Oleanolic acid inhibits colon cancer cell stemness and reverses chemoresistance by suppressing JAK2/STAT3 signaling pathway

Background:Oleanolic acid(OA),a pentacyclic triterpenoid exhibiting specific anti-cancer properties and highly effective antioxidant activity,was isolated from traditional Chinese medicinal herbs.Conversely,the OA that impacts colon cancer(CC)cells and its underlying mechanisms remain poorly understood.Methods:The cytotoxic effect of OA alone or OA-5-Fluorouracil(5-FU)combination on normal and CC cells was analyzed by methyl thiazolyl diphenyl-tetrazolium bromide(MTT).Then,the impact of OA on CC cell lines(LoVo and HT-29)proliferation and stemness were measured using colon formation and tumorsphere formation assays.Octamer-binding transcription factor 4(Oct4),Prominin-1(CD133),Nanog,and transcription factor SOX-2(SOX2)are cell stemness-related indicators whose expression was assessed usingfluorescence qPCR assay,Western blotting,and immunohistochemistry.The effect of OA on the proliferative potency of CC cells was evaluated using an in vivo model.Results:The stem-like characteristics and clone production of colon cancer cells were markedly reduced by OA alone or in combination with OA-5-FU.Moreover,OA increases the susceptibility of CC cells to 5-FU by blocking the cell stemness-related markers(CD133,Nanog,SOX2,and Oct4)expression levels both in vitro and in vivo,as well as by inactivating the activator of transcription 3(STAT3 signaling)and Janus kinase 2/signal transducer(JAK2).Conclusion:Thesefindings imply that oleanolic acid,both in vitro and in vivo,suppresses the JAK2/STAT3 pathway,which in turn reverses chemoresistance and decreases colon cancer cell stemness.Therefore,by reducing the recommended amount of 5-FU,this strategy may improve chemotherapeutic effectiveness and minimize undesired side effects.

Apoptosis of pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid in combination with horseradish peroxidase

AIM： To explore the mechanisms underlying the apoptosis of human pancreatic cancer BXPC-3 cells induced by indole-3-acetic acid （IAA） in combination with horseradish peroxidase （HRP）. METHODS： BXPC-3 cells derived from human pancreatic cancer were exposed to 40 or 80 μmol/L IAA and 1.2 μg/mL HRP at different times. Then, Mn- assay was used to detect the cell proliferation. Flow cytometry was performed to analyze cell cycle. Terminal deoxynucleotidyl transferasemediated dUTP nick end labeling assay was used to detect apoptosis. 2,7-Dichlorofluorescin diacetate uptake was measured by confocal microscopy to determine free radicals. Level of malondialdehyde （MDA） and activity of superoxide dismutase （SOD） were measured by biochemical methods. RESULTS： IAA/HRP initiated growth inhibition of BXPC-3 cells in a dose- and time-dependent manner. Flow cytometry revealed that the cells treated for 48 h were arrested at G1/G0. After exposure to 80 μmol/L IAA plus 1.2 μg/mL HRP for 72 h, the apoptosis rate increased to 72.5‰, which was nine times that of control. Content of MDA and activity of SOD increased respectively after treatment compared to control. Meanwhile, IAA/HRP stimulated the formation of free radicals. CONCLUSION： The combination of IAA and HRP can inhibit the growth of human pancreatic cancer BXPC-3 cells in vitro by inducing apoptosis.

Amperometric Determination of lndole-3-acetic Acid Based on Platinum Nanowires and Carbon Nanotubes

Platinum nanowire （PtNW） can be grown by electrodeposition in polycarbonate membrane, with the average diameter of the nanowires about 250 nm. The PtNW and multiwalled carbon nanotubes （CNT） are then dispersed into chitosan （CHIT） solution. The resulting PtNW-CNT-CHIT material brings new capabilities for electrochemical devices by using the synergistic action of the electrocatalytic activity of PtNW and CNT. By dropping the PtNW-CNT-CHIT film onto the glassy carbon （GO） electrode surface, and after evaporation an amperometric sensor for the determination of indole-3-acetic acid （IAA） was developed. The oxidation current of IAA increased significantly at the PtNW-CNT-CHIT film coated GC electrode, in contrast to that at the CNT-CHIT modified GC. The linear response of the sensor is from 50 ng/ml to 50 μg/ml with a detection limit of 25 ng/mL.

