Elsutohy Mohamed M, Selo Amjad, Chauhan Veeren M, Tendler Saul J B, Aylott Jonathan W
Boots Science Building, School of Pharmacy, University Park Campus, University of Nottingham Nottingham NG7 2RD UK
Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Al-Azhar University Assiut 71524 Egypt.
RSC Adv. 2018 Oct 19;8(62):35840-35848. doi: 10.1039/c8ra05929b. eCollection 2018 Oct 15.
Silica nanoparticles (SNPs) have been used as favoured platforms for sensor, drug delivery and biological imaging applications, due to their ease of synthesis, size-control and bespoke physico-chemical properties. In this study, we have developed a protocol for the synthesis of size-tuneable SNPs, with diameters ranging from 20 nm to 500 nm, through the optimisation of experimental components required for nanoparticle synthesis. This protocol was also used to prepare fluorescent SNPs, covalent linkages of fluorophores, to the nanoparticle matrix using 3-aminopropyltriethoxysilane (APTES). This enabled the fabrication of ratiometric, fluorescent, pH-sensitive nanosensors (75 nm diameter) composed SNPs covalently linked to two pH-sensitive fluorescent dyes Oregon Green (OG) and 5(6)-carboxyfluorescein (FAM) and a reference fluorescent dye 5-(6)-carboxytetramethylrhodamine (TAMRA), extending the dynamic range of measurement from pH 3.5 to 7.5. In addition, size-tuneable, core-shell SNPs, covalently linked to a fluorescent TAMRA core were synthesised to investigate distance-dependant fluorescence quenching between TAMRA and black hole quencher 2 (BHQ2®) using nanometre-sized silica shells as physical spacers. The results showed a significant fluorescence quenching could be observed over greater distances than that reported for the classical distance-dependent molecular fluorescence quenching techniques, the Förster (fluorescence) resonance energy transfer (FRET). The methods and protocols we have detailed in this manuscript will provide the basis for the reproducible production of size tunable SNPs, which will find broad utility in the development of sensors for biological applications.
由于易于合成、可控制尺寸以及具有定制的物理化学性质，二氧化硅纳米颗粒（SNPs）已成为传感器、药物递送和生物成像应用中备受青睐的平台。在本研究中，我们通过优化纳米颗粒合成所需的实验组件，开发了一种合成尺寸可调的SNPs的方案，其直径范围为20纳米至500纳米。该方案还用于制备荧光SNPs，即使用3-氨丙基三乙氧基硅烷（APTES）将荧光团共价连接到纳米颗粒基质上。这使得能够制造由共价连接到两种pH敏感荧光染料俄勒冈绿（OG）和5(6)-羧基荧光素（FAM）以及一种参考荧光染料5-(6)-羧基四甲基罗丹明（TAMRA）的SNPs组成的比率型、荧光、pH敏感纳米传感器（直径75纳米），将测量的动态范围扩展到pH 3.5至7.5。此外，合成了共价连接到荧光TAMRA核心的尺寸可调的核壳SNPs，以使用纳米尺寸的二氧化硅壳作为物理间隔物来研究TAMRA与黑洞猝灭剂2（BHQ2®）之间的距离依赖性荧光猝灭。结果表明，与经典的距离依赖性分子荧光猝灭技术即福斯特（荧光）共振能量转移（FRET）相比，在更大的距离上可以观察到显著的荧光猝灭。我们在本手稿中详细介绍的方法和方案将为尺寸可调的SNPs的可重复生产提供基础，这将在生物应用传感器的开发中具有广泛的用途。
