A Multifunctional Magnetic Red Blood Cell-Mimetic Micromotor for Drug Delivery and Image-Guided Therapy.

Inspired by nature, innovative devices have been made to imitate the morphology and functions of natural red blood cells (RBCs). Here, we report a red blood cell-mimetic micromotor (RBCM), which was fabricated based on a layer-by-layer assembly method and precisely controlled by an external rotating uniform magnetic field. The main framework of the RBCM was constructed by the natural protein zein and finally camouflaged with the RBC membrane. Functional cargos such as Fe3O4 nanoparticles and the chemotherapeutic agent doxorubicin were loaded within the wall part of the RBCM for tumor therapy. Due to the massive loading of Fe3O4 nanoparticles, the RBCM can be precisely navigated by an external rotating uniform magnetic field and be used as a magnetic resonance imaging contrast agent for tumor imaging. The RBCM has been proven to be biocompatible, biodegradable, magnetically manipulated, and imageable, which are key requisites to take micromotors from the chalkboard to clinics. We expect the RBC-inspired biohybrid device to achieve wide potential applications.

The Effect of Cage Shape on Nanoparticle-Based Drug Carriers: Anticancer Drug Release and Efficacy via Receptor Blockade Using Dextran-Coated Iron Oxide Nanocages.

Although a range of nanoparticles have been developed as drug delivery systems in cancer therapeutics, this approach faces several important challenges concerning nanocarrier circulation, clearance, and penetration. The impact of reducing nanoparticle size on penetration through leaky blood vessels around tumor microenvironments via enhanced permeability and retention (EPR) effect has been extensively examined. Recent research has also investigated the effect of nanoparticle shape on circulation and target binding affinity. However, how nanoparticle shape affects drug release and therapeutic efficacy has not been previously explored. Here, we compared the drug release and efficacy of iron oxide nanoparticles possessing either a cage shape (IO-NCage) or a solid spherical shape (IO-NSP). Riluzole cytotoxicity against metastatic cancer cells was enhanced 3-fold with IO-NCage. The shape of nanoparticles (or nanocages) affected the drug release point and cellular internalization, which in turn influenced drug efficacy. Our study provides evidence that the shape of iron oxide nanoparticles has a significant impact on drug release and efficacy.

Responsive polymer-fluorescent carbon nanoparticle hybrid nanogels for optical temperature sensing, near-infrared light-responsive drug release, and tumor cell imaging.

Fluorescent carbon nanoparticles (FCNPs) have been successfully immobilized into poly(N-isopropylacrylamide-co-acrylamide) [poly(NIPAM-AAm)] nanogels based on one-pot precipitation copolymerization of NIPAM monomers with hydrogen bonded FCNP-AAm complex monomers in water. The resultant poly(NIPAM-AAm)-FCNP hybrid nanogels can combine functions from each building block for fluorescent temperature sensing, cell imaging, and near-infrared (NIR) light responsive drug delivery. The FCNPs in the hybrid nanogels not only emit bright and stable photoluminescence (PL) and exhibit up-conversion PL properties, but also increase the loading capacity of the nanogels for curcumin drug molecules. The reversible thermo-responsive swelling/shrinking transition of the poly(NIPAM-AAm) nanogel can not only modify the physicochemical environment of the FCNPs to manipulate the PL intensity for sensing the environmental temperature change, but also regulate the releasing rate of the loaded anticancer drug. In addition, the FCNPs embedded in the nanogels can convert the NIR light to heat, thus an exogenous NIR irradiation can further accelerate the drug release and enhance the therapeutic efficacy. The hybrid nanogels can overcome cellular barriers to enter the intracellular region and light up the mouse melanoma B16F10 cells upon laser excitation. The demonstrated hybrid nanogels with nontoxic and optically active FCNPs immobilized in responsive polymer nanogels are promising for the development of a new generation of multifunctional materials for biomedical applications.

Magnetic iron oxide-fluorescent carbon dots integrated nanoparticles for dual-modal imaging, near-infrared light-responsive drug carrier and photothermal therapy.

Multifunctional hybrid nanoparticles (NPs, ∼100 nm) that combine magnetic Fe3O4 nanocrystals and fluorescent carbon dots (CDs) in porous carbon (C) were successfully synthesized using a one-pot solvothermal method by simply increasing the H2O2 concentration. The resultant Fe3O4@C-CDs hybrid NPs not only demonstrate excellent magnetic responsive properties (Ms = 32.5 emu g-1) and magnetic resonance imaging ability (r = 674.4 mM-1 s-1) from the Fe3O4 nanocrystal core, but also exhibit intriguing photoluminescent (quantum yield ∼6.8%) properties including upconversion fluorescence and excellent photostability from the CDs produced in the porous carbon. The hybrid NPs can enter the intracellular region and illuminate mouse melanoma B16F10 cells under different excitation wavelengths. Meanwhile, the mesoporous carbon shell and hydrophilic surface functional groups endow the hybrid NPs with high loading capacity (835 mg g-1) for the anti-cancer drug doxorubicin and excellent stability in aqueous solutions. More importantly, the hybrid NPs can absorb and convert near-infrared (NIR) light to heat due to the existence of CDs, and thus, can realise NIR-controlled drug release and combined photothermo/chemotherapy for high therapeutic efficacy. Such nanostructured Fe3O4@C-CDs hybrid NPs demonstrate great promise towards advanced nanoplatforms for simultaneous imaging diagnostics and high efficacy therapy.

Porous carbon protected magnetite and silver hybrid nanoparticles: morphological control, recyclable catalysts, and multicolor cell imaging.

A simple and facile synthetic strategy is developed to prepare a new class of multifunctional hybrid nanoparticles (NPs) that can integrate a magnetic core with silver nanocrystals embedded in porous carbon shell. The method involves a one-step solvothermal synthesis of Fe3O4@C template NPs with Fe3O4nanocrystals in the core protected by a porous carbon shell, followed by loading and in situ reduction of silver ions in the carbon shell in water at room temperature. The core-satellite and dumbbell-like nanostructures of the resulted Fe3O4@C-Ag hybrid NPs can be readily controlled by loading amount of silver ions. The hybrid NPs can efficiently catalyze the reduction reaction of organic dyes in water. The easy magnetic separation and high stability of the catalytically active silver nanocrystals embedded in the carbon shell enable the hybrid NPs to be recycled for reuse as catalysts. The hybrid NPs can also overcome cellular barriers to enter the intracellular region and light up the mouse melanoma B16F10 cells in multicolor modal, with no cytotoxicity. Such porous carbon protected Fe3O4@C-Ag hybrid NPs with controllable nanostructures and a combination of magnetic and noble metallic components have great potential for a broad range of applications in the catalytic industry and biomedical field.

Biomimetic assembly of proteins into microcapsules on oil-in-water droplets with structural reinforcement via biomolecular-recognition-based cross-linking of surface peptides.

By mimicking the stabilization of bacterial membranes with S-layer proteins, a novel process to fabricate highly stable protein microcapsules is introduced. In this strategy, engineered collagen peptides with site-specific biotinylation are assembled into microcapsules on the oil-in-water droplets, and the resulting microcapsules are reinforced by biomolecular-recognition-based cross-linking with the protein. Furthermore the microcapsules are shown to be versatile scaffolds for developing functionalized hierarchical colloidosomes for important biotechnological applications.