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Gene therapy is a promising strategy for treating ischemic disease by solving the dual dilemma of ischemia and inflammation. However, its development remains limited by inefficient gene transfection. Hence, we propose a “dual genes + all-adaptive carrier” idea. We have innovatively co-delivered eNOS gene and the ZNF580gene encoding its transcription factor to enhance the efficiency of eNOS expression. The overexpressed ZNF580protein significantly promotes angiogenesis viaregulating the transcription of multiple genes. This implies a potential synergistic effect of eNOS and ZNF580genes in anti-ischemic therapy. Additionally, we have designed an all-adaptive gene carrier with cascaded bio-responsive functions based on the characteristic bio-signals of the ischemic site (including extracellular excessive matrix metalloproteinase-2, the endo/lysosomal pH gradient and high cytoplasmic glutathione level). This carrier can sequentially overcome transfection bottlenecks and achieve high transfection. Excitingly, this cascaded bio-responsive delivery strategy remarkably enhanced blood perfusion, accelerated angiogenesis and alleviated inflammation in critical limb ischemia (CLI) mice, which was attributed to the combined effects of pro-angiogenic ZNF580expression and synergistically produced eNOS expression. Thereby, we believe that the co-delivery of eNOS and ZNF580genes assisted by a cascaded bio-responsive carrier is a powerful strategy to treat CLI.

Blood-contacting materials with antiplatelet aggregation and anticoagulant properties are in great demand in biomedical field. Herein, hydrophilic poly(ethylene glycol) (PEG) and antithrombotic peptide ACH11were coimmobilized onto Au to develop a multifunctional surface with remarkable hemocompatibility, antiprotein adsorption, antiplatelet aggregation, anticoagulant properties, and good histocompatibility. PEG can not only help the surface resist nonspecific protein adsorption and improve its hemocompatibility but also be a benefit for the immobilized ACH11to maintain its bioactivity in plasma. The anticoagulant peptide ACH11can endow the surface with the ability of activated coagulation factor Xa (FXa) inhibition and antiplatelet aggregation activities. Au was first aminated with 2-aminoethanethiol through strong Au–S bond, and then it was reacted with PEG-ACH11through active ester chemistry to prepare the multifunctional surface Au-PEG-ACH11, among which the heterobifunctional PEG served as a linker to immobilize antithrombotic ACH11. The surface chemical structure and composition quantified by attenuated total reflection Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy convinced us of the successful preparation of the PEG-ACH11modified Au surface. The surface micromorphology and topography of the modified surfaces were observed by field emission scanning electron microscopy and atomic force microscopy. The good hydrophilicity of the modified Au surface was confirmed by water contact analysis. Enzyme immunoassay analysis demonstrated that the activation level of FXa in plasma after incubation with Au-PEG-ACH11was obviously lower than that in control groups. In vitro hemocompatibility evaluation, including hemolysis rate, denaturation of adsorbed fibrinogen, and platelet adhesion and activation, indicated that Au-PEG-ACH11possessed good hemocompatibility. In vivo subcutaneous implantation assay also confirmed the milder tissue response of Au-PEG-ACH11. These results indicated that the multifunctional surface has great potential for biomedical application.

Polymeric gene carriers have been developed to deliver therapeutic genes for treating various genetic diseases. They may diminish the problems related with viral vectors in terms of safety, immunogenicity and mutagenesis. But inefficient endosomal release, cytoplasmic transport and nuclear entry are the main limiting issues in the usage of polymeric carriers. Different strategies have been proposed to functionalize gene carriers for individually overcoming these barriers. Towards this aim, various polymeric carriers have been developed and further modified with certain ligands and peptides to achieve properties like good cargo DNA protection, excellent colloidal stability, high cellular uptake efficiency, efficient endo/lysosome escape, efficient import into the nucleus and specificity to target cells. These multifunctional polymeric carriers are beneficial for efficient gene delivery. In this review, we provide a comprehensive summary of the interaction between gene and polymeric carriers and the mechanism and challenges of gene carriers. We also highlight and discuss the recent developments and advancements in the synthesis of ligand targeting and peptide functionalized gene carriers.

