纳米SiO2表面改性及其对阿维菌素吸附性能的影响

采用硅烷偶联剂KH-570对纳米SiO2进行了表面接枝改性,并探讨了改性材料对阿维菌素的吸附性能。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、傅立叶变换红外光谱(FTIR)等技术对表面改性纳米SiO2的结构和性能进行了分析。结果表明,纳米SiO2粒子经KH-570进行表面改性后,其分散性得以改善,对阿维菌素的包封率比改性前的大幅提高,提高率最高达92.6%。用KH-570改性的纳米SiO2可作为一种较为理想的新型生物农药载体。     

介孔活性炭阿维菌素载药系统的性能研究

研究了介孔活性炭对阿维菌素的载药特性,以判断其作为阿维菌素载体的可能性。以扫描电子显微镜、比表面积分析仪和粒度分析仪对其进行了物理性状表征。将其负载阿维菌素的能力与常规农药载体进行比较,并进一步分析和评价了该载药系统的吸附动力学特性、缓-控释性能和抗紫外光降解能力。结果表明:供试活性炭载体为不规则球形颗粒状介孔材料,平均粒径为814 nm,比表面积为1 719.25 cm2/g,孔容积为0.043 cm3/g,孔径为4.80 nm。吸收动力学数据符合伪二级动力学模型,对阿维菌素的载药量为220.6 mg/g,显著高于其他常规农药载体,呈现了优良的吸附性能;载药系统的释药时间从90 h延长到672 h以上,表现出了良好的缓释效果;紫外光照射72 h后,阿维菌素原药的分解率为77%,而有活性炭载体保护的阿维菌素的分解率为30% ,表明该载药系统有效地减缓了阿维菌素的光降解速率。研究表明,以介孔活性炭作为阿维菌素载体,可显著改善药物的缓-控释特性以及分散性和光稳定性。     

基于介孔二氧化硅纳米粒子的农药可控释放研究进展

鉴于介孔二氧化硅纳米粒子（mesoporous silica nanoparticles,MSNs）具有比表面积大、孔径可调节、孔道均匀、内外表面易于修饰和生物相容性好等优点,其在药物控释方面的应用已成为当前国内外研究的热点。本文综述了介孔二氧化硅纳米粒子的制备方法（软模板法、硬模板法和自模板法）,表征技术[扫描电镜分析（SEM）、透射电镜分析（TEM）、X射线衍射分析（XRD）、物理吸附分析、热重和差热分析（TGA-DTA）和傅里叶红外光谱分析（FT-IR）]及其在农药领域的研究应用状况,探讨了以介孔二氧化硅纳米粒子作为农药载体时存在的问题,并对其应用前景进行了展望。     

静电自组装法制备阿维菌素纳米囊悬浮剂及其对黄瓜根结线虫病的防治效果

为提高阿维菌素在土壤中的移动扩散能力,改善其对作物根结线虫病的防治效果,采用静电自组装法制备了3%阿维菌素纳米囊悬浮剂,测定了其贮存稳定性和释放性能,并通过土壤淋溶试验与土壤薄层层析试验评价了其在土壤中的移动性,验证了其对南方根结线虫Meloidogyne incognita 2龄幼虫 (J₂) 的室内毒力和田间防治效果。结果显示:阿维菌素纳米囊为球形,平均粒径 (D₅₀) 为276.81 nm,在释放液中,60 min时纳米囊悬浮剂中阿维菌素的累积释放率为57.59%,而对照乳油制剂中阿维菌素的累积释放率为94.53%。阿维菌素纳米囊悬浮剂在土壤中横向和纵向的移动距离均明显大于阿维菌素乳油,二者对根结线虫J₂在24 h时的LC₅₀值分别为0.257与0.427 mg/L。田间试验中,相同用量下分别采用漫灌法与混土法两种方式施药,药后60 d,3%阿维菌素纳米囊悬浮剂处理比3%阿维菌素乳油处理的防治效果分别高21.82%与4.81%;而药后100 d,前者比后者分别高28.98%与19.79%。表明将阿维菌素制剂纳米化可以增强其在土壤中的移动能力,提高其对黄瓜根结线虫病的防治效果。本研究结果可为开发适合于土壤施用的纳米化农药制剂提供依据。     

pH响应性吡唑醚菌酯/沸石咪唑酯骨架材料纳米颗粒的制备及抑菌活性

沸石咪唑酯骨架材料(ZIF-8)稳定性好,比表面积大,纳米粒径可调,具有酸敏感性.为研究其在农药递送中作为缓控释载体的性能和应用,以吡唑醚菌酯(pyraclostrobin,以下简称Pyr)为模式农药,以二价锌为配位中心,二甲基咪唑为有机配体,采用"一锅法"制备了pH响应性吡唑醚菌酯控释剂Pyr@ZIF-8;通过扫描电...     

