Xianqing Wang

Messenger RNA (mRNA) therapeutics are redefining treatment approaches in vaccines, cancer immunotherapy, protein replacement, and gene editing. Lipid nanoparticles have enabled early clinical successes, but they can be limited by liver-dominant biodistribution, long-term storage stability, and systemic tolerability. Polymeric delivery systems offer a versatile alternative, with tunable physicochemical properties enabling precise control over mRNA complexation, protection, release, and targeting. This review examines recent progress across polyethyleneimine derivatives, poly(β-amino ester)s, poly(amino acid)s, polyesters, dendrimers, charge-altering releasable transporters, and lipid-polymer hybrids. We highlight strategies such as structural modification, stimuli-responsive designs, and high-throughput polymer screening that enhance stability, reduce cytotoxicity, and enable organ- or cell-specific delivery. Addressing challenges in immunogenicity, biodistribution, and manufacturing scalability will be pivotal to translating these innovations into safe and effective mRNA therapeutics.

Hyperbranched poly(β-amino ester) (HPAE) is identified as a unique non-viral carrier capable of sustaining high-efficiency transfection under elevated plasmid concentrations, overcoming the aggregation and toxicity limitations of conventional lipid and PEI reagents. We demonstrate that transfection enhancement is driven by concentration-dependent synergism between membrane accumulation and endosomal escape. Guided by this mechanism, a half-volume transfection strategy was established to transiently elevate plasmid concentration without compromising cell viability, enabling superior lentivirus yield and purity. These findings define plasmid concentration as a previously overlooked regulatory axis in nanoparticle-mediated gene delivery and position HPAE as a high-performance platform for scalable therapeutic vector production.

Herein, a high‐throughput microfluidic platform is presented that addresses the challenges in lipid nanoparticles (LNPs) formulation screening and scale‐up through the design of micromixers with unique aerofoil structures. These structures are optimized to enhance mixing and LNP formation across a wide flow rate range (0.2–50 mL min ⁻¹ ), using minimal reagent volumes (as low as 0.1 mL) up to liter‐scale production. A high‐throughput formulation screening instrument named MiNANO‐form and a microfluidic cartridge with eight parallel channels is introduced, which enables simultaneous synthesis of multiple LNP formulations with excellent quality (size 38–150 nm and polydispersity index (PDI), PDI < 0.2) and reproducibility. In addition, for a seamless scale‐up, the platform consists of a custom‐made modular microfluidic unit, named MiNANO‐scale, capable of continuous LNP production at up to 50 mL min ⁻¹ . The platform's performance is validated through mRNA and pDNA transfection, as well as siRNA uptake studies in HEK293, A549, and CFBE cells.

Dystrophic epidermolysis bullosa (DEB) is a severe monogenic skin disorder resulting from mutations in the COL7A1 gene, which disrupts the synthesis of type VII collagen. This leads to impaired anchoring fibrils and results in dermoepidermal separation. The clinical manifestation of DEB varies significantly, ranging from localized blistering in milder forms to extensive blistering with subsequent severe complications such as vision loss and squamous cell carcinoma in more severe cases. Despite the recent approval of the first gene replacement therapy by the U.S. Food and Drug Administration, the majority of DEB patients still depend on palliative care, an indication of the continued unmet therapeutic needs. In the past two decades, there has been a rapid advancement of gene therapy techniques, extensive research efforts, and pre-clinical studies focusing on the correction of DNA, RNA, and protein defects specific to DEB. In this review, we provide a comprehensive update on the current state of gene engineering strategies for DEB, including gene replacement, pre-mRNA regulatory therapies, and gene editing techniques. In addition, this review critically evaluates the role and development of animal models in DEB research, which are crucial for the progression of therapeutic strategies. Our discussion aims to delineate the existing challenges and emphasize ongoing advancements in the gene therapy landscape for DEB, providing insights that may guide future research and clinical approaches.

Highly branched poly(β-amino ester) (HPAE) has become one of the most promising non-viral gene delivery vector candidates. When compared to other gene delivery vectors, HPAE has a broad molecular weight distribution (MWD). Despite significant efforts to optimize HPAE targeting enhanced gene delivery, the effect of different molecular weight (MW) components on transfection has rarely been studied. In this work, a new structural optimization strategy was proposed targeting enhanced HPAE gene transfection. A series of HPAE with different MW components was obtained through a stepwise precipitation approach and applied to plasmid DNA delivery. It was demonstrated that the removal of small MW components from the original HPAE structure could significantly enhance its transfection performance (e.g., GFP expression increased 7 folds at w/w of 10/1). The universality of this strategy was proven by extending it to varying HPAE systems with different MWs and different branching degrees, where the transfection performance exhibited an even magnitude enhancement after removing small MW portions. This work opened a new avenue for developing high-efficiency HPAE gene delivery vectors and provided new insights into the understanding of the HPAE structure–property relationship, which would facilitate the translation of HPAEs in gene therapy clinical applications.

Many polymeric gene delivery nano-vectors with hyperbranched structures have been demonstrated to be superior to their linear counterparts. The higher delivery efficacy is commonly attributed to the abundant terminal groups of branched polymers, which play critical roles in cargo entrapment, material-cell interaction, and endosome escape. Hyperbranched poly(β-amino ester)s (HPAEs) have developed as a class of safe and efficient gene delivery vectors. Although numerous research has been conducted to optimise the HPAE structure for gene delivery, the effect of the secondary amine residue on its backbone monomer, which is considered the non-ideal termination, has never been optimised. In this work, the effect of the non-ideal termination was carefully evaluated. Moreover, a series of HPAEs with only ideal terminations were synthesised by adjusting the backbone synthesis strategy to further explore the merits of hyperbranched structures. The HPAE obtained from modified synthesis methods exhibited more than twice the amounts of the ideal terminal groups compared to the conventional ones, determined by NMR. Their transfection performance enhanced significantly, where the optimal HPAE candidates developed in this study outperformed leading commercial benchmarks for DNA delivery, including Lipofectamine 3000, jetPEI, and jetOPTIMUS.