Recent progress of non-linear topological structure polymers: synthesis, and gene delivery

Currently, many types of non-linear topological structure polymers, such as brush-shaped, star, branched and dendritic structures, have captured much attention in the field of gene delivery and nanomedicine. Compared with linear polymers, non-linear topological structural polymers offer many advantages, including multiple terminal groups, broad and complicated spatial architecture and multi-functionality sites to enhance gene delivery efficiency and targeting capabilities. Nevertheless, the complexity of their synthesis process severely hampers the development and applications of nonlinear topological polymers. This review aims to highlight various synthetic approaches of non-linear topological architecture polymers, including reversible-deactivation radical polymerization (RDRP) including atom-transfer radical polymerization (ATRP), nitroxide-mediated polymerization (NMP), reversible addition-fragmentation chain transfer (RAFT) polymerization, click chemistry reactions and Michael addition, and thoroughly discuss their advantages and disadvantages, as well as analyze their further application potential. Finally, we comprehensively discuss and summarize different non-linear topological structure polymers for genetic materials delivering performance both in vitro and in vivo, which indicated that topological effects and nonlinear topologies play a crucial role in enhancing the transfection performance of polymeric vectors. This review offered a promising guideline for the design and development of novel nonlinear polymers and facilitated the development of a new generation of polymer-based gene vectors.

Emerging non-viral vectors for gene delivery

Gene therapy holds great promise for treating a multitude of inherited and acquired diseases by delivering functional genes, comprising DNA or RNA, into targeted cells or tissues to elicit manipulation of gene expression. However, the clinical implementation of gene therapy remains substantially impeded by the lack of safe and efficient gene delivery vehicles. This review comprehensively outlines the novel fastest-growing and efficient non-viral gene delivery vectors, which include liposomes and lipid nanoparticles (LNPs), highly branched poly(β-amino ester) (HPAE), single-chain cyclic polymer (SCKP), poly(amidoamine) (PAMAM) dendrimers, and polyethyleneimine (PEI). Particularly, we discuss the research progress, potential development directions, and remaining challenges. Additionally, we provide a comprehensive overview of the currently approved non-viral gene therapeutics, as well as ongoing clinical trials. With advances in biomedicine, molecular biology, materials science, non-viral gene vectors play an ever-expanding and noteworthy role in clinical gene therapy.

Stimulus-responsive drug/gene delivery system based on polyethylenimine cyclodextrin nanoparticles for potential cancer therapy

Combination therapy through simultaneous delivery of anti-cancer drugs and genes with nano-assembled structure has been proved to be a simple and effective approach for treating breast cancer. In this study, redox-sensitive folate-appended-polyethylenimine-β-cyclodextrin (roFPC) host-guest supramolecular nanoparticles (HGSNPs) were developed as a targeted co-delivery system of doxorubicin (Dox) and Human telomerase reverse transcriptase-small interfering RNA) hTERT siRNA) for potential cancer therapy. The nanotherapeutic system was prepared by loading adamantane-conjugated doxorubicin (Ad-Dox) into roFPC through the supramolecular assembly, followed by electrostatically-driven self-assembly between hTERT siRNA and roFPC/Ad-Dox. The roFPC' host-guest structures allow pH-dependent intracellular drug release in a sustained manner, as well as simultaneous and effective gene transfection. This co-delivery vector displayed combined anti-tumor properties of the Dox-enhanced gene transfection, good water-solubility, and biocompatibility, possesses considerably enhanced hemocompatibility, and especially targets folate receptor-positive cells only at low N/P levels to prompt effective cell apoptosis for cancer treatment.

Application of molecular docking in elaborating molecular mechanisms and interactions of supramolecular cyclodextrin

The cyclodextrin (CD)-based supramolecular nanomedicines have attracted growing interest because of their superior characteristics, including desirable biocompatibility, low toxicity, unique molecular structure and easy functionalization. The smart structures of CD impart host-guest interaction for meeting the multifunctional needs of disease therapy. However, it faces challenges in formulation design and inclusion mechanism clarification of the functional supramolecular assemblies owing to the complicated structures and mechanisms. Fortunately, molecular docking helps the researchers to comprehend the interaction between the drug and the target molecule for achieving high-through screening from the database. In this review, we summarized the category and characteristics of molecular docking along with the properties and applications of CD. Significantly, we highlighted the application of molecular docking in elaborating molecular mechanisms and simulating complex structures at molecular levels. The issues and development of CD and molecular docking were also presented to provide beneficial reference and new insights for supramolecular nano-systems.

