Mussel-Inspired Polydopamine Coated Iron Oxide Nanoparticles for Biomedical Application

Mussel-inspired polydopamine (PDA) coated iron oxide nanoparticles have served as a feasible, robust, and functional platform for various biomedical applications. However, there is scarcely a systemic paper reviewed about such functionalising nanomaterials to date. In this review, the synthesis of iron oxide nanoparticles, the mechanism of dopamine self-oxidation, the interaction between iron oxide and dopamine, and the functionality and the safety assessment of dopamine modified iron oxide nanoparticles as well as the biomedical application of such nanoparticles are discussed. To enlighten the future research, the opportunities and the limitations of functionalising iron oxide nanoparticles coated with PDA are also analyzed

In Vitro Safety Evaluation and In Vivo Imaging Studies of Superparamagnetic Iron Oxide Nanoparticles through Biomimetic Modification

Magnetic resonance imaging (MRI) is an advanced medical imaging diagnostic technique that utilizes different resonance signals generated by the signal strength of water content and the relaxation time of protons in water molecules under the influence of an external magnetic field. This technique requires contrast agents, such as Gd-DTPA and Gd-DOTA, which could increase the risk of renal fibrosis in patients with severe renal insufficiency. The magnetic moment or susceptibility of superparamagnetic iron oxide nanoparticle (SPION) is higher than that of other paramagnetic substances and could significantly reduce the dosage of the contrast agent required. In our previous work, the novel magnetic composite nanoparticles (abbreviated as c(RGDyK)-PDA-SPION) had been successfully synthesized by a facile and simple approach. Further evaluation had demonstrated that it had an average particle size of about 50 nm and uniform distribution, superparamagnetic properties, and good dispersion stability in water solution. Animal acute toxicity test also had proved that it had high safety in vivo. In this work, c(RGDyK)-PDA-SPION was further studied for the cell toxicity and effect on HepG2 cells in vitro, and the MRI imaging of this contrast agent in HepG2 tumor-bearing mice was also studied. It is an extension of the published work. The results showed that it possessed high safety and enrichment phenomenon on HepG2 cells in vitro. Animal experimental data preliminarily prove that the contrast agent could enhance the MRI T2-weighted imaging capability of HepG2 carcinoma in tumor-bearing mice and could be a potential T2 contrast agent

Phototheranostics for NIR fluorescence image guided PDT/PTT with extended conjugation and enhanced TICT

Introducing donor and acceptor into conjugated system can facilitate the intersystem crossing (ISC) rate to increase the generation of ROS. Twisted intramolecular charge transfer (TICT) state could favor enhance the nonradiative transition and photothermal conversion efficiency (PCE). Herein, diketopyrrolopyrrole (DPP) core functionalized benzene (PDDP), thiophene (TDPP), triphenylamine-conjugated benzene (TPA-PDDP) and thiophene (TPA-TDPP) derivatives were designed and synthesized. Electrochemistry experiments revealed the heavy atom effect and the introduction of triphenylamine reduced the energy level of TPA-TDPP and improved the ability to generate 1O2 (1O2 QY = 50%). In addition, in the aggregated state, introduction of thiophene, triphenylamine, and long alkyl chains promoted the twisting effect, preventing the intermolecular π-π interaction and enhancing the PCE of TPA-TDPP (38.7%). In vivo fluorescence imaging showed that TPA-TDPP NPs can target the tumor site with the enhanced permeability and retention (EPR) effect and presented excellent synergistic photodynamic/photothermal therapy