基于氧化硅介孔材料的啶酰菌胺纳米农药制备及其性能评价

为解决疏水性杀菌剂啶酰菌胺水分散性差、有效利用率低等问题,采用溶液吸附法,以2种介孔氧化硅分子筛SBA-15与FDU-12为载体构建负载啶酰菌胺的纳米载药体系,对2种纳米载体的形貌及结构等表征特性进行分析,并以立枯丝核菌Rhizoctonia solani为靶标对纳米农药的抑菌作用进行评价。结果表明:成功构建了负载啶酰菌胺的纳米载药体系Bos-SBA-15和Bos-FDU-12,2种纳米载体结构分布均匀,Bos-SBA-15纳米颗粒呈椭球棒状,Bos-FDU-12纳米颗粒呈颗粒状,粒径分别为680.33 nm和870.61 nm;X射线衍射分析和热重分析结果证明啶酰菌胺已成功装载到SBA-15和FDU-12中,载药量分别为31.49%和22.44%。Bos-SBA-15和Bos-FDU-12在高温54℃贮存14 d时分解率仅为4.87%和4.41%,表明所构建纳米农药具有良好的热稳定性。Bos-SBA-15和Bos-FDU-12纳米农药缓释性好,在288 h累积释放率达到69.42%和64.34%。Bos-SBA-15与BosFDU-12纳米农药对立枯丝核菌的EC_(50)分别为34.11μg/mL和41.54μg/mL,对立枯丝核菌后期生长阶段的抑制效果更显著。     

乳液聚合法制备阿维菌素微胶囊及其生物活性研究

利用乳液聚合法制备了阿维菌素微胶囊,其包裹率达99.98%,载药率达37.5%。用动态光散射粒度分析仪和冷场发射扫描电子显微镜进行了测试,结果显示,微胶囊颗粒平均粒径为278 nm,单分散性较好。渗透性与传导性试验结果表明,在植物体内,该阿维菌素微胶囊比乳油具有更好的渗透性与传导性。室内杀虫活性研究表明,该阿维菌素微胶囊制剂的杀虫活性与原药相近。     

纳米tio2对贮藏期南丰蜜桔抑菌性能研究

以酞酸丁酯为原料,在无水条件下,采用溶胶-凝胶法合成纳米二氧化钛粉末,通过正交实验法确定制备纳米二氧化钛的最佳工艺条件,并利用XRD衍射仪进行结构表征.采用牛津杯法研究纳米二氧化钛悬浮液对寄生于南丰蜜桔常见菌类的活性抑制效果,并进行实证性保鲜实验,重点考察纳米二氧化钛对贮藏期南丰蜜桔的抑菌性能.所制备的纳米二氧化钛平均粒径为14.6 nm,实际平均产率为90.83%,RSD为0.86%.结论是纳米二氧化钛对贮藏期南丰蜜桔具有一定的抑菌性能.     

基于介孔二氧化硅的鱼藤酮纳米颗粒的制备及其性能研究

纳米材料作为农药载体可提高农药稳定性和调控农药释放速率，是提高农药利用率的重要手段。介孔二氧化硅纳米粒子 (MSNs) 是一种具高比表面积、粒径与孔径可调节和生物相容性良好的纳米载体。鱼藤酮是非内吸性植物源杀虫剂，在环境中易降解。本研究先通过改良的软模板法制备出粒径均一的MSNs，再通过溶剂挥发法将鱼藤酮负载到MSNs中，制备得到载鱼藤酮MSNs (Rot@MSNs)，其载药率达31.6%，具有良好的缓释特性，缓释时间可达288 h以上；施药处理3 d后在番茄的上部叶片和下部叶片中均检测到了鱼藤酮，表明纳米载体MSNs提高了鱼藤酮在番茄植株中的内吸和传导能力。该研究对于减少农药使用量、降低环境污染等具有重要意义。     

