pH-responsive self-assembled nanoparticles for tumor-targeted drug delivery

Recent advances in the field of drug delivery have opened new avenues for the development of novel nanodrug delivery systems (NDDS) in cancer therapy. Self-assembled nanoparticles (SANPs) based on tumour microenvironment have great advantages in improving antitumor effect, and pH-responsive SANPs prepared by the combination of pH-responsive nanomaterials and self-assembly technology can effectively improve the efficacy and reduce the systemic toxicity of antitumor drugs. In this review, we describe the characteristics of self-assembly and its driving force, the mechanism of pH-responsive NDDS, and the nanomaterials for pH-responsive SANPs type. A series of pH-responsive SANPs for tumour-targeted drug delivery are discussed, with an emphasis on the relation between structural features and theranostic performance.

A Pyr-loaded polymer microparticle for effectively controlling Solenopsis invicta (Hymenoptera: Formicidae) in the nest

Human interference and incorrect use of pesticides are easy to induce red imported fire ant (RIFA) escape and migrate from a nest, resulting in ineffective control of RIFA. In order to avoid RIFA alert, we designed an amphiphilic PSI-mPEG-Boc-DAH loaded Pyr to make the microparticles with effective controlled release. The investigation showed that the quantity of Pyr released by Pyr@PSI-mPEG-Boc-DAH under acidic environment was only 36.40 ± 1.90% at 48 h, whereas the release rate of original Pyr was 75.23 ± 5.71%. And the RIFA mortality rate of 1 ppm Pyr in Pyr@PSI-mPEG-Boc-DAH microparticles at 48 h was only 7.78%, which was significantly lower than that of the Pyr (47.78%). Futhermore, the death rate increased sharply after 48 h, and reached 95.84% within a week after using Pyr@PSI-mPEG-Boc-DAH microparticles. Moreover, PSI-mPEG-Boc-DAH carriers could be absorbed and even transported to crop of the RIFA for subsequent trophallaxis by using fluorescence tracking. In the field experiment, the reduction rate of Pyr@PSI-mPEG-Boc-DAH treatment was achieved 99.89% after 7 d. Pyr@PSI-mPEG-Boc-DAH didn't cause RIFA to be alarmed within 48 h and could kill nearly all of ants in the nest after 7 d, which showed a very good control effect in the field experiment. This work provided a new idea and guidance for the effective control RIFA and the development of sustainable agriculture.

Development and characterization of chitosan nanoparticles containing an indanonic tricyclic spiroisoxazoline derivative using ion-gelation method: an in vitro study

Biodegradable nanoparticulate carriers are potentially applicable compounds in the administration of therapeutic agents and drug delivery. They have received much attention due to their biological characteristics such as biodegradability, biocompatibility, and bioadhesive. The objectives of this work are first, investigating the impact of two important parameters (i.e. chitosan or sodium tripolyphosphate (TPP) solution concentration and chitosan to TPP mass ratio) on the chitosan nanoparticles (CNPs) formation by ionic-gelation method and then, the synthesis and characterization of chitosan-based, biodegradable drug-loaded nanoparticles in the encapsulation of novel 4'-(4-(methylsulfonyl)phenyl)-3'-(3,4,5-trimethoxyphenyl)-4'H-spiro[indene-2,5'-isoxazol]-1(3H)-one (MTS) indanonic tricyclic spiroisoxazoline, which is a potent anticancer drug. The particle size, shape, zeta potential, drug loading capacity, in vitro release characteristics, and stability of the formulated drug-loaded nanoparticles of the different drug:carrier ratio has been studied. The results indicated that the particle size increased at the higher chitosan or TPP concentration while the mass ratio did not appear to be a significant parameter during the cross-linking process. The particle diameter and zeta potential of CNPs including MTS were approximately in the range of 256-350 nm and 24.08-38.70 mV, respectively. The entrapment efficiency steadily increased with increasing the concentration of the polymer in formulizations. Throughout 24 h, the in vitro release behavior was provided a sustained release from all the drug-loaded formulizations. The optimal formulization of CNPs based on drug content with a drug:carrier ratio of 1:2 did not change appreciably during 60-day storage at either 4 °C or the ambient temperature.

Redox-Responsive Disulfide Bond-Bridged mPEG-PBLA Prodrug Micelles for Enhanced Paclitaxel Biosafety and Antitumor Efficacy

The toxicity and side effects of traditional chemotherapeutic drugs are the main causes of chemotherapy failure. To improve the specificity and selectivity of chemotherapeutic drugs for tumor cells, a novel redox-sensitive polymer prodrug, polyethylene glycol-poly (β-benzyl-L-aspartate) (PEG-PBLA)-SS-paclitaxel (PPSP), was designed and synthesized in this study. The PPSP micelle was manufactured via high-speed dispersion stirring and dialysis. The particle size and zeta potential of this prodrug micelle were 63.77 ± 0.91 nm and −25.8 ± 3.24 mV, respectively. The micelles were uniformly distributed and presented a spherical morphology under a transmission electron microscope. In the tumor physiological environment, the particle size of the PPSP micelles and the release rate of paclitaxel (PTX) were significantly increased compared with those of mPEG-PBLA-CC-PTX (PPCP) micelles, reflecting the excellent redox-sensitive activity of the PPSP micelles. The inhibitory effect of PPSP on HepG2, MCF-7 and HL-7702 cell proliferation was investigated with MTT assays, and the results demonstrated that PPSP is superior to PTX with respect to the inhibition of two tumor cell types at different experimental concentration. Simultaneously PPSP has lower toxicity against HL-7702 cells then PTX and PPCP. Moreover, the blank micelle from mPEG-PBLA showed no obvious toxicity to the two tumor cells at different experimental concentrations. In summary, the redox-sensitive PPSP micelle significantly improved the biosafety and the anti-tumor activity of PTX.

Real-time monitoring of a controlled drug delivery system in vivo: construction of a near infrared fluorescence monomer conjugated with pH-responsive polymeric micelles

A self-assembled polymeric micelle from multifunctional amphiphilic copolymer with NIR and pH-sensitive groups can be used to monitor the dynamic process of its arriving at the tumor site in real time.