JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE
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2013
·Vol. 94
·期 8
·1614-1621
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IF 1.759
Xiao-Li Qin,Dong-Ming Lan,Jin-Feng Zhong,Lu Liu,Yong-Hua Wang,Bo Yang
BACKGROUND T1 lipase has received considerable attention due to its thermostability. Fatty acid specificity of T1 lipase (crude and purified) was investigated, and its potential in the synthesis of acylglycerols was also evaluated . RESULTS Fatty acid specificity of T1 lipase (crude and purified) was investigated in the esterification of fatty acids (C6:0 to C18:3), suggesting that crude and purified T1 lipase had the lowest preference for C18:0 [specificity constant (1/ α ) = 0.08] followed by C18:1 (1/ α = 0.12) and showed the highest preference for C8:0 (1/ α = 1). A structural model was constructed to briefly explore interactions between the lipase and its substrate. Furthermore, crude T1 lipase-catalysed synthesis of diacylglycerols (DAGs) and monoacylglycerols (MAGs) by esterification of glycerol with C18:1 was studied for evaluating its potential in acylglycerols synthesis. The optimal conditions were glycerol/oleic acid molar ratio 5:1, the lipase concentration 9.7 U g −1 of substrates, water content 50 g kg −1 of substrates and temperature 50 °C, which yielded 42.25% DAGs, 26.34% MAGs and 9.18% triacylglycerols at 2 h . CONCLUSION DAGs and MAGs were synthesised in good yields although C18:1 (a much poorer substrate) was used. Our work demonstrates that T1 lipase, which was discovered to show 1,3-regio-selectivity, is a promising biocatalyst for lipids modification. © 2013 Society of Chemical Industry
研究领域:
生物化学
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酶工程
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PubMed
高影响因子
Science China-Materials
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2024
·Vol. 67
·期 12
·4101-4110
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IF 6.8
Luo Meng,Guo Jiajing,Zhu Yi,Deng Jiali,Lu Hongwei,Li Lei,Wang Zhongling
Acidity-activatable magnetic resonance imaging (MRI) nanoprobes offer great potential for in vivo cancer imaging by targeting the acidic tumor microenvironment (TME). However, their effectiveness is limited by the delayed response at tumor sites and uncontrollable background noise, compromising imaging accuracy and reliability. Herein, an acidic TME-responsive nanoprobe, SPIO@ZIF-8@Gd (SZG), with dually activatable T 1 and T 2 MR signals is shown for acidity-selective contrast enhancement in a rapid response manner. It shows decreased T 1 and T 2 contrast intensity in normal physiological conditions. Once targeting acidic TME, the zeolitic imidazolate framework-8 (ZIF-8) layer undergoes instantaneous decomposition, releasing Gd 3+ ( T 1 -weighted), and exposing the inner SPIO ( T 2 -weighted) core, thereby sequentially recovering the signals. Compared to previously reported T 1 - T 2 nanoprobes, SZG demonstrates noticeable “dual activation” after just 30 min and reaches its peak 4 h after acid incubation. Additionally, it shows an excellent “acidity correlation” between relaxation times and pH values. When the SZG nanoprobe is used combined with “dual-contrast enhanced subtraction (DESI)”, the contrast difference between diseased and normal tissue can be increased by 10 times, which is significantly higher than traditional single-mode T 1 / T 2 contrast agents. Collectively, these findings demonstrate a rapid imaging strategy of dual-activation MR imaging of the acidic TME and simultaneous background suppression, thus paving the way for precise tumor malignancy differentiation, early tumor detection, and accurate tumor grading.
