查找使用阿拉丁产品的科研文献

pH-responsive polymer assisted aptamer functionalized magnetic nanoparticles for specific recognition and adsorption of proteins

Liping Zhao,Linsen Li,Chao Zhu,Murtaza Ghulam,Feng Qu

A new adsorbent based on pH-responsive polymer assisted aptamer functionalized magnetic nanoparticles was developed for specific recognition and efficient adsorption of proteins . Arising from the synergistic effect of specific affinity of apatamer on protein and tunable hydrophobic/hydrophilic property of pH-responsive polymer, the adsorbent exhibited excellent adsorption capacity for target protein. Notably, because of the pH-responsive property of the polymer, the adsorption and desorption process could be regulated through varying environmental pH. The resultant adsorbent that immobilized with lysozyme binding aptamer was successfully applied in specific recognition and efficient adsorption of lysozyme in egg white samples and good recovery results in the range of 95.2–103.2% were obtained. Moreover, the adsorbent immobilized with cytochrome C binding aptamer also exhibited satisfactory adsorption to cytochrome C. The synergistic effect of pH-responsive polymer and aptamer promoted the recognition selectivity and adsorption capacity to target protein, illustrating a facile way for construction of more specific protein adsorbents.

Development of oral curcumin based on pH-responsive transmembrane peptide-cyclodextrin derivative nanoparticles for hepatoma

Tiantian Wei,Yin Zhang,Meng Lei,Yanru Qin,Zhongjie Wang,Zhimeng Chen,Liefeng Zhang,Yongqiang Zhu

Herein, a pH-responsive cyclodextrin derivative (R6H4-CMβCD) with cell-penetrating ability was successfully synthesized, and curcumin-loaded nanoparticles (R6H4-CMβ [email protected] NPs, RCCNPs) were developed to improve its efficacy in hepatoma. RCCNPs could improve the cell uptake compared with CMβ [email protected] NPs (CCNPs) and were internalized into cells mainly through endocytosis mediated by reticulin and macropinocytosis . Furthermore, the accumulation of RCCNPs in hepatoma cells at pH 6.4 was higher than that at pH 7.4, indicating a pH-responsive uptake. Additionally, RCCNPs could escape from the lysosomes via the “proton sponge effect”, and a high apoptosis rate was detected. Importantly, in vivo experiments revealed that orally administered RCCNPs could exert excellent anti-cancer effects in tumor-bearing mice. Hematoxylin-eosin staining did not show significant histological changes in the major organs. Thus, our findings indicate the potential of R6H4-CMβCD as a nanopharmaceutical material, and RCCNPs as an effective delivery system for oral curcumin in cancer management.

Effect of precursor pH value on the structure and electrical properties of Bi1.5Zn1.0Nb1.5O7 thin films

Kailong Wei,Helei Dong,Qiulin Tan,Wenfang Kang,Shihui Yu,Jijun Xiong

Bi 1.5 Zn 1.0 Nb 1.5 O 7 (BZN) thin films are synthesized on a FTO (Fluorine -doped SnO 2 transparent conductive glass) substrate by an improved sol-gel method. The pH of the precursor is controlled by citric acid and ammonia, and the effect of pH on the crystal structure and electrical properties of the BZN films is studied. When the precursor pH is 5, the relative intensity of the diffraction peak of BZN films is the highest, the FWHM is the narrowest, and the crystallization degree is the highest, compared to those of BZN films synthesized from precursors at other pH, the crystallization energy offset of the element binding energy of the thin films is the smallest and the phase difference of the binding energy is the closest to the theoretical value, and the films have excellent electrical properties with permittivity of 120, loss tangent of 0.003, tunability of 14.8%, breakdown voltage of 0.43 MV/cm and energy storage density of 9.82 × 10 −2  J/cm 3 .

pH/Thermosensitive dual-responsive hydrogel based sequential delivery for site-specific acute limb ischemia treatment

Teng Zhang,Huan Ouyang,Shichen Liu,Lei Xiong,Zhiwei Zhong,Qingqing Wang,Zhuang Qiu,Yajia Ding,Weimin Zhou,Xiaolei Wang

Acute limb ischemia (ALI) is the most severe manifestation of peripheral artery disease, accompanied by pH/temperature-microenvironment changes in two different phases. In the acute phase, temperature and pH are significantly decreased, and reactive oxygen species (ROS) are excessively generated owing to the sharp reduction of blood perfusion. Afterwards, in the chronic phase, although the temperature gradually recovers, angiogenesis is delayed due to chronic vascular injury, skeletal muscle cell apoptosis and endothelial cell dysfunction. Current therapeutic strategies mainly focus on recanalization; however, their effects on scavenging ROS in the acute phase and promoting angiogenesis in the chronic phase are quite limited. Herein, an injectable pH and temperature dual-responsive poloxamer 407 (PF127)/hydroxymethyl cellulose (HPMC)/sodium alginate (SA)-derived hydrogel (FHSgel), encapsulating melatonin and diallyl trisulfide-loaded biodegradable hollow mesoporous silica nanoparticles (DATS@dHMSNs), is developed, which can intelligently respond to the different phases of ALI. In the acute phase of ischemia, the decreased pH results in the rapid release of melatonin to scavenge excessive ischemia-induced ROS. On the other hand, in the chronic repair phase, the recovered temperature triggers the sustained release of DATS@dHMSNs from the FHSgel, thus generating hydrogen sulfide (H2S) to enhance the angiogenesis and microcirculation reconstruction of ischemic limbs.

