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This paper reports the fabrication of a highly sensitive and reusable substrate for surface-enhanced Raman scattering (SERS) analysis. Core–shell metal–organic framework (MOF; HKUST-1)@Ag nanoparticles (NPs) are prepared on a screen-printed carbon electrode (SPCE) via in situ electrodeposition. The morphology and Ag coverage of core–shell structures can be easily controlled by electrodeposition potential and time without substrate motion. The HKUST-1(Cu)@Ag composites combine abundant SERS “hot spots” among the high-density Ag NPs and the excellent adsorption performance of the MOF, resulting in effective pre-concentration of analytes in close proximity to these “hot spots” and enhancement of SERS sensitivity. The optimized polyhedral HKUST-1@Ag structures exhibit high SERS activity for detecting 4-aminothiophenol at a concentration as low as 5 × 10−10 M. More importantly, the polyhedral HKUST-1@Ag composites provide high sensitivity for detection of polycyclic aromatic hydrocarbons (PAHs) while preserving the cyclability and selectivity required for reliable quantitative analysis. The method is effective over a wide range of PAH concentrations (0.5 nM to 0.5 M), with detection limits as low as hundreds of pM. This study offers a new method to tailor the structure of MOF-based SERS substrates for on-site screening or point-of-care applications.

Development of flexible surface-enhanced Raman spectroscopy (SERS) substrate with controllable "hot spots" has spurred increasing interest because of its unique structure and plasmonic properties. Here, charged poly(vinyl alcohol) microgels containing silver nanoparticles are developed by using microfluidic emulsification to produce a "smart" SERS sensor with charge screening and signals amplification. Importantly, this charged microgel enables the selective concentration of counter-charged molecules and induces the formation of assembled arrays at an immiscible liquid-liquid interface because of the electrostatic interaction. The SERS-active microgels arrays possess controllable structures and facilitate on-site determination of charged pesticides with an enhancement factor of 5.0 × 105. Such nanostructures present the ease of assembly, stability, and reproducibility which allow multiplex detection of analytes at aqueous and organic phases without any pretreatment of the complex matrix samples. The interfacial sensing platform for on-site SERS analysis of charged pesticides will open vast possibilities for a wide range of in-field applications.

Potassium inwardly-rectifying channel, subfamily J, member 12 (KCNJ12) gene is one promising candidate for economic traits because of its crucial roles in myoblast development. Here, a missense mutation (Cys>Arg), was firstly detected to locate in exon 3 of KCNJ12 from three Chinese cattle breeds by DNA-pool sequencing. Then, we performed the association analysis of this SNP with stature in three Chinese cattle populations (n = 820). Significantly positive correlation was revealed by reduced animal general linear model and the genotype of CC is the most excellent genotype in three breeds. Further, we measured the expression profiling of the KCNJ12 gene in various cattle tissues and primary bovine skeletal muscle cells. Ubiquitous expression with high abundance in muscle was observed. Further, in primary bovine skeletal muscle cells, the KCNJ12 mRNA expression was gradually up-regulated in differentiation medium (DM) compared with that in growth medium (GM), suggesting that KCNJ12 gene is involved in bovine myocyte differentiation. Conclusively, KCNJ12 gene is a functional candidate gene which can be used as molecular marker for beef cattle breeding.