Enhancing the biological activity of vaterite-containing β-dicalcium silicate cement by silane coupling agent for biomaterials

A review on the applications of Traditional Chinese medicine polysaccharides in drug delivery systems

Traditional Chinese medicine polysaccharides (TCMPs) are plentiful and renewable resources with properties such as biocompatibility, hydrophilicity, biodegradability, and low cytotoxicity. Because the polysaccharide molecular chain contains a variety of active groups, different polysaccharide derivatives can be easily produced through chemical modification. They have been increasingly used in drug delivery systems (DDS). However, the potential of polysaccharides is usually ignored due to their structural complexity, poor stability or ambiguity of mechanisms of actions. This review summarized the applications of TCMPs in DDS around four main aspects. The general characteristics of TCMPs as drug delivery carriers, as well as the relationships between structure and function of them were summarized. Meanwhile, the direction of preparing multifunctional drug delivery materials with synergistic effect by using TCMPs was discussed. This review aims to become a reference for further research of TCMPs and their derivatives, especially applications of them as carriers in pharmaceutical preparation industry.

Immobilisation of Cd(II) on biogenic and abiotic calcium carbonate

Ubiquitous calcium carbonate (biogenic or abiotic) exerted an important impact on the migration and transformation of heavy metal in the environment. Cd(II) pollution, common in China, has attracted much attention due to its critical toxicity. The purpose of this study is to compare the differences in adsorption and desorption characteristics of Cd(II) between biogenic CaCO₃ (BCa) induced by Bacillus subtilis and abiotic CaCO₃ [AR (analytical reagent grade)-CaCO₃ and limestone]. The results show that the adsorption data of BCa and abiotic CaCO₃ for Cd(II) more closely followed the Langmuir model compared to the Freundlich model. The maximum adsorption capacity (obtained from Langmuir isotherm) of BCa for Cd(II) (172.41 mg/g) was significantly greater than that of abiotic CaCO₃ (AR-CaCO₃: 6.31 mg/g, limestone: 21.01 mg/g), and its maximum desorption rate (1.48%) was significantly lower than that of abiotic CaCO₃ (AR-CaCO₃: 74.30%, limestone: 5.65%). Furthermore, the adsorption process of BCa is a spontaneous endothermic reaction and obeys pseudo-second-order kinetics. The obvious advantages of BCa are that it is easily obtained by bacterial culture, and another is its stronger immobilisation of Cd(II) compared to abiotic CaCO₃, giving a promising potential for heavy metal remediation.