研究领域:
医学影像学
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生物材料学
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DOI
高影响因子
Theranostics
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2016
·
IF 8.854
Zhengyang Jia,Lina Song,Fengchao Zang,Jiacheng Song,Wei Zhang,Changzhi Yan,Jun Xie,Zhanlong Ma,Ming Ma,Gaojun Teng,Ning Gu,Yu Zhang
Developing ultrasensitive contrast agents for the early detection of malignant tumors in liver is highly demanded. Constructing hepatic tumors specific targeting probes could provide more sensitive imaging information but still faces great challenges. Here we report a novel approach for the synthesis of ultra-small Fe 3 O 4 nanoparticles conjugated with c(RGDyK) and their applications as active-target T 1 -weighted magnetic resonance imaging (MRI) contrast agent (T 1 -Fe 3 O 4 ) for imaging tiny hepatic tumors in vivo . RGD-modified T 1 -Fe 3 O 4 nanoprobes exhibited high r 1 of 7.74 mM -1 s -1 and ultralow r 2 /r 1 of 2.8 at 3 T, reflecting their excellent T 1 contrast effect at clinically relevant magnetic field. High targeting specificity together with favorable biocompatibility and strong ability to resist against non-specific uptake were evaluated through in vitro studies. Owing to the outstanding properties of tumor angiogenesis targeting with little phagocytosis in liver parenchyma, hepatic tumor as small as 2.2 mm was successfully detected via the T 1 contrast enhancement of RGD-modified T 1 -Fe 3 O 4 . It is emphasized that this is the first report on active-target T 1 imaging of hepatic tumors, which could not only significantly improve diagnostic sensitivity, but also provide post therapeutic assessments for patients with liver cancer.
研究领域:
医学影像学
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纳米医学
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肿瘤学
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DOI
PubMed
高影响因子
Theranostics
·
2019
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IF 8.063
Yuqing Miao,Qian Xie,Huan Zhang,Jing Cai,Xiaoli Liu,Ju Jiao,Shanshuang Hu,Anujit Ghosal,Yu Yang,Haiming Fan
The development of a highly efficient, low-toxicity, ultrasmall ferrite nanoparticle-based T 1 contrast agent for high-resolution magnetic resonance imaging (MRI) is highly desirable. However, the correlations between the chemical compositions, in vitro T 1 relaxivities, in vivo nano-bio interactions and toxicities remain unclear, which has been a challenge in optimizing the in vivo T 1 contrast efficacy. Methods : Ultrasmall (3 nm) manganese ferrite nanoparticles (Mn x Fe 3-x O 4 ) with different doping concentrations of the manganese ions (x = 0.32, 0.37, 0.75, 1, 1.23 and 1.57) were used as a model system to investigate the composition-dependence of the in vivo T 1 contrast efficacy. The efficacy of liver-specific contrast-enhanced MRI was assessed through systematic multiple factor analysis, which included the in vitro T 1 relaxivity, in vivo MRI contrast enhancement, pharmacokinetic profiles (blood half-life time, biodistribution) and biosafety evaluations ( in vitro cytotoxicity testing, in vivo blood routine examination, in vivo blood biochemistry testing and H&E staining to examine the liver). Results : With increasing Mn doping, the T 1 relaxivities initially increased to their highest value of 10.35 mM -1 s -1 , which was obtained for Mn 0.75 Fe 2.25 O 4 , and then the values decreased to 7.64 m M -1 s -1 , which was obtained for the Mn 1.57 Fe 1.43 O 4 nanoparticles. Nearly linear increases in the in vivo MRI signals (ΔSNR) and biodistributions (accumulation in the liver) of the Mn x Fe 3-x O 4 nanoparticles were observed for increasing levels of Mn doping. However, both the in vitro and in vivo biosafety evaluations suggested that Mn x Fe 3-x O 4 nanoparticles with high Mn-doping levels (x > 1) can induce significant toxicity. Conclusion : The systematic multiple factor assessment indicated that the Mn x Fe 3-x O 4 (x = 0.75-1) nanoparticles were the optimal T 1 contrast agents with higher in vivo efficacies for liver-specific MRI than those of the other compositions of the Mn x Fe 3-x O 4 nanoparticles. Our work provides insight into the optimization of ultrasmall ferrite nanoparticle-based T 1 contrast agents by tuning their compositions and promotes the translation of these ultrasmall ferrite nanoparticles for clinical use of high-performance contrast-enhanced MRI.
