Simply constructed chitosan nanocarriers with precise spatiotemporal control for efficient intracellular drug delivery

Graphene oxide-functionalized molecular beacon for real-time interference-free detection of Ki-67 mRNA in living cells

Molecular beacons (MBs) based on hairpin-shaped oligonucleotides are captivating owing to their capability to enable effective real-time detection of cytosolic mRNA in living cells. However, DNase in the nucleus and lysosome could induce the degradation of oligonucleotides in MBs, leading to the generation of false-positive signals. Herein, a graphene oxide (GO) nanosheet was applied as a nanocarrier for MBs to greatly enhance the anti-interference of the easily designed nanoprobe. Advantageously, the absorption capacity of GO for MBs increased with the decrease in pH values, providing the MB-GO nanoprobe with the ability to detect the expression of cytosolic Ki-67 mRNA without interference from DNase Ⅱ in lysosomes. Moreover, the size of GO nanosheets was considerably higher than that of the nuclear pore complex (NPC), which prevented nanoprobes from transition through the NPCs, thereby avoiding the generation of false-positive signals in the nucleus. Altogether, the present work affords a convenient approach for the successful detection of Ki-67 mRNA expression in the cytosol without interference from DNase Ⅰ/Ⅱ in the nucleus/lysosome, which may be potentially further applied for the detection of other cytosolic RNAs.

Chitosan-based nanoscale systems for doxorubicin delivery: Exploring biomedical application in cancer therapy

Green chemistry has been a growing multidisciplinary field in recent years showing great promise in biomedical applications, especially for cancer therapy. Chitosan (CS) is an abundant biopolymer derived from chitin and is present in insects and fungi. This polysaccharide has favorable characteristics, including biocompatibility, biodegradability, and ease of modification by enzymes and chemicals. CS-based nanoparticles (CS-NPs) have shown potential in the treatment of cancer and other diseases, affording targeted delivery and overcoming drug resistance. The current review emphasizes on the application of CS-NPs for the delivery of a chemotherapeutic agent, doxorubicin (DOX), in cancer therapy as they promote internalization of DOX in cancer cells and prevent the activity of P-glycoprotein (P-gp) to reverse drug resistance. These nanoarchitectures can provide co-delivery of DOX with antitumor agents such as curcumin and cisplatin to induce synergistic cancer therapy. Furthermore, co-loading of DOX with siRNA, shRNA, and miRNA can suppress tumor progression and provide chemosensitivity. Various nanostructures, including lipid-, carbon-, polymeric- and metal-based nanoparticles, are modifiable with CS for DOX delivery, while functionalization of CS-NPs with ligands such as hyaluronic acid promotes selectivity toward tumor cells and prevents DOX resistance. The CS-NPs demonstrate high encapsulation efficiency and due to protonation of amine groups of CS, pH-sensitive release of DOX can occur. Furthermore, redox- and light-responsive CS-NPs have been prepared for DOX delivery in cancer treatment. Leveraging these characteristics and in view of the biocompatibility of CS-NPs, we expect to soon see significant progress towards clinical translation.

Glutathione-sensitive IPI-549 nanoparticles synergized with photodynamic Chlorin e6 for the treatment of breast cancer

We combined phosphoinositol-3-kinin inhibitor IPI-549 and photodynamic Chlorin e6 (Ce6) on carboxymethyl chitosan to develop a novel drug delivery nanoparticle (NP) system (Ce6/CMCS-DSP-IPI549) and evaluate its glutathione (GSH) sensitivity and targeting ability for breast cancer treatment. The NPs were spherical with a uniform size of 218.8 nm, a stable structure over 7 days. The maximum encapsulation efficiency was 64.42%, and NPs drug loading was 8.05%. The NPs released drugs within tumor cells due to their high GSH concentration, while they maintained structural integrity in normal cells, which have low GSH concentration. The cumulative release rates of IPI-549 and Ce6 at 108 h were 70.67% and 40.35% (at GSH 10 mM) and 8.11% and 2.71% (at GSH 2μM), respectively. The NPs showed a strong inhibitory effect on 4T1 cells yet did not affect human umbilical vein endothelial cells (HUVECs). After irradiation by a 660 nm infrared laser for 72 h, the survival rate of 4T1 cells was 15.51%. Cellular uptake studies indicated that the NPs could accurately release drugs into tumor cells. In addition, the NPs had a good photodynamic effect and promoted the release of reactive oxygen species to damage tumor cells. Overall, the combination therapy of IPI-549 and Ce6 is safe and effective, and may provide a new avenue for the treatment of breast cancer.

The Synergism of Platinum-Gold Bimetallic Nanoconjugates Enhances 5-Fluorouracil Delivery In Vitro

Nanoparticle application has significantly impacted the field of medicine. The need to develop novel drugs with higher therapeutic potential has stimulated the development of innovative delivery strategies to mitigate the potent side effects associated with known chemotherapeutic drugs. This paper describes the synthesis of platinum-gold bimetallic nanoparticles (PtAuBNps), their functionalisation with chitosan, and entrapment of the anticancer drug 5-fluorouracil (5-FU). All PtAuBNps and their drug nanocomposites were physico-chemically characterised, displaying desirable properties with regards to shape, size (<120 nm) and colloidal stability. 5-FU binding and loading capacities in PtAuBNps were found to be 90.17% and 22.56%, respectively. In vitro cytotoxicity profiles determined using the MTT and SRB assays reflected up to 65% cell death in the MCF-7, HepG2 and Caco-2 cell lines. These nanocomposites exhibited excellent physiochemical attributes, high specificity towards cancer cells, with a pH-sensitive drug release in a simulated acidic tumour microenvironment through zero-order release kinetics. In addition, they possessed the potential to traverse the mucosal lining facilitating oral drug administration. Overall, 5-FU encapsulation improved the bioavailability of the drug in cancer cells, with the promise of enhancing its therapeutic effect, biocompatibility and safety. These positive results highlight PtAuBNps as promising in vitro delivery systems and merits future in vivo research.

Synthesis and characterization of a novel organosilane-functionalized chitosan nanocarrier as an efficient gene delivery system: Expression of green fluorescent protein

Semi-essential arginine amino acid was selected to synthesis an organosilane linker for modifying chitosan biopolymer. The novel organosilane linker which was chemically synthesized by reaction of arginine with 3‑chloropropyl trimethoxy silane, covalently bonded to the chitosan amino group. The chemical structure of resulting nanocarrier was characterized by ¹H NMR, wide-X-ray diffraction, TEM, FESEM and EDX. A maximum retardation capacity of the nanocarrier to the plox plasmid was obtained 3 at physiological pH (7.4). The mean of cell viability and cytotoxicity of the nanocarrier was determined 85% by MTT assay. In addition, the gene transfection of the nanocarrier was obtained top of 20% gene expression. The studies have shown very good DNase 1 enzyme protection of plasmid by the nanocarrier.

A multi-responsive biomimetic nano-complex platform for enhanced gene delivery

RNA interference (RNAi) is widely regarded as a promising technology for disease treatment, yet one major obstacle for its clinical application is the lack of enhanced siRNA delivery vehicles to circumvent complex extra- and intracellular barriers.