Multimodules integrated functional DNA nanomaterials for intelligent drug delivery

Construction of an Enzymatically Controlled DNA Nanomachine for One-Step Imaging of Telomerase in Living Cells

Telomerase is a basic reverse transcriptase that maintains the telomere length in cells, and accurate and specific sensing of telomerase in living cells is critical for medical diagnostics and disease therapeutics. Herein, we demonstrate for the first time the construction of an enzymatically controlled DNA nanomachine with endogenous apurinic/apyrimidinic endonuclease 1 (APE1) as a driving force for one-step imaging of telomerase in living cells. The DNA nanomachine is designed by rational engineering of substrate probes and reporter probes embedded with an enzyme-activatable site (i.e., AP site) and their subsequent assembly on a gold nanoparticle (AuNP). Upon recognition and cleavage of the AP site in the substrate probe by APE1, the loop of the substrate probe unfolds, exposing telomeric primer (TP) with the 3'-OH end. Subsequently, the TP is elongated by telomerase at the 3'-OH end to generate a long telomeric product. The resultant telomeric product acts as a swing arm that can hybridize with a reporter probe to initiate the APE1-powered walking reaction, ultimately generating a significantly enhanced fluorescence signal. Notably, endogenous APE1 is used as the driving force of the DNA nanomachine, avoiding the introduction of exogenous auxiliary cofactors into the cellular microenvironment. Owing to the high kinetics and high amplification efficiency of the APE1-powered DNA nanomachine, this strategy enables one-step sensitive sensing of telomerase in vitro and in vivo. It can successfully discriminate telomerase activity between cancer cells and normal cells, screen telomerase inhibitors, and monitor the variations of telomerase activity in living cells, offering a prospective platform for molecular diagnostics and drug discovery.

ROS-Responsive Self-Degradable DNA Nanogels for Targeted Anticancer Drug Delivery

Here, a reactive oxygen species (ROS)-responsive targeted anticancer drug delivery system was developed by embedding a nitrophenyl tetramethyl-dioxaborolanyl benzyl carbamate (NBC)-modified deoxyribonuclease I (DNase I) in a DNase-degradable aptamer-based DNA nanogel. The DNA nanogel was formed by hybridization of three types of building blocks, namely, Y-shaped monomer 1 with three sticky ends, Y-shaped monomer 2 with two sticky ends and an aptamer end, and a DNA linker with two sticky ends. Single doxorubicin (DOX) or ribonuclease A (RNase A) as well as the combination of DOX and RNase A were effectively loaded into the nanogels, wherein DOX was embedded into DNA skeleton, while RNase A was encapsulated into nanogel matrix. The blocked enzymatic activity of DNase I due to NBC modification could be restored upon intracellular ROS-triggered NBC deprotection, resulting in self-degradation of the nanogels to release both DOX and RNase A. Consequently, the DOX and RNase A coloaded nanogels significantly inhibited the proliferation of MCF-7 cells through a synergistic effect. To sum up, this DNA-based drug delivery system with ROS-responsive self-degradation properties should be promising for application in targeted and synergistic cancer therapy.

Intelligent nanomaterials for cancer therapy: recent progresses and future possibilities

Intelligent nanomedicine is currently one of the most active frontiers in cancer therapy development. Empowered by the recent progresses of nanobiotechnology, a new generation of multifunctional nanotherapeutics and imaging platforms has remarkably improved our capability to cope with the highly heterogeneous and complicated nature of cancer. With rationally designed multifunctionality and programmable assembly of functional subunits, the in vivo behaviors of intelligent nanosystems have become increasingly tunable, making them more efficient in performing sophisticated actions in physiological and pathological microenvironments. In recent years, intelligent nanomaterial-based theranostic platforms have showed great potential in tumor-targeted delivery, biological barrier circumvention, multi-responsive tumor sensing and drug release, as well as convergence with precise medication approaches such as personalized tumor vaccines. On the other hand, the increasing system complexity of anti-cancer nanomedicines also pose significant challenges in characterization, monitoring and clinical use, requesting a more comprehensive and dynamic understanding of nano-bio interactions. This review aims to briefly summarize the recent progresses achieved by intelligent nanomaterials in tumor-targeted drug delivery, tumor immunotherapy and temporospatially specific tumor imaging, as well as important advances of our knowledge on their interaction with biological systems. In the perspective of clinical translation, we have further discussed the major possibilities provided by disease-oriented development of anti-cancer nanomaterials, highlighting the critical importance clinically-oriented system design.

Tissue-Engineered Nanomaterials Play Diverse Roles in Bone Injury Repair

Nanomaterials with bone-mimicking characteristics and easily internalized by the cell could create suitable microenvironments in which to regulate the therapeutic effects of bone regeneration. This review provides an overview of the current state-of-the-art research in developing and using nanomaterials for better bone injury repair. First, an overview of the hierarchical architecture from the macroscale to the nanoscale of natural bone is presented, as these bone tissue microstructures and compositions are the basis for constructing bone substitutes. Next, urgent clinical issues associated with bone injury that require resolution and the potential of nanomaterials to overcome them are discussed. Finally, nanomaterials are classified as inorganic or organic based on their chemical properties. Their basic characteristics and the results of related bone engineering studies are described. This review describes theoretical and technical bases for the development of innovative methods for repairing damaged bone and should inspire therapeutic strategies with potential for clinical applications.

Spatio-Temporal Controlled Gene-Chemo Drug Delivery in a DNA Nanocomplex to Overcome Multidrug Resistance of Cancer Cells

Multidrug resistance (MDR) in cancer cells is a substantial limitation to the success of chemotherapy. The spatio-temporal controlled gene-chemo therapeutics strategy is expected to surmount the limitation of MDR. We herein develop a DNA nanocomplex to achieve intrinsic stimuli-responsive spatio-temporal controlled gene-chemo drug delivery, overcoming MDR of cancer cells. The drug delivery system consisted of a restriction endonuclease (HhaI)-degradable DNA hydrogel layer, an acid-responsive HhaI nanocapsule (HhaI-GDA), and a glutathione (GSH)-sensitive dendritic mesoporous organosilica nanoparticle (DMON). The DNA hydrogel layer consisted of a DNA network formed through interfacial assembly from ultralong single-stranded DNA (ssDNA), which contained multiple tandem repeated antisense oligonucleotides (ASOs). DMON had dendritic mesopores for enhanced loading of anti-tumor drug doxorubicin (DOX). Upon cellular uptake of the DNA nanocomplex, the GDA shell was degraded at a lysosomal microenvironment, and the activity of HhaI was activated, leading to accurate cleavage ultralong ssDNA to release ASO as gene drugs, which down-regulated the expression of MDR-related P glycoprotein. Spatio-temporal sequentially, DMONs containing disulfide bonds responded to intracellular GSH to release DOX for enhanced chemotherapy.