Enrichi Francesco
Associazione Coordinamento Interuniversitario Veneto per le Nanotecnologie, via delle Industrie 5, 30175 Marghera (Venice), Italy.
Ann N Y Acad Sci. 2008;1130:262-6. doi: 10.1196/annals.1430.030.
This work presents the morphological and optical properties of luminescent silica spheres, discussing applications in bioimaging and biosensing. The spheres are obtained by the hydrolysis and condensation of tetraethylorthosilicate (TEOS) and can be synthesized by following either a basic or an acidic route. Luminescence emission is induced after incorporation of aminopropyltriethoxysilane (APTES) during synthesis or by introducing an optically active element, such as erbium, or other rare-earth elements. The luminescence properties of APTES-functionalized silica spheres have been investigated and optimized by varying the annealing temperature. On the other hand, erbium incorporation in silica spheres was also studied and the corresponding Er(3+) luminescence emission at 1.54 microm was evaluated for intensity and lifetime. The basic pH environment in the synthesis allows good control of the size of the spheres (approximately 200 nm in diameter), whereas the acidic route produces a wide dispersion in particle size (200-5000 nm). Both these approaches, however, can be followed to obtain an efficient photoluminescence (PL) emission for the APTES-functionalized silica spheres after 400-600 degrees C thermal treatment. If Er(NO(3))(3) is introduced in the basic solution, a rapid precipitation of Er(OH)(3) occurs, but erbium can be easily and efficiently incorporated in the acid-synthesized spheres, showing high PL intensity at 1.54 microm with lifetime of 3.9 ms. Finally, I discuss perspectives for the applications of these luminescent silica spheres, in particular as biological markers for bioimaging and biosensing.
这项工作展示了发光二氧化硅微球的形态和光学性质，并讨论了其在生物成像和生物传感中的应用。这些微球通过原硅酸四乙酯（TEOS）的水解和缩合获得，可通过碱性或酸性路线合成。在合成过程中加入氨丙基三乙氧基硅烷（APTES）或引入光学活性元素（如铒或其他稀土元素）后可诱导发光发射。通过改变退火温度，对APTES功能化二氧化硅微球的发光性质进行了研究和优化。另一方面，还研究了二氧化硅微球中铒的掺入情况，并对1.54微米处相应的Er(3+)发光发射的强度和寿命进行了评估。合成过程中的碱性pH环境能够很好地控制微球的尺寸（直径约200纳米），而酸性路线则会导致粒径有很大的分散性（200 - 5000纳米）。然而，经过400 - 600摄氏度的热处理后，这两种方法都可以用于获得APTES功能化二氧化硅微球的高效光致发光（PL）发射。如果在碱性溶液中引入Er(NO(3))(3)，会迅速生成Er(OH)(3)沉淀，但铒可以很容易且高效地掺入酸合成的微球中，在1.54微米处显示出高PL强度，寿命为3.9毫秒。最后，我讨论了这些发光二氧化硅微球的应用前景，特别是作为生物成像和生物传感的生物标记物。
