A Coordinative Dendrimer Achieves Excellent Efficiency in Cytosolic Protein and Peptide Delivery

Exosome engineering for efficient and targeted drug delivery: Current status and future perspective

Exosomes are membrane-bound vesicles that are released by most cells. They carry nucleic acids, cytokines, growth factors, proteins, lipids, and metabolites. They are responsible for inter- and intracellular communications and their role in drug delivery is well defined. Exosomes have great potential for therapeutic applications, but the clinical use is restricted because of limitations in standardized procedures for isolation, purification, and drug delivery. Bioengineering of exosomes could be one approach to achieve standardization and reproducible isolation for clinical use. Exosomes are important transporters for targeted drug delivery because of their small size, stable structure, non-immunogenicity, and non-toxic nature, as well as their ability to carry a wide variety of compounds. These features of exosomes can be enhanced further by bioengineering. In this review, possible exosome bioengineering approaches, their biomedical applications, and targeted drug delivery are discussed.

Electrochemical Single-Cell Protein Therapeutics Using a Double-Barrel Nanopipette

Single-cell protein therapeutics is expected to promote our in-depth understanding of how a specific protein with a therapeutic dosage treats the cell without population averaging. However, it has not yet been tackled by current single-cell nanotools. We address this challenge by the use of a double-barrel nanopipette, in which one lumen was used for electroosmotic cytosolic protein delivery and the other was customized for ionic evaluation of the consequence. Upon injection of protein DJ-1 through the delivery lumen, upregulation of the antioxidant protein could protect neural PC-12 cells against oxidative stress from phorbol myristate acetate exposure, as deduced by targeting of the cytosolic hydrogen peroxide by the detecting lumen. The nanotool developed in this study for single-cell protein therapeutics provides a perspective for future single-cell therapeutics involving different therapeutic modalities, such as peptides, enzymes and nucleic acids.

Metal-Organic Framework-Based Composites for Protein Delivery and Therapeutics

Owing to high bioactivity and specificity, protein drugs have achieved great success in both diagnosis and therapy. The idea of delivering active proteins directly to targets is becoming more and more attractive. However, due to their large size and environmental sensitivity, it is not easy for proteins to maintain bioactivity in extracellular fluids and cross cell membrane without being damaged. A series of techniques and carriers have been developed to deliver proteins. Thereinto, metal-organic frameworks (MOFs), which are made of metal ions connected by organic linkers, are one of the most important vehicles for protein delivery. Their porous structures, stability, biocompatibility, reproducibility, and the possibility for further functionalities offer great potential for protein delivery. In this review, recent developments of protein encapsulated by MOF nanoparticles, including mechanism of treatment, structural design, loading capacity, delivery, and release properties of proteins, are summarized, and the relationship between structure and performance is emphasized. Meanwhile, further improvements and implementations are discussed.

In Vivo Tracking of Fluorinated Polypeptide Gene Carriers by Positron Emission Tomography Imaging

Fluorinated polymers have attracted increasing attention in gene delivery and cytosolic protein delivery in recent years. In vivo tracking of fluorinated polymers will be of great importance to evaluate their biodistribution, clearance, and safety. However, tracking of polymeric carriers without changing their chemical structures remains a huge challenge. Herein, we reported a series of fluorinated poly-l-(lysine) (F-PLL) with high gene transfection efficiency and excellent biodegradation. Radionuclide ¹⁸F was radiolabeled on F-PLL by halogen replacement without chemical modification. The radiolabeling of F-PLL offers positron emission tomography (PET) imaging for in vivo tracking of the polymers. The biodistribution of F-PLL and the DNA complexes revealed by micro-PET imaging illustrated the rapid clearance of fluorinated polymers from liver and intestine after intravenous administration. The results demonstrated that the polymer F-PLL will not be accumulated in the liver and spleen when administrated as a gene carrier. This work presents a new strategy for in vivo tracking fluorinated polymers via PET imaging.