Integration of G-Quadruplex and Pyrene as a Simple and Efficient Ratiometric Fluorescent Platform That Programmed by Contrary Logic Pair for Highly Sensitive and Selective Coralyne (COR) Detection.

The effective and accurate detection of the anticancer drug coralyne (COR) is highly significant for drug quality control, medication safety and good health. Although various COR sensors have been reported in recent years, previous ones can only exhibit single-signal output (turn ON or turn OFF) with poor reliability and anti-interference ability. Therefore, exploring novel platform with dual-signal response for COR detection is urgently needed. Herein, we reported the first ratiometric fluorescent platform for highly sensitive and selective COR detection by integrating G-quadruplex (G4) and Pyrene (Py) as signal probes and harnessing A-COR-A interaction. In the absence of COR, the platform shows a low fluorescence signal of PPIX (F642) and a high one of Py monomer (F383). With the addition of COR, two delicately designed poly-A ssDNAs will hybridize with each other via A-COR-A coordination to form complete G4, yielding the increased fluorescence signal of PPIX and the decreased one of Py due to the formation of Py excimer. Based on the above mechanism, we constructed a simple and efficient sensor that could realize the ratiometric fluorescent detection of COR with high sensitivity and selectivity. A linear relationship between F642/F383 and COR's concentration is obtained in the range from 1 nM to 8 µM. And the limit of detection of COR could reach to as low as 0.63 nM without any amplification, which is much lower than that of most COR sensors reported so far. Notably, the logical analysis of COR can be carried out under the control of a "YES-NOT" contrary logic pair, enabling the smart dual-channel response with an adequate S/N ratio and improved reliability and anti-interference ability. Moreover, this system also presents satisfactory performance in fetal bovine serum (FBS) samples.

Differences in Soil Microbial Community Composition Between Suppressive and Root Rot-Conducive in Tobacco Fields.

Soil microorganism has a profound influence on planting growth and disease suppression. However, the difference in microbial community structure between suppressive and root rot-conducive soil and the mechanism of controlling soil-borne diseases by microorganisms in suppressive soil were not clear. To provide a theoretical foundation for prevention and control of root rot, this paper investigated the change of community structure in rhizosphere soil between suppressive and root rot-conducive tobacco fields. Soil samples were collected during before transplanting, vigorous growing period, and mature period of the tobacco, and bacteria and fungi were analyzed using 16S rRNA and 18S rRNA gene sequencing, respectively. Results showed that bacteria were more sensitive to the change between suppressive and root rot-conducive soil, and fungi were more sensitive to the change of different tobacco growth periods. Compared with conducive soil, tobacco suppressive soil can resist the invasion of pathogens, especially fungi, by regulating soil microbial community structure, and the potential pathogen Boeremia was always lower. Fusarium, the root rot pathogen, decreased rapidly in the mature period in suppressive soil. Moreover, norank_o_Gaiellales and unclassified_f_Trichocomaceae had a critical role in suppressive soil in the process of inhibiting root rot, which was obvious in the mature stage. Overall, the results indicated that the composition and structure of the microbial community significantly altered between suppressive and conducive soil along with the growth of tobacco, and suppressive soil could inhibit the occurrence of soil-borne diseases by boosting beneficial bacteria and inhibiting the potential pathogens.

Modification of a nitrocellulose membrane with nanofibers for sensitivity enhancement in lateral flow test strips.

Lateral-flow analysis (LFA) is a convenient, low-cost, and rapid detection method, which has been widely used for screening of diseases. However, sensitivity enhancement in LFA is still a focus in this field and remains challenging. Herein, we propose an electrospinning coating method to modify the conventional nitrocellulose (NC) membrane and optimize the liquid flow rate for enhancing the sensitivity of the NC based LFA strips in the detection of human chorionic gonadotropin (HCG) and luteinizing hormone (LH). It can be seen that coating the NC membrane with nitrocellulose fibers could obtain a NC based strip with HCG and LH detection limits of 0.22 and 0.36 mIU mL-1 respectively, and a quantitative linear range of 0.5-500 mIU mL-1. The results show that electrospinning is effective in modifying conventional NC membranes for LFA applications.

Fabrication of PAN Electrospun Nanofibers Modified by Tannin for Effective Removal of Trace Cr(III) in Organic Complex from Wastewater.

Removal of chromium ions is significant due to their toxicity and harmfulness, however it is very difficult to remove trace Cr(III) complexed with organics because of their strong stability. Herein, a novel electrospun polyacrylonitrile (PAN) nanofibers (NF) adsorbent was fabricated and modified by tannic acid (TA) by a facile blend electrospinning approach for removal of trace Cr(III) in an organic complex. Utilizing the large specific area of nanofibers in the membrane and the good affinity of tannic acid on the nanofibers for hydrolyzed collagen by hydrophobic and hydrogen bonds, the as-prepared PAN-TA NFM exhibited good adsorption toward Cr(III)-collagen complexes and effective reduction of total organic carbon in tannage wastewater. The maximal adsorption capacity of Cr(III) is 79.48 mg g-1 which was obtained at the pH of 7.0 and initial Cr(III) concentration of 50 mg g-1. Importantly, the batch adsorption could decrease the Cr(III) concentration from 10-20 mg L-1 to under 1.5 mg L-1, which showed great application potential for the disposal of trace metal ions in organic complexes from wastewater.

The fabrication of mechanically durable and stretchable superhydrophobic PDMS/SiO2 composite film.

Stretchable superhydrophobic film was fabricated by casting silicone rubber polydimethylsiloxane (PDMS) on a SiO2 nanoparticle-decorated template and subsequent stripping. PDMS endowed the resulting surface with excellent flexibility and stretchability. The use of nanoparticles contributed to the sustained roughening of the surface, even under large strain, offering mechanically durable superhydrophobicity. The resulting composite film could maintain its superhydrophobicity (water contact angle ≈ 161° and sliding angle close to 0°) under a large stretching strain of up to 100% and could withstand 500 stretching-releasing cycles without losing its superhydrophobic properties. Furthermore, the obtained film was resistant to long term exposure to different pH solutions and ultraviolet light irradiation, as well as to manual destruction, sandpaper abrasion, and weight pressing.

A CuNi/C Nanosheet Array Based on a Metal-Organic Framework Derivate as a Supersensitive Non-Enzymatic Glucose Sensor.

Bimetal catalysts are good alternatives for non-enzymatic glucose sensors owing to their low cost, high activity, good conductivity, and ease of fabrication. In the present study, a self-supported CuNi/C electrode prepared by electrodepositing Cu nanoparticles on a Ni-based metal-organic framework (MOF) derivate was used as a non-enzymatic glucose sensor. The porous construction and carbon scaffold inherited from the Ni-MOF guarantee good kinetics of the electrode process in electrochemical glucose detection. Furthermore, Cu nanoparticles disturb the array structure of MOF derived films and evidently enhance their electrochemical performances in glucose detection. Electrochemical measurements indicate that the CuNi/C electrode possesses a high sensitivity of 17.12 mA mM-1 cm-2, a low detection limit of 66.67 nM, and a wider linearity range from 0.20 to 2.72 mM. Additionally, the electrode exhibits good reusability, reproducibility, and stability, thereby catering to the practical use of glucose sensors. Similar values of glucose concentrations in human blood serum samples are detected with our electrode and with the method involving glucose-6-phosphate dehydrogenase; the results further demonstrate the practical feasibility of our electrode.