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Research of the relationship of intracellular acidification and apoptosis in Hela cells based on pH nanosensors

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Science China Chemistry 2007年第2期50卷 258-265页

作者： HE XiaoXiao wang Yan wang kemin PENG JiaoFeng LIU Fang TAN WeiHong State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry&Chemical EngineeringInstitute of Bio-logical TechnologyHunan UniversityChangsha 410082China Engineering Center for Biomedicine Hunan UniversityChangsha 410082China Institute of Life Science and Biological Technology Hunan UniversityChangsha 410082China Engineering Research Center for Bio-Nanotechnology of Hunan Province Changsha 410082China

In this paper,the relationship of intracellular acidification and apoptosis in Hela cells induced by vin-cristine sulfate has been studied by use of the ratiometric pH nanosensors that have been developed by our group,employing fluorescein isothiocyanate(FITC) doped as the pH-sensitive dye and Tris(2,2'-bipyidyl) dichlororuthenium(II) hexahydrate(RuBpy) doped as reference dye. The pH change of the Hela cells induced by vincristine sulfate has been monitored in vivo,in situ and real time by use of the ratiometric pH nanosensors. The experimental results show that the pH of the apoptotic Hela cells induced by vincristine sulfate has been acidified from 7.11 to 6.51,and the percentage of intra-cellular acidification is correlated with the induced concentration and incubation time of the vincristine sulfate. The further study of the percentage of intracellular acidification and the percentage of apop-tosis of Hela cells at the same time reveals that apoptosis of Hela cells induced by vincristine sulfate is preceded by intracellular acidification. These results would provide theoretical foundation for the therapy of cancer through interfering the pH of cells by use of vincristine sulfate or other anti-cancer drugs.

关键词： ratiometric pH nanosensors vincristine sulfate Hela cells intracellular acidification apoptosis of cells

Temperature-sensitive goldnanotube array membranes modified with poly(N-isopropylacrylamide)

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Chinese Science Bulletin 2008年第5期53卷 727-732页

作者： YANG XiaoHai WU YingBen wang Qing wang kemin wang ShengFeng Biomedical Engineering Center State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and ChemicalEngineering Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province Hunan University Changsha 410082 China

A kind of temperature-sensitive nanotube array membrane was developed by modifying gold-nanotube array membranes with poly(N-isopropylacrylamide) (PNIPAm). The permeation ability of the mem-branes at different temperatures was investigated using sodium fluorescein and quantum dots as probes. The results showed that the pore diameter of nanotube was changed due to the reversible re-sponse of PNIPAm-modified membranes to temperature, and then the permeation ability of the mem-branes was changed. The permeation of fluorescence probes was slow and even almost blocked at 25℃ (below the lower critical solution temperature, LCST), since PNIPAm formed expanded structures and decreased the pore size. While at 40℃ (above the LCST), the permeation was increased, since PNIPAm became compact structures and the pore diameter was increased. Furthermore, the permea-tion ability of the temperature-sensitive nanotube array membranes could be adjusted reversibly and it is possible to use the membranes in nanofluidic devices, nanogates, etc.

关键词：金纳米管阵列纳米薄膜温度敏感性纳米技术

A pH-responsive activatable aptamer probe for targeted cancer imaging based on i-motif-driven conformation alteration

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Science China Chemistry 2016年第7期59卷 802-808页

作者： Lv'an Yan Hui Shi Dinggeng He Xiaoxiao He kemin wang Fengzhou Xu State Key Laboratory of Chemo/Biosensing and Chemometrics Hunan University Changsha 410082 China College of Biology Hunan University Changsha 410082 China College of Chemistry and Chemical Engineering Hunan University Changsha 410082 China Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province Hunan University Changsha 410082 China

We present here a pH-responsive activatable aptamer probe for targeted cancer imaging based on i-motif-driven conformation alteration. This pH-responsive activatable aptamer probe is composed of two single-stranded DNA. One was used for target recognition, containing a central, target specific aptamer sequence at the 3＇-end and an extension sequence at the 5＇-end with 5-carboxytetramethylrhodamine （TAMRA） label （denoted as strand A）. The other （strand ｜）, being competent to work on the formation of i-motif structure, contained four stretches of the cytosine （C） rich domain and was labeled with a Black Hole Quencher 2 （BHQ2） at the 3＇-end. At neutral or slightly alkaline pH, strand ｜ was hybridized to the extension sequence of strand A to form a double-stranded DNA probe, termed i-motif-based activatable aptamer probe （I-AAP）. Because of proximity- induced energy transfer, the I-AAP was in a ＂signal off＇ state. The slightly acidic pH enforced the strand I to form an intramo- lecular i-motif and then initiated the dehybridization of I-AAP, leading to fluorescence readout in the target recognition. As a demonstration, AS1411 aptamer was used for MCF-7 cells imaging. It was displayed that the I-AAP could be carried out for target cancer cells imaging after being activated in slightly acidic environment. The applicability of I-AAP for tumor tissues imaging has been also investigated by using the isolated MCF-7 tumor tissues. These results implied the I-AAP strategy is promising as a novel approach for cancer imaging.