研究领域:
医学影像学
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纳米医学
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材料科学
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产品关联
DOI
PubMed
高影响因子
Nature Communications
·
2022
·Vol. 13
·期 1
·1-12
·
IF 17.694
Lu Hongwei,Chen An,Zhang Xindan,Wei Zixiang,Cao Rong,Zhu Yi,Lu Jingxiong,Wang Zhongling,Tian Leilei
Magnetic resonance imaging (MRI) is a non-invasive imaging technology to diagnose health conditions, showing the weakness of low sensitivity. Herein, we synthesize a contrast agent, SPIO@SiO 2 @MnO 2 , which shows decreased T 1 and T 2 contrast intensity in normal physiological conditions. In the acid environment of tumor or inflamed tissue, the manganese dioxide (MnO 2 ) layer decomposes into magnetically active Mn 2+ (T 1 -weighted), and the T 1 and T 2 signals are sequentially recovered. In addition, both constrast quenching-activation degrees of T 1 and T 2 images can be accurately regulated by the silicon dioxide (SiO 2 ) intermediate layer between superparamagnetic iron oxide (SPIO) and MnO 2 . Through the “dual-contrast enhanced subtraction” imaging processing technique, the contrast sensitivity of this MRI contrast agent is enhanced to a 12.3-time difference between diseased and normal tissue. Consequently, SPIO@SiO 2 @MnO 2 is successfully applied to trace the tiny liver metastases of approximately 0.5 mm and monitor tissue inflammation.
研究领域:
医学影像
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癌症研究
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材料科学
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生物医学工程
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DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2018
·Vol. 28
·期 32
·1802281
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IF 13.325
Chen Bai,Zhengyang Jia,Lina Song,Wei Zhang,Yi Chen,Fengchao Zang,Ming Ma,Ning Gu,Yu Zhang
To achieve the accurate diagnosis of tumor with the magnetic resonance imaging (MRI), nanomaterials-based contrast agents are developed rapidly. Here, a tumor targeting nanoprobe of c(RGDyK) modified ultrasmall sized iron oxide is reported with high saturation magnetization and high T 1 -weighted imaging capability, attributed to a large number of paramagnetic centers on the surface of nanoprobes and rapid water proton exchange rate (inner sphere model), as well as strong superparamagnetism (outer sphere model). These nanoprobes could actively target and gradually accumulate at the tumor site with a time-dependent T 1 –T 2 contrast enhancement imaging effect. In in vivo MRI experiments, the nanoprobes exhibit the best T 1 contrast enhancement at 30 min after intravenous administration, followed by gradually vanishing and generating T 2 contrast enhancement with increasing time at tumor site. This is likely due to time-dependent nanoprobes aggregation in tumor, in good agreement with in vitro experiment where aggregated nanoprobes display larger r 2 / r 1 value (19.1) than that of the dispersed nanoprobes (2.8). This dynamic property is completely different from other T 1 -T 2 dual-modal nanoprobes which commonly exhibit the T 1 - and T 2 -weighted enhancement effect at the same time. To sum up, these c(RGDyK) modified ultrasmall Fe 3 O 4 nanoprobes have significant potential to improve the diagnostic accuracy and sensitivity in MRI.
研究领域:
生物医学工程
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纳米医学
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影像诊断学
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DOI
高影响因子
ACS Applied Bio Materials
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2018
·
IF 0
Guohai Liang,Jiamei Han,Qiubo Hao
Extremely small-sized iron oxide nanoparticles (ESIONs) have been accepted as a potential alternative to gadolinium-based contrast agents for enhanced T1-weighted MR imaging. Recently developed zwitterion-coated ESIONs showed a high T1 contrast power and efficient renal clearing ability, but the tedious preparation steps that required high-cost, unfriendly experimental conditions and a sophisticated phase transition process would likely hinder their clinical translation. Herein, we present a one-pot gram-scale synthesis of zwitterion-capped ultrasmall iron oxide nanoparticles (ZUIONs). The nanoparticles have a core size as small as 3.7 nm and display high colloidal stability in various buffers. The r1 relaxivity of 2.4 mM–1 s–1 and r2/r1 ratio as low as 2.2 at 1.0 T guarantee their application as effective T1 MRI contrast agents. In vivo studies showed that ZUIONs could induce a significant contrast enhancement in blood pool and be eliminated from the body mainly through the renal excretion pathway. The combined advantageous features including facile preparation, excellent biocompatibility, strong T1 MRI contrast effect, appropriate circulation time, and renal clearable property would render ZUIONs attractive for practical applications.