NIR imaging-guided combined photodynamic therapy and chemotherapy by a pH-responsive amphiphilic polypeptide prodrug

Zheng Ruan,Le Liu,Wei Jiang,Shuya Li,Yucai Wang,Lifeng Yan

pH-Sensitive doxorubicin conjugated polymeric micelles entrapped with near infrared (NIR) photosensitizer BODIPY (which works as an imaging agent at the same time) were designed and synthesized by ring opening polymerization of N-carboxyanhydride with mPEG-NH2 as the initiator, following reaction with doxorubicin to form the hydrazone-bond linker for pH responsiveness. Then the NIR dye (BODIPY) was loaded in the micelles for both bioimaging and photodynamic therapy (PDT). A significant cytotoxicity of NIR imaging-guided combined PDT and chemotherapy could be found by MTT assays, which was also confirmed with a fluorescence microscope, indicating a new kind of polymeric nanoparticle for potential theranostic treatment of cancers. In addition, the energy density of the laser for the PDT is extremely low.

pH-Sensitive Polypeptide Conjugated with Carborane Clusters and Cyanine for NIR Bioimaging and Multi-Therapies

Ruan Zheng,Yuan Pan,Jing Titao,Xing Tao,Yan Lifeng

A novel pH-sensitive carborane and cyanine dye conjugated polypeptide and its micelles has been designed and synthesized for potential near infrared fluorescence imaging-guided boron neutron capture therapy (BNCT). The amphiphilic polymer we synthesized with tertiary amine as functional group could self-assemble to micelle nanoparticles at neutral pH, and responsive to acidic solution for the disassembly of the micelles for drug release. The tertiary amine sensitive induced process was observed via dynamic light scattering (DLS) and transmission electron microscopy (TEM). The efficiency of cell killing ability is studied by MTT assays and fluorescence microscope measurement, indicating a new intelligent system for potential NIR imaging-guided therapy.

A pH-responsive nanocontainer based on hydrazone-bearing hollow silica nanoparticles for targeted tumor therapy

Liangliang Dai,Qingfeng Zhang,Xinkun Shen,Qiang Sun,Caiyun Mu,Hao Gu,Kaiyong Cai

A pH-responsive drug delivery system based on hollow mesoporous silica nanoparticles (HMSNs) was fabricated for targeted tumor therapy by using hydrazone bonds as pH-sensitive linkers and hyaluronic acid (HA) molecules as both blocking and targeting agents. HMSNs were synthesized with good dispersion and dimensions of around 88 nm. Detailed material characterisation suggested that the drug delivery system was successfully constructed. It displayed a fast pH stimulus response for controlled drug release in vitro. Besides, systematic biological investigations revealed that the drug delivery system had good biocompatibility, which could effectively target tumor cells and deliver therapeutic cargo to induce tumor cell apoptosis in vitro and suppression of tumor growth in vivo. This study reports a promising drug delivery system for potential clinical application against tumor therapy.

Acute and chronic toxicity of tetrabromobisphenol A to three aquatic species under different pH conditions

Qun He,Xinghao Wang,Ping Sun,Zunyao Wang,Liansheng Wang

Tetrabromobisphenol A (TBBPA) is a well-known brominated flame retardant. It has been detected in the environment and shows high acute toxicity to different organisms at high concentrations. In this work, the effects of pH and dimethyl sulfoxide (DMSO) on the acute toxicity of TBBPA to Daphnia magna and Limnodrilus hoffmeisteri were tested, and the oxidative stress induced by TBBPA in livers of Carassius auratus was assessed using four biomarkers. The integrated biomarker response (IBR) was applied to assess the overall antioxidant status in fish livers. Moreover, fish tissues (gills and livers) were also studied histologically. The results showed that low pH and DMSO enhanced the toxicity of TBBPA. Furthermore, changes in the activity of antioxidant enzymes and glutathione level suggested that TBBPA generates oxidative stress in fish livers. The IBR index revealed that fish exposed to 3   mg/L TBBPA experienced more serious oxidative stress than exposed to acidic or alkaline conditions. The histopathological analysis revealed lesions caused by TBBPA. This study provides valuable toxicological information of TBBPA and will facilitate a deeper understanding on its potential toxicity in realistic aquatic environments.

