Hydrogels for Nucleic Acid Drugs Delivery

Nucleic acid drugs are one of the hot spots in the field of biomedicine in recent years, and play a crucial role in the treatment of many diseases. However, its low stability and difficulty in target drug delivery are the bottlenecks restricting its application. Hydrogels are proven to be promising for improving the stability of nucleic acid drugs, reducing the adverse effects of rapid degradation, sudden release, and unnecessary diffusion of nucleic acid drugs. In this review, the strategies of loading nucleic acid drugs in hydrogels are summarized for various biomedical research, and classify the mechanism principles of these strategies, including electrostatic binding, hydrogen bond based binding, hydrophobic binding, covalent bond based binding and indirect binding using various carriers. In addition, this review also describes the release strategies of nucleic acid drugs, including photostimulation-based release, enzyme-responsive release, pH-responsive release, and temperature-responsive release. Finally, the applications and future research directions of hydrogels for delivering nucleic acid drugs in the field of medicine are discussed.

Non-Viral Carriers for Nucleic Acids Delivery: Fundamentals and Current Applications

Over the past decades, non-viral DNA and RNA delivery systems have been intensively studied as an alternative to viral vectors. Despite the most significant advantage over viruses, such as the lack of immunogenicity and cytotoxicity, the widespread use of non-viral carriers in clinical practice is still limited due to the insufficient efficacy associated with the difficulties of overcoming extracellular and intracellular barriers. Overcoming barriers by non-viral carriers is facilitated by their chemical structure, surface charge, as well as developed modifications. Currently, there are many different forms of non-viral carriers for various applications. This review aimed to summarize recent developments based on the essential requirements for non-viral carriers for gene therapy.

Sodium Alginate-Doping Cationic Nanoparticle As Dual Gene Delivery System for Genetically Bimodal Therapy

Photodynamic therapy occupies an important position in cancer therapy because of its minimal invasiveness and high spatiotemporal precision, and photodynamic/gene combined therapy is a promising strategy for additive therapeutic effects. However, the asynchronism and heterogeneity between traditional chemical photosensitizers and nucleic acid would restrict the feasibility of this strategy. KillerRed protein, as an endogenous photosensitizer, could be directly expressed and take effect in situ by transfecting KillerRed reporter genes into cells. Herein, a simple and easily prepared sodium alginate (SA)-doping cationic nanoparticle SA@GP/DNA was developed for dual gene delivery. The nanoparticles could be formed through electrostatic interaction among sodium alginate, polycation, and plasmid DNA. The title complex SA@GP/DNA showed good biocompatibility and gene transfection efficiency. Mechanism studies revealed that SA doping could facilitate the cellular uptake and DNA release. Furthermore, SA@GP/DNA was applied to the codelivery of p53 and KillerRed reporter genes for the synergistic effect combining p53-mediated apoptosis therapy and KillerRed-mediated photodynamic therapy. The ROS generation, tumor cell growth inhibition, and apoptosis assays proved that the dual-gene transfection could mediate the better effect compared with single therapy. This rationally designed dual gene codelivery nanoparticle provides an effective and promising platform for genetically bimodal therapy.

Chitosan-Crosslinked Low Molecular Weight PEI-Conjugated Iron Oxide Nanoparticle for Safe and Effective DNA Delivery to Breast Cancer Cells

Breast cancer has attracted tremendous research interest in treatment development as one of the major threats to public health. The use of non-viral carriers for therapeutic DNA delivery has shown promise in treating various cancer types, including breast cancer, due to their high DNA loading capacity, high cell transfection efficiency, and design versatility. However, cytotoxicity and large sizes of non-viral DNA carriers often raise safety concerns and hinder their applications in the clinic. Here we report the development of a novel nanoparticle formulation (termed NP-Chi-xPEI) that can safely and effectively deliver DNA into breast cancer cells for successful transfection. The nanoparticle is composed of an iron oxide core coated with low molecular weight (800 Da) polyethyleneimine crosslinked with chitosan via biodegradable disulfide bonds. The NP-Chi-xPEI can condense DNA into a small nanoparticle with the overall size of less than 100 nm and offer full DNA protection. Its biodegradable coating of small-molecular weight xPEI and mildly positive surface charge confer extra biocompatibility. NP-Chi-xPEI-mediated DNA delivery was shown to achieve high transfection efficiency across multiple breast cancer cell lines with significantly lower cytotoxicity as compared to the commercial transfection agent Lipofectamine 3000. With demonstrated favorable physicochemical properties and functionality, NP-Chi-xPEI may serve as a reliable vehicle to deliver DNA to breast cancer cells.

