Smart organic-inorganic nanohybrids based on amphiphilic block copolymer micelles and functional silsesquioxane nanoparticles

High Performance Fluorescent Turn-On Probe for Amitriptyline Based on Hybrid Nanoassembly of Organic-Inorganic Nanoparticles

Fluorescence methods have gained enormous attention due to their ease in use, simplicity, selectivity and sensitivity. Fluorescent chemosensors respond instantly by converting molecular recognition to fluorescent signals. The consumption of pharmaceutical products by living beings is on great increase. The disposal of such compounds in the environment is a matter of great concern as these compounds enter aquatic environment and show accumulation in tissues of aquatic organisms. In the present study, we have utilized naphthalimide based receptors to fabricate organic nanoparticles (ONPs). These ONPs were used for the development of hybrid nanoassemblies, and the developed nanoassemblies were characterized with the help of transmission electron microscopy and dynamic light scattering studies. The photophysical studies were performed and the hybrid assembly developed using receptor 2 demonstrated a turn-on fluorescence emission behavior on binding with Amitriptyline. The present sensing system acted as promising candidate for determination of Amitriptyline among other contending drug molecules. The established system can recognize Amitriptyline up to a detection limit of 48 nM in aqueous medium. Electrochemical recognition studies show binding of hybrid nanoassembly of receptor 2 with Amitriptyline with limit of detection of 21 nM.

Dually responsive gold-iron oxide heterodimers: merging stimuli-responsive surface properties with intrinsic inorganic material features

We demonstrate a versatile approach for the preparation of dually responsive smart inorganic heterostructures (HSs) with the potential for exploitation in nanomedicine. We utilize Au-Fe_xO_y dimers as templates for generating smart inorganic HSs with a pH-responsive coating and a thermo-responsive coating attached to iron oxide and gold nanoparticles (NPs), respectively. First, a thiol-modified thermo-responsive (PNIPAAM-co-PEGA) polymer could be selectively attached to the gold domain by ligand exchange. The sequential attachment of a catechol-modified initiator to the iron oxide surface enables the in situ polymerization of a pH-responsive (PDMAEA) polymer. As hereby shown, the presence of the two distinct polymer domains on each NP subdomain enables each side of the HS to be loaded with different agents. Indeed, by a gel electrophoresis experiment we demonstrate the loading of siRNA on the pH-responsive polymer and the loading of Nile Blue dye, used as a drug model molecule, on the thermo-responsive polymer. The smart HSs exhibited good biocompatibility and downregulated GFP production when loaded with anti-GFP siRNA molecules. In addition, an investigation of the magnetic relaxivity times revealed that the high R2 relaxivity values of the HSs suggest their potential as contrast agents in magnetic resonance imaging (MRI) applications.

Design and Synthesis of Functional Silsesquioxane-Based Hybrids by Hydrolytic Condensation of Bulky Triethoxysilanes

This paper presents a short overview of recent advances in the design and synthesis of organic-inorganic hybrids using silsesquioxane-based nanoparticles having nanometer size, relatively narrow size distribution, high functionalities, and various characteristic features, mainly focusing on our recent researches related to the subject. A highlight of this paper is the water-soluble silsesquioxane-based nanoparticles, including hydroxyl-functionalized and cationic silsesquioxanes, which were synthesized via the one-step condensation of the bulky triethoxysilane precursors. The design and synthesis of R-SiO1.5/SiO2and R-SiO1.5/TiO2hybrids by hydrolytic cocondensation of a triethoxysilane precursor and metal alkoxides are briefly introduced. This paper also deals with recent results in stimuli-responsive hybrids based on the water-soluble silsesquioxane nanoparticles and fluorinated and amphiphilic silsesquioxane hybrids.