Tumor-targeted drug delivery with simultaneous cancer imaging is highly desirable for personalized medicine. Herein, we report a supramolecular approach to design a promising class of multifunctional nanoparticles based on molecular recognition of nucleobases, which combine excellent tumor-targeting capability via aptamer, controlled drug release, and efficient fluorescent imaging for cancer-specific therapy. First, an amphiphilic prodrug dioleoyl clofarabine was self-assembled into micellar nanoparticles with hydrophilic nucleoside analogue clofarabine on their surface. Thereafter, two types of single-stranded DNAs that contain the aptamer motif and fluorescent probe Cy5.5, respectively, were introduced onto the surface of the nanoparticles via molecular recognition between the clofarabine and the thymine on DNA. These drug-containing multifunctional nanoparticles exhibit good capabilities of targeted clofarabine delivery to the tumor site and intracellular controlled drug release, leading to a robust and effective antitumor effect in vivo.

AbstractBased on their structural similarity to natural nucleobases, nucleoside analogue therapeutics were integrated into DNA strands through conventional solid-phase synthesis. By elaborately designing their sequences, floxuridine-integrated DNA strands were synthesized and self-assembled into well-defined DNA polyhedra with definite drug-loading ratios as well as tunable size and morphology. As a novel drug delivery system, these drug-containing DNA polyhedra could ideally mimic the Trojan Horse to deliver chemotherapeutics into tumor cells and fight against cancer. Both in vitro and in vivo results demonstrate that the DNA Trojan horse with buckyball architecture exhibits superior anticancer capability over the free drug and other formulations. With precise control over the drug-loading ratio and structure of the nanocarriers, the DNA Trojan horse may play an important role in anticancer treatment and exhibit great potential in translational nanomedicine.

Structural DNA nanotechnology, an emerging technique that utilizes the nucleic acid molecule as generic polymer to programmably assemble well-defined and nano-sized architectures, holds great promise for new material synthesis and constructing functional nanodevices for different purposes. In the past three decades, rapid development of this technique has enabled the syntheses of hundreds and thousands of DNA nanostructures with various morphologies at different scales and dimensions. Among them, discrete three-dimensional (3D) DNA nanostructures not only represent the most advances in new material design, but also can serve as an excellent platform for many important applications. With precise spatial addressability and capability of arbitrary control over size, shape, and function, these nanostructures have drawn particular interests to scientists in different research fields. In this review article, we will briefly summarize the development regarding the synthesis of discrete DNA 3D nanostructures with various size, shape, geometry, and topology, including our previous work and recent progress by other groups. In detail, three methods majorly used to synthesize the DNA 3D objects will be introduced accordingly. Additionally, the principle, design rule, as well as pros and cons of each method will be highlighted. As functions of these discrete 3D nanostructures have drawn great interests to researchers, we will further discuss their cutting-edge applications in different areas, ranging from novel material synthesis, new device fabrication, and biomedical applications, etc. Lastly, challenges and outlook of these promising nanostructures will be given based on our point of view.

As the gold standard polymer for drug delivery system, polyethylene glycol (PEG) has excellent biocompatibility. It's reported that the low nonspecific interactions between PEG and body contribute to its biocompatibility. However, here we discover dynamic biological interactions exist between PEG and cells on the molecular level. PEG (2 kD) can induce metabolism modulations and survival autophagy by creating an intracellular hypoxic environment, which act as cellular survival strategies in response to the hypoxia. In the cellular adaption process during hypoxia, PEG-treated cells decrease energy consumption by reducing cell growth rate, increase energy supply by amino acid catabolism in a short period, and survival autophagy over a relatively long period, to keep energy homeostasis and survival. Our research provides molecular insights for understanding the mechanism underlying the excellent biocompatibility of PEG, which will be of fundamental importance for further related studies on other polymers and development of polymeric materials with improved characteristics.Download high-res image (338KB)Download full-size image

