAMP amplicons. To enable the nicking reaction to occur just near the barcode regions, the recognition sequence of the nicking endonuclease (NEase) was also introduced into the FIP primer. After the nicking reaction, pyrosequencing started at the nicked 3' end when the added deoxyribonucleoside triphosphate (dNTP) was complementary to the non-nicked strand. To efficiently encode multiple targets, the barcodes were designed with a reporter base and two stuffer bases, so that the decoding of a target-specific barcode only required a single peak in a pyrogram. We have successfully detected the four kinds of pathogens including hepatitis B virus (HBV), hepatitis C virus (HCV), human immunodeficiency virus (HIV), and Treponema pallidum (TP), which are easily infected in blood, by a 4-plex LAMP in a single tube, indicating that barcoded LAMP coupled with NEase-mediated pyrosequencing is a simple, rapid, and reliable way in multiple target identification.