Enteric pH responsive cargo release from PDA and PEG coated mesoporous silica nanoparticles: a comparative study in Drosophila melanogaster

pH and redox dual response nano-suppository for the treatment of ulcerative colitis

To improve treatment compliance and reach sustained and controlled drug release in the colon, we developed a hollow mesoporous silica nano-suppository that responded to both pH and redox stimuli. Firstly, we prepared hollow mesoporous silica nanoparticles containing disulfide bonds (HMSN-SS) and loaded them with 5-ASA. Secondly, we modified the surface of HMSN-SS with polydopamine (PDA) and chitosan (CS) and molded the suppository, which we named 5-ASA@HMSN-SS-PDA-CS (5-ASA@HSPC). By administering 5-ASA@HSPC rectally, it acted directly on the affected area. CS helped the nanoparticles adhere to the colon's surface, while PDA dissociates from HMSN-SS due to protonation in the acidic environment of the ulcerative colon. The disulfide bonds were destroyed by the reducing environment of the colon, leading to a stable and slow release of encapsulated 5-ASA from the pores of HMSN. Finally, in vitro release experiments and in vivo pharmacokinetic and pharmacodynamic experiments had demonstrated that 5-ASA@HSPC exhibited a slow and steady action at the colonic site, with an excellent safety profile. This novel approach showed great potential in the treatment of ulcerative colitis.

Applications of polydopaminic nanomaterials in mucosal drug delivery

Polydopamine (PDA) is a biopolymer with unique physicochemical properties, including free-radical scavenging, high photothermal conversion efficiency, biocompatibility, biodegradability, excellent fluorescent and theranostic capacity due to their abundant surface chemistry. Thus, PDA is used for a myriad of applications including drug delivery, biosensing, imaging and cancer therapy. Recent reports present a new functionality of PDA as a coating nanomaterial, with major implications in mucosal drug delivery applications, particularly muco-adhesion and muco-penetration. However, this application has received minimal traction in the literature. In this review, we present the physicochemical and functional properties of PDA and highlight its key biomedical applications, especially in cancer therapy. A detailed presentation of the role of PDA as a promising coating material for nanoparticulate carriers intended for mucosal delivery forms the core aspect of the review. Finally, a reflection on key considerations and challenges in the utilizing PDA for mucosal drug delivery, along with the possibilities of translation to clinical studies is expounded.

CRISPR/Cas9-3NLS/sgHMGA2@PDA nanosystem is the potential efficient gene editing therapy for gastric cancer with HMGA2 high expression

Gene therapy is one of the target therapies with promising clinical use for gastric cancer (GC). However, the delivery of the CRISPR/Cas9/sgRNA (RNP) gene editing tool severely limits the practical therapeutic effect of GC. Therefore, it is a great challenge to develop an RNP delivery system that is simple to prepare and can rapidly encapsulate RNP while achieving high delivery and gene editing efficiency. We developed, for the first time, the CRISPR/Cas9@PDA nano-delivery system that can achieve high-efficiency delivery (95%) of CRISPR/Cas9_-3NLS/sgHMGA2 and high-efficient HMGA2 gene editing (82%) of GC cells. In particular, the experiment’s weak alkaline environment can not only protect the activity of CRISPR/Cas9_-3NLS/sgHMGA2 but also trigger the self-polymerization of polydopamine (PDA). Meanwhile, the presence of KE in the CRISPR/Cas9 amino acid sequence can achieve the directional growth of PDA, thus forming a core–shell structure that protects CRISPR/Cas9_-3NLS/sgHMGA2. This efficient CRISPR/Cas9_-3NLS/sgHMGA2 delivery and HMGA2 gene editing ability has also been verified in mice, which can significantly inhibit tumor growth in mice. The success of building the delivery system and its ideal treating effect give hope to the efficacious treatment for the GC patients with HMGA2 high expression.

From Bioinspired Glue to Medicine: Polydopamine as a Biomedical Material

Biological structures have emerged through millennia of evolution, and nature has fine-tuned the material properties in order to optimise the structure-function relationship. Following this paradigm, polydopamine (PDA), which was found to be crucial for the adhesion of mussels to wet surfaces, was hence initially introduced as a coating substance to increase the chemical reactivity and surface adhesion properties. Structurally, polydopamine is very similar to melanin, which is a pigment of human skin responsible for the protection of underlying skin layers by efficiently absorbing light with potentially harmful wavelengths. Recent findings have shown the subsequent release of the energy (in the form of heat) upon light excitation, presenting it as an ideal candidate for photothermal applications. Thus, polydopamine can both be used to (i) coat nanoparticle surfaces and to (ii) form capsules and ultra-small (nano)particles/nanocomposites while retaining bulk characteristics (i.e., biocompatibility, stability under UV irradiation, heat conversion, and activity during photoacoustic imaging). Due to the aforementioned properties, polydopamine-based materials have since been tested in adhesive and in energy-related as well as in a range of medical applications such as for tumour ablation, imaging, and drug delivery. In this review, we focus upon how different forms of the material can be synthesised and the use of polydopamine in biological and biomedical applications.