•We proposed a new strategy based on electrospray technique to prepare dual-responsive nanogels of pH and redox sensitive.•A biodegradable and multi-responsive poly(ether urethane) (PEU) was synthesized via a facile one-pot method and used as the electrospray material.•The electrospray dual-responsive nanogels may have potential to be a tumor-sensitive drug delivery system.•It demonstrated that the materials which can form hydrogels in physiological condition may be used to prepare nanogels by electrospray method.•It implies that the application range of these materials may be expanded with the more simple and efficient electrospray method for preparing nanogels.In this work, we proposed a new strategy based on electrospray technique to prepare nanogels. Compared with other methods of preparing nanogels, electrospray technique is more simple and efficient. A biodegradable and multi-responsive poly(ether urethane) (PEU) was synthesized via a facile one-pot method and used as the electrospray material. By using electrospray technique, pH- and redox-responsive poly(ether urethane) nanogels were prepared. The morphologies of the electrospray nanoparticles before and after swelling were demonstrated to be spherical and uniform, as characterized by scanning electron microscope (SEM) and transmission electron microscopy (TEM). Dynamic light scattering (DLS) results showed that the mean hydrodynamic diameter of nanogels was about 500 nm. The pH- and redox-sensitive behaviors of nanogels were studied with DLS and TEM. In acidic media the nanogels dissociated, while in the presence of GSH the nanogels degraded. The nanogels suspension was stored at 4 °C and was stable without aggregation for at least 30 days. Doxorubicin (DOX) can be further loaded into the poly(ether urethane) nanogels. The electrospray nanogels can change the release rate of loaded drug in response to pH and GSH stimuli.

•A method to design pH-sensitive chitosan-based polyelectrolyte nanogels is reported.•The charge-reversible property of polyanion relies on its hydrolysis in acidic media.•The formation of nanogels depends on MW of polyelectrolytes and titration order.•Nanogels disintegrate rapidly in an hour at pH 5.0 but are stable at pH 7.4.•The disintegration behavior of nanogels is consistent with polyanion's hydrolysis.A novel approach to design pH-sensitive and disintegrable polyelectrolyte nanogels composed of citraconic-based N-(carboxyacyl) chitosan (polyanion) and quaternary chitosan (polycation) was reported. Firstly, the hydrolysis of citraconic-modified chitosan was monitored using fluorescamine assay and it could selectively dissociate in acidic media (e.g., pH ∼5.0) due to the isomerization during the addition of citraconic anhydride to chitosan. Secondly, the self-assembly behaviors of different polyelectrolyte pairs between citraconic-based chitosan and quaternary chitosan were investigated via colloidal titration assay. It was indicated that the difference in molecular weight (MW) of opposite charged polyelectrolytes played an important role on the formation of polyelectrolyte nanogels. Results showed that polyelectrolyte nanogels (ca. 300 nm in size) only formed when polyanion and polycation had a very large difference in MW. The pH-sensitive behavior of polyelectrolyte nanogels was comprehensively investigated by dynamic light scattering (DLS) and transmission electron microscope (TEM). The incorporation of charge-conversional citraconic-based chitosan into polyelectrolyte complexes has provided an effective approach to prepare polyelectrolyte nanogels which were very stable at neutral pH but disintegrated quickly in acidic media.

•Core–shell nanoparticles were fabricated by coaxial tri-capillary electrospray-template removal method.•The electrosprayed microparticles presented core–shell–corona structure.•The nanoparticles were downsized to 106 nm by adjusting flow rate of corona fluid.•The nanoparticles displayed excellent dispersion stability and low cytotoxicity.•Paclitaxel loading content in the nanoparticles was achieved as high as 50 wt%.This study proposed a new strategy based on a coaxial tri-capillary electrospray-template removal process for producing nanosized polylactide-b-polyethylene glycol (PLA-PEG) particles with a core–shell structure. Microparticles with core–shell–corona structures were first fabricated by coaxial tri-capillary electrospray, and core–shell nanoparticles less than 200 nm in size were subsequently obtained by removing the PEG template from the core–shell–corona microparticles. The nanoparticle size could be modulated by adjusting the flow rate of corona fluid, and nanoparticles with an average diameter of 106 ± 5 nm were obtained. The nanoparticles displayed excellent dispersion stability in aqueous media and very low cytotoxicity. Paclitaxel was used as a model drug to be incorporated into the core section of the nanoparticles. A drug loading content in the nanoparticles as high as 50.7 ± 1.5 wt% with an encapsulation efficiency of greater than 70% could be achieved by simply increasing the feed rate of the drug solution. Paclitaxel exhibited sustained release from the nanoparticles for more than 40 days. The location of the paclitaxel in the nanoparticles, i.e., in the core or shell layer, did not have a significant effect on its release.