Many marine bacteria secrete exopolysaccharides (EPSs), which are made up of a substantial component of the macro-molecules surrounding cells. Recently, the wide demand for EPSs for food, cosmetics, pharmaceutical and other applications has led to great interest in them. In this study, an EPS produced by marine bacteria Aerococcus uriaeequi HZ strains (EPS-A) was isolated and purified to examine its structure and biological function. The molecular weight of EPS-A analyzed by high-performance liquid gel filtration chromatography (HPGFC) is found to have a number average of 2.22 × 10⁵ and weight average of 2.84 × 10⁵, respectively. High-performance liquid chromatography (HPLC) and Fourier-transform–infrared (FT–IR) analysis indicate that EPS-A was a polysaccharide composed of glucose and a little mannose. In addition, the flocculating rate of sewage of EPS-A was 79.90%. The hygroscopicity studies showed that hygroscopicity of EPS-A was higher than chitosan but lower than that of sodium hyaluronate. The moisture retention of EPS-A showed similar retention activity to both chitosan and sodium hyaluronate. EPS-A also can scavenge free radicals including both OH• free radical and O₂•⁻ free radical and the activity to O₂•⁻ free radical is similar to vitamin C. Safety assessment on mice indicated that the EPS-A is safe for external use and oral administration. EPS-A has great potential for applications in medicine due to its characteristics mentioned above.

Epothilones constitute a new class of microtubule-stabilizing anti-cancer agents with promising preclinical and clinical activity. However, its systemic application still causes some toxic side effects. To reduce these undesired effects, advanced drug delivery systems based on cell targeting carriers are needed currently. In this study, the high quality bacterial ghosts of the probiotic Escherichia coli Nissle 1917 (EcN) were prepared in a large scale and retained fully intact surface structures for specific attachment to mammalian cells. The EcN ghosts could be efficiently loaded with the low hydrophilic drug Epothilone B (Epo B) and the maximal load efficiency was approximately 2.5% (w/w). Cytotoxicity assays revealed that Epo B-ghosts exhibited enhanced anti-proliferative properties on the HeLa cells. The Epo B associated with EcN ghosts was more cytotoxic at least 10 times than the free Epo B at the same concentrations. Apoptosis assays showed that both Epo B-ghosts and free Epo B induced time course-dependent apoptosis and necrosis in HeLa cells, respectively. While the former induced more apoptosis and necrosis than the latter. Furthermore, the cytochrome C release and the activation of caspase-3 were more remarkable after treatment with the Epo B-ghosts compared to the free Epo B, which implied that Epo B-ghosts might more effectively induce the apoptosis mediated by mitochondrial pathway in HeLa cells. Therefore, the higher anti-proliferative effects of the Epo B-ghosts on the HeLa cells were mediated by mitochondrial pathway of apoptosis. The EcN ghosts may provide a useful drug delivery carrier for drug candidates in cancer therapy.

This paper proposes a modified car-following model for the heterogeneous traffic flow with connected autonomous vehicles (CAVs) and human-driven vehicles (HDVs), which considers different car-following modes and heterogeneous reaction time delays of vehicles. The proposed model uses the vehicle’s own state and the front vehicle’s acceleration to adjust the vehicle’s motion. Based on the modified model and the control theory, the string stability condition of the heterogeneous traffic flow is given. Then, a robust control scheme is designed for the heterogeneous traffic system with different car-following modes and multiple delays, and its stabilizing effect is analyzed by linear matrix inequalities (LMIs). Next, considering the external disturbance in the actual driving environment, this paper performs robust $H_{\infty}$ control synthesis for the heterogeneous traffic flow with the proposed controller. Finally, the theoretical results are verified by simulation experiments. Numerical results show that introducing the adjustment term with a certain parameter range and increasing the CAV penetration rate can strengthen the stability of the heterogeneous traffic flow, while increasing reaction time delays reduces the stability of the heterogeneous traffic. In addition, compared with the existing control method, the proposed control scheme can make vehicles in the platoon run more smoothly under disturbance, thus improving the performance of the traffic system. Furthermore, the impact of the proposed car-following model and $H_{\infty}$ controller on the macroscopic performance of the heterogeneous traffic system is also discussed.