Synthesis,Spectroscopic Characterization,Thermogravimetric and Biological Activity Evaluation of Te(Ⅳ),Se(Ⅳ),V(Ⅲ),Nb(Ⅴ),Ta(Ⅴ)Complexes With Indole-3-Acetic Acid Plant Hormone Ligand

Te(Ⅳ),Se(Ⅳ),V(Ⅲ),Nb(Ⅴ)and Ta(Ⅴ)complexes of indole-3-acetic acid(IAAH)ligand were synthesized,characterized by elemental analysis and various spectroscopic techniques like,IR,1H-NMR,X-ray powder diffraction,UV-Visible,thermogravimetry analysis,magnetic measurements,molar conductance and surface morphology using SEM.All the synthesized complexes of IAAH ligand have 1∶2 stoichiometry of the types[Te(IAA)2(NH 3)2]·2Cl(Ⅰ),[Se(IAA)2(NH 3)2]·2Cl(Ⅱ),[V(IAA)2(NH 3)(Cl)](Ⅲ),[Nb(IAA)2(Cl)3](Ⅳ),and[Ta(IAA)2(Cl)3](Ⅴ).Spectral analysis indicates octahedral geometry for the Te(Ⅳ),Se(Ⅳ)and V(Ⅲ)complexes,whereas both Nb(Ⅴ)and Ta(Ⅴ)have a seven-coordination.The bonding sites are the oxygen atoms of carboxylate group for the deprotonated indole-3-acetic acid(IAA)ligand.The thermogravimetry analysis studies gave evidence for the presence of other coordinated molecules(Cl or NH 3)in the composition of IAA complexes,which were further supported by IR and micro analytical measurements.The higher molar conductance data of tellurium and selenium(Ⅳ)complexes reveal that these chelates are electrolytes,while low conductivity values for the vanadium(Ⅲ),niobium and tantalum(Ⅴ)chelates indicated a non-electrolytes.To test the antibacterial property of the five complexes in this study,four bacterial strains Klebsiella(G-),Escherichia coli(G-),Staphylococcus aureus(G+)and Staphylococcus epidermidis(G+)were used in the investigation.The effects of the five complexes in the cytotoxicity of Caco-2 and Mcf-7 human cancer cell lines were studied Neutral red uptake assay for the estimation of cell viability/cytotoxicity protocol.

The Difference of Sensitivity between BXPC-3 and K562 Cells by Treatments with Combination of Indole-3-acetic Acid and Horseradish Peroxidase

The difference of sensitivity to indole- 3-acetic acid （ IAA ） combined with horseradish peroxidase （HRP） in K562 and BXPC- 3 cells was investigated. The cell proliferation was determined by MTF assay. The cell cycle and apoptosis of K562 and BXPC-3 cells were examined by a fluorescence flow cytometer （FCM） and terminal deoxynacleotidyl transferase-mediated dUTP nick-end labeling （TUNEL） respectively. The experimental results show that IAA and HRP could inhibit BXPC- 3 cell proliferation greatly compared with K562 cell during the first 48 h . The cell cycle was arrested predominantly at G2/ M phase in K562 and BXPC- 3 cells. The cell apoptosis of K562 and BXPC- 3 was induced by IAA/ HRP. There was a significant difference between the two cell lines since BXPC-3 cells were more sensitive than K562 cells by treatments with combination of IAA and HRP.

