Cellular gene delivery via poly(hexamethylene biguanide)/pDNA self-assembled nanoparticles

Polyhexamethylene biguanidine coated silver nanoparticles embedded into chitosan thiourea/PVA nanofibers as wound healing mats: In vitro and in vivo studies

Burn injuries are prone to infection, leading to significant public health concerns and economic implications. There is a growing demand to develop innovative wound dressings with antibacterial activity. In this study, silver nanoparticles coated with polyhexamethylene biguanidine (Ag/PHMBG) were embedded into chitosan thiourea (CST) nanofibers as a novel multifunctional wound healing mat for treating second-degree burn wounds. Structural, mechanical, and biological properties of nanofibers were investigated using FE-SEM, XRD, ATR-FTIR, and In vitro degradation. The animal study was performed to investigate the suitability of the polymeric mats as a wound healing/dressing system. FE-SEM analysis revealed that the average diameter of the obtained uniform and bead-less Ag/PHMBG-loaded CST nanofibers was around 75 nm. CST-based nanofibers with 3 wt% Ag/PHMBG (PCT3) demonstrated notable antimicrobial efficacy against both S. aureus and P. aeruginosa, achieving 95 % growth inhibition within 3 days while exhibiting no cytotoxic effects on normal fibroblast cells. In addition, CST nanofibers have good breathability with a water vapor transmittance rate of 2.9 ± 0.41-4.4 ± 0.47 kg/m2. d. The animal studies showed that the wound healing and tissue regeneration process by PCT3 nanofibers were faster than the other groups. In conclusion, CST-based nanofibers are a potentially promising substitute for conventional wound dressings in clinical applications.

Sterilized Polyhexanide-Releasing Chitosan Membranes with Potential for Use in Antimicrobial Wound Dressings

Wound infection is a common complication of chronic wounds. It can impair healing, which may not occur without external help. Antimicrobial dressings (AMDs) are a type of external help to infected chronic wounds. In this study, highly porous membranes made of only chitosan and containing the antiseptic polyhexanide (poly(hexamethylene biguanide); PHMB) were prepared by cryogelation, aiming to be used in AMDs. These membranes exhibited a water swelling capacity of 748%, a water drop penetration time of 11 s in a dry membrane and a water vapor transmission rate of 34,400 g H2O/m2/24 h when in contact with water. The best drug loading method involved simultaneous loading by soaking in a PHMB solution and sterilization by autoclaving, resulting in sterilized, drug-loaded membranes. When these membranes and a commercial PHMB-releasing AMD were assayed under the same conditions, albeit far from the in vivo conditions, their drug release kinetics were comparable, releasing PHMB for ca. 6 and 4 h, respectively. These membranes exhibited high antibacterial activity against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa, which are bacterial species commonly found in infected wounds and blood clotting activity. The obtained results suggest that these membranes may have potential for use in the development of AMDs.

Polyhexanide-Releasing Membranes for Antimicrobial Wound Dressings: A Critical Review

The prevalence of chronic, non-healing skin wounds in the general population, most notably diabetic foot ulcers, venous leg ulcers and pressure ulcers, is approximately 2% and is expected to increase, driven mostly by the aging population and the steady rise in obesity and diabetes. Non-healing wounds often become infected, increasing the risk of life-threatening complications, which poses a significant socioeconomic burden. Aiming at the improved management of infected wounds, a variety of wound dressings that incorporate antimicrobials (AMDs), namely polyhexanide (poly(hexamethylene biguanide); PHMB), have been introduced in the wound-care market. However, many wound-care professionals agree that none of these wound dressings show comprehensive or optimal antimicrobial activity. This manuscript summarizes and discusses studies on PHMB-releasing membranes (PRMs) for wound dressings, detailing their preparation, physical properties that are relevant to the context of AMDs, drug loading and release, antibacterial activity, biocompatibility, wound-healing capacity, and clinical trials conducted. Some of these PRMs were able to improve wound healing in in vivo models, with no associated cytotoxicity, but significant differences in study design make it difficult to compare overall efficacies. It is hoped that this review, which includes, whenever available, international standards for testing AMDs, will provide a framework for future studies.

Non-viral Vectors in Gene Therapy: Recent Development, Challenges, and Prospects

Gene therapy has been experiencing a breakthrough in recent years, targeting various specific cell groups in numerous therapeutic areas. However, most recent clinical studies maintain the use of traditional viral vector systems, which are challenging to manufacture cost-effectively at a commercial scale. Non-viral vectors have been a fast-paced research topic in gene delivery, such as polymers, lipids, inorganic particles, and combinations of different types. Although non-viral vectors are low in their cytotoxicity, immunogenicity, and mutagenesis, attracting more and more researchers to explore the promising delivery system, they do not carry ideal characteristics and have faced critical challenges, including gene transfer efficiency, specificity, gene expression duration, and safety. This review covers the recent advancement in non-viral vectors research and formulation aspects, the challenges, and future perspectives.

Boosting transfection efficiency: A systematic study using layer-by-layer based gene delivery platform

Nowadays, the nanoparticle-based delivery approach is becoming more and more attractive in gene therapy due to its low toxicity and immunogenicity, sufficient packaging capacity, targeting, and straightforward, low-cost, large-scale good manufacturing practice (GMP) production. A number of research works focusing on multilayer structures have explored different factors and parameters that can affect the delivery efficiency of pDNA. However, there are no systematic studies on the performance of these structures for enhanced gene delivery regarding the gene loading methods, the use of additional organic components and cell/particle incubation conditions. Here, we conducted a detailed analysis of different parameters such as (i) strategy for loading pDNA into carriers, (ii) incorporating both pDNA and organic additives within one carrier and (iii) variation of cell/particle incubation conditions, to evaluate their influence on the efficiency of pDNA delivery with multilayer structures consisting of inorganic cores and polymer layers. Our results reveal that an appropriate combination of all these parameters leads to the development of optimized protocols for high transfection efficiency, compared to the non-optimized process (> 70% vs. < 7%), and shows a good safety profile. In conclusion, we provide the proof-of-principle that these multilayer structures with the developed parameters are a promising non-viral platform for an efficient delivery of nucleic acids.