Schottky Interface Enabled Electrospun Rhodium Oxide Doped Gold for Both pH Sensing and Glucose Measurements in Neutral Buffer and Human Serum.

This study has focused on adjusting sensing environment from basic to neutral pH and improve sensing performance by doping electrodeposited gold (Au) with metal oxide for nonenzymatic glucose measurements in forming a Schottky interface for superior glucose sensing with detailed analysis for the sensing mechanism. The prepared sensor also holds the ability to measure pH with the identical electrospun metal oxide-electrodeposited Au, which composed a dual sensor (glucose and pH sensor) through applying chronoamperometry and open circuit potential methods. The rhodium oxide nanocoral structure was fabricated with an electrospinning precursor solution, followed by a calcination process, and it was mixed with electrodeposited nanocoral gold to form the Schottky interface by constructing a p-n type heterogeneous junction for improved sensitivity in glucose detection. The prepared materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectrometry (XPS), etc. The prepared materials were used for both pH responsive testing and amperometric glucose measurements. The rhodium oxide nanocoral doped gold demonstrated a sensitivity of 3.52 µA mM-1 cm-2 and limit of detection of 20 µM with linear range up to 3 mM glucose concentration compared to solely electrodeposited gold for a sensitivity of 0.46 µA mM-1 cm-2 and a limit of detection of 450 µM. The Mott-Schottky method was used for the analysis of an electron transfer process from noble metal to metal oxide to electrolyte in demonstrating the improved sensitivity at neutral pH for glucose measurements due to the Schottky barrier adjustment mechanism at an applied flat band potential of 0.3 V. This work opens a new venue in illustrating the metal oxide/metal materials in the glucose neutral response mechanism. In the end, human serum samples were tested against current commercial glucose meter to certify the accuracy of the proposed sensor.

The OsGAPC1-OsSGL module negatively regulates salt tolerance by mediating abscisic acid biosynthesis in rice.

Plants frequently encounter adverse conditions and stress during their lives. Abscisic acid (ABA) plays a crucial role in response to salt stress, and dynamic regulation of ABA levels is essential for plant growth and stress resistance. In this study, we identified a transcription factor, OsSGL (Oryza sativa Stress tolerance and Grain Length), which acts as a negative regulator in salt stress, controlling ABA synthesis. OsSGL-overexpressing and mutant materials exhibited sensitivity and tolerance to salt stress, respectively. Notably, under salt treatment, several ABA-related genes, including the ABA synthesis enzyme OsNCED3 and the ABA response gene OsRAB21, were bound by OsSGL, leading to the inhibition of their transcription. Additionally, we found that a key enzyme involved in glycolysis, OsGAPC1, interacted with OsSGL and enhanced the inhibitory effect of OsSGL on OsNCED3. Upon salt stress, OsGAPC1 underwent acetylation and then translocated from the nucleus to the cytoplasm, partially alleviating the inhibitory effect of OsSGL on OsNCED3. Identification of the OsGAPC1-OsSGL module revealed a negative regulatory mechanism involved in the response of rice to salt stress. This discovery provides insight into the dynamic regulation of ABA synthesis in plants under salt stress conditions, highlighting the delicate balance between stress resistance and growth regulation.

Iridium oxide-modified reference screen-printed electrodes for point-of-care portable electrochemical cortisol detection.

Cortisol is a well-known stress biomarker; this study focuses on using electrochemical immuno-sensing to measure the concentration of cortisol selectively and sensitively in artificial samples. Anti-cortisol antibodies have been immobilised on polycrystalline Au electrodes via strong covalent thiol bonds, fabricating an electrochemical bio-immunosensor for cortisol detection. IrOx was then anodically electrodeposited as a reference electrode on a commercial screen-printed electrode and electrochemical impedance spectrometry (EIS) studies were used to correlate the electrochemical response to cortisol concentration and the induced changes in charge transfer resistance (Rct). A linear relationship between the Rct and the logarithm of cortisol concentration was found in concentrations ranging from 1 ng/mL to 1 mg/mL with limit of detection at 11.85 pg/mL (32.69 pM). The modification of the reference electrode with iridium oxide has greatly improved the reproducibility of the screen-printed electrode. The sensing system can provide a reliable and sensitive detection approach for cortisol measurements.

Iridium oxide and cobalt hydroxide microfluidic-based potentiometric pH sensor.