THE APPLICATION OF SEROTONIN AND 5-HVDROXYINDOLE-3-ACETIC ACID IN THE DIAGNOSIS OF APUDOMA

In our report, the values of whole blood serotonin (5-HT) in 87 apudoma patients (diagnosed by operation and pathology) were summarized. Among them, the levels of urinary 5-hydroxyindole-3-acetic acid (5-HIAA) of 44 patients were also tested. The results showed that both parametres of apudoma patients were higher than those of non-apudoma, post-operative patients of apudoma as well as the normal. The increasing extent of the levels of whole blood 5-HT and urinary 5-HIAA in small intestinal carcihoid was the most obvious one but that of rectum was not. The referable diagnostic values suggested were: 5-HT>130 ng ml, 5-HIAA>30 mg/ 24 hours.

Allosterically activating SHP2 by oleanolic acid inhibits STAT3-Th17 axis for ameliorating colitis

Src homology 2 domain-containing tyrosine phosphatase 2(SHP2)is an essential tyrosine phosphatase that is pivotal in regulating various cellular signaling pathways such as cell growth,differentiation,and survival.The activation of SHP2 has been shown to have a therapeutic effect in colitis and Parkinson's disease.Thus,the identification of SHP2 activators and a complete understanding of their mechanism is required.We used a two-step screening assay to determine a novel allosteric activator of SHP2 that stabilizes it in an open conformation.Oleanolic acid was identified as a suitable candidate.By binding to R362,K364,and K366 in the active center of the PTP domain,oleanolic acid maintained the active open state of SHP2,which facilitated the binding between SHP2 and its substrate.This oleanolic acid-activated SHP2 hindered Th17 differentiation by disturbing the interaction between STAT3 and IL-6Rαand inhibiting the activation of STAT3.Furthermore,via the activation of SHP2 and subsequent attenuation of the STAT3-Th17 axis,oleanolic acid effectively mitigated colitis in mice.This protective effect was abrogated by SHP2 knockout or administration of the SHP2 inhibitor SHP099.These findings underscore the potential of oleanolic acid as a promising therapeutic agent for treating inflammatory bowel diseases.

Lateral root elongation in maize is related to auxin synthesis and transportation mediated by N metabolism under a mixed NO_(3)^(–) and NH_(4)^(+) supply

A mixed nitrate (NO_(3)^(–)) and ammonium (NH_(4)^(+)) supply can promote root growth in maize (Zea mays),however,the changes in root morphology and the related physiological mechanism under different N forms are still unclear.Here,maize seedlings were grown hydroponically with three N supplied in three different forms (NO_(3)^(–)only,75/25 NO_(3)^(–)/NH_(4)^(+)and NH_(4)^(+)only).Compared with sole NO_(3)^(–)or NH_(4)^(+),the mixed N supply increased the total root length of maize but did not affect the number of axial roots.The main reason was the increased total lateral root length,while the average lateral root (LR) length in each axle was only slightly increased.In addition,the average LR density of 2nd whorl crown root under mixed N was also increased.Compared with sole nitrate,mixed N could improve the N metabolism of roots (such as the N influx rate,nitrate reductase (NR) and glutamine synthase (GS)enzyme activities and total amino content of the roots).Experiments with exogenously added NR and GS inhibitors suggested that the increase in the average LR length under mixed N was related to the process of N assimilation,and whether the NR mediated NO synthesis participates in this process needs further exploration.Meanwhile,an investigation of the changes in root-shoot ratio and carbon (C) concentration showed that C transportation from shoots to roots may not be the key factor in mediating lateral root elongation,and the changes in the sugar concentration in roots further proved this conclusion.Furthermore,the synthesis and transportation of auxin in axial roots may play a key role in lateral root elongation,in which the expression of ZmPIN1B and ZmPIN9 may be involved in this pathway.This study preliminarily clarified the changes in root morphology and explored the possible physiological mechanism under a mixed N supply in maize,which may provide some theoretical basis for the cultivation of crop varieties with high N efficiency.

