Monitoring the distribution of internalized silica nanoparticles inside cells via direct stochastic optical reconstruction microscopy.

Understanding the exact localization of nanoparticles within cell is of particular importance for rational design of high-effective nanomedicines. In the present study, direct stochastic optical reconstruction microscopy (dSTORM) is employed to elucidate the precise localization of nanoparticles within cells owing to its superiority of nanometric resolution, multicolour ability and minimal invasiveness. The localization of the Cy5 labelled mesoporous silica nanoparticles (MSNs-Cy5) in MCF-7 cells are monitored by dSTORM and conventional fluorescence microscopy, respectively. The dSTORM images demonstrate much higher spatial resolution for locating MSNs-Cy5 within cells compared to that of the conventional fluorescence images. Moreover, the distribution of MSNs-Cy5 within three cell lines over time are obtained. For the MCF-7 and HeLa cells, MSNs-Cy5 nanoparticles distribute nearly all around the cytoplasm after 5 h incubation. In contrast, MSNs-Cy5 nanoparticles within NIH 3T3 cells are quite different that they are found to be either attached to or embedded into cell membranes, without penetrating into the cytoplasm. Overall, we provide a practical method to reveal the in situ precise imaging of nanoparticles in cells with nanometric resolution precision. This method may open up new opportunities for organelle-specific targeting drug delivery to achieve maximum therapeutic benefit.

Cofactor-free oxidase-mimetic nanomaterials from self-assembled histidine-rich peptides.

Natural oxidases mainly rely on cofactors and well-arranged amino acid residues for catalysing electron-transfer reactions but suffer from non-recovery of their activity upon externally induced protein unfolding. However, it remains unknown whether residues at the active site can catalyse similar reactions in the absence of the cofactor. Here, we describe a series of self-assembling, histidine-rich peptides, as short as a dipeptide, with catalytic function similar to that of haem-dependent peroxidases. The histidine residues of the peptide chains form periodic arrays that are able to catalyse H2O2 reduction reactions efficiently through the formation of reactive ternary complex intermediates. The supramolecular catalyst exhibiting the highest activity could be switched between inactive and active states without loss of activity for ten cycles of heating/cooling or acidification/neutralization treatments, demonstrating the reversible assembly/disassembly of the active residues. These findings may aid the design of advanced biomimetic catalytic materials and provide a model for primitive cofactor-free enzymes.

Dynamic Detection of Active Enzyme Instructed Supramolecular Assemblies In Situ via Super-Resolution Microscopy.

Inspired by the self-assembly phenomena in nature, the instructed self-assembly of exogenous small molecules in a biological environment has become a prevalent process to control cell fate. Despite mounting examples of versatile bioactivities, the underlying mechanism remains less understood, which is in large hindered by the difficulties in the identification of those dynamic assemblies in situ. Here, with direct stochastic optical reconstruction microscopy, we are able to elucidate the dynamic morphology transformation of the enzyme-instructed supramolecular assemblies in situ inside cancer cells with a resolution below 50 nm. It indicates that the assembling molecules endure drastically different pathways between cell lines with different phosphatase activities and distribution. In HeLa cells, the direct formation of intracellular supramolecular nanofibers showed slight cytotoxicity, which was due to the possible cellular secretory pathway to excrete those exogenous molecules assemblies. In contrast, in Saos-2 cells with active phosphatase on the cell surface, assemblies with granular morphology first formed on the cell membranes, followed by a transformation into nanofibers and accumulation in cells, which induced Saos-2 cell death eventually. Overall, we provided a convenient method to reveal the in situ dynamic nanomorphology transformation of the supramolecular assemblies in a biological environment, in order to decipher their diverse biological activities.

Assembled Vitamin B2 Nanocrystals with Optical Waveguiding and Photosensitizing Properties for Potential Biomedical Application.

Great success has been achieved in recent years in the development of synthetic or assembled nanobiomaterials. Among these, biomolecule-based nanoarchitectures with special optical property are of particular interest. Here, we demonstrate that vitamin B2 nanocrystals assembled as nanorods can be obtained with precise control. Excitingly, such one-dimensional nanostructures not only exhibit intrinsic optical waveguiding properties but also the ability to sensitize oxygen to produce reactive oxygen species. With these properties, we applied the obtained vitamin B2 nanorods under remotely localized light illumination into single tumour cells in vitro for anticancer photodynamic therapy. Further, vitamin B2 nanorods were explored for in vivo photodynamic therapy by using a tumour model. With such bionanostructures, new features and functions of vitamin B2 and its derivatives have been developed.

