Development of novel dye-doped silica nanoparticles for biomarker application

Abstract

We report the development of novel luminescent nanoparticles composed of inorganic luminescent dye, Tris(2,2'-bipyridyl) dichlororuthenium (II) hexahydrate, doped inside a silica network. These dye doped silica (DDS) nanoparticles have been synthesized using a water-in-oil microemulsion technique in which controlled hydrolysis of the tetraethyl orthosilicate leads to the formation of monodispersed nanoparticles. They are prepared with a variety of sizes: small (5+/-1 nm), medium (63+/-4 nm), and large (400+/-10 nm), which shows the efficiency of the microemulsion technique for the synthesis of uniform nanoparticles. All these nanoparticles are suitable for biomarker application since they are much smaller than cellular dimension. These nanoparticles are highly photostable in comparison to most commonly used organic dyes. These nanoparticles have been characterized by various microscopic and spectroscopic techniques. The amount of dye content in these nanoparticles has been optimized to eliminate self-quenching. It has been observed that maximum luminescence intensity is achieved when the dye content is around 20 wt%. Silica surface of DDS nanoparticles is available for surface modification and bioconjunction. For demonstration as a biomarker, the DDS nanoparticle's surface has been biochemically modified to attach membrane-anchoring groups and applied successfully to stain human leukemia cells.

Photophysical Properties of Dye-Doped Silica Nanoparticles Bearing Different Types of Dye−Silica Interactions

“…36 However, it should be noted that at high loadings dye molecules such as Rubpy can selfquench, resulting in a quantum yield reduction. 29,30,37,38 The quantum yields of silica encapsulated TMR-Dex and TMR-APTES were determined to be ∼1.3 and 3.55 times higher than quantum yields of the TMR-Dex and TMR-APTES molecules in water, respectively. The effect of silica encapsulation on the quantum yield of the three dyes will be discussed in detail below.…”

Multiple Fluorescent Labeling of Silica Nanoparticles with Lanthanide Chelates for Highly Sensitive Time-Resolved Immunofluorometric Assays

“…Preparation details are provided in the Materials and Methods of the Data Supplement that accompanies the online version of this article at http://www.clinchem.org/content/vol53/issue8. Briefly, we synthesized bare silica nanoparticles using reverse microemulsion (26,27 ). We introduced amino groups to the surfaces of these particles by treatment with (3-aminopropyl)trimethoxylsilane (APTMS) (28 ).…”

Luminescent and Magnetic Nanoparticulates as Biomarkers

“…Silica is water dispersible, resistant to microbial attack and practically nontoxic at the dose levels required for diagnostic and therapeutic purposes 5) . Silica particles are also resistant to swelling which allows their synthesis in a wide selection of solvents without altering the porosity and minimizing the leaching of dye 6) . These chemically stable and highly fluorescent optical probes improve detection sensitivity and provide enhanced contrast when used for bioimaging.…”