Uniform and porous chitosan-based microparticles with injectable and shape-memory properties are particularly attractive due to their promising application potential for tissue engineering and regenerative medicine. However, simple and efficient methods for producing this kind of microparticle are still desirable. In this study, we report that uniform, injectable, and shape-memory chitosan microsponges were efficiently prepared by combining microfluidic emulsion with further freezing and in situ thawing processes without using any potentially cytotoxic chemical cross-linker. The produced chitosan microsponges have controllable size and could be easily injected with syringe needles. Structural observations confirmed that the chitosan microsponge had an interconnected porous structure with pore size of several micrometers and could withstand a large compressive strain of ∼93% and then recover ∼96% of its initial diameter without structural damage. The chitosan microsponges showed a high porosity (∼84%) and swelling ratio (∼3800%) as well as good antibacterial activity. Additionally, an in vitro cell coculturing investigation revealed that they also had good biocompatibility and exhibited great superiority to support cell adhesion and proliferation in three dimensions. The kind of chitosan microsponge presented here has great potential to serve as cell carriers for biomedical applications, especially as injectable scaffolds for regeneration and reconstruction of tissue defects.

Rice can accumulate more organic and inorganic arsenic (iAs) than other crop plants. In this study, the localization of As in rice grains was investigated using High Performance Liquid Chromatography-Inductively Coupled Plasma Mass Spectrometry (HPLC-ICP-MS) based on 26 rice varieties collected from two provinces. In all the samples, the total As contents in polished rice were 0.03–0.37 mg/kg, with average values of 0.28 and 0.21 mg/kg for two sample sets. The results of the determination of arsenic speciation in different components of rice grain showed that in the polished and brown rice the mean value of arsenite (As(III)) was nearly twice than that of arsenate (As(V)). The regional difference was observed in both total As contents and As speciation. The reason may be that As(III) is more mobile than As(V) in a dissociated form and because of soil properties, rice varieties, and the growing environment. The proportion of iAs and the total As in rice bran was higher than that in polished rice, and this is because As tends accumulate between the husk and the endosperm. In our study, selenium could alleviate the risk of arsenic toxicity at the primary stage of rice growth. Co-exposure to As and Se in germinated rice indicated that the reduction in As accumulation in polished rice reached 73.8%, 76.8%, and 78.3% for total As, As(III), and As(V) when compared with rice treated with As alone. The addition of Se (0.3 mg/kg) along with As significantly reduced the As amount in different parts of germinated rice. Our results indicated that Se biofortification could alleviate the As accumulation and toxicity in rice crops.