研究领域:
医学影像学
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纳米医学
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生物材料
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DOI
PubMed
RSC Advances
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2016
·Vol. 6
·期 27
·22575-22585
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IF 3.289
Yuan-Peng Rui,Bo Liang,Fenglin Hu,Jie Xu,Yi-Feng Peng,Pei-Hao Yin,Yourong Duan,Chunfu Zhang,Hongchen Gu
Ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles with high stability in physiological conditions have great potential for T1-weighted MRI. In the current study, we developed a procedure for ultra-large-scale production of USPIOs (1.5 kg per batch) for T1-weighted MRI. The USPIOs were coated with poly(acrylic acid) (PAA@USPIOs). They were uniform in size (∼4.5 nm) and very stable in physiological conditions even after being sterilized in an autoclave. Due to their small size, the PAA@USPIOs demonstrated good T1 MRI contrast effect and could be used for both first-pass and steady-state magnetic resonance angiography (MRA). After being injected with PAA@USPIOs at the dose of 135 μmol Fe per kg, the head–neck vasculatures and abdominal artery of rabbits and the coronary artery of pigs could be clearly visualized by T1-weighted MRI. Moreover, PAA@USPIOs were highly tolerable by animals. Our study indicated that the procedure developed in this study has great promise for large-scale production of USPIOs for T1-weighted MRI for future clinical applications.
研究领域:
医学影像学
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纳米医学
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生物材料
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产品关联
DOI
高影响因子
MOLECULES
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2022
·Vol. 27
·期 20
·6929
·
IF 4.927
Lei Yang,Mohammad Javad Afshari,Jianxian Ge,Dandan Kou,Lei Chen,Dandan Zhou,Cang Li,Shuwang Wu,Leshuai Zhang,Jianfeng Zeng,Jian Zhong,Roland H. Stauber,Mingyuan Gao
Hypoxia is a common biological condition in many malignant solid tumors that plays an imperative role in regulating tumor growth and impacting the treatment’s therapeutic effect. Therefore, the hypoxia assessment is of great significance in predicting tumor development and evaluating its prognosis. Among the plenty of existing tumor diagnosis techniques, magnetic resonance imaging (MRI) offers certain distinctive features, such as being free of ionizing radiation and providing images with a high spatial resolution. In this study, we develop a fluorescent traceable and hypoxia-sensitiveT1-weighted MRI probe (Fe3O4-Met-Cy5.5) via conjugating notable hypoxia-sensitive metronidazole moiety and Cy5.5 dye with ultrasmall iron oxide (Fe3O4) nanoparticles. The results of in vitro and in vivo experiments show that Fe3O4-Met-Cy5.5 has excellent performance in relaxivity, biocompatibility, and hypoxia specificity. More importantly, the obvious signal enhancement in hypoxic areas indicates that the probe has great feasibility for sensing tumor hypoxia viaT1-weighted MRI. These promising results may unlock the potential of Fe3O4nanoparticles asT1-weighted contrast agents for the development of clinical hypoxia probes.Keywords:tumor hypoxia;ultrasmall iron oxide nanoparticles;magnetic resonance imaging;metronidazole
研究领域:
医学影像
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纳米技术
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肿瘤学
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生物医学工程
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产品关联
DOI
PubMed
高影响因子
SOLID STATE NUCLEAR MAGNETIC RESONANCE
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2018
·
IF 2.674
Xiaobing Lou,Ming Shen,Chao Li,Qun Chen,Bingwen Hu
Many pharmaceutical samples have notably long 1 H T 1 (proton spin-lattice relaxation time), leading to lengthy experiments lasting several days in solid-state NMR studies. In this work, we propose the use of ball milling on the pharmaceutical samples to reduce the 1 H T 1 , which also leads to enhanced sensitivity in { 1 H}- 13 C Cross-Polarization (CP) experiments due to reduced particle sizes and increased surface areas of the samples. Experimentally, we determined that depending on the substrates and milling time, the signal-to-noise ratio (S/N) of a 1D 13 C CP spectrum can be increased by a factor of 3–6, which means that the experimental time can be shortened by a factor of 9–36. Furthermore, the application of simple ball-milling within a short time avoids the amorphization of the studied samples such that no signal due to amorphous state is observed in the 13 C CP spectrum. This simple ball milling method used for sensitivity enhancement can be further applied in the SS-NMR studies of pharmaceutical samples.
