Current Organic Chemistry - Volume 21, Issue 23, 2017

Over the past decade, host-guest complexes have become increasingly targeted as new tools to bind organic molecules onto the surfaces of nanostructured materials. The chemical bond between organic molecules and nanostructures has evolved in recent years, from a covalent bond through simple anchor groups, to binding through highly tunable linker-anchor units, to binding through interfacial host-guest chemistry. This review provides an overview of host-guest systems prepared from molecular hosts as cyclodextrins, cucurbiturils, calixarenes, carcerands, cavitands, and their applications in nanoscience. The binding onto quantum dots, metal nanoparticles, inorganic metal oxides, magnetic nanoparticles and carbon-based nanostructured materials and the application of the resulting heterosupramolecular structures are discussed with a focus on the most recent developments. Overall, this review illustrates how supramolecular chemistry and host-guest chemistry can be employed to anchor photo-and redox- active organic molecules to nanostructures producing sophisticated materials or functional devices oriented that can be employed in fundamental research as well as in a variety of technologically relevant applications.

Background: In this review, we summarized the relevance of anisotropic morphologies in the synthesis and applications of metal nanoparticles, including Janus nanoparticles. In recent years, the control over the shape of metal particles has successfully achieved. Non-spherical gold nanoparticles such as rods, wires, cubes, triangular prisms, decahedra, or octahedra exhibit unique properties that differ from those of symmetric, spherical gold nanoparticles. Objective: This article provides a general view of current research in the field of anisotropic metal nanoparticles. We begin by explaining the relevance of anisotropic metal nanoparticles in the field of nanotechnology. Then, we distinguish between physical and chemical method frequently performed for the preparation of metallic nanoparticles. In this review we only focus in chemical methods, and the following sections divide the most recently published procedures in two different methods for chemical synthesis: seed-mediated growth and seedless procedures. For each of these routes, we present the fabrication of metal particles in aqueous or organic media. Conclusion: In this review, we also describe numerous procedures for the functionalization of several anisotropic morphologies with silica, poly(N-isopropylacrylamide) (pNIPAM), as well as the fabrication of bimetallic core shell structures. We hope that this review will help the scientists to carry out several general routes for the synthesis of non-spherical particles to exploit their efficacy for wide applications.

Background: Reaching the target cell has been the ultimate goal of nanoparticle-based drug delivery because many drugs do not have the adequate physicochemical properties to reach or be taken up by target cells. Therefore, site-specific drug delivery systems have been sought, aiming at overcoming many biological barriers, thus improving drug performance. Objective: Lipid nanoparticles emerged as a promising alternative for the usual colloidal drug carriers, prepared with non-toxic solid physiological lipids and stabilized by common pharmaceutical surfactants. In addition to the controlled or triggered release, solid lipid nanoparticles (SLN) can be designed to afford longer circulation times improving the efficiency of drug delivery to the site of action. Over the past 20 years, several passive or active functionalization approaches have been successfully applied to lipid nanoparticles intended for targeting. A variety of ligands may be functionally SLN-attached including various internalizable ligands, specific targeted peptides, saccharide ligands, or therapeutic molecules (e.g. antibodies or enzymes). Conclusion: The present review focuses on the surface modification of lipid nanoparticles either SLN, nanostructured lipid carriers (NLC), lipid drug conjugate nanoparticles (LDC) or lipid nanocapsules (LNC) with specific molecules with the aim of improving its therapeutic and targeting performance.

Cancer is a disease in which cells show an atypical behavior and begin to divide abnormally without control. Furthermore, these cells can spread to other tissues and result in the development of new tumors. It is very difficult to find a treatment that discriminates between tumor cells and healthy cells because cancerous cells are from the person who has the disease and they are not an external and foreign pathogen easily recognizable by the immune system. Thus, the treatments that currently exist for cancer disease are quite nonspecific and they also attack healthy cells, producing a highly specific toxicity and, therefore, severe side effects. Moreover, drugs used in cancer treatment are metabolized and eliminated rapidly from the body, the administration of large amounts of drugs necessarily leading to the increase of the unspecific toxicity produced by the drug. Nanotechnology may provide the solution to these problems by the synthesis of nanoplatforms that are able to make these drugs more specific for tumoral tissues, thus increasing the drug half-life in the body and thereby reducing non-specific toxicity and thus the side effects of the drugs. Some of the strategies employed in the field of nanotechnology against cancer to improve anti-tumor therapy are, for example, overcome by the MDR phenotype, which has some tumor cells (thanks to different materials used in the synthesis of nanoparticles), active targeting against tumor cells (because of its union with different structures that recognize tumor cells) or make the nanoparticles sensitive to certain conditions that allow the release of the drug transported to the tumor site (for example conditions of acidity or alkalinity of the environment). For these reasons, nanotechnology applied to the biomedical sciences has been having a great development in recent years. In this chapter, we review the different therapeutic strategies in the fight against cancer in which nanotechnology can help, describing the materials most widely used in tumor therapy, presenting a great versatility thanks to which nanomedical platforms can be used to overcome the current limitations in the use of free antitumor drugs.

Background: Advances in the medicinal nanotechnology have given upward thrust to multifunctional efficient nanocarriers that can be engineered with tunable physico-chemical traits to deliver one or extra healing agent(s) appropriately and selectively to the most cancers cells, focusing on intracellular organellespecific drug delivery. Objective: Large pores of mesoporous silica nanoparticles allow the other particles to be filled with a drug through endocytosis. These emerge as highly attractive class of drug and gene delivery vectors. Gold nanoparticles can also pack different sizes and several ligands, in order to gain function of targeting tumor cells. Conclusion: In the present review, we compile the recent advances in mesoporous silica and gold nanoparticles as carriers of drugs and genes to tumors by passive and active approaches with descriptive examples. In addition, market status of mesoporous silica and gold based nanodrugs has been discussed. Finally, the efforts are made to discuss the current challenges and future prospectives.