Exclusive Core-Janus Satellite Assembly Based on Au-Ag Janus Self-Aligned Distributions with Abundant Hotspots for Ultrasensitive Detection of CA19-9.

The development of surface-enhanced Raman scattering (SERS) probes with high sensitivity and stability is imminent to improve the accuracy of cancer diagnosis. Here, an exclusive core-Janus satellite (CJS) assembly was constructed by a hierarchical assembly strategy in which the Au-Ag Janus satellite is vertically self-aligned on the core surface. In the process, a silica shell template was ingeniously employed to asymmetrically mask the presatellites for the in situ formation of the Janus structure, and a series of Janus satellites with different morphologies were developed by regulating the encapsulated area of the presatellites. The ordered-oriented arrangement of Au-Ag Janus and unique heterojunction morphology permit CJS assemblies, featuring two types of plasmonic nanogaps, including intrananocrevices for individual Janus and internanogaps between neighboring Janus, thereby multiplying the "hotspots" compared to conventional core-monotonous satellites, which contributes to superior SERS activity. As anticipated, the enhancement factor of CJS assemblies was as high as 3.8 × 108. Moreover, it is intriguing that the directional distribution and head physically immobilized by Janus provided uniform and stable SERS signals. The SERS probe based on the CJS assembly for the detection of carbohydrate antigen 19-9 resulted in an ultrahigh sensitivity with a limit of detection of 3.7 × 10-5 IU·mL-1, which is nearly 10 times lower than other SERS probes, and a wide detection range of 3 × 10-5 to 1 × 104 IU·mL-1. The CJS assembly with excellent SERS performance is promising to advance further development of the early diagnosis of pancreatic cancer.

Biodiversity and antifouling activity of fungi associated with two soft corals from the South China Sea.

Bacteria in corals have been studied in detail in the past decades. However, the biodiversity and bioactivity of fungi in corals are still poorly understood. This study investigated the biodiversity and antifouling activity of fungi in soft corals Cladiella krempfi and Sarcophyton tortuosum from the South China Sea. A high diverse and abundant fungal community was found in the two soft corals. Furthermore, five isolates shared 83-95% similarity with their closest relatives, indicating that they might be novel species in genera Phaeoshaeria and Mucor. In addition, approximately 50% of the representative isolates exhibited distinct antifouling activity. In particular, isolates Fungal sp. SCAU132 and Fungal sp. SCAU133 displayed very strong antifouling activity against Bugula neritina, suggesting they can provide a potential resource for further investigation on isolation of novel antifouling metabolites. To our knowledge, this study is the first report to investigate the biodiversity and antifouling activity of fungi in C. krempfi and S. tortuosum.