Magic of Architecting Oligo‐DNAs: 3D Structure‐Dependent Stability and Programmable Specificity to Tumor Cells

Zipper-Confined DNA Nanoframe for High-Efficient and High-Contrast Imaging of Heterogeneous Tumor Cell

Current study in the heterogeneity and physiological behavior of tumor cells is limited by the fluorescence in situ hybridization technology in terms of probe assembly efficiency, background suppression capability, and target compatibility. In a typically well-designed assay, hybridization probes are constructed in a confined nanostructure to achieve a rapid assembly for efficient signal response, while the excessively high local concentration between different probes inevitably leads to nonspecific background leakage. Inspired by the fabric zipper, we propose a novel confinement reaction pattern in a zipper-confined DNA nanoframe (ZCDN), where two kinds of hairpin probes are independently anchored respective tracks. The metastable states of the dual tracks can well avoid signal leakage caused by the nonspecific probe configuration change. Biomarker-mediated proximity ligation reduces the local distance of dual tracks, kinetically triggering an efficient allosteric chain reaction between the hairpin probes. This method circumvents nonspecific background leakage while maintaining a high efficiency in responding to targets. ZCDN is employed to track different cancer biomarkers located in both the cytoplasm and cytomembrane, of which the expression level and oligomerization behavior can provide crucial information regarding intratumoral heterogeneity. ZCDN exhibits high target response efficiency and strong background suppression capabilities and is compatible with various types of biological targets, thus providing a desirable tool for advanced molecular diagnostics.

Metal-organic framework-based photodynamic combined immunotherapy against the distant development of triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is an aggressive, metastatic and apparently drug-resistant subtype of breast cancer with a higher immune response compared to other types of breast cancer. Photodynamic therapy (PDT) has been gaining popularity for its non-invasive nature, minimal side effects, and spatiotemporally controlled benifits. The use of metal-organic frameworks (MOFs) loaded with programmed death-ligand 1 inhibitors (iPD-L1) offers the possibility of combining PDT with immunotherapy.

METHOD

Here, we construct PCN-224, a MOFs with good biocompatibility and biodegradability for the delivery of the PD-L1 small molecule inhibitor BMS-202 to achieve a synergistic anti-tumor strategy of PDT and immunotherapy. Hyaluronic acid (HA) modified PEG (HA-PEG) was synthesized for the outer layer modification of the nanocomplex, which prolongs its systemic circulation time.

RESULTS

In vitro cellular experiments show that the nanocomplexes irradiated by 660 nm laser has a strong ability to produce singlet oxygen, which effectively induce PDT. PDT with strong immunogenicity leads to tumor necrosis and apoptosis, and induces immunogenic cell death, which causes tumor cells to release danger associated molecular patterns. In combination with iPD-L1, the combination therapy stimulates dendritic cell maturation, promotes T-cell activation and intratumoral infiltration, and reshapes the tumor immune microenvironment to achieve tumor growth inhibition and anti-distant tumor progression.

CONCLUSIONS

MOFs-based nano-systems as a platform for combination therapy offer a potentially effective strategy for the treatment of TNBC with high metastatic rates.

Size-Controlled DNA Tile Self-Assembly Nanostructures Through Caveolae-Mediated Endocytosis for Signal-Amplified Imaging of MicroRNAs in Living Cells