Protocol for Proximity-Dependent Proteomic Profiling in Yeast Cells by APEX and Alk-Ph Probe

Yi Li,Keke Liu,Ying Zhou,Jing Yang,Peng Zou

Summary Alk-Ph is a clickable APEX2 substrate developed for spatially restricted protein/RNA labeling in intact yeast cells. Alk-Ph is more water soluble and cell wall permeable than biotin-phenol substrate, allowing more efficient profiling of the subcellular proteome in microorganisms. We describe the protocol for Alk-Ph probe synthesis, APEX2 expression, and protein/RNA labeling in yeast and the workflow for quantitative proteomic experiments and data analysis. Using the yeast mitochondria as an example, we provide guidelines to achieve high-resolution mapping of subcellular yeast proteome and transcriptome. For complete details on the use and execution of this protocol, please refer to Li et al. (2020) .

Co-delivery of erlotinib and doxorubicin by pH-sensitive charge conversion nanocarrier for synergistic therapy

Yongju He,Zhigui Su,Lingjing Xue,Hui Xu,Can Zhang

Pretreatment of lung cancer cells with epidermal growth factor receptor (EGFR) inhibitor erlotinib has been recently reported that could dramatically synergize their apoptotic response to DNA damage agent doxorubicin (DOX). To translate this synergistic therapy into in vivo anticancer therapy and clinical practice, we designed a novel pH-sensitive charge conversion nanocarrier (M-HHG 2 C 18 -L) that contained erlotinib/DOX combination and produced a sequential staggered drug release for synergistic lung cancer therapy. In this study, a synthetic zwitterionic oligopeptide lipid (1,5-dioctadecyl- l -glutamyl2-histidyl-hexahydrobenzoic acid, HHG 2 C 18 ) was used to construct a pH-sensitive lipid bilayer (HHG 2 C 18 -L), which was subsequently applied to coat amino-functionalized mesoporous silica nanoparticles (MSN-NH 2 ). Erlotinib and DOX were separately incorporated into HHG 2 C 18 -L and MSN-NH 2 respectively to obtain pH-sensitive charge conversion erlotinib/DOX co-delivery nanoparticles (M-HHG 2 C 18 -L(E   +   D)). We confirmed that M-HHG 2 C 18 -L(E   +   D) were able to reverse surface zeta potential from negative to positive at tumor extracellular pH, thus facilitating the targeted cancer cell internalization. Furthermore, as erlotinib was sequestered in the exterior lipid bilayer and the controlled release ability of MSN-NH 2 , erlotinib released faster than DOX during the cellular transport. Additionally, HHG 2 C 18 -L became more positive at tumor intracellular pH and enhanced Coulombic repulsion with MSN-NH 2 , leading to increased sequential staggered release of erlotinib and DOX. Due to the pretreatment and time-staggered inhibition of EGFR with erlotinib and the enhanced intracellular release of DOX to the nucleus, the maximized synergistic cell killing effect was achieved. Compared to non-sensitive erlotinib/DOX co-delivery nanoparticles (M-SPC-L(E   +   D)) and simultaneous DRUG coadministration. M-HHG 2 C 18 -L(E   +   D) with sequential staggered drug release and pH-sensitive charge conversional properties showed great synergistic effects in antiproliferation and apoptosis of A549 human cancer cells in vitro. The in vivo study demonstrated that M-HHG 2 C 18 -L(E   +   D) exhibited considerable tumor accumulation and potent suppression of tumor growth in Lewis lung carcinoma tumor bearing mice. It was also demonstrated that M-HHG 2 C 18 -L(E   +   D) showed no systemic toxicity and possessed distinguished effect on extending survival period. These results suggested that M-HHG 2 C 18 -L(E   +   D) had great potential application in cancer treatment.

A novel ratiometric fluorescent probe for the detection of mitochondrial pH dynamics during cell damage

Gaoqing Fu,Guoxing Yin,Tingting Niu,Wei Wu,Hui Han,Haimin Chen,Peng Yin

A sensitive fluorescent probe (E)-4-(3-(benzo[d]thiazol-2-yl)-4-hydroxy-5-methylstyryl)-1-methylpyridin-1-ium iodide (HBTMP) for the monitoring of pH in mitochondria was rationally exploited. This novel probe exhibited remarkable pH-dependent behavior in the linear range of 5.5–8.0, along with a pKa value of 6.829 ± 0.02627. A large Stokes shift of 205 nm was obtained. This fluorescent probe demonstrated good biocompatibility and high sensitivity for detecting the dynamic changes in mitochondrial pH in living cells and zebrafish. The results of the CCCP (m-chlorophenyl hydrazone) treatment experiment indicated that the probe can effectively monitor changes in mitochondrial pH caused by cell damage.

Folate-mediated and pH-responsive chidamide-bound micelles encapsulating photosensitizers for tumor-targeting photodynamic therapy

Zhiqiang Ma,Pengwei Hu,Changyong Guo,Dan Wang,Xingjie Zhang,Min Chen,Qirong Wang,Miao Sun,Peiyu Zeng,Fengkun Lu,Linhong Sun,Lan She,Hongtao Zhang,Jianzhong Yao,Feng Yang