Exponential Amplification-Induced Activation of CRISPR/Cas9 for Sensitive Detection of Exosomal miRNA.

As an important component of highly heterogeneous exosomes, exosomal microRNAs (miRNAs) have great potential as noninvasive biomarkers for cancer diagnosis. Therefore, a sensitive and simple sensor is the key for its clinical application. Herein, we designed an exponential amplification reaction (EXPAR) to induce the reactivation of the CRISPR-associated protein 9/small guide RNA (Cas9/sgRNA) complex, thus achieving sensitive and visual exosomal miRNAs-21 (miR-21) fluorescence sensing. In this design, we inactivated the sgRNA by hybridizing sgRNA and blocker DNA. Then, we used a trigger DNA to hybridize with miR-21 and produced a lot of activated DNA by EXPAR. Those activated DNA further hybridized with blocker DNA and released the free sgRNA to form the activated Cas9/sgRNA complex. Based on the quick cleavage of activated Cas9/sgRNA complex, the reporter DNA labeled by SYBR Green I was released from the surface of the magnetic nanoparticles (MNPs) into the supernatant, and thus was used to sensitively quantify the miRNAs concentration with a limit of detection of 3 × 103 particles/mL. In addition, this fluorescence sensor has also been successfully employed to distinguish healthy people and cancer patients by naked-eye observation of the fluorescence, thus demonstrating its great potential for accurate and point-of-care cancer diagnosis.

A Facile Method to Prepare a Superhydrophobic Magnesium Alloy Surface.

The application of superhydrophobic materials has been handicapped by complex processes and poor environmental friendliness. Magnesium alloys are widely used in daily production due to their low density and good casting properties. A facile and environmentally friendly method was proposed to prepare a superhydrophobic layer with coral-like microstructure on the surface of AZ91D magnesium alloy by high temperature heating. The prepared superhydrophobic surface has a contact angle of 159.1° and a rolling angle of 4.8°. The corrosion current of superhydrophobic surface has been reduced by about two orders of magnitude relative to the magnesium alloy substrate and its inhibition efficiency is 96.94%, which demonstrates its great corrosion resistance. In addition, the superhydrophobic surface has great thermal stability. When the temperature rises to 190 °C, the contact is still above 150°. Excellent self-cleaning and advantages in preparation efficiency, environmental protection and cost-effectiveness will boost its good application prospects.

Impact of Pb on Chlamydomonas reinhardtii at Physiological and Transcriptional Levels.

Trace elements stress is one of the most damaging abiotic stresses in environment. Nevertheless, the defense mechanism in microalgae remains poorly understood. In this study, physiological and molecular methods were performed to analyze the defense responses in green alga Chlamydomonas reinhardtii. It was speculated that the defense responses might mainly be due to the regulation of hormone signaling, indicating its potential role in alleviating the Pb toxicity besides other physiological and molecular defense responses like decrease in growth rate, chlorophyll content and photosynthesis efficiency, intensification of antioxidative mechanisms, regulation of transcription factors, trace elements chelation, and sequestration into vacuole via trace elements transporters. The sole differentially expressed ATP-binding cassette (ABC) transporters indicated that ABC transporters might play a very important role in the transport and relocation of Pb in C. reinhardtii. Additionally, our data provide the required knowledge for future investigations regarding Pb toxicity and defense mechanisms in algae, and detection of trace elements pollution in environment.