Self-Propelled Nanomotors for Thermomechanically Percolating Cell Membranes.

We report a near-infrared (NIR) light-powered Janus mesoporous silica nanomotor (JMSNM) with macrophage cell membrane (MPCM) cloaking that can actively seek cancer cells and thermomechanically percolate cell membrane. Upon exposure to NIR light, a heat gradient across the Janus boundary of the JMSNMs is generated by the photothermal effect of the Au half-shells, resulting in a self-thermophoretic force that propels the JMSNMs. In biological medium, the MPCM camouflaging can not only prevent dissociative biological blocks from adhering to JMSNMs but also improve the seeking sensitivity of the nanomotors by specifically recognizing cancer cells. The biofriendly propulsion and recognition capability enable JMSNMs to achieve the active seeking and bind to the membrane of cancer cells. Subsequent illumination with NIR then triggers the photothermal effect of MPCM@JMSNMs to thermomechanically perforate the cytomembranes for guest molecular injection. This approach integrates the functions of active seeking, cytomembranes perforating, and thermomechanical therapy in nanomotors, which may pave the way to apply self-propelled motors in biomedical fields.

Magnetic Mesoporous Silica Nanoparticles Cloaked by Red Blood Cell Membranes: Applications in Cancer Therapy.

Targeted drug delivery is an emerging technological strategy that enables nanoparticle systems to be responsive for tumor therapy. Magnetic mesoporous silica nanoparticles (MMSNs) were cloaked with red blood cell membrane (RBC). This integrates long circulation, photosensitizer delivery, and magnetic targeting for cancer therapy. In vivo experiments demonstrate that RBC@MMSNs can avoid immune clearance and achieve magnetic field (MF)-induced high accumulation in a tumor. When light irradiation is applied, singlet oxygen rapidly generates from hypocrellin B (HB)-loaded RBC@MMSN and leads to the necrosis of tumor tissue. Such a RBC-cloaked magnetic nanocarrier effectively integrates immunological adjuvant, photosensitizer delivery, MF-assisted targeting photodynamic therapy, which provides an innovative strategy for cancer therapy.

DNA origami/gold nanorod hybrid nanostructures for the circumvention of drug resistance.

We herein demonstrate that DNA origami can work as a multifunctional platform integrating a chemotherapeutic drug (doxorubicin), gold nanorods and a tumour-specific aptamer MUC-1, to realize the effective circumvention of drug resistance. Doxorubicin (DOX) was loaded efficiently onto DNA origami through base pair intercalation and surface-modified gold nanorods (AuNRs) were assembled onto the DNA origami through DNA hybridization. Due to the active targeting effect of the assembled aptamers, the multifunctional nanostructures achieved increased cellular internalization of DOX and AuNRs. Upon near-infrared (NIR) laser irradiation, the P-glycoprotein (multidrug resistance pump) expression of multidrug resistant MCF-7 (MCF-7/ADR) cells was down-regulated, achieving the synergistically chemotherapeutic (DOX) and photothermal (AuNRs) effects.

Macrophage Cell Membrane Camouflaged Au Nanoshells for in Vivo Prolonged Circulation Life and Enhanced Cancer Photothermal Therapy.

Macrophage cell membrane (MPCM)-camouflaged gold nanoshells (AuNS) that can serve as a new generation of photothermal conversion agents for in vivo photothermal cancer therapy are presented. They are constructed by the fusion of biocompatible AuNSs and MPCM vesicles. The resulting MPCM-coated AuNSs exhibited good colloidal stability and kept the original near-infrared (NIR) adsorption of AuNSs. Because AuNS carried high-density coverage of MPCMs, the totally functional portions of macrophage cells membrane were grafted onto the surface of AuNSs. This surface functionalization provided active targeting ability by recognizing tumor endothelium and thus improved tumoritropic accumulation compared to the red blood cell membrane-coating approach. These biomimetic nanoparticles significantly enhance in vivo blood circulation time and local accumulation at the tumor when administered systematically. Upon NIR laser irradiation, local heat generated by the MPCM-coated AuNS achieves high efficiency to suppress tumor growth and selectively ablate cancerous cells within the illuminated zone. Therefore, MPCM-coated AuNSs remained the natural properties of their source cells, which may improve the efficacy of photothermal therapy modulated by AuNSs and other noble-metal nanoparticles.