齐墩果酸对S180荷瘤小鼠细胞色素C和Caspase-3表达的影响

目的:探讨齐墩果酸诱导荷瘤小鼠肿瘤细胞凋亡作用机制。方法:将接种S180腹水瘤的小鼠随机分为模型组,齐墩果酸高、中、低剂量组,环磷酰胺组。采用免疫组化法检测肿瘤组织中细胞色素C和Caspase-3蛋白表达水平。结果:齐墩果酸对S180荷瘤小鼠细胞色素C和Caspase-3蛋白表达水平明显提高,与模型组比较差异显著(P<0.01),具有诱导肿瘤细胞凋亡作用。结论:齐墩果酸能上调S180荷瘤小鼠肿瘤细胞内细胞色素C和Caspase-3蛋白的表达,通过线粒体凋亡通路诱导肿瘤细胞凋亡而发挥抗肿瘤作用。

高效液相色谱法测定栀子根中齐墩果酸3-乙酸酯含量

目的建立高效液相色谱法测定栀子根中齐墩果酸3-乙酸酯含量的方法。方法样品采用不同种类、不同浓度、不同时间的酸水解,将栀子根中齐墩果酸3-乙酸酯水解成齐墩果酸后,用二氯甲烷萃取、蒸干、甲醇定容,制备供试液,再采用高效液相色谱法测定其含量。结果样品的甲醇提取液加盐酸2 mL,加热回流4 h,水解较好。齐墩果酸3-乙酸酯在1.102 5～11.025μg范围内线性关系良好,r=0.999 8,平均回收率为96.00%(RSD=1.34%)。结论本方法操作简便,重复性好,专属性强,可用于栀子根的质量控制。

川西獐牙菜单体齐墩果酸上调阻塞性胆汁淤积大鼠肝脏核受体Lrh-1和胆酸转运蛋白Mrp3的表达

目的建立胆道结扎的大鼠模型,观察川西獐牙菜活性单体齐墩果酸(oleanolic acid,OA)对胆道结扎所致的肝外胆汁淤积的保护作用,及其对多药耐药相关蛋白3(multidrug resistanceassociated protein 3,Mrp3)、核受体Lrh-1的调控作用。方法采用随机数字表法将15只SD大鼠分为3组:假结扎组(Sham组)、胆道结扎组(BDL组)、齐墩果酸组(BDL+OA组),每组5只。分别用生理盐水、齐墩果酸处理7 d后,收集组织标本,HE染色检测肝脏损伤程度,Western blot及RT-PCR检测Mrp3和Lrh-1在蛋白及mRNA水平的变化。结果 HE染色结果显示BDL+OA组肝脏损伤程度较胆道结扎组明显减轻;Western blot结果表明BDL+OA组Mrp3表达较Sham组增加2.4倍,Lrh-1表达增加1.8倍;RT-PCR结果显示BDL+OA组Mrp3表达较Sham组增加3.2倍,Lrh-1表达升高2.2倍。结论川西獐牙菜单体齐墩果酸对胆道结扎所致大鼠胆汁淤积性肝损伤具有保护作用,而这种保护作用可能与Lrh-1、Mrp3有关。

微生物转化法合成3-氧代齐墩果酸及其条件优化

以齐墩果酸为底物,选取雷斯青霉(Penicilliumraistrickii)、赭曲霉(Aspergillus ochraceus)和黑根霉(Rhi-zopus nigricans)三种微生物对其进行转化,采用TLC、HPLC方法检测转化产物。结果表明,雷斯青霉和赭曲霉对齐墩果酸有转化能力,其中雷斯青霉转化能力较高,主产物为3-氧代齐墩果酸;对雷斯青霉生物转化条件进行优化,确定最佳工艺条件为:投料时间36 h、转化时间48 h、转化pH值5.5、转化温度28℃、最大底物加入量不超过100 mg.L-1、DMF体积分数0.6%。在此条件下,齐墩果酸转化率可达7.95%、3-氧代齐墩果酸生成率达50.97%。用雷斯青霉对齐墩果酸进行衍生化,是一种合成3-氧代齐墩果酸新方法。

