Controllable Heparin-Based Comb Copolymers and Their Self-assembled Nanoparticles for Gene Delivery

Genetically light-enhanced immunotherapy mediated by a fluorinated reduction-sensitive delivery system

The lack of safe and efficient therapeutic agent delivery platforms restricts combined therapy's effect, and combined cancer therapy's multi-component delivery effect needs improvement. The novel gene delivery system SS-HPT-F/pMIP-3β-KR was proposed to construct fluorine-containing degradable cationic polymers SS-HPT-F by a mild and simple amino-epoxy ring-opening reaction. By modifying the fluorinated alkyl chain, the delivery efficiency of the plasmid was greatly improved, and the cytoplasmic transport of biomolecules was completed. At the same time, a combination plasmid (MIP-3β-KillerRed) was innovatively designed for the independent expression of immune and photodynamic proteins. Which was efficiently transported to the tumor site by SS-HPT-F. The MIP-3β is expressed as an immune chemokine realize the immune mobilization behavior. The photosensitive protein KillerRed expressed in the tumor killed cancer cells under irradiation and released the exocrine immune factor MIP-3β. The immunogenic cell death (ICD) produced by photodynamic therapy (PDT) also induced the immune response of the organism. The synergistic effect of PDT and MIP-3β mobilized the immune properties of the organism, providing light-enhanced immune combination therapy against malignant tumors. Therefore, in subcutaneous tumor-bearing and metastatic animal models, the carrier tumor growth and mobilize organism produce an immune response without systemic toxicity. This work reports the first efficient gene delivery system that achieves light-enhanced immunotherapy.

A review on multifaceted biomedical applications of heparin nanocomposites: Progress and prospects

Advances in polymer-based nanocomposites have revolutionized biomedical applications over the last two decades. Heparin (HP), being a highly bioactive polymer of biological origin, provides strong biotic competence to the nanocomposites, broadening the horizon of their applicability. The efficiency, biocompatibility, and biodegradability properties of nanomaterials significantly improve upon the incorporation of heparin. Further, inclusion of structural/chemical derivatives, fractionates, and mimetics of heparin enable fabrication of versatile nanocomposites. Modern nanotechnological interventions have exploited the inherent biofunctionalities of heparin by formulating various nanomaterials, including inorganic/polymeric nanoparticles, nanofibers, quantum dots, micelles, liposomes, and nanogels ensuing novel functionalities targeting diverse clinical applications involving drug delivery, wound healing, tissue engineering, biocompatible coatings, nanosensors and so on. On this note, the present review explicitly summarises the recent HP-oriented nanotechnological developments, with a special emphasis on the reported successful engagement of HP and its derivatives/mimetics in nanocomposites for extensive applications in the laboratory and health-care facility. Further, the advantages and limitations/challenges specifically associated with HP in nanocomposites, undertaken in this current review are quintessential for future innovations/discoveries pertaining to HP-based nanocomposites.

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.

Biomedical applications of engineered heparin-based materials

Heparin is a negatively charged polysaccharide with various chain lengths and a hydrophilic backbone. Due to its fascinating chemical and physical properties, nontoxicity, biocompatibility, and biodegradability, heparin has been extensively used in different fields of medicine, such as cardiovascular and hematology. This review highlights recent and future advancements in designing materials based on heparin for various biomedical applications. The physicochemical and mechanical properties, biocompatibility, toxicity, and biodegradability of heparin are discussed. In addition, the applications of heparin-based materials in various biomedical fields, such as drug/gene delivery, tissue engineering, cancer therapy, and biosensors, are reviewed. Finally, challenges, opportunities, and future perspectives in preparing heparin-based materials are summarized.

Ionizable drug delivery systems for efficient and selective gene therapy

Gene therapy has shown great potential to treat various diseases by repairing the abnormal gene function. However, a great challenge in bringing the nucleic acid formulations to the market is the safe and effective delivery to the specific tissues and cells. To be excited, the development of ionizable drug delivery systems (IDDSs) has promoted a great breakthrough as evidenced by the approval of the BNT162b2 vaccine for prevention of coronavirus disease 2019 (COVID-19) in 2021. Compared with conventional cationic gene vectors, IDDSs can decrease the toxicity of carriers to cell membranes, and increase cellular uptake and endosomal escape of nucleic acids by their unique pH-responsive structures. Despite the progress, there remain necessary requirements for designing more efficient IDDSs for precise gene therapy. Herein, we systematically classify the IDDSs and summarize the characteristics and advantages of IDDSs in order to explore the underlying design mechanisms. The delivery mechanisms and therapeutic applications of IDDSs are comprehensively reviewed for the delivery of pDNA and four kinds of RNA. In particular, organ selecting considerations and high-throughput screening are highlighted to explore efficiently multifunctional ionizable nanomaterials with superior gene delivery capacity. We anticipate providing references for researchers to rationally design more efficient and accurate targeted gene delivery systems in the future, and indicate ideas for developing next generation gene vectors.