A Photosensitizer-Loaded DNA Origami Nanosystem for Photodynamic Therapy.

Photodynamic therapy (PDT) offers an alternative for cancer treatment by using ultraviolet or visible light in the presence of a photosensitizer and molecular oxygen, which can produce highly reactive oxygen species that ultimately leading to the ablation of tumor cells by multifactorial mechanisms. However, this technique is limited by the penetration depth of incident light, the hypoxic environment of solid tumors, and the vulnerability of photobleaching reduces the efficiency of many imaging agents. In this work, we reported a cellular level dual-functional imaging and PDT nanosystem BMEPC-loaded DNA origami for photodynamic therapy with high efficiency and stable photoreactive property. The carbazole derivative BMEPC is a one- and two-photon imaging agent and photosensitizer with large two-photon absorption cross section, which can be fully excited by near-infrared light, and is also capable of destroying targets under anaerobic condition by generating reactive intermediates of Type I photodynamic reactions. However, the application of BMEPC was restricted by its poor solubility in aqueous environment and its aggregation caused quenching. We observed BMEPC-loaded DNA origami effectively reduced the photobleaching of BMEPC within cells. Upon binding to DNA origami, the intramolecular rotation of BMEPC became proper restricted, which intensify fluorescence emission and radicals production when being excited. After the BMEPC-loaded DNA origami are taken up by tumor cells, upon irradiation, BMEPC could generate free radicals and be released due to DNA photocleavage as well as the following partially degradation. Apoptosis was then induced by the generation of free radicals. This functional nanosystem provides an insight into the design of photosensitizer-loaded DNA origami for effective intracellular imaging and photodynamic therapy.

Biointerfacing polymeric microcapsules for in vivo near-infrared light-triggered drug release.

Seeking safe and effective water-soluble drug carriers is of great significance in nanomedicine. To achieve this goal, we present a novel drug delivery system based on biointerfacing hollow polymeric microcapsules for effectively encapsulating water-soluble antitumor drug and gold nanorod (GNR) functionalization for triggered release of therapeutic drugs on-demand using low power near-infrared (NIR) radiation. The surface of polymeric microcapsules is covered with fluidic lipid bilayers to decrease the permeability of the wall of polymeric capsules. The temperature increase upon NIR illumination deconstructs the structure of the lipid membrane and polyelectrolyte multilayers, which in turn results in the rapid release of encapsulated water-soluble drug. In vivo antitumor tests demonstrate that this microcapsule has the effective ability of inhibiting tumor growth and preventing metastases. Real time in vivo fluorescence imaging results confirm that capsules can be excreted gradually from the animal body which in turn demonstrates the biocompatibility and biodegradation of these biointerfacing GNR-microcapsules. This intelligent system provides a novel anticancer platform with the advantages of controlled release, biological friendliness and credible biosafety.

The Directional Observation of Highly Dynamic Membrane Tubule Formation Induced by Engulfed Liposomes.

Highly dynamic tubular structures in cells are responsible for exchanges between organelles. Compared with bacterial invasion, the most affordable and least toxic lipids were found in this study to be gentle and safe exogenous stimuli for the triggering of membrane tubules. A specific lipid system was internalized by NIH3T3 cells. Following cellular uptake, the constructed liposomes traveled towards the nucleus in aggregations and were gradually distributed into moving vesicles and tubules in the cytosol. The triggered tubules proceeded, retreated or fluctuated along the cytoskeleton and were highly dynamic, moving quickly (up to several microns per second), and breaking and fusing frequently. These elongated tubules could also fuse with one another, giving rise to polygonal membrane networks. These lipid systems, with the novel property of accelerating intracellular transport, provide a new paradigm for investigating cellular dynamics.

