多氯联苯是一种持久性有机污染物,它在环境中极难分解,并通过食物链可在生物体内富集,从而对生态系统和人类健康造成严重危害。目前,多氯联苯在土壤、垃圾处理厂、天然水域及水生生物体内仍广泛存在,所以,亟需建立一种快速、灵敏、抗干扰的痕量检测方法。本项工作以金包裹二氧化硅的球形纳米颗粒(SiO2@Au)为探针,采用表面增强拉曼光谱(Surface-Enhanced Raman Spectroscopy,SERS)技术对多氯联苯进行痕量检测。研究中,我们制备了不同大小、形状均一的金包裹二氧化硅球形纳米粒子(SiO2@Au)(粒径范围为200~310 nm),并将制备好的纳米粒子用于溶液中PCB-77的检测。结果发现,在红外激光激发下,所制备的SiO2@Au纳米粒子对PCB-77分子都显示了较好的SERS检测效果,而用200 nm 的SiO2@Au纳米颗粒检测PCB-77,其检测低限可达10-7 M。这项工作为环境中的有机污染物痕量检测提供了一种有效可行的方法。

Among the several types of inorganic nanoparticles available, silica nanoparticles (SNP) have earned their relevance in biological applications namely, as bioimaging agents. In fact, fluorescent SNP (FSNP) have been explored in this field as protective nanocarriers, overcoming some limitations presented by conventional organic dyes such as high photobleaching rates. A crucial aspect on the use of fluorescent SNP relates to their surface properties, since it determines the extent of interaction between nanoparticles and biological systems, namely in terms of colloidal stability in water, cellular recognition and internalization, tracking, biodistribution and speci- ficity, among others. Therefore, it is imperative to understand the mechanisms underlying the interaction between biosystems and the SNP surfaces, making surface functionalization a relevant step in order to take full advantage of particle properties. The versatility of the surface chemistry on silica platforms, together with the intrinsic hydrophilicity and biocompatibility, make these systems suitable for bioimaging applications, such as those mentioned in this review.

Oxygen and carbon dioxide sensors are involved in many chemical and biochemical reactions. Consequently, considerable efforts over years have been devoted to discover and improve suitable techniques for measuring gas concentrations by optical fiber sensors. Optical gas sensors consist of a gas-sensitive dye entrapped in a matrix with a high permeability to gas. With such sensors, gas concentration is evaluated based upon the reduction in luminescence intensity caused by gas quenching of the emitting state. However, the luminescence quenching effect of oxygen is highly sensitive to temperature. Thus, a simple, low-cost plastic optical fiber sensor for dual sensing of temperature and oxygen is presented. Also, a modified Stern-Volmer model is introduced to compensate for the temperature drift while the temperature is obtained by above dual sensor. Recently, we presented highly-sensitive oxygen and dissolved oxygen sensors comprising an optical fiber coated at one end with platinum (II) meso-tetrakis(pentafluorophenyl)porphyrin (PtTFPP) and PtTFPP entrapped core-shell silica nanoparticles embedded in an n-octyltriethoxysilane(Octyl-triEOS)/tetraethylorthosilane (TEOS) composite xerogel. Also, two-dimensional gas measurement for the distribution of chemical parameters in non-homogeneous samples is developed and is of interest in medical and biological researches.

以二苯甲酰甲烷(DBM)、邻菲罗琳(phen)和丙烯酸(AA)为配体，制备了铕的配合物Eu(Ⅲ)(DBM)2-(phen) (AA)。利用Stber法合成了SiO2纳米粒。通过超声辅助，将脂溶性的强荧光铕配合物吸附到SiO2纳米粒上，再包覆阳离子聚电解质聚二烯丙基二甲基氯化铵(PDAC)和阴离子聚电解质聚丙烯酸(PAA)，从而制备了Eu(Ⅲ) (DBM)2 (phen) (AA)@SiO2/PDAC/PAA荧光纳米粒。采用透射电镜、紫外光谱、红外光谱、荧光光谱和Zeta电位等技术对荧光纳米粒进行了表征。作为一种新型的荧光纳米探针，该荧光纳米粒具有粒度均一且分布窄、荧光强度大、低泄漏和光稳定性好等优点，而表面包覆的PAA带有丰富的羧基，可直接与生物分子大量连接，可作为优良的时间分辨荧光标记物用于各种高灵敏生物检测中。