Assembly of Linear Nano-Chains from Iron Oxide Nanospheres with Asymmetric Surface Chemistry

Abstract

Besides the multifunctionality, another equally important aspect of nanoparticles is their engineerability to control the geometrical and chemical properties during fabrication. In this work, we exploited this aspect to define asymmetric surface chemistry of an iron oxide nanosphere by controlling the topology of ligand expression on its surface resulting in a particle with two faces, one displaying only amines and the other only thiols. Specifically, amine-functionalized iron oxide nanospheres were attached on a solid support via a crosslinker containing a disulfide bridge. Liberation of the nanosphere using thiolytic cleavage created thiols on the portion of the particle's surface that interacted with the solid support. Employing a solid-phase strategy and a step-by-step addition of particles, the two unique faces on the same nanosphere served as fittings to assemble them into linear nano-chains. Assembly of chains with various lengths and aspect ratios was controlled by the size and number of the added nanospheres. The characteristics of those chains showed a high degree of uniformity indicating the exceptional control of the synthetic process. Notably, one of the unique properties of the iron oxide nano-chains was an increased magnetic relaxivity, indicating their potential use as contrast agents for magnetic resonance imaging.

The effects of particle size, shape, density and flow characteristics on particle margination to vascular walls in cardiovascular diseases

“…been developed and constructed from three to four nanospheres covalently linked together for microvascular targeting in the diagnosis and treatment of cancerous and metastasis diseases [77][78][79][80][81][82][83]. However, there have been no reports on the use of nanochains in atherosclerosis.…”

Shaping Cancer Nanomedicine: The Effect of Particle Shape on The In Vivo Journey of Nanoparticles

“…Furthermore, nanomedicine’s multifunctional abilities to seek, search, and destroy has been exploited to develop various therapeutic, imaging, and theranostic agents, which are under preclinical and clinical evaluation [6]. In addition to the control over the size of nanoparticles, the engineerable nature of nanoparticles has led to nanostructures with various shapes [7, 8] and new properties [9, 10]. In this 50 year lifetime, nanomedicine has grown from an “exotic” research area to a mainstream scientific field.…”

“…These nanoparticles are manufactured from a wide range of materials and also vary in flexibility. Using different methods, particles are generated with two-dimensional polygonal shapes [60–67], three-dimensional polyhedral shapes [68–72], rod shapes [73–79], branched structures [80–83], and other complex shapes such as snowflakes [81], flowers [81], thorns [81], hemispheres [84, 85], cones [85, 86], urchins [87, 88], filamentous particles [52], biconcave discoids [89], worms [8], trees [90], dendrites [91], necklaces [92], and chains [9, 55, 93, 94]. Importantly, the ability to produce drug product with a high level of consistency and reproducibility is critical in the pharmaceutical industry.…”

“…Furthermore, a nanofabrication technology based on Dip-Pen nanolithography has enabled commercial manufacturing of nanoparticles of various shapes and structures from a variety of different materials [96]. In addition, by adapting a solid-phase chemistry strategy, nanospheres can be assembled into oblong chain-like nanoparticles of various aspect ratios, which can be scaled up relatively easily [9]. …”

Shape matters: synthesis and biomedical applications of high aspect ratio magnetic nanomaterials

“…Another attractive feature of this approach is the fact that it displays binding sites that are not normally accessible under physiological conditions, while other typical receptor-mediated nanoparticle delivery systems require upregulation of cell-surface receptors. 120 Peiris et al developed a multicomponent nanomaterial for enhanced delivery of chemotherapeutics consisting of three iron oxide nanospheres and one doxorubicin-loaded liposome covalently assembled in a nanochain 89 with a length of 100 nm. 90 The magnetic nature of the nanoparticles was used to trigger the controlled release of the drug from the liposomes upon exposure to a radiofrequency (RF) field (Fig.…”