A Self-Assembled DNA Origami-Gold Nanorod Complex for Cancer Theranostics.

A self-assembled DNA origami (DO)-gold nanorod (GNR) complex, which is a dual-functional nanotheranostics constructed by decorating GNRs onto the surface of DNA origami, is demonstrated. After 24 h incubation of two structured DO-GNR complexes with human MCF7 breast cancer cells, significant enhancement of cell uptake is achieved compared to bare GNRs by two-photon luminescence imaging. Particularly, the triangle shaped DO-GNR complex exhibits optimal cellular accumulation. Compared to GNRs, improved photothermolysis against tumor cells is accomplished for the triangle DO-GNR complex by two-photon laser or NIR laser irradiation. Moreover, the DO-GNR complex exhibits enhanced antitumor efficacy compared with bare GNRs in nude mice bearing breast tumor xenografts. The results demonstrate that the DO-GNR complex can achieve optimal two-photon cell imaging and photothermal effect, suggesting a promising candidate for cancer diagnosis and therapy both in vitro and in vivo.

Near-Infrared-Activated Nanocalorifiers in Microcapsules: Vapor Bubble Generation for In†Vivo Enhanced Cancer Therapy.

Photothermal therapy based on gold nanostructures has been widely investigated as a state-of-the-art noninvasive therapy approach. Because single nanoparticles cannot harvest sufficient energy, self-assemblies of small plasmonic particles into large aggregates are required for enhanced photothermal performance. Self-assembled gold nanorods in lipid bilayer-modified microcapsules are shown to localize at tumor sites, generate vapor bubbles under near-infrared light exposure, and subsequently damage tumor tissues. The polyelectrolyte multilayer enables dense packing of gold nanorods during the assembly process, which leads to the formation of vapor bubbles around the excited capsules. The resulting vapor bubbles achieve a high efficiency of suppressing tumor growth compared to single gold nanorods. In vivo experiments demonstrated the ability of soft-polymer multilayer microcapsules to cross the biological barriers of the body and localize at target tissues.

Macrophage Cell Membrane Camouflaged Mesoporous Silica Nanocapsules for In Vivo Cancer Therapy.

Engineering natural macrophage cell membrane-camouflaged mesoporous silica nanocapsules can reduce the arrested percentage of immune cells and tissues, effectively prolong the survival time of nanoparticles in blood circulation system, and improve the accumulation in tumor.

One-pot ultrafast self-assembly of autofluorescent polyphenol-based core@shell nanostructures and their selective antibacterial applications.

We demonstrate that large-scale autofluorescent tea polyphenol (TP)-based core@shell nanostructures can be assembled by one-pot preparation under microwave irradiation within 1 min. The formation mechanism of the heterogeneous well-defined core@shell nanocomposites involves microwave-assisted oxidation-inducing self-assembly and directed aggregation. The strategy is general to construct Ag@TP and Au@TP nanocomposites. Moreover, a simple galvanic replacement reaction was introduced to synthesize hollow Au/Ag@TP bioconjugates with near-infrared (NIR) absorption, which could be exploited for NIR cancer diagnosis and treatment. It could be expected that more complex alloy@TP nanostructures can be obtained under proper reaction conditions. Furthermore, as a first application, it is shown that the heterogeneous Ag@TP nanostructures can strongly inhibit Escherichia coli growth, while they exhibit no obvious normal cell toxicity. The sharp contrast of the two effects promises that the nanocomposites are excellent low toxicity biomaterials for selective antibacterial treatment.

Cell membrane tracker based on restriction of intramolecular rotation.

The fluorescence of tetraphenylethylene (TPE), an archetypal luminogen, is induced by restriction of intramolecular rotation (RIR). TPE was grafted with palmitic acid (PA) onto a hydrophilic peptide to yield a cell membrane tracker named TR4. TR4 was incorporated into liposomes, where it showed significant RIR characteristics. When cells were incubated with TR4, cytoplasmic membranes were specifically labeled. TR4 shows excellent photostability and low cytotoxicity.

Peptide p160-coated silica nanoparticles applied in photodynamic therapy.

