Exploring the structure–property relationships of ultrasonic/MRI dual imaging magnetite/PLA microbubbles: magnetite@Cavity versus magnetite@Shell systems

Poly(acrylic acid)-grafted magnetite nanoparticle conjugated with pyrrolidinyl peptide nucleic acid for specific adsorption with real DNA

Magnetite nanoparticle conjugated with pyrrolidinyl peptide nucleic acid (MNP@PNA) was synthesized for use as both a magnetic nano-support and a probe for specific adsorption with complementary deoxyribonucleic acid (DNA). MNP@PNA with the size ranging between 120 and 170 nm in diameter was prepared via a free radical polymerization of acrylic acid in the presence of acrylamide-grafted MNP to obtain negatively charged magnetic nanoclusters, followed by ionic adsorption with PNA. According to fluorescence spectrophotometry and gel electrophoresis, this MNP@PNA can differentiate between fully matched, single-base mismatched and fully mismatched synthetic DNAs tagged with different fluorophores. UV-vis spectrophotometry and gel electrophoresis indicated that MNP@PNA can be used for specific adsorption with real DNA (zein gene of maize) having complementary sequence with the PNA probe. This novel anionic MNP conjugated with the PNA probe might be potentially applicable for use as a magnetic support for DNA base discrimination and might be a promising tool for testing genetic modification.

Multimodal micro, nano, and size conversion ultrasound agents for imaging and therapy

Ultrasound (US) is one of the most commonly used clinical imaging techniques. However, the use of US and US-based intravenous agents extends far beyond imaging. In particular, there has been a surge in the fabrication of multimodality US contrast agents and theranostic US agents for cancer imaging and therapy. The unique interaction of US waves with microscale and nanoscale agents has attracted much attention in the development of contrast agents and drug-delivery vehicles. The dimensions of the agent not only dictate how it behaves in vivo, but also how it interacts with US for imaging and drug delivery. Furthermore, these agents are also unique due to their ability to convert from the nanoscale to the microscale and vice versa, having imaging and therapeutic utility in both dimensions. Here, we review multimodality and multifunctional US-based agents, according to their size, and also highlight recent developments in size conversion US agents. WIREs Nanomed Nanobiotechnol 2016, 8:796-813. doi: 10.1002/wnan.1398 For further resources related to this article, please visit the WIREs website.