DNA has gained great attention because of its unique structure, excellent molecular recognition property, and biological functions. When married with versatile synthetic polymers, the DNA conjugated polymer hybrids, known as DNA block copolymers (DBCs), have been launched and well developed for the syntheses of new materials and nanostructures with different functions in the past several decades. Compared to conventional synthetic block copolymers, using DNA as a building block provides several advantages over other polymer candidates, such as molecular recognition, programmable self-assembly, biocompatibility, and sequence-encoded information. In this review, recent developments in this area will be summarized and meaningful breakthroughs will be highlighted. We will discuss representative examples of recent progress in the syntheses, structure manipulations, and applications of DBCs.Download high-res image (110KB)Download full-size imageOrganic polymers are combined with DNA resulting DNA block copolymers (DBCs) that can simultaneously show the properties of the polymer and DNA. We will discuss some examples of recent developments in the syntheses, structure manipulations, and applications of DBCs.

Discrete and symmetric three-dimensional (3D) DNA nanocages have been revoked as excellent candidates for various applications, such as guest component encapsulation and organization (e.g. dye molecules, proteins, inorganic nanoparticles, etc.) to construct new materials and devices. To date, a large variety of DNA nanocages has been synthesized through assembling small individual DNA motifs into predesigned structures in a bottom-up fashion. Most of them rely on the assembly using multiple copies of single type of motifs and a few sophisticated nanostructures have been engineered by co-assembling multi-types of DNA tiles simultaneously. However, the availability of complex DNA nanocages is still limited. Herein, we demonstrate that highly symmetric DNA nanocages consisted of binary DNA point-star motifs can be easily assembled by deliberately engineering the sticky-end interaction between the component building blocks. As such, DNA nanocages with new geometries, including elongated tetrahedron (E-TET), rhombic dodecahedron (R-DOD), and rhombic triacontahedron (R-TRI) are successfully synthesized. Moreover, their design principle, assembly process, and structural features are revealed by polyacryalmide gel electrophoresis (PAGE), atomic force microscope (AFM) imaging, and cryogenic transmission electron microscope imaging (cryo-TEM) associated with single particle reconstruction.Download high-res image (150KB)Download full-size imageDNA elongated tetrahedron (E-TET), rhombic dodecahedron (R-DOD), and rhombic triacontahedron (R-TRI) consisting of binary point-star motifs were successfully synthesized through deliberately engineering the sticky-end interaction between the component building blocks.

Photodynamic therapy (PDT) induced hypoxia can significantly upregulate the expression of vascular endothelial growth factor (VEGF) at the tumor-stromal interface, resulting in a promoted angiogenesis. Thus, an angiogenesis vessel-targeting nanoparticle (AVT-NP) consisting of photosensitizer, angiogenic vessel-targeting peptide, and bioreductive prodrug is developed for a chemo-photo synergistic cancer therapy, with which anti-cancer effect is achieved first by PDT and immediately followed with hypoxia-activated cytotoxic free radicals. With targeting capability, the AVT-NPs can effectively accumulate at the tumor site due to the promoted angiogenesis in response to PDT-induced hypoxia. The more nanoparticles delivered to the tumor tissue, the higher efficacy of PDT can be achieved, resulting in a more severe hypoxia and increased angiogenesis. Therefore, the prodrug embedded AVT-NP functions as a positive feedback amplifier in the combinational chemo-photo treatment and indeed achieves an enhanced anti-tumor effect in both in vitro and in vivo studies.Download high-res image (340KB)Download full-size image

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide, especially in developed countries. Although patients’ overall survival has been improved by either conventional chemotherapy or newly developed anti-angiogenesis treatment based on its highly vascularized feature, the relatively low therapeutic efficacy and severe side effects remain big problems in clinical practice. In this study, we describe an easy method to construct a novel matrix metalloproteinase-2 (MMP-2) responsive nanocarrier, which can load hydrophobic agents (camptothecin and sorafenib) with high efficiency to exert synergistic efficacy for CRC treatment. The drug-containing nanoparticles can particularly respond to the MMP-2 and realize the controlled release of payloads at the tumor site. Moreover, both in vitro and in vivo studies have demonstrated that this responsive nanoparticle exhibits much higher therapeutic efficacy than that of single antitumor agents or combined drugs coadministrated in traditional ways.