Peptide p160-conjugated mesoporous silica nanoparticles (MSN) were fabricated and loaded with photosensitizer hypocrellin B (HB). The results indicate that the nanocomposites have better selectivity for cancer cells and higher cytotoxicity in photodynamic therapy in vitro. The nanocomposites can be used as a novel candidate in photodynamic therapy. This may be a general and promising method to modify nanoparticles to improve their cell affinity.

DNA origami as an in vivo drug delivery vehicle for cancer therapy.

Many chemotherapeutics used for cancer treatments encounter issues during delivery to tumors in vivo and may have high levels of systemic toxicity due to their nonspecific distribution. Various materials have been explored to fabricate nanoparticles as drug carriers to improve delivery efficiency. However, most of these materials suffer from multiple drawbacks, such as limited biocompatibility and inability to engineer spatially addressable surfaces that can be utilized for multifunctional activity. Here, we demonstrate that DNA origami possessed enhanced tumor passive targeting and long-lasting properties at the tumor region. Particularly, the triangle-shaped DNA origami exhibits optimal tumor passive targeting accumulation. The delivery of the known anticancer drug doxorubicin into tumors by self-assembled DNA origami nanostructures was performed, and this approach showed prominent therapeutic efficacy in vivo. The DNA origami carriers were prepared through the self-assembly of M13mp18 phage DNA and hundreds of complementary DNA helper strands; the doxorubicin was subsequently noncovalently intercalated into these nanostructures. After conducting fluorescence imaging and safety evaluation, the doxorubicin-containing DNA origami exhibited remarkable antitumor efficacy without observable systemic toxicity in nude mice bearing orthotopic breast tumors labeled with green fluorescent protein. Our results demonstrated the potential of DNA origami nanostructures as innovative platforms for the efficient and safe drug delivery of cancer therapeutics in vivo.

Self-propelled Janus mesoporous silica nanomotors with sub-100 nm diameters for drug encapsulation and delivery.

The synthesis of an innovative self-propelled Janus nanomotor with a diameter of about 75 nm that can be used as a drug carrier is described. The Janus nanomotor is based on mesoporous silica nanoparticles (MSNs) with chromium/platinum metallic caps and propelled by decomposing hydrogen peroxide to generate oxygen as a driving force with speeds up to 20.2 µm s(-1) (about 267 body lengths per second). The diffusion coefficient (D) of nanomotors with different H2 O2 concentrations is calculated by tracking the movement of individual particles recorded by means of a self-assembled fluorescence microscope and is significantly larger than free Brownian motion. The traction of a single Janus MSN nanomotor is estimated to be about 13.47×10(-15) N. Finally, intracellular localization and drug release in vitro shows that the amount of Janus MSN nanomotors entering the cells is more than MSNs with same culture time and particle concentrations, meanwhile anticancer drug doxorubicin hydrochloride loaded in Janus MSNs can be slowly released by biodegradation of lipid bilayers in cells.

Selective inhibition of breast cancer stem cells by gold nanorods mediated plasmonic hyperthermia.

Cancer stem cells (CSCs) have been identified in a variety of cancers and emerged as a new target for cancer therapy. CSCs are resistant to many current cancer treatments, including chemotherapy and radiation therapy. Therefore, eradication of this cell population is a primary objective in cancer therapy. Here, we report gold nanorods (AuNRs) mediated photothermal treatment can selectively eliminate CSCs in MCF-7 breast cancer cells. It significantly reduced the aldehyde dehydrogenase positive (ALDH(+)) cells subpopulation and the mammosphere formation ability of treated cells. Also, the gene expression of stem cell markers was decreased. Cellular uptake assay revealed that polyelectrolyte conjugated AuNRs could be internalized by CSCs much more and faster than non cancer stem cells (NCSCs), which might be the main reason for the selective elimination of CSCs. We further loaded salinomycin (SA), a CSCs inhibitor with polyelectrolyte conjugated AuNRs to get a synergistic CSCs inhibition. Enhanced inhibition of CSCs was obtained by NIR light triggered drug release and hyperthermia. This CSCs-targeted thermo-chemotherapy platform provides a new combinatorial strategy for efficient inhibition of CSCs, which is promising to improve cancer treatment and may overcome the chemoresistance and recurrence of cancer.