Dual pH-Responsive Shell-Cleavable Polycarbonate Micellar Nanoparticles for in Vivo Anticancer Drug Delivery

Intelligent Cellulose Nanofibers with Excellent Biocompatibility Enable Sustained Antibacterial and Drug Release via a pH-Responsive Mechanism

Novel nanosized biomass-based pH-responsive cellulose nanofibers (CNF-PEI) with excellent biocompatibility were tailored by grafting polyethylenimine (PEI) onto carboxylated cellulose nanofibers (CNF-COOH); the active site (-COOH, 0.96 mmol/g) was anchored on cellulose nanofibers (CNFs) to introduce PEI with a high density (10.57 mmol/g) of amino groups. The as-prepared CNF-PEI not only maintained the good properties of CNFs but also possessed excellent biocompatibility and pH-responsive properties, offering interesting possibilities for pH-induced sustained drug release and medical dressing. The CNF-PEI showed rapid wettability conversion from hydrophilic, underwater superoleophobic (WCA = 20.7°, OCA = 159.3°) to hydrophobic, superoleophilic (WCA = 129.6°, OCA = 29.7°) in response to pH change from acidic conditions to alkaline conditions. The antibacterial activity of CNF-PEI toward Escherichia coli and Listeria monocytogenes was 100% and 94.6% under acidic conditions, respectively. Furthermore, the pH-responsive mechanism of CNF-PEI was revealed by XPS, ¹³C NMR, ¹H NMR, and AFM analyses.

A smart ATP-responsive chemotherapy drug-free delivery system using a DNA nanostructure for synergistic treatment of breast cancer in vitro and in vivo

This study demonstrated a chemotherapy drug-free delivery system for breast cancer treatment based on a simple DNA nanostructure composed of sequence 1 containing ATP and AS1411 aptamers and sequence 2 containing antimiR-21. The DNA nanostructure was used for co-delivery of KLA peptide and antimiR-21 as antiapoptotic agents. These therapeutic agents could not be internalised into eukaryotic cells freely which is one of the great features of this targeting platform. The presented delivery system was ATP-responsive, leading to disassembly of the DNA nanostructure in high ATP concentration of cancer cells and restoration of the function of antimiR-21 in these cells. The DNA nanostructure was associated with high cellular uptake by MCF-7 and 4T1 cells due to expression of nucleolin as target of AS1411 on their plasma membranes, while the developed targeting platform could not be internalised into CHO cells because of lack of the active targeting moiety on their surfaces. Furthermore, the results showed that co-delivery of antimiR-21 and KLA peptide using the DNA nanostructure could efficiently prohibit tumour growth in vitro and in vivo and induce a synergistic anticancer activity. Thus, this work provides a new ATP-responsive nanotargeting delivery system and synergistic chemotherapy drug-free regimen for cancer treatment.

Light-enhanced hypoxia-responsive and azobenzene cleavage-triggered size-shrinkable micelles for synergistic photodynamic therapy and chemotherapy

The micelles self-assembled from POEGMA-b-PCL-Azo-PCL-b-POEGMA present light-enhanced hypoxia-responsive and azobenzene cleavage-triggered size-shrinkable properties for synergistic photodynamic therapy and chemotherapy.

Development and disassembly of single and multiple acid-cleavable block copolymer nanoassemblies for drug delivery

Acid-degradable block copolymer-based nanoassemblies are promising intracellular candidates for tumor-targeting drug delivery as they exhibit the enhanced release of encapsulated drugs through their dissociation.

A bottlebrush-architectured dextran polyprodrug as an acidity-responsive vector for enhanced chemotherapy efficiency

Compared to normal tissues, unique conditions in the tumor microenvironment, such as a lower pH, can induce accurate release of a drug into specific lesions. This strategy provides an efficient approach to overcome the issues of unexpected drug leakage and poor circulation stability, thereby reducing the side effects and enhancing the effect of cancer treatment. In this study, we designed a class of acid activatable supramolecular nano-prodrugs (DOM@DOX) with a bottlebrush architecture based on the dextran (DEX) polysaccharide, which connects with a hydrophilic polyethylene glycol chain by atom transfer radical polymerization and further conjugates with an anticancer drug doxorubicin (DOX) at the backbone of the copolymer via an acidity-responsive hydrazine bond. Furthermore, the DOM@DOX prodrug has a high drug loading up to 48 wt% for DOX, and the prodrug can maintain a stable nano-sized spherical shape in aqueous solution by a self-assembly strategy. In an acidic environment inside tumor cells, the hydrazine bond of the prodrug breaks, leading to the release of DOX from parental micelles. Owing to the small size of the carrier, the prodrug exhibits good intratumoral permeability, good circulation stability and significant tumor suppression efficiency in tumor-bearing mouse models, which is beneficial for the development of new generation nanomedicine for enhanced chemotherapy.