鱼藤酮水基纳米悬浮剂的特性及对松材线虫的杀虫作用

为改善鱼藤酮制剂的分散性,提高其悬浮率、稳定性及生物活性,制备了鱼藤酮纳米悬浮剂。该剂型为水基剂型,环境扫描电子显微镜和高效液相色谱检测结果显示,在鱼藤酮的水基纳米悬浮剂中,鱼藤酮悬浮颗粒的平均粒径为127.1 nm±31.8 nm,鱼藤酮的包封率为81.7%±3.5%,该制剂悬浮率高达99.23%±0.49%,抗光照分解的稳定性增强,36 h紫外光照射后鱼藤酮纳米悬浮剂中残存的鱼藤酮浓度比鱼藤酮丙酮溶液提高68.9%。以LC50表示的24 h对松材线虫的毒力鱼藤酮纳米悬浮剂是鱼藤酮丙酮溶液的7.5倍。     

Controlled release of avermectin from porous hollow silica nanoparticles

Porous hollow silica nanoparticles (PHSNs) with a diameter of ca 100 nm and a pore size of ca 4.5 nm were synthesized via a sol-gel route using inorganic calcium carbonate nanoparticles as templates. The synthesized PHSNs were subsequently employed as pesticide carriers to study the controlled release behaviour of avermectin. The avermectin-loaded PHSN (Av-PHSN) samples were characterized by BET, thermogravimetric analysis and IR, showing that the amount of avermectin encapsulated in the PHSN carrier could reach 58.3% w/w by a simple immersion loading method, and that most of the adsorption of avermectin on the Av-PHSN carrier might be physical. Avermectin may be loaded on the external surface, the pore channels in the wall and the inner core of the PHSN carriers, thus leading to a multi-stage sustained-release pattern from the Av-PHSN samples. Increasing pH or temperature intensified the avermectin release.     

Study of UV-shielding properties of novel porous hollow silica nanoparticle carriers for avermectin

The shielding protection given by self-prepared porous hollow silica nanoparticles (PHSN) to pesticides from degradation by UV light was investigated using avermectin as a model pesticide. It was demonstrated that PHSN carriers with a shell thickness of approximately 15 nm and a pore diameter of 4-5 nm have an encapsulation capacity of 625 g kg(-1) for avermectin using a supercritical fluid loading method. PHSN carriers exhibited remarkable UV-shielding properties for avermectin. This was affected by the intensity of UV light, the pH and the temperature of the release medium. Rises in UV intensity, pH and/or temperature reduced the UV protection of PHSN for avermectin. In addition, avermectin loaded into the inner core of the PHSN carriers was released slowly into the release medium for about 30 days following a typical sustained-release pattern. It thus appears that PHSN carriers have a promising future in applications requiring sustained pesticide release.     

新型pH响应性噻虫嗪纳米脂质体的制备及其杀虫活性

为提高农药利用率，减少环境风险，提高农药靶向性，利用胆固醇和硬脂胺通过自组装形成的非磷脂类纳米脂质体作为农药载体，构建了具有缓控释特性的噻虫嗪纳米脂质体。电镜和粒度分析结果表明，该纳米制剂呈现出良好的分散性和稳定性，载药后的纳米粒径为173.7 nm ± 1.6 nm，载药量为8.97%，带有正电荷的脂质体与噻虫嗪间存在静电相互作用。体外释放试验结果表明，相对于原药组8 h内完全释放，噻虫嗪纳米脂质体8 h累计释放率为62%，实现了噻虫嗪的缓释效果。制备的噻虫嗪纳米脂质体具有碱性pH敏感性，其中当pH值为10.0时噻虫嗪的释放速率显著提高，有助于噻虫嗪在鳞翅目昆虫独特的碱性pH中肠环境中进行响应性释放和积累。以亚洲玉米螟Ostrinia furnacalis为模式昆虫的杀虫活性试验结果表明，有效成分为0.6 mg/mL的噻虫嗪纳米脂质体较原药组的杀虫活性更佳，作用1 d后原药组仅部分影响其生命活动，而纳米脂质体组存活率已降至60%以下，表现出纳米脂质体载体提高了噻虫嗪对玉米螟的杀虫活性。以非磷脂类脂质体作为农药载体，为农药活性成分的定向可控递送和缓控释提供了新的理论依据与技术途径，不仅可高效提高农药利用率，同时具备经济和环境友好等优势，具有广阔的应用前景。     

