Trehalose-polyamine/DNA nanocomplexes: impact of vector architecture on cell and organ transfection selectivity

A novel family of precision-engineered gene vectors with well-defined structures built on trehalose and trehalose-based macrocycles (cyclotrehalans) comprising linear or cyclic polyamine heads have been synthesized through procedures that exploit click chemistry reactions. The strategy was conceived to enable systematic structural variations and, at the same time, ensuring that enantiomerically pure vectors are obtained. Notably, changes in the molecular architecture translated into topological differences at the nanoscale upon co-assembly with plasmid DNA, especially regarding the presence of regions with short- or long-range internal order as observed by TEM. In vitro and in vivo experiments further evidenced a significant impact on cell and organ transfection selectivity. Altogether, the results highlight the potential of trehalose-polyamine/pDNA nanocomplex monoformulations to achieve targeting transfection without the need for any additional cell- or organ-sorting component.

The combined plasma membrane coating and cluster bombing strategy for improved tumor-targeting gene delivery of silicon nanoclusters

With the promising biosafety and favorable cell imaging efficiency, silicon quantum dots (SiQDs) was broadly exploited as non-viral gene carriers in recent years. However, the low transfection efficiency and weak targeting ability hindered its further clinical applications. In this study, the combined plasma membrane coating and cluster bombing strategy was adopted to enhance the gene delivery potential of silicon quantum dots nanoclusters (SiNC). Initially, SiNC was generated via 3, 3'-Dithiodipropionic acid (DipA) crosslinking of SiQDs, then the obtained nanoclusters were coated by distinct plasma membrane. Interestingly, cell membrane coated SiNC (CM-SiNC) underwent particle size change, the typical character of "cluster bombing", when exposed to high GSH concentration, which was observed in the tumor microenvironment. Meanwhile, CM-SiNC can be efficiently uptaken by HEK 293T and HeLa cells, therefore transferring DNA into those cells. More importantly, among the particles coated by HeLa (HeLa-M), Red Blood (RBC-M) or RAW267.4 (RAW-M) cell membrane, HeLa cell membrane coating exhibited better cellular uptake and transfection efficiency in HeLa cells, which suggested the encouraging tumor targeting ability. In sum, these data suggested that cluster bombing of SiNC could be beneficial for physical stability and biodistribution, the additional plasma membrane coating further endowed SiNC the efficient gene delivery and tumor targeting ability. Therefore, CM-SiNC had the potential as a gene delivery vector and its application should be further addressed in vivo.

Luminescent Water-Dispersible Nanoparticles Engineered from Copper(I) Halide Cluster Core and P,N-Ligand with an Optimal Balance between Stability and ROS Generation

The present work introduces the solvent exchange procedure as a route for conversion of the Cu4I4L2 complex, where the Cu4I4 cluster core is coordinated with two P,N-ligands (L), into an aqueous colloid. The analysis of both colloidal and supernatant phases revealed some losses in CuI going from the initial Cu4I4L2 complex to Cu2I2L3-based nanoparticles. The comparative analysis of IR, 31P NMR spectroscopy, ESI mass-spectrometry and luminescence data argued for a contribution of the “butterfly”-like structures of the Cu2I2 cluster core to Cu2I2L3-based nanoparticles, although the amorphous nature of the latter restricted structure evaluation from the PXRD data. The green luminescence of the colloids revealed their chemical stability under pH variations in the solutions of some amino acids and peptides, and to specify the temperature and concentration conditions triggering the oxidative degradation of the nanoparticles. The spin trap-facilitated ESR study indicated that the oxidative transformations were followed by the generation of reactive oxygen species (ROS). The physiological temperature level (310 K) enhanced the ROS generation by nanoparticles, but the ROS level was suppressed in the solution of GSH at pH = 7.0. The cytotoxicity of nanoparticles was evaluated in the M-HeLa cell line and is discussed in correlation with their cell internalization and intracellular oxidative transformations.

Research Status and Prospect of Non-Viral Vectors Based on siRNA: A Review

Gene therapy has attracted much attention because of its unique mechanism of action, non-toxicity, and good tolerance, which can kill cancer cells without damaging healthy tissues. siRNA-based gene therapy can downregulate, enhance, or correct gene expression by introducing some nucleic acid into patient tissues. Routine treatment of hemophilia requires frequent intravenous injections of missing clotting protein. The high cost of combined therapy causes most patients to lack the best treatment resources. siRNA therapy has the potential of lasting treatment and even curing diseases. Compared with traditional surgery and chemotherapy, siRNA has fewer side effects and less damage to normal cells. The available therapies for degenerative diseases can only alleviate the symptoms of patients, while siRNA therapy drugs can upregulate gene expression, modify epigenetic changes, and stop the disease. In addition, siRNA also plays an important role in cardiovascular diseases, gastrointestinal diseases, and hepatitis B. However, free siRNA is easily degraded by nuclease and has a short half-life in the blood. Research has found that siRNA can be delivered to specific cells through appropriate vector selection and design to improve the therapeutic effect. The application of viral vectors is limited because of their high immunogenicity and low capacity, while non-viral vectors are widely used because of their low immunogenicity, low production cost, and high safety. This paper reviews the common non-viral vectors in recent years and introduces their advantages and disadvantages, as well as the latest application examples.

pH-Driven Intracellular Nano-to-Molecular Disassembly of Heterometallic [Au2L2]{Re6Q8} Colloids (L = PNNP Ligand; Q = S2- or Se2-)

The present work introduces a simple, electrostatically driven approach to engineered nanomaterial built from the highly cytotoxic [Au₂L₂]²⁺ complex (Au₂, L = 1,5-bis(p-tolyl)-3,7-bis(pyridine-2-yl)-1,5-diaza-3,7-diphosphacyclooctane (PNNP) ligand) and the pH-sensitive red-emitting [{Re₆Q₈}(OH)₆]^4- (Re₆-Q, Q = S^2- or Se^2-) cluster units. The protonation/deprotonation of the Re₆-Q unit is a prerequisite for the pH-triggered assembly of Au₂ and Re₆-Q into Au₂Re₆-Q colloids, exhibiting disassembly in acidic (pH = 4.5) conditions modeling a lysosomal environment. The counter-ion effect of polyethylenimine causes the release of Re₆-Q units from the colloids, while the binding with lysozyme restricts their protonation in acidified conditions. The enhanced luminescence response of Re₆-S on the disassembly of Au₂Re₆-S colloids in the lysosomal environment allows us to determine their high lysosomal localization extent through the colocalization assay, while the low luminescence of Re₆-Se units in the same conditions allows us to reveal the rapture of the lysosomal membrane through the use of the Acridine Orange assay. The lysosomal pathway of the colloids, followed by their endo/lysosomal escape, correlates with their cytotoxicity being on the same level as that of Au₂ complexes, but the contribution of the apoptotic pathway differentiates the cytotoxic effect of the colloids from that of the Au₂ complex arisen from the necrotic processes.