Construction of GSH-triggered cationic fluoropolymer as two-in-one nanoplatform for combined chemo/gene therapy

The combined chemo-gene therapy has become a promising approach for enhanced anti-cancer treatment. However, effective co-delivery of therapeutic gene and drug into target cells and tissues remains a major obstacle....

Cleavable poly(ethylene glycol) branched chain-modified Antheraea pernyi silk fibroin as a gene delivery carrier

Aim: To obtain a gene carrier that can effectively deliver loaded therapeutic genes to tumor cells, avoid toxic effects on normal cells and reduce nonspecific adsorption of plasma proteins. Methods: The conjugate of poly(ethylene glycol) (PEG) and MMP2SSP (PEG-MMP2SSP) was covalently coupled to cationized Antheraea pernyi silk fibroin (CASF) through disulfide bond exchange reaction to obtain a PEG-MMP2SSP-modified CASF (CASFMP). Results: The PEG chains were effectively cleaved from the CASFMP by MMP2. CASFMP/pDNA complexes inhibited human fibrosarcoma cell proliferation, and its cytotoxicity to human normal embryonic kidney cells was significantly lower than that of poly(ethylenimine)/pDNA after coculturing with cells for 24 h. Conclusion: CASFMP is a promising compound for use in gene therapy.

One-Pot Synthesis-Biocompatible Copper-Tripeptide Complex as a Nanocatalytic Medicine to Enhance Chemodynamic Therapy

Chemodynamic therapy (CDT) is a kind of method utilizing hydroxyl radicals (^•OH) generated by Fenton or Fenton-like reactions in situ to kill tumor cells. Copper, a cofactor of many intracellular enzymes, which has good biocompatibility, is a transition metal with extremely high efficiency in the Fenton-like reaction. However, when the intracellular free copper exceeds the threshold, it will bring serious side effects. Hence, we used the chelation between glutathione (GSH) and copper ions to produce a nanocatalytic drug, which was named as Cu-GSSG NPs, to fix free copper. With the aid of hydrogen peroxide (H₂O₂) in vitro, Cu-GSSG NPs catalyzed it to ^•OH radicals, which could be confirmed by the electron spin resonance spectrum and the degradation experiment of methylene blue. Based on these results, we further studied the intracellular properties of Cu-GSSG NPs and found that Cu-GSSG NPs could react with the overexpressed H₂O₂ in tumor cells to produce ^•OH radicals effectively by the Fenton-like reaction to induce cell death. Therefore, Cu-GSSG NPs could be a kind of potential "green" nanocatalytic drug with good biocompatibility to achieve CDT.

Synthesis of Copolymers Polyethyleneimine-co-Polyphenylalanine as Gene and Drug Codelivery Carrier

In this study, a series of hyperbranched copolymers polyethyleneimine-co-polyphenylalanine (PEI-co-PPhe) are synthesized by ring-opening polymerization with phenylalanine-N-carboxyanhydride as monomer and PEI-25k as initiator, using as a gene and drug codelivery carrier. Among them, PEI-co-PPhe (1:170) is selected out from transfection efficiency and cytotoxicity tests. Then, doxorubicin-cis-aconitic anhydride (CAD) and BCl2-shRNA (as a therapeutic gene) are coloaded into the PEI-co-PPhe carrier to form PEI-co-PPhe/Bcl2-shRNA/CAD complexes as a codeliver system. When the mass ratio of PEI-co-PPhe:Bcl2-shRNA:CAD is 5:1:1, the codeliver system has the most obvious synergistic therapeutic effect against B16F10 cells. Confirmed by confocal laser scanning microscope and flow cytometry, compared with drug and gene alone, the codeliver complexes can be endocytosed into B16F10 cells efficiently. As a result, the appropriate length of PPhe grafted on PEI will improve the gene transfer efficiency and decrease cytotoxicity, as well as effective codelivery of gene and drug into cancer cells to be a promising codelivery carrier for cancer therapy.