Calcium-based nanomaterials and their interrelation with chitosan: optimization for pCRISPR delivery

There have been numerous advancements in the early diagnosis, detection, and treatment of genetic diseases. In this regard, CRISPR technology is promising to treat some types of genetic issues. In this study, the relationship between calcium (due to its considerable physicochemical properties) and chitosan (as a natural linear polysaccharide) was investigated and optimized for pCRISPR delivery. To achieve this, different forms of calcium, such as calcium nanoparticles (CaNPs), calcium phosphate (CaP), a binary blend of calcium and chitosan including CaNPs/Chitosan and CaP/Chitosan, as well as their tertiary blend including CaNPs-CaP/Chitosan, were prepared via both routine and green procedures using Salvia hispanica to reduce toxicity and increase nanoparticle stability (with a yield of 85%). Such materials were also applied to the human embryonic kidney (HEK-293) cell line for pCRISPR delivery. The results were optimized using different characterization techniques demonstrating acceptable binding with DNA (for both CaNPs/Chitosan and CaNPs-CaP/Chitosan) significantly enhancing green fluorescent protein (EGFP) (about 25% for CaP/Chitosan and more than 14% for CaNPs-CaP/Chitosan).

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40097-021-00446-1.

Stimuli-Responsive Poly(aspartamide) Derivatives and Their Applications as Drug Carriers

Poly(aspartamide) derivatives, one kind of amino acid-based polymers with excellent biocompatibility and biodegradability, meet the key requirements for application in various areas of biomedicine. Poly(aspartamide) derivatives with stimuli-responsiveness can usually respond to external stimuli to change their chemical or physical properties. Using external stimuli such as temperature and pH as switches, these smart poly(aspartamide) derivatives can be used for convenient drug loading and controlled release. Here, we review the synthesis strategies for preparing these stimuli-responsive poly(aspartamide) derivatives and the latest developments in their applications as drug carriers.

Transferrin-targeting redox hyperbranched poly(amido amine)-functionalized graphene oxide for sensitized chemotherapy combined with gene therapy to nasopharyngeal carcinoma

A drug and gene co-delivery system with chemotherapeutic sensibilization was prepared and used for nasopharyngeal carcinoma therapy. For this purpose, the graphene oxide (GO) was conjugated with the redox hyperbranched poly(amido amine) (HPAA) and then the targeting molecule, transferrin (Tf), was also conjugated. The obtained Tf-HPAA-GO could co-deliver docetaxel (DOC) and MMP-9 shRNA plasmid (pMMP-9) effectively and showed the targeting effect to HNE-1 cells. The co-delivery system showed the effective drug and gene delivery ability with high cytotoxicity and gene transfection efficiency. Besides that, Tf-HPAA-GO/DOC also showed the chemotherapeutic sensibilization effect, the formulation containing HPAA segments showed much higher cytotoxicity than free DOC. Benefiting from the sensibilization effect and DOC/pMMP-9 co-delivery strategy, this Tf-HPAA-GO/DOC/pMMP-9 co-delivery system exhibited the significantly improved therapeutic efficacy to HNE-1 tumor in a combined manner which was confirmed by in vitro and in vivo assays. This strategy provided an easily delivery system combining the drug/gene co-delivery, chemotherapeutic sensibilization, and targeting into one single platform, which showed a promising application in cancer therapy.

Disassembly and tumor-targeting drug delivery of reduction-responsive degradable block copolymer nanoassemblies

Review on recent strategies to synthesize novel disulfide-containing reductively-degradable block copolymers and their nanoassemblies as being classified with the number, position, and location of the disulfide linkages toward effective tumor-targeting intracellular drug delivery exhibiting enhanced release of encapsulated drugs.