Preparation of ZnO nanoparticles for bio‐imaging applications

Abstract

ZnO nanoparticles were prepared by using a gas evaporation method. As ZnO is a luminescent and less toxic material, it can be useful in imaging applications. The nanoparticles prepared in our laboratory showed intense exciton emission in the UV‐blue region. They were processed and surface treated to be compatible for bio‐conjugation. We were able to prepare good dispersions and water‐soluble ZnO nanoparticles from our experiments. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Surface Treatment of Zinc Oxide Nanoparticles by Silica Coating and Evaluation of Their Dispersibility and Photoluminescent Properties

“…A Zn metal (99.99%; The NILACO, Tokyo, Japan) was melted and evaporated by the arc discharge between a carbon cathode and a Zn metal anode, and the ZnO nanoparticles were formed by the reaction of evaporated zinc and oxygen in the air [3]. The conditions of the arc discharge were the pressure of 20 kPa, the current of 50 A, and the air flow late of 5 L/min.…”

“…Zinc Oxide (ZnO) is a direct wide band gap (3.37 eV) compound semiconductor and regarded as a promising ultraviolet optoelectronic material [1][2][3]. To achieve efficient excitonic laser action at room temperature, the binding energy of the exciton must be much higher than the thermal energy (26 meV) [1].…”

“…Although the characterization of native point defects in ZnO is still a question of debate [14], the band energy of the typical defect emissions were reported as follows; for example, that of V O , V Zn , and Zn i , were around 2.5 eV [15,16], 2.35 eV [17,18], and 2.9 eV [19], respectively. Generally the exciton emission of ZnO nanoparticles is decreased in solvents [3]. There are many advantages to utilize the exciton emission of ZnO; first, the sharp emission is similar to the emission from quantum dots because the exciton emission has the atom-like energy level, second, to make relatively low price fluorescent reagents compared to quantum dots because we do not need controlling the size of ZnO nanoparticle with submicron order like quantum dots.…”

Nanoparticles in biomedical applications

“…However, the surface of ZnO nanoparticles needs to be modified to protect them in biological systems as they can be dissolved easily in water and acidic solutions. Also to use ZnO nanoparticles for fluorescence in imaging, the nanoparticles need to be doped as the ZnO bandwidth is in the UV region and UV light cannot penetrate tissue and is also harmful to cells and tissue [203][204][205][206].…”

The effects of oxygen-catalysed and heat treatment on the precipitation synthesised ZnO nanoparticles

“…As the structures are in nanometre scale, ZnO exhibits properties that are different from their bulk counterpart and their performances are enhanced resulting from the high surface to volume ratio properties. Among diverse morphology of ZnO nanostructures, ZnO nanoparticles have received enormous attention during recent years since it offers wide area of application such as sensor [14], photocatalyst [15], transparent UV protection film [16], bio-imaging and drug delivery [17]. Resulting from the widespread ZnO nanoparticles applicability, many methods to produce ZnO nanoparticles in uniform size and volume have been developed via solution chemical route and physical vapour deposition (PVD).…”