Glycosaminoglycan-Based Hydrogel Delivery System Regulates the Wound Microenvironment to Rescue Chronic Wound Healing

Chronic wounds cannot proceed through the normal, orderly, and timely sequence of repair. The adverse cycle between excess reactive oxide species (ROS) and a persistent inflammatory response is an important mechanism of impaired wound healing. Herein, by combining the intrinsic bioactivities of natural polysaccharides and natural drugs, a glycosaminoglycan-based hydrogel delivery system is proposed to regulate the wound microenvironment. Dynamic supramolecular cross-linking enables the hydrogel to easily encapsulate the drug and fully fill the wound area. As the backbone of the hydrogel, heparin captures inflammatory chemokines at the wound site, while hyaluronic acid mimics the function of ECM. The hydrophobic drug curcumin has been ingeniously encapsulated in the hydrogel through micellization, thereby exerting good ROS scavenging ability and anti-inflammatory activity. Evaluations in diabetic mice showed that this antioxidant and anti-inflammatory hydrogel was effective in reducing the influx of immune cells at the wound site and in down-regulating the inflammatory response. Accelerated wound healing was also observed, as evidenced by faster re-epithelialization and better ECM remodeling. The proposed hydrogel can regulate the microenvironment of wounds from multiple aspects and thereby achieve regression of wound repair, which may provide a new therapeutic strategy for chronic wounds.

Novel branched amphiphilic peptides for nucleic acids delivery

Highly efficient and safe non-viral vectors for nucleic acids delivery have attracted much attention due to their potential applications in gene therapy, gene editing and vaccination against infectious diseases, and various materials have been investigated and designed as delivery vectors. Herein, we designed a series of branched amphiphilic peptides (BAPs) and tested their applications as pDNA/mRNA delivery vectors. The BAP structure was inspired by the phospholipids, in which lysine oligomers were used as the "polar head", segments containing phenylalanine, histidine and leucine were used as the "hydrophobic tails", and a lysine residue was used as the branching point. By comparing the gel retardation, particle sizes and zeta potentials of the BAP/pDNA complexes of the short-branch BAPs (BAP-V1 ∼ BAP-V4), we determined the optimal lysine oligomer was K₆. However, their cell transfection efficiencies were not satisfactory, and thus three long-branch BAPs (BAP-V5 ∼ BAP-V7) were further designed. In these long-branch BAPs, more hydrophobic residues were added and the overall amphiphilicity increased accordingly. The results showed that these three BAPs could effectively compact the nucleic acids, including both pDNA and mRNA, and all could transfect nucleic acids into HEK 293 cells, with low cytotoxicity. Among the three long-branch BAPs, BAP-V7 (bis(FFLFFHHH)-K-K₆) showed the best transfection efficiency at N/P = 10, which was better than the commercial transfection reagent PEI-25 K. These results indicate that increased amphiphilicity would also benefit for BAP mediated nucleic acid delivery. The designed BAPs provide more documents of such novel type of nucleic acids delivery vectors, which is worth of further investigation as a new gene theranostic platforms.

Multiple-therapy strategies via polysaccharides-based nano-systems in fighting cancer

Polysaccharide-based biomaterials (e.g., chitosan, dextran, hyaluronic acid, chondroitin sulfate and heparin) have received great attention in healthcare, particularly in drug delivery for tumor therapy. They are naturally abundant and available, outstandingly biodegradable and biocompatible, and they generally have negligible toxicity and low immunogenicity. In addition, they are easily chemically or physically modified. Therefore, PSs-based nanoparticles (NPs) have been extensively investigated for the enhancement of tumor treatment. In this review, we introduce the synthetic pathways of amphiphilic PS derivatives, which allow the constructs to self-assemble into NPs with various structures. We especially offer an overview of the emerging applications of self-assembled PSs-based NPs in tumor chemotherapy, photothermal therapy (PTT), photodynamic therapy (PDT), gene therapy and immunotherapy. We believe that this review can provide criteria for a rational and molecular level-based design of PS-based NPs, and comprehensive insight into the potential of PS-based NPs used in multiple cancer therapies.

