Recent progress on DNA block copolymer

DNA-Based Complexes and Composites: A Review of Fabrication Methods, Properties, and Applications

Deoxyribonucleic acid (DNA), a macromolecule that stores genetic information in organisms, has recently been gradually developed into a building block for new materials due to its stable chemical structure and excellent biocompatibility. The efficient preparation and functional integration of various molecular complexes and composite materials based on nucleic acid skeletons have been successfully achieved. These versatile materials possess excellent physical and chemical properties inherent to certain inorganic or organic molecules but are endowed with specific physiological functions by nucleic acids, demonstrating unique advantages and potential applications in materials science, nanotechnology, and biomedical engineering in recent years. However, issues such as the production cost, biological stability, and potential immunogenicity of DNA have presented some unprecedented challenges to the application of these materials in the field. This review summarizes the cutting-edge manufacturing techniques and unique properties of DNA-based complexes and composites and discusses the trends, challenges, and opportunities for the future development of nucleic acid-based materials.

Recent advances in peptide-based therapeutic strategies for breast cancer treatment

Breast cancer is the leading cause of cancer-related fatalities in female worldwide. Effective therapies with low side effects for breast cancer treatment and prevention are, accordingly, urgently required. Targeting anticancer materials, breast cancer vaccines and anticancer drugs have been studied for many years to decrease side effects, prevent breast cancer and suppress tumors, respectively. There are abundant evidences to demonstrate that peptide-based therapeutic strategies, coupling of good safety and adaptive functionalities are promising for breast cancer therapy. In recent years, peptide-based vectors have been paid attention in targeting breast cancer due to their specific binding to corresponding receptors overexpressed in cell. To overcome the low internalization, cell penetrating peptides (CPPs) could be selected to increase the penetration due to the electrostatic and hydrophobic interactions between CPPs and cell membranes. Peptide-based vaccines are at the forefront of medical development and presently, 13 types of main peptide vaccines for breast cancer are being studied on phase III, phase II, phase I/II and phase I clinical trials. In addition, peptide-based vaccines including delivery vectors and adjuvants have been implemented. Many peptides have recently been used in clinical treatments for breast cancer. These peptides show different anticancer mechanisms and some novel peptides could reverse the resistance of breast cancer to susceptibility. In this review, we will focus on current studies of peptide-based targeting vectors, CPPs, peptide-based vaccines and anticancer peptides for breast cancer therapy and prevention.

Self-assembly of alkyl-perylenebisdiimide-DNA amphiphiles and control of their morphology through cyclodextrin-based host-guest interaction

Amphiphilic alkyl-perylenebisdiimide-DNA hybrids self-assemble into spherical micelles and transform into nanofibers upon the addition of β-cyclodextrins due to host-guest interaction. A competitive guest can induce the nanofibers to reversibly change back to spherical micelles. Both spherical micelles and nanofibers can anchor functional molecules at the corona through DNA hybridization.

Combination of DNA with polymers

The preparation and applications of DNA containing polymers are comprehensively reviewed, and they are in the form of DNA−polymer covalent conjugators, supramolecular assemblies and hydrogels for advanced materials with promising features.

Hydrophobic Interaction: A Promising Driving Force for the Biomedical Applications of Nucleic Acids

The comprehensive understanding and proper use of supramolecular interactions have become critical for the development of functional materials, and so is the biomedical application of nucleic acids (NAs). Relatively rare attention has been paid to hydrophobic interaction compared with hydrogen bonding and electrostatic interaction of NAs. However, hydrophobic interaction shows some unique properties, such as high tunability for application interest, minimal effect on NA functionality, and sensitivity to external stimuli. Therefore, the widespread use of hydrophobic interaction has promoted the evolution of NA-based biomaterials in higher-order self-assembly, drug/gene-delivery systems, and stimuli-responsive systems. Herein, the recent progress of NA-based biomaterials whose fabrications or properties are highly determined by hydrophobic interactions is summarized. 1) The hydrophobic interaction of NA itself comes from the accumulation of base-stacking forces, by which the NAs with certain base compositions and chain lengths show properties similar to thermal-responsive polymers. 2) In conjugation with hydrophobic molecules, NA amphiphiles show interesting self-assembly structures with unique properties in many new biosensing and therapeutic strategies. 3) The working-mechanisms of some NA-based complex materials are also dependent on hydrophobic interactions. Moreover, in recent attempts, NA amphiphiles have been applied in organizing macroscopic self-assembly of DNA origami and controlling the cell-cell interactions.