关键词： aptamer pH-responsive activatable probe cancer cell imaging i-motif tissue imaging

Phase-separated bienzyme compartmentalization as artificial intracellular membraneless organelles for cell repair

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Science China Chemistry 2023年第3期66卷 845-852页

作者： Yanwen Zhang Shixin wang Yuling Yan Xiaoxiao He Zefeng wang Shaohong Zhou Xiaohai Yang kemin wang Jianbo Liu State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringKey Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan ProvinceHunan UniversityChangsha 410082China

Implanting artificial organelles in living cells is capable of correcting cellular dysfunctionalities for cell repair and biomedical applications. In this work, phase-separated bienzyme-loaded coacervate microdroplets are established as a model of artificial membraneless organelles in endothelial dysfunctional cells for the cascade enzymatic production of nitric oxide(NO) with a purpose of correcting cellular NO deficiency. We prepared the coacervate microdroplets via liquid-liquid phase separation of oppositely charged polyelectrolytes, in which glucose oxidase/horseradish peroxidase-mediated cascade reaction was compartmented. After the coacervate microdroplets were implanted in NO-deficient dysfunctional cells, the compartments maintained a phase-separated liquid droplet structure, which facilitated a significant enhancement of NO production in the dysfunctional cells. The recovery of NO production was further exploited to inhibit clot formation in blood plasma located in the cell suspension. This demonstrated a proof-of-concept design of artificial organelles in dysfunctional cells for cell repair and anticoagulation-related medical applications. Our results demonstrate an approach for the construction of coacervate droplets through phase separation for the generation of artificial membraneless organelles, which can be designed to provide an array of functionalities in living organisms that have the potential to be used in the field of cell engineering and medical therapy.

关键词： artificial membraneless organelles coacervate microdroplets nitric oxide liquid-liquid phase separation cell repair

Pledgee competition, strategic disclosure, and future crash risk

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China Journal of Accounting Research 2019年第3期12卷 271-291页

作者： Xiaoxi Li Jing Liu kemin wang School of Management Jinan UniversityChina School of Accounting Capital University of Economics and BusinessChina School of Management Fudan UniversityChina

We investigate whether pledgee competition affects the disclosure choice of firms whose controlling shareholders pledge their *** find that pledgee competition is positively related to pledge firms’ annual report tone *** positive relationship is stronger for pledge firms with lower credit quality and non-state-owned enterprise pledge *** corroborating our results, higher pledgee competition increases the future crash risk of pledge ***, our results suggest that competition pressure induces pledgees to lower their monitoring incentives to remain competitive in the marketplace, thus leading to pledge firms’ bad news hoarding behavior.

关键词： Share pledge Pledgee competition Tone management

China-US trade dispute investigations and corporate earnings management strategy

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China Journal of Accounting Research 2020年第4期13卷 339-359页

作者： Dongdong Li Fan Shi kemin wang School of Accounting Zhongnan University of Economics and LawChina School of Management Fudan UniversityChina

This paper studies Chinese firms’earnings management strategy in response to the trade dispute investigations initiated by the *** 2001 to *** topic is important given the increasingly severe international trade environment and the significant influence of macro economy on financial *** find that firms affected by the U.S.-initiated trade dispute investigations engage in more upward earnings ***,the result is more pronounced in firms with a more negative market reaction around the announcement of the ***-sectional tests provide evidence that the positive relation is stronger among firms whose *** revenue and management ownership is high,firms in provinces with weak investor protection,and firms that performed well one year after initiation of the ***,investors react positively to the earnings management by the affected *** results are robust to a variety of sensitivity ***,our findings suggest that companies will manage their earnings upward to mitigate the negative impacts of the U.S.-initiated trade dispute investigations.