心律宁胶囊中齐墩果酸-3-O-β-D-吡喃葡萄糖醛酸苷浓度HPLC检测方法的建立及评价

目的：采用高效液相色谱（HPLC）法测定心律宁胶囊中齐墩果酸-3-O-β-D-吡喃葡萄糖醛酸苷的浓度，探讨影响心律宁胶囊中齐墩果酸-3-O-β-D-喃葡萄糖醛酸苷浓度测定的各种因素。方法：采用HPLC法测定齐墩果酸-3-O-β-D-吡喃葡萄糖醛酸苷浓度。色谱柱为HypersilC18柱（4．6mm×250．0mm，5．0μm），流动相为乙腈-1％冰醋酸（56：44），检测波长为210nm，速流为I．00mL·min^-1，柱温30℃。结果：在本色谱条件下，齐墩果酸-3-O-β-D-喃葡萄糖醛酸苷的分离效果良好，在14．80～26．64μg内呈良好的线性关系（r=0．9999），平均加样回收率为97．4％，相对标准偏差（RSD）为1．4％。结论：采用HPLC法测定心律宁胶囊中齐墩果酸-3-O-β-D-喃葡萄糖醛酸苷浓度简便、准确、专属性强，HPLC可作为心律宁胶囊浓度测定的质量控制方法。

齐墩果酸对人卵巢癌SKOV3细胞增殖、侵袭、转移的影响及其作用机制研究

目的:探讨齐墩果酸抑制人卵巢癌SKOV3细胞增殖、侵袭、转移的作用及其机制。方法:采用CCK-8法检测不同浓度齐墩果酸(10、20、40、60、80、100μmol/L)作用12、24、36、48 h对卵巢癌SKOV3细胞增殖能力的影响;采用Transwell实验观察低、高剂量齐墩果酸(20、40μmol/L)作用24 h对SKOV3细胞迁移及侵袭能力的影响;采用Western Blotting法检测低、高剂量齐墩果酸对SKOV3细胞中核因子κB p65(NF-κB p65)、肝再生磷酸酶3(PRL-3)、肿瘤坏死因子α(TNF-α)、白细胞介素6(IL-6)、上皮钙黏着蛋白E(E-cadherin)等蛋白表达的影响;运用脂多糖(LPS)诱导和NF-κB p65质粒转染SKOV3细胞,采用Western blotting法和实时荧光定量PCR考察低、高剂量齐墩果酸对NF-κB/PRL-3通路相关蛋白及其mRNA表达的影响。结果:随着齐墩果酸给药浓度的增加和作用时间的延长,SKOV3细胞的增殖能力有随之降低的趋势,各剂量组的细胞存活率均显著低于对照组(P<0.05或P<0.01)。低、高剂量的齐墩果酸组的迁移和侵袭细胞数均显著减少(P<0.05或P<0.01),且其NF-κB p65、PRL-3、TNF-α、IL-6蛋白的相对表达量均显著降低,E-cadherin蛋白的相对表达量均显著升高(P<0.05或P<0.01)。经LPS刺激后,LPS模型组细胞中NF-κB p65、PRL-3、TNF-α、IL-6蛋白及其m RNA的相对表达量较对照组显著升高,E-cadherin蛋白及其m RNA的相对表达量均显著降低(P<0.05或P<0.01);低、高剂量齐墩果酸组细胞中NF-κB p65、PRL-3、TNF-α、IL-6蛋白及其mRNA的相对表达量均显著降低,E-cadherin蛋白及其m RNA的相对表达量均显著升高(P<0.05或P<0.01)。在NF-κB p65过表达SKOV3细胞中,低、高剂量齐墩果酸同样能够显著下调NF-κB p65、PRL-3、TNF-α、IL-6蛋白的表达,显著上调E-cadherin蛋白的表达(P<0.05或P<0.01)。结论:齐墩果酸能够通过调控NF-κB/PRL-3信号通路来抑制人卵巢癌细胞SKOV3的增殖、侵袭、转移。