Nucleic acid nanotechnology for cancer treatment

Cancer is one of the most prevalent potentially lethal diseases. With the increase in the number of investigations into the uses of nanotechnology, many nucleic acid (NA)-based nanostructures such as small interfering RNA, microRNA, aptamers, and immune adjuvant NA have been applied to treat cancer. Here, we discuss studies on the applications of NA in cancer treatment, recent research trends, and the limitations and prospects of specific NA-mediated gene therapy and immunotherapy for cancer treatment. The NA structures used for cancer therapy consist only of NA or hybrids comprising organic or inorganic substances integrated with functional NA. We also discuss delivery vehicles for therapeutic NA and anti-cancer agents, and recent trends in NA-based gene therapy and immunotherapy against cancer.

Self-Assembly of Supramolecular DNA Amphiphiles through Host-Guest Interaction and Their Stimuli-Responsiveness

Smart DNA nanostructures have found potential application in material science and biomedicine. Most building blocks are DNA amphiphiles covalently synthesized from DNA and hydrophobic molecules. Here, the noncovalent approach based on the host-guest interaction between cucurbit[7]uril (CB[7]) and two hydrophobic guests with different topologies is utilized to modularly construct supramolecular DNA amphiphiles including DNA-CB[7]/ferrocene derivative and DNA-CB[7]/adamantine derivative. Both of the supramolecular DNA amphiphiles assemble into uniform spherical micelles, which can encapsulate hydrophobic Nile Red molecules and anchor gold nanoparticles through DNA hybridization. In addition, 1-adamantanamine hydrochloride, a competitive guest with a strong binding constant with CB[7], induces the dissociation of DNA-CB[7]/ferrocene derivative micelles. More importantly, the redox properties of ferrocene induce reversible morphology changes between the spherical micelles and the dissociated state. These stimuli-responsive DNA supra-amphiphilic micelles, as novel vehicles, expand the family of smart DNA nanostructures.

Oligonucleotide-Polymer Conjugates: From Molecular Basics to Practical Application

DNA exhibits many attractive properties, such as programmability, precise self-assembly, sequence-coded biomedical functions, and good biocompatibility; therefore, DNA has been used extensively as a building block to construct novel nanomaterials. Recently, studies on oligonucleotide-polymer conjugates (OPCs) have attracted increasing attention. As hybrid molecules, OPCs exhibit novel properties, e.g., sophisticated self-assembly behaviors, which are distinct from the simple combination of the functions of DNA and polymer, making OPCs interesting and useful. The synthesis and applications of OPCs are highly dependent on the choice of the polymer block, but a systematic summary of OPCs based on their molecular structures is still lacking. In order to design OPCs for further applications, it is necessary to thoroughly understand the structure-function relationship of OPCs. In this review, we carefully categorize recently developed OPCs by the structures of the polymer blocks, and discuss the synthesis, purification, and applications for each category. Finally, we will comment on future prospects for OPCs.

Atom Transfer Radical Polymerization for Biorelated Hybrid Materials

Proteins, nucleic acids, lipid vesicles, and carbohydrates are the major classes of biomacromolecules that function to sustain life. Biology also uses post-translation modification to increase the diversity and functionality of these materials, which has inspired attaching various other types of polymers to biomacromolecules. These polymers can be naturally (carbohydrates and biomimetic polymers) or synthetically derived and have unique properties with tunable architectures. Polymers are either grafted-to or grown-from the biomacromolecule's surface, and characteristics including polymer molar mass, grafting density, and degree of branching can be controlled by changing reaction stoichiometries. The resultant conjugated products display a chimerism of properties such as polymer-induced enhancement in stability with maintained bioactivity, and while polymers are most often conjugated to proteins, they are starting to be attached to nucleic acids and lipid membranes (cells) as well. The fundamental studies with protein-polymer conjugates have improved our synthetic approaches, characterization techniques, and understanding of structure-function relationships that will lay the groundwork for creating new conjugated biomacromolecular products which could lead to breakthroughs in genetic and tissue engineering.