Macromolecular design and preparation of polymersomes

From drug delivery to nanoreactors and protocells, polymersomes have gained considerable interest from researchers due to their novel applications.

Dual signal amplification by polysaccharide and eATRP for ultrasensitive detection of CYFRA 21-1 DNA

Cytokeratin fragment antigen 21-1 (CYFRA 21-1) DNA is a crucial biomarker closely associated with non-small cell lung cancer. Here, we fabricated a novel electrochemical biosensor for ultrasensitive detection of CYFRA 21-1 DNA via polysaccharide and electrochemically mediated atom transfer radical polymerization (eATRP) dual signal amplification. Specifically, thiolated peptide nucleic acid (PNA) probes at 5'-terminals are immobilized on the gold electrode surface for specific recognition of CYFRA 21-1 DNA (tDNA). After hybridization, hyaluronic acid (HA) is linked to the hybridized PNA/DNA duplexes via the recognized carboxylate-Zr⁴⁺-phosphate chemistry. Then multiple initiators of the polymerization reaction are introduced via esterification reaction. Lastly, large numbers of electro-active monomers are successfully grafted from the initiation sites of functionalized HA by eATRP reaction, significantly amplifying the electrochemical signal. Under optimal conditions, the constructed sensor can detect as low as 9.04 aM tDNA. Further, this proposed biosensor can also be applied to the direct detection of double-stranded DNA (dsDNA), obtaining 0.12 fM as the detection limit. Besides, this strategy shows high selectivity for mismatched bases and excellent applicability for CYFRA 21-1 DNA detection in the serum samples. Given its high sensitivity, selectivity, ease of operation, low cost and environmental friendliness, this biosensor has considerable potential in early diagnosis and biomedical application.

Unlockable Nanocomplexes with Self-Accelerating Nucleic Acid Release for Effective Staged Gene Therapy of Cardiovascular Diseases

Nucleic acid (NA)-based therapy is proposed to address serious diseases such as cardiovascular diseases (CVDs). Powerful NA delivery vehicles are essential for effective gene therapy. Herein, a novel type of delivery vehicle, an unlockable core-shell nanocomplex (Hep@PGEA) with self-accelerating NA release, is structurally designed. Hep@PGEA is composed of disulfide-bridged heparin nanoparticle (HepNP) core and low-toxicity PGEA cationic shell. In comparison with NA, heparin, a negatively charged polysaccharide macromolecule, exhibits stronger interactions with cationic species. Upon the breakdown of redox-responsive HepNP cores, unlocked heparin would interact with the outer cationic shells and replace the condensed NA to facilitate NA release. Such unique Hep@PGEA is successfully explored for effective miRNA-pDNA staged gene therapy of myocardial infarction (MI), one of the most serious CVDs. With the progression of MI, glutathione amounts in heart tissues increase. MiR-499 (for the inhibition of cardiomyocyte apoptosis) and plasmid encoding vascular endothelial growth factor (for the promotion of angiogenesis) are sequentially delivered for systemic treatment of MI. Such treatment produces impressive results in restoring heart function and suppressing cardiac hypertrophy. Due to the wide existence of redox agents in cells, the proposed unlockable delivery nanovehicle and staged therapy strategy can provide new methods to effectively treat different serious diseases.

Statistical versus block fluoropolymers in gene delivery

A statistical fluorocopolymer shows dramatically higher transfection efficiency in gene delivery than a block one.

Multifunctional Gene Carriers with Enhanced Specific Penetration and Nucleus Accumulation to Promote Neovascularization of HUVECs in Vivo

Recently, gene therapy has attracted much attention, especially for the treatment of vascular disease. However, it is still challenging to develop the gene carriers with high biocompatibility as well as highly efficient gene delivery to overcome multiple barriers. Herein, a frequently used cell-penetrating peptide PKKKRKV (TAT) was selected as a functional sequence of the gene carrier with distinctive cell-penetrating ability. REDV peptide with selectively targeting function for endothelial cells (ECs) and nuclear localization signals (NLS) were integrated with this TAT peptide to obtain a highly efficient gene delivery system with ECs specificity and nucleus accumulation capacity. Besides, the glycine sequences with different repeat numbers were inserted into the above integrated peptide. These glycine sequences acted as a flexible spacer arm to exert the targeting, cell-penetrating, and nucleus accumulation functions of each functional peptide. Three tandem peptides REDV-G_m-TAT-G_m-NLS (m = 0, 1, and 4) complexed with pZNF580 plasmid to form gene complexes. The results of hemocompatibility and cytocompatibility indicated that these peptides and gene complexes were nontoxic and biocompatible. The internalization efficiency and mechanism of these gene complexes were investigated. The internalization efficiency was improved as the introduction of targeting REDV and glycine sequence, and the REDV-G₄-TAT-G₄-NLS/pZNF580 (TP-G4/pZNF580) complexes showed the highest cellular uptake among the gene complexes. The TP-G4/pZNF580 complexes also presented significantly higher internalization efficiency (∼1.36 times) in human umbilical vein endothelial cells (HUVECs) than human umbilical artery smooth muscle cells. TP-G4/pZNF580 complexes substantially promoted the expression of pZNF580 by confocal live cell imaging, gene delivery efficiency, and HUVECs migration assay. The in vitro and in vivo revascularization ability of transfected HUVECs was further enhanced obviously. In conclusion, these multifunctional REDV-G_m-TAT-G_m-NLS peptides offer a promising and efficacious delivery option for neovascularization to treat vascular diseases.