阿维菌素缓控释载药体系的构建及应用研究进展

利用先进的功能材料和制备工艺，可以改善农药制剂的性能，提高农药稳定性，调控农药释放，提高农药利用率。阿维菌素作为一种广谱高效的抗生素类杀虫杀螨生物农药，广泛应用于农业、畜牧业和卫生等方面，但在紫外光和微生物作用下易分解，影响其药效的发挥。选择合适载体材料，优化制备工艺，既可以解决阿维菌素的稳定性问题，又可以提高其应用性能。本文综述了不同阿维菌素缓控释载药体系的构建及应用研究进展，从载体材料、制备工艺、释放特性、光稳定性以及其他性能等方面进行阐述，分析了目前研究中存在的问题及未来的研究方向。     

Stabilized polymeric nanoparticles for controlled and efficient release of bifenthrin

BACKGROUND: Nanoparticle formulations of pesticides have been proposed to produce a better spatial distribution of the pesticide on leaf surfaces, which provides better efficiency. Nanoparticles are well studied for drug delivery and sustained release but not in the agricultural sciences, because of the difficulty in generating stable pesticide nanoparticles with controlled particle size distribution and because the processes to generate nanoparticles are usually costly. In this paper, a model pesticide, bifenthrin, has been prepared in nanoparticle form by using the Flash NanoPrecipitation process. The process involves rapid micromixing to effect supersaturation, and polymer assembly to control particle size. RESULTS: A multi-inlet vortex mixer (MIVM) was developed to provide rapid micromixing, high supersaturation and rapid nucleation and growth of bifenthrin nanoparticles. Several polymeric stabilizers were tested. With an increase in pesticide loading from 50 to 91%, nanoparticle size increased from 100 to 200 nm. The stability of the nanoparticle dispersions was followed for more than 12 days. The steric stability caused by the corona structure of the hydrophilic block of the polymers prevents nanoparticles aggregation. Ostwald ripening is responsible for the slow particle size growth observed. CONCLUSION: Flash NanoPrecipitation using an MIVM provides a cost-effective process to produce stable pesticide nanoparticle suspensions. Nanoparticle size depends on supersaturation, pesticide loading and type of polymer. Nanoparticle pesticides potentially provide higher efficiency, better uniformity of coverage for highly active compounds and less exposure to workers, relative to compounds solubilized in organic solvents.     

A novel chitosan-poly(lactide) copolymer and its submicron particles as imidacloprid carriers

BACKGROUND: The aim of the present work was to synthesise novel amphiphilic chitosan–co‐(D,L‐lactide) (chitosan–PLA) copolymers and to study the formation of pesticide‐loaded polymeric submicron particles. These copolymeric submicron particle systems are expected to be potential candidates for applications in pesticide delivery. RESULTS: The chemical structures of the copolymers were confirmed by Fourier transform infrared spectroscopy (FT‐IR), ¹H nuclear magnetic resonance (¹H NMR) and thermogravimetric analysis (TGA). Imidacloprid as a lipophilic model pesticide can be incorporated into chitosan–PLA submicron particles by nanoprecipitation and the emulsion/solvent evaporation method. Size, the size distribution, the imidacloprid loading content (LC) and the imidacloprid release behaviour were investigated. CONCLUSION: Conjugation of PLA to chitosan was shown to be an available method for the preparation of submicron particles for lipophilic pesticide delivery. The imidacloprid‐loaded submicron particles showed a sustained release process. As the mass ratio of copolymer to imidacloprid increased, the submicron particles size and LC decreased. The chitosan–PLA submicron particles could be useful as pesticide carriers for imidacloprid delivery systems. Copyright © 2011 Society of Chemical Industry     