Signal-amplified imaging of microRNAs (miRNAs) is a promising strategy at the single-cell level because liquid biopsy fails to reflect real-time dynamic miRNA levels. However, the internalization pathways for available conventional vectors predominantly involve endo-lysosomes, showing nonideal cytoplasmic delivery efficiency. In this study, size-controlled 9-tile nanoarrays are designed and constructed by integrating catalytic hairpin assembly (CHA) with DNA tile self-assembly technology to achieve caveolae-mediated endocytosis for the amplified imaging of miRNAs in a complex intracellular environment. Compared with classical CHA, the 9-tile nanoarrays possess high sensitivity and specificity for miRNAs, achieve excellent internalization efficiency by caveolar endocytosis, bypassing lysosomal traps, and exhibit more powerful signal-amplified imaging of intracellular miRNAs. Because of their excellent safety, physiological stability, and highly efficient cytoplasmic delivery, the 9-tile nanoarrays can realize real-time amplified monitoring of miRNAs in various tumor and identical cells of different periods, and imaging effects are consistent with the actual expression levels of miRNAs, ultimately demonstrating their feasibility and capacity. This strategy provides a high-potential delivery pathway for cell imaging and targeted delivery, simultaneously offering a meaningful reference for the application of DNA tile self-assembly technology in relevant fundamental research and medical diagnostics.

Roles of MXenes in biomedical applications: recent developments and prospects

....With the development of nanomedical technology, the application of various novel nanomaterials in the biomedical field has been greatly developed in recent years. MXenes, which are new inorganic nanomaterials with ultrathin atomic thickness, consist of layered transition metal carbides and nitrides or carbonitrides and have the general structural formula M_n+1X_nT_x (n = 1-3). Based on the unique structural features of MXenes, such as ultrathin atomic thickness and high specific surface area, and their excellent physicochemical properties, such as high photothermal conversion efficiency and antibacterial properties, MXenes have been widely applied in the biomedical field. This review systematically summarizes the application of MXene-based materials in biomedicine. The first section is a brief summary of their synthesis methods and surface modification strategies, which is followed by a focused overview and analysis of MXenes applications in biosensors, diagnosis, therapy, antibacterial agents, and implants, among other areas. We also review two popular research areas: wearable devices and immunotherapy. Finally, the difficulties and research progress in the clinical translation of MXene-based materials in biomedical applications are briefly discussed.

Polydopamine-coated i-motif DNA/Gold nanoplatforms for synergistic photothermal-chemotherapy

The combination of photothermal therapy with chemotherapy has gradually developed into promising cancer therapy. Here, a synergistic photothermal-chemotherapy nanoplatform based on polydopamine (PDA)-coated gold nanoparticles (AuNPs) were facilely achieved via the in situ polymerization of dopamine (DA) on the surface of AuNPs. This nanoplatform exhibited augmented photothermal conversion efficiency and enhanced colloidal stability in comparison with uncoated PDA shell AuNPs. The i-motif DNA nanostructure was assembled on PDA-coated AuNPs, which could be transformed into a C-quadruplex structure under an acidic environment, showing a characteristic pH response. The PDA shell served as a linker between the AuNPs and the i-motif DNA nanostructure. To enhance the specific cellular uptake, the AS1411 aptamer was introduced to the DNA nanostructure employed as a targeting ligand. In addition, Dox-loaded NPs (DAu@PDA-AS141) showed the pH/photothermal-responsive release of Dox. The photothermal effect of DAu@PDA-AS141 elicited excellent photothermal performance and efficient cancer cell inhibition under 808 nm near-infrared (NIR) irradiation. Overall, these results demonstrate that the DAu@PDA-AS141 nanoplatform shows great potential in synergistic photothermal-chemotherapy.

The wending rhombus: Self-assembling 3D DNA crystals

In this perspective, we provide a summary of recent developments in self-assembling three-dimensional (3D) DNA crystals. Starting from the inception of this subfield, we describe the various advancements in structure that have led to an increase in the diversity of macromolecular crystal motifs formed through self-assembly, and we further comment on the future directions of the field, which exploit noncanonical base pairing interactions beyond Watson-Crick. We then survey the current applications of self-assembling 3D DNA crystals in reversibly active nanodevices and materials engineering and provide an outlook on the direction researchers are taking these structures. Finally, we compare 3D DNA crystals with DNA origami and suggest how these distinct subfields might work together to enhance biomolecule structure solution, nanotechnological motifs, and their applications.