Utilization of a Multiple Cloning Site as a Versatile Platform for DNA Triblock Copolymer Synthesis

DNA-containing block copolymers have utility in a wide range of biomedical applications. However, synthesis of these hybrid materials, especially ones with complex chain structures, remains to be a major challenge. Here, we report the use of a combination of restriction enzyme sites and ligation enzymes to synthesize DNA triblock copolymers. In contrast to triblock structures held together by DNA hybridization, the newly synthesized DNA triblocks have all blocks connected by covalent bonds. The improved stability of the triblocks against environmental factors such as urea denaturing is confirmed. Furthermore, we incorporate a multiple cloning site (MCS) into the DNA block copolymers and show that the restriction sites can be cut by their corresponding restriction enzymes, generating diblocks with different sticky ends. By utilizing these sticky ends of specific sequences, the cut diblocks are further ligated to create a variety of triblock copolymers with different DNA center blocks and synthetic polymer end blocks. This study presents a versatile platform based on MCS for the synthesis and regeneration of a range of DNA-containing block copolymers.

Stressing the Role of DNA as a Drug Carrier: Synthesis of DNA-Drug Conjugates through Grafting Chemotherapeutics onto Phosphorothioate Oligonucleotides

To stress the role of deoxyribonucleic acid (DNA) as a drug carrier, an efficient conjugation strategy in which chemotherapeutics can be grafted onto a phosphorothiolated DNA backbone through the reaction between the phosphorothioate group (PS) and a benzyl bromide group is proposed. As a proof of concept, benzyl-bromide-modified paclitaxel (PTX) is employed to graft onto the DNA backbone at the PS modification sites. Due to the easy preparation of phosphorothiolated DNA at any desired position during its solid-phase synthesis, diblock DNA strands containing both normal phosphodiester segment (^PO DNA) and phosphorothiolate segment (^PS DNA) are directly grafted with a multitude of PTXs without using complicated and exogenous linkers. Then, the resulting amphiphilic ^PO DNA-blocked-(^PS DNA-grafted PTX) conjugates (^PO DNA-b-(^PS DNA-g-PTX)) assemble into PTX-loaded spherical nucleic acid (SNA)-like micellar nanoparticles (PTX-SNAs) with a high drug loading ratio up to ≈53%. Importantly, the ^PO DNA segment maintains its molecular recognition property and biological functions, which allows the as-prepared PTX-SNAs to be further functionalized with tumor-targeting aptamers, fluorescent probe strands, or antisense sequences. These multifunctional PTX-SNAs demonstrate active tumor-targeting delivery, efficient inhibition of tumor growth, and the reversal of drug resistance both in vitro and in vivo for comprehensive antitumor therapy.

Polygemcitabine nanogels with accelerated drug activation for cancer therapy

Polygemcitabine nanogels assembled from DNA-like polygemcitabine undergo rapid intracellular degradation to generate active gemcitabine derivatives for enhanced cancer therapy.

Amphiphilic DNA Organic Hybrids: Functional Materials in Nanoscience and Potential Application in Biomedicine

Due to the addressability and programmability, DNA has been applied not merely in constructing static elegant nanostructures such as two dimensional and three dimensional DNA nanostructures but also in designing dynamic nanodevices. Moreover, DNA could combine with hydrophobic organic molecules to be a new amphiphilic building block and then self-assemble into nanomaterials. Of particular note, a recent state-of-the-art research has turned our attention to the amphiphilic DNA organic hybrids including small molecule modified DNA (lipid-DNA, fluorescent molecule-DNA, etc.), DNA block copolymers, and DNA-dendron hybrids. This review focuses mainly on the development of their self-assembly behavior and their potential application in nanomaterial and biomedicine. The potential challenges regarding of the amphiphilic DNA organic hybrids are also briefly discussed, aiming to advance their practical applications in nanoscience and biomedicine.

Floxuridine-containing nucleic acid nanogels for anticancer drug delivery

Herein, we report the self-assemblies of floxuridine-containing DNA and RNA nanogels with a precise drug loading ratio as effective drug delivery systems. Based on the structural similarity between the nucleoside analogue floxuridine (F) and the natural nucleoside thymidine (T), F can be incorporated into nucleic acid strands via either solid-phase synthesis or enzyme-mediated transcription. With the retained property of molecular recognition, the synthesized F-integrated DNA or RNA strands can be used as building units and further assembled into nucleic acid based spherical nanogels, which can be efficiently taken up by cancer cells and then release the therapeutic agents. As such, the drug-containing nucleic acid nanogels exhibit excellent inhibitory activity against cancer cells.