Differences of Plasma Levels of Tryptophan, Serotonin, 5-Hydroxyindole Acetic Acid, and Kynurenine between Healthy People and Patients of Major Monopolar Depression at Various Age and Gender

Background: It is not well analyzed whether there are differences in plasma levels of tryptophan (TRP) metabolites between healthy control people (HC) and patients of major monopolar depression (MMD). Methods: Ultra high-speed liquid chromatography/mass spectrometry has been used for the simultaneous determination of plasma levels of tryptophan metabolites in depressive patients. Results: There are no significant differences between plasma levels of TRP between HC and MMD. Plasma levels of TRP of HC are higher in young men, young women, old men, and old women in this order. Serotonin (5-HT) levels are higher in MMD than HC. Plasma levels of 5-HIAA of HC are also higher than those of patients of MMD. Plasma levels of kynurenine (KYN) of healthy old men and old women are higher than those of young men and old women. Plasma levels of KYN are higher in old women and young men of MMD than those of HC. Conclusion: Plasma levels of 5-HT are higher in patients of MMD than those of HC, which may suggest that use of drugs inhibiting the 5-HT transportation may increase plasma levels of 5-HT in MMD.

The auxin transporter OsAUX1 regulates tillering in rice(Oryza sativa)

Tillering is an important agronomic trait of rice(Oryza sativa)that affects the number of effective panicles,thereby affecting yields.The phytohormone auxin plays a key role in tillering.Here we identified the high tillering and semi-dwarf 1(htsd1)mutant with auxin-deficiency root characteristics,such as shortened lateral roots,reduced lateral root density,and enlarged root angles.htsd1 showed reduced sensitivity to auxin,but the external application of indole-3-acetic acid(IAA)inhibited its tillering.We identified the mutated gene in htsd1 as AUXIN1(OsAUX1,LOC_Os01g63770),which encodes an auxin influx transporter.The promoter sequence of OsAUX1 contains many SQUAMOSA PROMOTER BINDING PROTEIN-LIKE(SPL)binding sites,and we demonstrated that SPL7 binds to the OsAUX1 promoter.TEOSINTE BRANCHED1(OsTB1),a key gene that negatively regulates tillering,was significantly downregulated in htsd1.Tillering was enhanced in the OsTB1 knockout mutant,and the external application of IAA inhibited tiller elongation in this mutant.Overexpressing OsTB1 restored the multi-tiller phenotype of htsd1.These results suggest that SPL7 directly binds to the OsAUX1 promoter and regulates tillering in rice by altering OsTB1 expression to modulate auxin signaling.

Sulfur nutrient availability regulates root elongation by affecting root indole-3-acetic acid levels and the stem cell niche

Sulfur is an essential macronutrient for plants with numerous biological functions. However, the influence of sulfur nutrient availability on the regulation of root development remains largely unknown. Here, we report the response of Arabidopsis thaliana L. root development and growth to different levels of sulfate, demonstrating that low sulfate levels promote the primary root elongation. By using various reporter lines, we examined in vivo IAA level and distribution, cell division,and root meristem in response to different sulfate levels.Meanwhile the dynamic changes of in vivo cysteine, glutathione,and IAA levels were measured. Root cysteine, glutathione, and IAA levels are positively correlated with external sulfate levels in the physiological range, which eventually affect root system architecture. Low sulfate levels also downregulate the genes involved in auxin biosynthesis and transport, and elevate the accumulation of PLT1 and PLT2. This study suggests that sulfate level affects the primary root elongation by regulating the endogenous auxin level and root stem cell niche maintenance.