韭菜中毒死蜱残留量与高光谱特征参数的相关性建模

本研究目的在于分析农药残留量(pesticide residue,PR)与高光谱中响应特征参数之间的关系,并利用筛选的光谱特征参数建立反演毒死蜱残留量的有效模型。首先采用ASD Fieldspec高光谱仪测得韭菜样本的光谱,通过气相色谱-质谱联用(GC-MS)法测得毒死蜱残留量(PR)值;分析样本光谱反射率值及其一阶微分值与毒死蜱残留量的相关性,计算33个高光谱特征参数与毒死蜱残留量的相关性;根据相关系数高低选择敏感的光谱特征参数;最后采用最佳相关系数下的光谱特征参数对毒死蜱残留量进行建模反演。相关性分析结果显示:近红外波段789~867 nm范围内一阶微分光谱值与PR值呈正相关,1 860 nm处一阶微分光谱值(first-order differential 1 860 nm,FD1860)与PR值紧密相关;在33个高光谱特征参数中,近红外一阶微分总和(the sum of first-order differential near infrared,SDnir)与PR值呈良好的正相关关系。基于此,文章以供试样本的FD1860和SDnir观测值为自变量,分别建立了3个预测毒死蜱残留量的模型,即线性、二次多项式及指数模型,并采用交叉验证测试方法检验了模型的合理性。对实验所得决定系数R2和预测均方根误差(RMSE)的评价结果表明,以SDnir为自变量构建的模型稳定性强,其二次多项式模型是最佳反演毒死蜱残留量的有效模型。因此,样本的高光谱特征参数SDnir的变化幅度直接反映了韭菜样本中毒死蜱残留量的变化,表明运用蔬菜的高光谱特征参数反演蔬菜中农药残留量的方法是可行的。     

Improved biological effects of uniconazole using porous hollow silica nanoparticles as carriers

BACKGROUND: The aim of this work is to prepare a controlled‐release formulation of uniconazole using porous hollow silica nanoparticles (PHSNs) as carrier, and to investigate the biological effects on rice growth. RESULTS: PHSNs with a shell thickness of ～15 nm and a particle size of 80–100 nm were synthesised through a sol–gel route using nanosized calcium carbonate particles as templates. Simple immersing (SI) and supercritical fluid drug loading (SFDL) technologies were employed to load uniconazole into PHSNs with loading efficiencies of ～22 and ～26% respectively. The prepared uniconazole‐loaded PHSNs (UCZ‐PHSNs) by SI and SFDL both demonstrated sustained release properties, and the latter showed better controlled release ability with a slower release rate. Compared with free uniconazole, UCZ‐PHSNs exhibited a weaker growth retardation effect in the early stage but more significant retardation ability in later stages for agar‐cultured rice seedlings. For the rice that grew in clay, UCZ‐PHSNs demonstrated a weaker plant height retardation effect than free uniconazole at the early jointing stage by foliar spraying, but exhibited a stronger retardation capacity than free uniconazole by being applied into soil before seedling transplantation. CONCLUSION: The results indicated that the prepared UCZ‐PHSNs possessed good controlled‐release properties and had improved retardation effects on rice growth. It is recommended that UCZ‐PHSNs be applied into soil before seedling transplantation rather than administered by foliar spraying at the early jointing stage. Copyright © 2011 Society of Chemical Industry     

负载咪鲜胺介孔二氧化硅粒子的制备及性能与安全性评价

介孔二氧化硅粒子 (MSNs) 可作为载体用于制备高载药量的农药缓控释剂,从而实现农药减量化使用和生态环境保护的目的。本研究采用“一锅法”制备了负载咪鲜胺的介孔二氧化硅载药粒子 (prochloraz@MSNs),并对其外观形貌、载药量、释放行为、抑菌作用以及对非靶标生物的安全性进行了系统研究。结果表明:所制备的prochloraz@MSNs呈规则球形,粒径均匀,平均粒径约240 nm,载药量为40.6%,释放速率与pH值和温度相关,酸性、碱性及高温条件均有利于其中咪鲜胺的释放。与常规制剂咪鲜胺乳油相比,prochloraz@MSNs对稻瘟病菌和小麦赤霉病菌的抑制效果更好,持效期更长;对斑马鱼、蚯蚓和人体肺部BEAS-2B细胞的毒性较低。因此,prochloraz@MSNs作为一种高效、低毒、安全的农药新剂型,在植物病害的可持续治理中将具有很好的发展潜力。