In this work, a pH-responsively controlled-release chlorpyrifos (PRCRC) was developed using a nanosystem consisting of chlorpyrifos (CPF), polydopamine (PDA), attapulgite (ATP), and calcium alginate (CA). Therein, CPF was adsorbed in the nanonetwork-structured PDA-modified ATP (PA) to obtain CPF-PA through hydrogen bonds and electrostatic attraction. Subsequently, CPF-PA combined with CA to form porous CPF-PA-CA hydrogel spheres (actually PRCRC) through cross-linking reaction, wherein PA acted as the skeleton. PRCRC spheres tended to collapse in alkaline solution and promoted the release of CPF, thus displayed a good pH-responsively controlled release performance, which was proved by the control efficacy test on grubs. Besides, the system could effectively protect CPF molecules from degradation under ultraviolet light. Importantly, the PA-CA hydrogel possessed a benign biocompatibility on Escherichia coli and foxtail millet, showing a high biosafety. Therefore, this work provides a promising approach to improve the utilization efficiency and prolong duration of pesticide, which might have a huge potential application prospect.

Brain ischemic stroke is one of the most common causes of death and disability, currently has no efficient therapeutic strategy in clinic. Due to irreversible functional neurons loss and neural tissue injury, stem cell transplantation may be the most promising treatment approach. Neural stem cells (NSCs) as the special type of stem cells only exist in the nervous system, can differentiate into neurons, astrocytes, and oligodendrocytes, and have the abilities to compensate insufficient endogenous nerve cells and improve the inflammatory microenvironment of cell survival. In this review, we focused on the important role of NSCs therapy for brain ischemic stroke, mainly introduced the methods of optimizing the therapeutic efficacy of NSC transplantation, such as transfection and overexpression of specific genes, pretreatment of NSCs with inflammatory factors, and co-transplantation with cytokines. Next, we discussed the potential problems of NSC transplantation which seriously limited their rapid clinical transformation and application. Finally, we expected a new research topic in the field of stem cell research. Based on the bystander effect, exosomes derived from NSCs can overcome many of the risks and difficulties associated with cell therapy. Thus, as natural seed resource of nervous system, NSCs-based cell-free treatment is a newly therapy strategy, will play more important role in treating ischemic stroke in the future.

Incorporation of T and T contrast material in one nanosystem performing their respective MR contrast role and simultaneously serving as an efficient drug delivery system (DDS) has a significant potential application for clinical diagnosis and chemotherapy of cancer. However, inappropriate incorporation always encountered many issues, such as low contact area of T contrast material with water-proton, inappropriate distance between T contrast material and water molecule, and undesirable disturbance of T contrast material for T imaging. Those issues seriously limited the T or T contrast effect. In this work, we developed a yolk-like FeO@GdO nanoplatform functionalized by polyethylene glycol and folic acid (FA), which could efficiently exert their tumor targeted T-T dual-mode MR imaging and drug delivery role. First, this nanoplatform possessed a high longitudinal relaxation rate (r) (7.91 mM s) and a stronger transverse relaxation rate (r) (386.5 mM s) than that of original FeO (268.1 mM s). Second, cisplatin could be efficiently loaded into this nanoplatform (112 mg/g) and showed pH-responsive release behavior. Third, this nanoplatform could be effectively internalized by HeLa cells with time and dosage dependence. Fourth, the FA receptor-mediated nanoplatform displayed excellent T-T dual mode MR contrast enhancement and anticancer activity both in vitro and in vivo. Fifth, no apparent toxicity for vital organs was observed with systemic delivery of the nanoplatform in vivo. Thus, this nanoplatform could be a potential nanotheranostic for tumor targeted T-T dual-mode MR imaging and chemotherapy.