Uptake and intracellular fate of peptide surface-functionalized silica hybrid magnetic nanoparticles in vitro

Recently, the use of nanomaterials as intracellular targeting tools for theranostics has gained heightened interest. Despite the clear advantages posed by surface-functionalized nanoparticles (NPs) in this regard, limited understanding currently exists due to difficulties in reliably synthesizing NPs with surface functionalizations adequate for use in such applications, as well as the manner of analytics used to assess the cellular uptake and intracellular localization of these NPs. In the present study, two key surface functionalities (a nuclear localization sequence (NLS) and integrin-ligand (cRGD)) are attached to the surface of multifunctional, silica hybrid magnetic nanoparticles (SHMNPs) containing a polyethylene glycol (PEG) polymer coating using a well-described, reliable, and reproducible microreactor set-up. Subsequent analytical interpretation, via laser scanning confocal, transmission electron and dark-field microscopy, as well as flow cytometry, of the interaction of SHMNPs-PEG-cRGD-NLS with macrophage (J774A.1) and epithelial (HeLa) cells shows internalization of the SHMNPs-PEG-cRGD-NLS in both cell types up to 24 h after 20 μg mL⁻¹ exposure, as well as increasing aggregation inside of vesicles over this time period. The findings of this study show that by incorporating a variety of state-of-the-art analytical and imaging approaches, it is possible to determine the specific effectiveness of surface peptide and ligand sequences upon multifunctional SHMNPs

Preparation and characterization of functional silica hybrid magnetic nanoparticles

We report on the synthesis and characterization of functional silica hybrid magnetic nanoparticles (SHMNPs). The co-condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) in presence of superparamagnetic iron oxide nanoparticles (SPIONs) leads to hybrid magnetic silica particles that are surface-functionalized with primary amino groups. In this work, a comprehensive synthetic study is carried out and completed by a detailed characterization of hybrid particles׳ size and morphology, surface properties, and magnetic responses using different techniques. Depending on the mass ratio of SPIONs and the two silanes (TEOS and APTES), we were able to adjust the number of surface amino groups and tune the magnetic properties of the superparamagnetic hybrid particles

Amino covalent binding approach on iron oxide nanoparticle surface: toward biological applications

We report on the synthesis and the surface modification of different types of magnetic iron oxide particles by developing an original process based on diazonium salts chemistry. Particles were first coated with amino groups and then subjected to polyethylene glycol (PEG) surface modification. They were subsequently characterized by Transmission electron microscopy, infrared spectroscopy, diffraction light scattering and by Zeta potential. To show the efficiency of this surface modification method, the potential cytotoxicity and (pro-)inflammatory effect of the PEG magnetic particles were also analyzed in vitro. This covalently surface modification approach based on diazonium salts chemistry provides individually dispersed, PEG-modified magnetic nanoparticles suitable for biological applications

Multi-functional magnetic photoluminescent photocatalytic polystyrene-based micro- and nano-fibers Obtained by electrospinning

This work reports on the implementation of electrospinning (ES) as a facile route to encapsulate nano-engineered materials in a polystyrene (PS) matrix. We applied ES to co-encapsulate two kinds of nanoparticles, i.e., upconversion nanophosphors (UCNPs) and superparamagnetic iron oxide nanoparticles (SPIONs), in polystyrene (PS)-based micro- and nano-fibers (PSFs). This approach made it possible to integrate near-infrared (NIR) light-sensitive 500-nm β-NaYF₄:Yb, Er UCNPs with 10-nm γ-Fe₂O₃ SPIONs in PS fibers. During the ES process, PSFs were additionally loaded with a well-established singlet oxygen (¹∆g) photosensitizer, rose bengal (RB). The thus obtained PSFs revealed the promising features of prospective multi-functional magnetic photoluminescent photocatalytic nano-constructs

Magnetic microreactors for efficient and reliable magnetic nanoparticle surface functionalization

Microreactors have attracted wide attention in the nano- and biotechnology fields because they offer many advantages over standard liquid phase reactions. We report the development of a magnetic microreactor for reliable, fast and efficient surface functionalization of superparamagnetic iron oxide nanoparticles (SPIONs). A comprehensive study of the development process in terms of setup, loading capacity and efficiency is described. We performed experimental and computational studies in order to evaluate the trapping efficiencies, maximum loading capacity and magnetic alignment of the nanoparticles. The results showed that capacity and trapping efficiencies are directly related to the flow rate, elution time and reactor type. Based on our results and the developed magnetic microreactor, we describe a model multistep surface derivatization procedure of SPIONs