AN AMPEROMETRIC BIOSENSOR BASED ON COVALENT IMMOBILIZATION OF ASCORBATE OXIDASE ON BIOCOMPATIABLE AND LOW-TOXIC POLY(THIOPHENE-3-ACETIC ACID) MATRIX

The biocompatiable and low-toxic poly（thiophene-3-aeetic acid） （PTAA） matrix was successfully electrosynthesized in ionic liquid 1-butyl-3-metbylimidazolium hexafluorophosphate （BmimPF6） in comparison with the electrosynthesis of PTAA matrix in acetonitrile （ACN）. Ascorbate oxidase （AO） was used as a model for the development and application of biosensor. Vitamin C （VC） biosensors were facilely fabricated by the covalent immobilization of AO molecules on PTAA matrices electrosynthesized in ACN containing tetrabutylammonium tetrafluoroborate and BmimPF6, respectively. Electrochemical impedance spectroscopy, scanning electron microscopy and FTIR spectroscopy indicated that AO molecules were covalently immobilized on PTAA matrices. Parameters of the as-obtained biosensors such as working potential, pH and temperature have been optimized. The amperometric biosensor based on PTAA matrix electrosynthesized in BmimPF6 exhibited wider linear range, lower detection limit, higher sensitivity and bioaffinity, and better operational and storage stability than that electrosynthesized in ACN under optimal conditions. The as-obtained biosensor based on PTAA matrix electrosynthesized in BmimPF6 was employed for the detection of VC content in comme：rcial juices, and the result was close to the data given by manufacturers. Excellent results indicate that the PTAA matrix electrosynthesized in ionic liquid is a promising platform for the covalent immobilization of biologically-active species and the development of biosensors.

ELECTROSYNTHESES OF FREE-STANDING POLY(THIOPHENE-3-ACETIC ACID) FILM IN MIXED ELECTROLYTES OF BORON TRIFLUORIDE DIETHYL ETHERATE AND TRIFLUOROACETIC ACID

High quality free-standing poly（thiophene-3-acetic acid） （PTAA）, a water-soluble polythiophene derivative, was uccessfully electrosynthesized in boron trifluoride diethyl etherate （BFEE） ＋ 25% （by volume） trifluoroacetic acid （TFA） at 9wer potential （0.38 V versus Pt）. The carboxyl group makes PTAA highly soluble in water, facilitating its potential pplication as a blue-light-emitting material. PTAA films with conductivity of 7 S cm-1 obtained from this medium showed ,etter redox activity and thermal stability. The structure and morphology of the polymer were studied by UV-Vis, FT-IR, H-NMR spectra and scanning electron microscopy, respectively.

One-step co-electrodeposition of graphene oxide doped poly(hydroxymethylated-3,4-ethylenedioxythiophene) film and its electrochemical studies of indole-3-acetic acid

A novel graphene oxide （GO） doped poly（hydroxymethylated-3,4-ethylenedioxythiophene） （PEDOTM） film has been achieved via one-step co-electrodeposition and utilized for electrochemical studies of indole-3-acetic acid （IAA）. The incorporation of GO into PEDOTM film facilitated the electrocatalytic activity and exhibited a favorable interaction between the PEDOTM/GO film and the phytohormone during the oxidation of IAA. Under optimized conditions, differential pulse voltammetry and square wave voltammetry were used for the quantitative analysis of IAA, respectively, each exhibiting a wide linearity range from 0.6 μmol L-1 to 10 μmol L-1 and 0.05 μmol L-1 to 40 μmol L-1, good sensitivity with a low detection Iimit of 0.087 μmol L-1 and 0.033μmol L T, respectively, as well as good stability. With the notable advantages of a green, sensitive method, expeditious response and facile operation, the as-prepared PEDOTM/GO organic-inorganic composite film provides a promising platform for electrochemical studies of IAA.