Related Systems: New Insights into Biosensing, Bioimaging, Genomics, Diagnostics, and Therapy Jun Yao,† Mei Yang,† and Yixiang Duan*,†,‡ †Research Center of Analytical Instrumentation, Analytical and Testing Center, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China ‡Research Center of Analytical Instrumentation, College of Life Sciences, Sichuan University, Chengdu, Sichuan 610064, China

Chemistry, Biology, and Medicine of Fluorescent Nanomaterials and Related Systems: New Insights into Biosensing, Bioimaging, Genomics, Diagnostics, and Therapy

The use of labelling or staining agents has greatly assisted the study of complex biological interactions in the field of biology. In particular, fluorescent labelling of biomolecules has been demonstrated as an indispensable tool in many biological studies. Types of fluorescent labelling agents that are commonly used include conventional classes of organic fluorophores such as fluorescein and cyanine dyes, as well as newer types of inorganic nanoparticles such as QDs, and novel fluorescent latex/silica nanobeads. The newer classes of fluorescent labels are gaining increasing popularity in place of their predecessors due to their better optical properties such as possessing an enhanced photostability and a larger Stokes shift over conventional organic fluorophores, for example. This paper gives an overview of the recent advances on these luminescent nanomaterials with emphases on their optical characteristics that are crucial in fluorescence microscopy, both advantages and limitations in their usage as well as challenges they face, and puts forward the future direction of fluorescent labels in the area of biolabelling.

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Luminescent nanomaterials for biological labelling

Mesoporous SBA-15 HPLC evaluation for controlled gentamicin drug delivery.

Review: Bioanalytical applications of biomolecule-functionalized nanometer-sized doped silica particles

Bioactive, luminescent and mesoporous europium-doped hydroxyapatite as a drug carrier.

Nanometer-sized fluorescent hybrid silica (NFHS) particles were prepared for use as sensitive and photostable fluorescent probes in biological staining and diagnostics. The first step of the synthesis involves the covalent modification of 3-aminopropyltrimethoxysilane with an organic fluorophore, such as fluorescein isothiocyanate, under N2 atmosphere for getting a fluorescent silica precursor. Then the NFHS particles, with a diameter of well below 40 nm, were prepared by controlled hydrolysis of the fluorescent silica precursor with tetramethoxysilane (TMOS) 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. Furthermore, since the fluorophores are covalently bound to the silica network, there is no migration, aggregation and leakage of the fluorophores. In comparison with common single organic fluorophores, these particle probes are brighter, more stable against photobleaching and do not suffer from intermittent on/off light emission (blinking). We have used these newly developed NFHS particles as a fluorescent marker to label antibodies, using silica immobilization method, for the immunoassay of human alpha-fetoprotein (AFP). The detection limit of this method was down to 0.05 ng mL(-1) under our current experimental conditions. We think this material would attract much attention and be applied widely in biotechnology.

Nanometer fluorescent hybrid silica particle as ultrasensitive and photostable biological labels

Flow injection fluorescence immunoassay for gentamicin using sol-gel-derived mesoporous biomaterial.

New mimetic enzymatic sandwich immunoassay system by using oligo(N-isopropylacrylamide) with an active terminal group as a separating support

Fluorescence immunoassay system based on the use of a pH-sensitive phase-separating polymer

A new fluorimetric immunoassay for alpha-fetoprotein (AFP) has been developed using a novel promising mimetic peroxidase, iron(III) tetrasulfonatophthalocyanine (FeTSPc), as a labeling reagent to catalyze the fluorescence reaction of P- hydroxyphenylacetic acid (P-HPA) and hydrogen peroxide (H2O2). In the competitive immunoassay, anti-AFP antibody was coated on a 96-well plate (polystyrene) and a constant amount of FeTSPc-labeled AFP and a known amount of test solution were added. Non-labeled and FeTSPc-labeled AFP compete for binding to the plate-bound antibody. After the immunoreaction, the immunochemically adsorbed FeTSPc-AFP conjugate moiety was determined by measuring the fluorescence produced in a solution containing P-HPA and H2O2. AFP can be determined in the concentration range of 1-300 ng mL(-1) with a detection limit of 0.5 ng mL(-1).

Ma-Tai Ding

Papers

Nanometer fluorescent hybrid silica particle as ultrasensitive and photostable biological labels

Flow injection fluorescence immunoassay for gentamicin using sol-gel-derived mesoporous biomaterial.

New mimetic enzymatic sandwich immunoassay system by using oligo(N-isopropylacrylamide) with an active terminal group as a separating support

Fluorescence immunoassay system based on the use of a pH-sensitive phase-separating polymer

Fluorescence immunoassay of alpha-fetoprotein with iron(III) tetrasulfonatophthalocyanine as a mimetic enzyme labeling reagent.