Synthesis of amphiphilic ABA triblock oligomer via ATRP and its surface properties

A series of novel amphiphilic ABA-type poly(tridecafluorooctylacrylate)-poly(ethylene glycol)-poly(tridecafluorooctylacrylate) (henceforth referred to as p-TDFA-PEG-p-TDFA) triblock oligomers were successfully synthesized via atom transfer radical polymerization (ATRP) using well-defined Br-PEG-Br as macroinitiator and copper as catalyst. The block oligomers were characterized by Fourier transform infrared (FTIR) spectroscopy and 1H and 19F nuclear magnetic resonances (NMR). Gel permeation chromatography (GPC) showed that the block oligomers have been obtained with narrow molecular weight distributions of 1.22–1.33. X-ray photoelectron spectroscopy (XPS) was carried out to confirm the attachment of p-TDFA-PEG-p-TDFA onto the silicon substrate, together with the chemical compositions of p-TDFA-PEG-p-TDFA. The wetabilities of the oligomer films were measured by water contact angles (CAs). Water CAs of p-TDFA-PEG-p-TDFA film were measured and their morphologies were tested by atomic force microscopy (AFM). The result showed that the CAs of the oligomer films, which possess fluoroalkyl groups assembled on the outer surface, increase after heating due to the migration of fluoroalkyl groups and the resulted microphase separation of the p-TDFA-PEG-p-TDFA.

Versatile Functionalization of Polysaccharides via Polymer Grafts: From Design to Biomedical Applications

Because of their biocompatibility, biodegradability, and unique bioactive properties, polysaccharides have been recognized and directly applied as excellent candidates for various biomedical applications. In order to introduce more functionalities onto polysaccharides, various modification methods were applied to improve the physical-chemical and biochemical properties. Grafting polysaccharides with functional polymers with limited reaction sites maximizes the structural integrity. To the best of our knowledge, great efforts have been made by scientists across the world, including our research group, to explore different strategies for the synthesis and design of controllable polymer-grafted polysaccharides. By the application of some reasonable strategies, a series of polymer-grafted polysaccharides with satisfactory biocharacteristics were obtained. The first strategy involves facile modification of polysaccharides with living radical polymerization (LRP). Functionalized polysaccharides with diverse grafts can be flexibly and effectively achieved. The introduced grafts include cationic components for nuclei acid delivery, PEGylated and zwitterionic moieties for shielding effects, and functional species for bioimaging applications as well as bioresponsive drug release applications. The second synthetic model refers to biodegradable polymer-grafted polysaccharides prepared by ring-opening polymerization (ROP). Inspired by pathways to introduce initiation sites onto polysaccharides, the use of amine-functionalized polysaccharides was explored in-depth to trigger ROP of amino acids. A series of poly(amino acid)-grafted polysaccharides with advanced structures (including linear, star-shaped, and comb-shaped copolymers) were developed to study and optimize the structural effects. In addition, biodegradable polyester-grafted polysaccharides were prepared and utilized for drug delivery. Another emerging strategy was to design polysaccharide-based assemblies with supramolecular structures. A variety of assembly techniques using non-covalent interactions were established to construct different types of polysaccharide-based assemblies with various bioapplications. On the basis of these strategies, polymer-grafted polysaccharides with controllable functions were reported to be well-suited for different kinds of biomedical applications. The exciting results were obtained from both in vitro and in vivo models. Viewing the rapid growth of this field, the present Account will update the concepts, trends, perspectives, and applications of functionalized polysaccharides, guiding and inspiring researchers to explore new polysaccharide-based systems for wider applications.