Charge‐Functionalized and Structurally Enhanced (Cryo)Hybrids from Acrylic (Co)Monomers and Kaolin: Altering Physicochemical Properties via Cryotropic Gelation

The potential to improve mechanical, structural, and mechanochemical properties of charge‐functionalized poly(N,N‐dimethylaminoethyl methacrylate) (PDMAEMA)‐based hybrid cryogels is investigated. The simple and versatile synthesis of hybrid cryogels with high strength and toughness using cationic DMAEMA and ionic comonomer 2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid has been proposed via in situ free‐radical crosslinking (cryo)polymerization by which the properties of virgin polymer can be modulated to required applications by incorporation of inorganic filler kaolin (KLN). Two factors affecting swelling and elasticity of hybrid gels (referred as PDA/KLNm), KLN content and gel preparation temperature, are studied. The optimum KLN concentration for desired swelling and modulus of elasticity is determined as 0.80% (w/v). Effective crosslinking density of hybrid hydrogels increases with KLN addition and this dependence is expressed by a quadratic polynomial as a function of KLN concentration. The results show that obtained hybrid gels with multiresponsive properties could be regarded as “smart materials” in sensing and actuation applications. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1758–1778     

One‐pot synthesis of composite microspheres with core‐shell structure

One‐pot synthesis of thermoresponsive magnetic composite microspheres with a poly(N‐isopropylacrylamide) (PNIPAM) shell and a Fe₃O₄ core is demonstrated. Temperature sensitivity of PNIPAM was adopted to design the novel synthesis pathway. The as‐prepared composite microspheres have an obvious core‐shell structure with a mean size of approximately 250 nm. The Fe₃O₄ core is approximately 5 nm and the thickness of the PNIPAM shell is approximately 10 nm. The content of Fe₃O₄ in the composite microspheres can be controlled by this method. The composite microspheres experience a swelling and shrinking process in water by adjusting the temperature below and above the lower critical solution temperature (LCST) around 32 °C. These microspheres also show fine response to an external magnetic field. This work presents a platform to synthesize organic/inorganic composite microspheres in a facile and efficient approach. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2702–2708     

Optical Devices Constructed from Multiresponsive Microgels

Novel multiresponsive microgels based on poly(N‐isopropylacrylamide) were synthesized to contain triphenylmethane leucohydroxide, and used to construct etalons. The optical properties of the resultant etalons were investigated, and their response to ultraviolet and visible irradiation, solution pH changes, and the presence of a mimic of the nerve agent Tabun characterized. We clearly show that the optical properties of the device depended dramatically on these stimuli. This investigation illustrates the versatility of the microgel‐based etalon structure, and showcases the clear utility of such devices for remote actuation, color tunable optics, sensing, and potential remotely triggered drug delivery applications.     

Intracellular Breakable and Ultrasound‐Responsive Hybrid Microsized Containers for Selective Drug Release into Cancerous Cells

This work reports an efficient and straightforward strategy to fabricate hybrid microsized containers with reduction‐sensitive and ultrasound‐responsive properties. The ultrasound and reductive sensitivity are visualized using scanning electron microscopy, with the results showing structural decomposition upon ultrasound irradiation and in the presence of reducing agent. The ultrasound‐responsive functionalities of hybrid carriers can be used as external trigger for rapid controlled release, while prolonged drug release can be achieved in the presence of reducing agent. To evaluate the potential for targeted drug delivery, hybrid microsized containers are loaded with the anticancer drug doxorubicin (Dox). Such hybrid capsules can undergo structural intracellular degradation after cellular uptake by human cervical cancer cell line (HeLa), resulting in Dox release into cancer cells. In contrast, there is no Dox release when hybrid capsules are incubated with human mesenchymal stem cells (MSCs) as an example of normal human cells. The cell viability results indicate that Dox‐loaded capsules effectively killed HeLa cells, while they have lower cytotoxicity against MSCs as an example of healthy cells. Thus, the newly developed intracellular‐ and ultrasound‐responsive microcarriers obtained via sol‐gel method and layer‐by‐layer technique provide a high therapeutic efficacy for cancer, while minimizing adverse side effect.