pH-responsive nanomicelles of poly(ethylene glycol)-poly(ε-caprolactone)-poly(L-histidine) for targeted drug delivery

Here, a novel pH-responsive block copolymer, poly (ethylene glycol)-poly(ε-caprolactone)-poly(L-histidine) (PEG-PCL-PHis), was synthesized and designed for anti-cancer drug delivery with excellent biocompatible, biodegradable, and strong drug loading efficiency. ¹H-NMR, IF-IR, and GPC were used to characterize the structure of the PEG-PCL-PHis copolymer. In addition, the morphology, particle size, Zeta potential, and critical micelle concentration (CMC) of different degree of polymerization were determined by transmission electron microscopy (TEM), dynamic light scattering granulometer (DLS), and fluorescence spectrometer, respectively. The strong affinity between the core of micelles and hydrophobic drug was manifested with 15.09% drug loading content and 84.65% entrapment efficiency. In vitro release of DOX from the block copolymer micelle demonstrated, the PEG-PCL-PHis copolymer micelle has stable and durable drug releasing ability accompanied with pH-sensitivity. From the mechanism of cellular uptake the micelles, the pathway of drug release was captured by confocal laser scanning microscope. These experiments demonstrated the safe delivery for anticancer medicine through this novel copolymer. In conclusion, the PEG-PCL-PHis copolymer micelle has great potential to become a safe drug carrier for cancer chemotherapy.

Dimeric Prodrug Self-Delivery Nanoparticles with Enhanced Drug Loading and Bioreduction Responsiveness for Targeted Cancer Therapy

Efficient drug accumulation in tumor cells is essential for cancer therapy. Herein, we developed dimeric prodrug self-delivery nanoparticles (NPs) with enhanced drug loading and bioreduction responsiveness for triple negative breast cancer (TNBC) therapy. Specially designed camptothecin dimeric prodrug (CPTD) containing a disulfide bond was constructed to realize intracellular redox potential controlled drug release. Direct conjugation of hydrophobic CPTD to poly(ethylene glycol) PEG₅₀₀₀, a prodrug-based amphiphilic CPTD-PEG₅₀₀₀ co-polymer was synthesized, which could encapsulate parental CPTD prodrug spontaneously and form ultrastable NPs due to the highly analogous structure. Such dimeric prodrug self-delivery nanoparticles showed ultrahigh stability with critical micelle concentration as low as 0.75 μg/mL and remained intact during endocytosis. In addition, neurotensin (NT), a 13 amino acid ligand, was further modified on the nanoparticles for triple negative breast cancer (TNBC) targeting. Optimized NT-CPTD NPs showed improved pharmacokinetics profile and increased drug accumulation in TNBC lesions than free CPT, which largely reduced the systemic toxicity and presented an improved anticancer efficacy in vivo. In summary, with advantages of extremely high drug loading capacity, tumor microenvironmental redox responsiveness, and targeted TNBC accumulation, NT-CPTD NPs showed their potential for effective triple negative breast cancer therapy.

In vitro evaluation of the antitumor effect of bismuth lipophilic nanoparticles (BisBAL NPs) on breast cancer cells

Aim

The objective of this study was to evaluate the antitumor activity of lipophilic bismuth nanoparticles (BisBAL NPs) on breast cancer cells.

Materials and methods

The effect of varying concentrations of BisBAL NPs was evaluated on human MCF-7 breast cancer cells and on MCF-10A fibrocystic mammary epitheliocytes as noncancer control cells. Cell viability was evaluated with the MTT assay, plasma membrane integrity was analyzed with the calcein AM assay, genotoxicity with the comet assay, and apoptosis with the Annexin V/7-AAD assay.

Results

BisBAL NPs were spherical in shape (average diameter, 28 nm) and agglomerated into dense electronic clusters. BisBAL NP induced a dose-dependent growth inhibition. Most importantly, growth inhibition was higher for MCF-7 cells than for MCF-10A cells. At 1 µM BisBAL NP, MCF-7 growth inhibition was 51%, while it was 11% for MCF-10A; at 25 µM BisBAL NP, the growth inhibition was 81% for MCF-7 and 24% for MCF-10A. With respect to mechanisms of action, a 24-hour exposure of 10 and 100 µM BisBAL NP caused loss of cell membrane integrity and fragmentation of tumor cell DNA. BisBAL NPs at 10 µM were genotoxic to and caused apoptosis of breast cancer cells.

Conclusion

BisBAL NP-induced growth inhibition is dose dependent, and breast cancer cells are more vulnerable than noncancer breast cells. The mechanism of action of BisBAL NPs may include loss of plasma membrane integrity and a genotoxic effect on the genomic DNA of breast cancer cells.