关键词： China-US trade disputes Earnings management Market valuation

mRNA detection in living cell using phosphorothioate-modified molecular beacon

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Chinese Science Bulletin 2009年第9期54卷 1507-1514页

作者： TANG HongXing YANG XiaoHai wang kemin TAN WeiHong LI Wei State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical Engineering Biomedical Engineering Center and Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province Hunan University Changsha 410082 China

In this study, GFP mRNA in COS-7 cell and GFP-transfected COS-7 cell was detected in real time using phosphorothioate-modified molecular beacon based on living cell imaging method. Results showed that phosphorothioate-modified molecular beacon still kept the advantages of molecular beacon, such as, excellent selectivity, high sensitivity, and no separation detection. In addition, this modification could significantly increase the nuclease resistance of molecular beacon. Phosphorothioate-modified molecular beacon can efficiently reduce the false positive signal and improve the accuracy of living cell mRNA detection.

关键词：分子信标分离检测 mRNA 活细胞灯塔绿色荧光蛋白基因 ph 基因转染

NIR-triggered drug delivery system based on phospholipid coated ordered mesoporous carbon for synergistic chemo-photothermal therapy of cancer cells

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Chinese Chemical Letters 2020年第12期31卷 3158-3162页

作者： Anman Zhang Luo Hai Tianzheng wang Hong Cheng Man Li Xiaoxiao He kemin wang State Key Laboratory of Chemo/Biosensing and Chemometrics College of BiologyCollere of chemistry and Chemical EngineerigHunan Uiverity ste keyLaboratory for Bic-Nanotechnology and Molecular Engineering of Hunan ProvinceChargsha 410082China

Chemo-photothermal treatment is one of the most efficient strategies for cancer ***,traditional drug carriers without near-infrared absorption capacity need to be loaded with materials behaving photothermal properties,as it results in complicated synthesis process,inefficient photothermal effects and hindered NIR-mediated drug *** we report a facile synthesis of a polyethylene glycol(PEG)linked liposome(PEG-liposomes)coated doxorubicin(DOX)-loaded ordered mesoporous carbon(OMC)nanocomponents(PEG-LIP@OMC/DOX)by simply sonicating DOX and OMC in PEG-liposomes *** as-obtained PEG-LIP@OMC/DOX exhibits a nanoscale size(600±15 nm),a negative surface potential(-36.70 mV),high drug loading(131.590 mg/g OMC),and excellent photothermal *** PEG-LIP@OMC/DOX can deliver loaded DOX to human MCF-7 breast cancer cells(MCF-7)and the cell toxicity viability shows that DOX unloaded PEG-LIP@OMC has no cytotoxicity,confirming the PEG-LIP@OMC itself has excellent *** NIR-triggered release studies demonstrate that this NIR-responsive drug delivery system enables on-demand drug ***,cell viability results using human MCF-7 cells demonstrated that the combination of NIR-based hyperthermal therapy and triggered chemothe rapy can provide higher therapeutic efficacy than re spective monothe *** these excellent features,we believe that this phospholipid coating based multifunctional delivery system strategy should promote the application of OMC in nanomedical applications.

关键词： Ordered mesoporous carbon Polyethylene glycol linked liposomes Stimuli-responsive drug delivery system NIR-triggered drug delivery Chemo-photothermal therapy

A photosensitizer-loaded zinc oxide-polydopamine core-shell nanotherapeutic agent for photodynamic and photothermal synergistic therapy of cancer cells

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Chinese Chemical Letters 2020年第1期31卷 189-192页

作者： Ri Wu Huizhen wang Luo Hai Tianzheng wang Min Hou Dinggeng He Xiaoxiao He kemin wang State Key Laboratory of Chemo/Biosensing and Chemometrics College of Chemistry and Chemical EngineeringHunan UniversityChangsha 410082China Key Laboratory for Bio-Nanotechnology and Molecular Engineering of Hunan Province College of BiologyHunan UniversityChangsha 410082China

In clinical cancer research,it is quite promising to develop multimodal synergistic therapeutic *** and photothermal synergistic therapy is a very desirable multimodal therapy ***,we report a facile and simple method to construct a nanotherapeutic agent for photodynamic and photothermal *** nanotherapeutic agent(ZnO@Ce6-PDA)is composed of a ZnO nanoparticle core,an interlayer of photosensitizer chlorin e6(Ce6)and an outer layer of polydopamine(PDA).Due to the existence of Ce6,the ZnO@Ce6-PDA can efficiently generate singlet oxygen(1O2)under 660 nm laser ***,the ZnO@Ce6-PDA can serve as a photothermal agent,because of the excellent photothermal conversion efficiency of the PDA coating layer in the presence of 780 nm *** results demonstrated that the designed nanotherapeutic agent had outstanding phototoxicity upon the combination of laser irradiation at 660 and 780 ***,our work proves that the ZnO@Ce6-PDA is a promising photodynamic/photothermal dual-modal nanotherapeutic agent for enhanced cancer therapy.

关键词： Ce6 Polydopamine Photodynamic therapy Photothermal therapy