Recent advances in the nanomaterials, such as luminescent quantum dots, latex fluorescent nanospheres and dye-doped silica nanoparticles, have opened a promising field toward the development of luminescent biolabel. I...Recent advances in the nanomaterials, such as luminescent quantum dots, latex fluorescent nanospheres and dye-doped silica nanoparticles, have opened a promising field toward the development of luminescent biolabel. In this paper, we develop a kind of novel nanometer-sized fluorescent hybrid silica(NFHS) particles used as a sensitive and photostable fluorescent probe in biological staining and diagnostics. The NFHS particles are prepared by controlled hydrolysis of the fluorophore silica precursor using the reverse micelle technique. The fluorophores are dispersed homogeneously in the silica network of the NFHS particles and well protected from the environmental oxygen. In comparison with single organic fluorophores without incorporation, these nanoparticle probes are brighter, more stable against photobleaching and do not suffer from intermittent on/off light emission(blinking). The NFHS particles have also shown unique advantages over the existing common organic fluorophores, quantum dots, and latex-based fluorescent particles for biomolecule recognition in the following four major points: easy preparation, good photostability, high sensitivity, and low toxicity. The approach proposed in this article for making NFHS nanoparticles is a general one, and it is not restricted to a particular type of fluorophore molecule as selected in this study.展开更多
采用溶胶-凝胶法制备纳米SiO_2微球并对其接枝改性,与壳聚糖/淀粉溶液复合后应用于圣女果保鲜包装中。通过扫描电镜、红外光谱、粒径分析等表征,考察纳米SiO_2成球工艺参数和接枝改性效果;并研究了添加不同质量分数的改性纳米SiO_2微球...采用溶胶-凝胶法制备纳米SiO_2微球并对其接枝改性,与壳聚糖/淀粉溶液复合后应用于圣女果保鲜包装中。通过扫描电镜、红外光谱、粒径分析等表征,考察纳米SiO_2成球工艺参数和接枝改性效果;并研究了添加不同质量分数的改性纳米SiO_2微球对壳聚糖/淀粉/纳米SiO_2复合膜溶液保鲜效果的影响。结果表明:添加5 m L浓氨水、2.8 m L正硅酸四乙酯、40 m L乙醇并通过缓慢滴加的方式制备得到的微球粒径均一、分散性好;经硅烷偶联剂KH550接枝改性后的纳米SiO_2微球,能够改善复合膜的多项性能;当添加质量分数为3%的改性纳米SiO_2微球时,壳聚糖/淀粉/纳米SiO_2复合膜的保鲜效果较好。展开更多
A new idea for specific surface area standard reference materials (SRM) which are made of nonporous mono-disperse SiO2 spheres and the true specific surface area can be calculated accurately from their diameters is pr...A new idea for specific surface area standard reference materials (SRM) which are made of nonporous mono-disperse SiO2 spheres and the true specific surface area can be calculated accurately from their diameters is presented.Firstly,the mono-disperse SiO2 spheres were synthesized in bulk.Secondly,the spheres were modified to make them nonporous.Thirdly,the characteristic dimensions,such as the size,density of the spheres,were determined accurately.Finally,the specific surface areas were measured by using a static volumetric type Brunauer-Emmett-Teller (BET) (nitrogen gas) instrument.The experimental results showed that the micro-holes on the surface of mono-disperse SiO2 spheres were almost be sealed by calcining at the temperature of 1000℃ for three hours.The BET surface area was larger than the geometric specific surface area and the values of the deviation were 1.2 m2·g-1,2.0 m2·g-1 and 3.6 m2·g-1 for mono-disperse SiO2 spheres with diameters 1150 nm,453 nm and 269 nm respectively.In this case,the theoretical value can be used as reference for the determination of the specific surface area of nonporous mono-disperse SiO2 spheres SRMs.展开更多
文摘Recent advances in the nanomaterials, such as luminescent quantum dots, latex fluorescent nanospheres and dye-doped silica nanoparticles, have opened a promising field toward the development of luminescent biolabel. In this paper, we develop a kind of novel nanometer-sized fluorescent hybrid silica(NFHS) particles used as a sensitive and photostable fluorescent probe in biological staining and diagnostics. The NFHS particles are prepared by controlled hydrolysis of the fluorophore silica precursor using the reverse micelle technique. The fluorophores are dispersed homogeneously in the silica network of the NFHS particles and well protected from the environmental oxygen. In comparison with single organic fluorophores without incorporation, these nanoparticle probes are brighter, more stable against photobleaching and do not suffer from intermittent on/off light emission(blinking). The NFHS particles have also shown unique advantages over the existing common organic fluorophores, quantum dots, and latex-based fluorescent particles for biomolecule recognition in the following four major points: easy preparation, good photostability, high sensitivity, and low toxicity. The approach proposed in this article for making NFHS nanoparticles is a general one, and it is not restricted to a particular type of fluorophore molecule as selected in this study.
文摘采用溶胶-凝胶法制备纳米SiO_2微球并对其接枝改性,与壳聚糖/淀粉溶液复合后应用于圣女果保鲜包装中。通过扫描电镜、红外光谱、粒径分析等表征,考察纳米SiO_2成球工艺参数和接枝改性效果;并研究了添加不同质量分数的改性纳米SiO_2微球对壳聚糖/淀粉/纳米SiO_2复合膜溶液保鲜效果的影响。结果表明:添加5 m L浓氨水、2.8 m L正硅酸四乙酯、40 m L乙醇并通过缓慢滴加的方式制备得到的微球粒径均一、分散性好;经硅烷偶联剂KH550接枝改性后的纳米SiO_2微球,能够改善复合膜的多项性能;当添加质量分数为3%的改性纳米SiO_2微球时,壳聚糖/淀粉/纳米SiO_2复合膜的保鲜效果较好。
文摘A new idea for specific surface area standard reference materials (SRM) which are made of nonporous mono-disperse SiO2 spheres and the true specific surface area can be calculated accurately from their diameters is presented.Firstly,the mono-disperse SiO2 spheres were synthesized in bulk.Secondly,the spheres were modified to make them nonporous.Thirdly,the characteristic dimensions,such as the size,density of the spheres,were determined accurately.Finally,the specific surface areas were measured by using a static volumetric type Brunauer-Emmett-Teller (BET) (nitrogen gas) instrument.The experimental results showed that the micro-holes on the surface of mono-disperse SiO2 spheres were almost be sealed by calcining at the temperature of 1000℃ for three hours.The BET surface area was larger than the geometric specific surface area and the values of the deviation were 1.2 m2·g-1,2.0 m2·g-1 and 3.6 m2·g-1 for mono-disperse SiO2 spheres with diameters 1150 nm,453 nm and 269 nm respectively.In this case,the theoretical value can be used as reference for the determination of the specific surface area of nonporous mono-disperse SiO2 spheres SRMs.