Small interfering RNA (siRNA)-based therapy is an emerging treatment to address serious cardiovascular disease. It is essential to construct highly efficient vehicles for therapeutic siRNA intracellular delivery. Extracellular signal-regulated kinase-2 (ERK2) siRNA (abbreviated as ERK2-siRNA) is known as a type of siRNA to selectively silence the expression of ERK2. Herein, a type of ternary delivery system characterized by an endosome-selective-self-accelerating-escape ability was designed and prepared for the purpose of inhibiting the migration of vascular smooth muscle cells (VSMCs) in vitro. This system was called ternary ERK2-siRNA complexes (abbreviated as TRCs-Aco), which were fabricated viasequential electrostatic self-assembly of a star-shaped cell-penetrating peptide based on polyhedral oligomeric silsesquioxane (POSS-(C-G-R8-G-W)16), ERK2-siRNA and a pH-sensitive anionic polymer of cis-aconitic anhydride grafted -poly(l-lysine). Importantly, TRCs-Aco could break down the obstacle of biocompatibility-silencing efficiency. In comparison with the parent binary siRNA complexes (abbreviated as BRCs), which are composed of POSS-(C-G-R8-G-W)16and ERK2-siRNA, our designed TRCs-Aco revealed more excellent biocompatibility including hemocompatibility and cytocompatibility. Unexpectedly, TRCs-Aco exhibited stronger ERK2 silencing efficiency at the level of mRNA and protein, which was mainly due to its remarkable self-accelerating endosomal escape. Definitive evidence demonstrated that this ternary ERK2-siRNA delivery system significantly prevented the migration of VSMCs and decreased the dermal thickness in bleomycin-treated mice. In brief, this unique structured system could provide a valuable nanoplatform for highly efficient siRNA delivery in VSMCs, and it might hold great potential in guiding ERK2-siRNA-based proliferative disease therapy.

Gene therapy meets one serious bottleneck in clinical application, namely, lack of safe and efficient gene delivery systems. In order to solve this problem, we designed a lowly cytotoxic and highly efficient gene delivery system for the transfection of endothelial cells. Octa(3-ammoniumpropyl)octasilsesquioxane octachloride reacted with 2-bromoisobutyryl bromide under alkaline condition, and sequentially initiated 2-(dimethylamino)ethyl methacrylate (DMAEMA) and poly(ethylene glycol) monomethacrylate (PEGMA) via atom transfer radical polymerization (ATRP) to prepare the eight-arm copolymer with a biocompatible polyhedral oligomericsilsesquioxane (POSS). The side chain ends of the comblike PPEGMA were double-bonded to facilitate the attachment of CAGW or CAG-TAT-NLS functional peptide, thereby enabling the star-shaped copolymers with multifunction. The peptide-functionalized star-shaped copolymers were self-assembled into nanoparticles (NPs) and used to condense pEGFP-ZNF580 (pDNA) to prepare the NPs/pDNA complexes. These complexes had low toxicity as confirmed by MTT. The results of fluorescence microscopy and flow cytometry showed that these multitargeting functionalized gene complexes could effectively transfect endothelial cells. Their transfection efficiency is higher than the positive control PEI 25 kDa group. Moreover, the Western blot test, wound healing assay, and in vitro tube formation assay also demonstrated that the transfected cells showed high migration and enhanced angiogenesis. The pDNA was effective delivered and expressed in endothelial cells by these multitargeting functionalized gene complexes, and promoted cell migration and tube formation. These star-shaped copolymers with comblike structure and a POSS core are a potential gene carrier for gene therapy.

Cementitious materials inevitably develop cracks, posing a serious threat to the long-term security of infrastructure, especially in the complex underground environment of cementing engineering. Microcapsules are facing the problem of encapsulated structure damage during the mixing and breaking difficultly during self-healing when applied in cementitious materials, resulting in the decline of self-healing efficiency. Herein, the calcium alginate water-adaptive microcapsules (CaAlg-NS/E-51) were prepared via an O/W/O emulsion, and the water adaptability of the shell was applied to achieve a rapid brittle–ductile transition by absorbing water. The water adaptability of the microcapsule is conducive to resisting shear stress during stirring due to the decreased elastic modulus and the increased ductility of the shell when it absorbs water. Meanwhile, the water-bearing shell loses water and becomes brittle during dry curing, making it prone to fracture when self-healing. In the self-healing measurement, the self-healing efficiency of cementitious specimens with microcapsules absorbing water for 10 min improved by 234.9 and 60.0% at 1 and 7 days, respectively, compared with those containing dry microcapsules, owing to the water adaptability of the shell.