Microliter volume pH determination is of great importance in the biomedical and industrial applications. The current available pH meter and measurement techniques are hard to reach the high demand of microliter volume pH determination in a repeatable, stable, and sensitivity manner. This work aims to fill the gap of microliter volume pH measurements while maintaining good sensing performance. The electrodeposited iridium oxide and cobalt hydroxide along with gold electrode served as working, counter, and reference electrode, respectively, for 10-12 µL volume pH measurements with Nernst constant of 55.9 ± 4.4 mV/pH. The electrodeposited thin film was further characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), Raman spectrometry, etc. to confirm its morphology and composition. The constructed pH sensor was used for human serum sample measurements to confirm the suitability of future applications. The results show that it has only 0.80% variation compared to a commercial pH meter with a limit of detection (LOD, or resolution) of ± 0.01 pH. It holds a great potential to be used in the future for microliter volume in situ pH measurements.

An Integration of MicroRNA and Transcriptome Sequencing Analysis Reveal Regulatory Roles of miRNAs in Response to Chilling Stress in Wild Rice.

A chromosome single segment substitution line (CSSL) DC90, which was generated by introgressing CTS-12, a locus derived from common wild rice (Oryza rufipogon Griff.), into the 9311 (Oryza sativa L. ssp. indica) background, exhibits a chilling tolerance phenotype under chilling stress. Here, an integration of microRNA (miRNA) deep sequencing and transcriptomic sequencing analysis was performed to explore the expression profiles of miRNAs and their target genes mediated by CTS-12 under chilling stress, and to reveal the possible regulatory mechanisms of miRNAs that are involved in chilling tolerance. Integration analysis revealed that a number of differentially expressed miRNAs (DEMs) and putative target genes with different expression patterns and levels were identified in 9311 and DC90 under chilling stress. KEGG enrichment analysis revealed that the target genes that are regulated by chilling-induced miRNAs are involved in the regulation of various biological processes/pathways, including protein biosynthesis, redox process, photosynthetic process, and chloroplast development in two genotypes. CRISPR/Cas9 editing of the target genes of the key DEMs in a chilling tolerant rice variety Zhonghua 11 (ZH11) found that LOC_Os11g48020 (OsGL1-11), one of the putative target genes of osa-miR1846a/b-5p and encoding a wax synthesis protein, is correlated with a chilling stress tolerance phenotype, implying osa-miR1846a/b-5p/OsGL1-11 plays an important role in CTS-12-mediated chilling stress tolerance regulatory pathway(s). Therefore, we speculate that the CTS-12 may regulate the key miRNA target genes in response to chilling stress by differential regulation of miRNAs in wild rice, thereby resulting in the variation of chilling tolerance phenotype between 9311 and DC90.

Crystallization, rheology and mechanical properties of the blends of poly(l-lactide) with supramolecular polymers based on poly(d-lactide)-poly(ε-caprolactone-co-δ-valerolactone)-poly(d-lactide) triblock copolymers.

In this study, we investigated the blending of poly(l-lactide) (PLLA) with supramolecular polymers based on poly(d-lactide)-poly(ε-caprolactone-co-δ-valerolactone)-poly(d-lactide) (PDLA-PCVL-PDLA) triblock copolymers as an efficient way to modify PLLA. The supramolecular polymers (SMP) were synthesized by the terminal functionalization of the PDLA-PCVL-PDLA copolymers with 2-ureido-4[1H]-pyrimidinone (UPy). The structure, thermal properties and rheological behavior of the synthesized supramolecular polymers were studied; we found that the formation of the UPy dimers expanded the molecular chain of the polymer and the incorporation of the UPy groups suppressed the crystallization of polymers. In addition, the synthesized supramolecular polymers had a low glass transition temperature of about -50 °C, showing the characteristics of elastomers. On this basis, superior properties such as a fast crystallization rate, high melt strength, and toughness of fully bio-based, i.e., PLA-based materials were achieved simultaneously by blending PLLA with the synthesized supramolecular polymers. In the PLLA/SMP blends, PLLA could form a stereocomplex with its enantiomeric PDLA blocks of supramolecular polymers, and the stereocomplex crystals with the cross-linking networks reinforced the melt strength of the PLLA/SMP blends. The influences of the SMP composition and the SMP content in the PLLA matrix on crystallization and mechanical properties were analyzed. The supramolecular polymers SMP0.49 and SMP1.04 showed a reverse effect on the crystallization of PLLA. Tensile tests revealed that the lower content of the synthesized supramolecular polymers could achieve toughening of the PLLA matrix. Therefore, the introduction of supramolecular polymers based on PDLA-PCVL-PDLA is an effective way to control the crystallization, rheology and mechanical properties of PLLA.