研究领域:
药学
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物理化学
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DOI
PubMed
高影响因子
ACS Applied Materials & Interfaces
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2013
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IF 5.008
Mengxin Zhang,Yuhua Cao,Yu Chong,Yufei Ma,Hailu Zhang,Zongwu Deng,Chunhong Hu,Zhijun Zhang
Magnetic resonance imaging (MRI) is a powerful and widely used clinical technique in cancer diagnosis. MRI contrast agents (CAs) are often used to improve the quality of MRI-based diagnosis. In this work, we developed a positive T1 MRI CA based on graphene oxide (GO)–gadolinium (Gd) complexes. In our strategy, diethylenetriaminepentaacetic acid (DTPA) is chemically conjugated to GO, followed by Gd(III) complexation, to form a T1 MRI CA (GO–DTPA–Gd). We have demonstrated that the GO–DTPA–Gd system significantly improves MRI T1 relaxivity and leads to a better cellular MRI contrast effect than Magnevist, a commercially used CA. Next, an anticancer drug, doxorubicin (DOX), was loaded on the surface of GO sheets via physisorption. Thus-prepared GO–DTPA–Gd/DOX shows significant cytotoxicity to the cancer cells (HepG2). This work provides a novel strategy to build a GO-based theranostic nanoplatform with T1-weighted MRI, fluorescence imaging, and drug delivery functionalities.
研究领域:
生物医学工程
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材料科学
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分子影像
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癌症研究
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纳米技术
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DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY
·
2013
·Vol. 91
·期 1
·55-62
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IF 1.592
Qin Xiao-Li,Huang Hui-Hua,Lan Dong-Ming,Wang Yong-Hua,Yang Bo
Typoselectivity of crude CBD-T1 lipase ( Geobacillus sp. T1 lipase fused with a cellulose binding domain) was investigated. Multi-competitive reaction mixtures including a set of n -chain fatty acids (C8:0, C10:0, C12:0, C14:0, C18:1 n-9, C18:2 n-6 and C18:3 n-3) and tripalmitin-enriched triacylglycerols were studied in hexane. The crude CBD-T1 lipase discriminated strongly against C18:1 n-9 [competitive factor ( α ) = 0.23] and showed the highest preference for C8:0 ( α = 1). Utilizing the catalytic properties of crude CBD-T1 lipase, acidolysis of soybean oil with C8:0 was selected as a model reaction to investigate the ability of the lipase to produce MLM-type (medium-long-medium) structured lipids. Several reaction parameters (added water amount, reaction temperature, substrate molar ratio and reaction time) examined for incorporating C8:0 into soybean oil, the optimum conditions were: 1:3 (soybean oil/C8:0) of molar ratio, 3 mL of hexane, 50 °C of temperature, 48 h of reaction time, 20 % of crude CBD-T1 lipase (w/w total substrates), and 7.5 % of water (w/w enzyme). Under these conditions, the incorporation of C8:0 was 29.6 mol%. The results suggest that crude CBD-T1 lipase, which showed different fatty acid specificity profiles, is a potential biocatalyst for the modification of fats and oils.
研究领域:
生物化学
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食品科学
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DOI
高影响因子
危险品化学品经营许可证（带存储）