Development of a nontoxic and efficient gene delivery vector based on histidine grafted chitosan

Antioxidant Stress of Transdermal Gene Delivery by Non-Viral Gene Vectors Based on Chitosan-Oligosaccharide

Oxidative stress initiated by reactive oxygen species (ROS) is the cause of many acquired or congenital skin diseases. Oral antioxidants or using topical antioxidants preparations may bring the nonspecific distribution of drugs or anaphylaxis due to repeated use. In this study, a biocompatible gene vector by cross-linking of chitosan-oligosaccharide (CSO) and N,N'-cystamine-bis-acrylamide (CBA) was synthesized (CSO-CBA), which could carry therapeutic genes into the skin, express functional proteins in epidermal cells, and play an efficient antioxidant effect. Infrared and ¹H NMR spectrum data showed that CSO-CBA was successfully synthesized. Gel electrophoresis results showed that the gene could be successfully compressed by the carrier and can be released in a reducing environment. Hemolysis experiments showed that the carrier had good biocompatibility. Transdermal gene delivery experiments proved that the vector can bring genes into the skin, express functional proteins, and protect the skin from reactive oxygen species damage after 7 days of administration. Skin compatibility experiments show that our therapy is biocompatible. Our study provides a minimally invasive and painless, high-biocompatibility, and long-term effective treatment for skin damage caused by reactive oxygen species, which has a potential application.

Application of Peptides in Construction of Nonviral Vectors for Gene Delivery

Gene therapy, which aims to cure diseases by knocking out, editing, correcting or compensating abnormal genes, provides new strategies for the treatment of tumors, genetic diseases and other diseases that are closely related to human gene abnormalities. In order to deliver genes efficiently to abnormal sites in vivo to achieve therapeutic effects, a variety of gene vectors have been designed. Among them, peptide-based vectors show superior advantages because of their ease of design, perfect biocompatibility and safety. Rationally designed peptides can carry nucleic acids into cells to perform therapeutic effects by overcoming a series of biological barriers including cellular uptake, endosomal escape, nuclear entrance and so on. Moreover, peptides can also be incorporated into other delivery systems as functional segments. In this review, we referred to the biological barriers for gene delivery in vivo and discussed several kinds of peptide-based nonviral gene vectors developed for overcoming these barriers. These vectors can deliver different types of genetic materials into targeted cells/tissues individually or in combination by having specific structure-function relationships. Based on the general review of peptide-based gene delivery systems, the current challenges and future perspectives in development of peptidic nonviral vectors for clinical applications were also put forward, with the aim of providing guidance towards the rational design and development of such systems.

Intelligent poly(l-histidine)-based nanovehicles for controlled drug delivery

Stimuli-responsive drug delivery systems based on polymeric nanovehicles are among the most promising treatment regimens for malignant cancers. Such intelligent systems that release payloads in response to the physiological characteristics of tumor sites have several advantages over conventional drug carriers, offering, in particular, enhanced therapeutic effects and decreased toxicity. The tumor microenvironment (TME) is acidic, suggesting the potential of pH-responsive nanovehicles for enhancing treatment specificity and efficacy. The synthetic polypeptide poly(l-histidine) (PLH) is an appropriate candidate for the preparation of pH-responsive nanovehicles because the pK_a of PLH (approximately 6.0) is close to the pH of the acidic TME. In addition, the pendent imidazole rings of PLH yield pH-dependent hydrophobic-to-hydrophilic phase transitions in the acidic TME, triggering the destabilization of nanovehicles and the subsequent release of encapsulated chemotherapeutic agents. Herein, we highlight the state-of-the-art design and construction of pH-responsive nanovehicles based on PLH and discuss the future challenges and perspectives of this fascinating biomaterial for targeted cancer treatment and "benchtop-to-clinic" translation.