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Bacterial-derived lipopolysaccharides (LPS) can cause defective intestinal barrier function and play an important role in the development of inflammatory bowel disease. In this study, a nanocarrier based on chitosan and fucoidan was developed for oral delivery of berberine (Ber). A sulfonated fucoidan, fucoidan-taurine (FD-Tau) conjugate, was synthesized and characterized by Fourier transform infrared (FTIR) spectroscopy. The FD-Tau conjugate was self-assembled with berberine and chitosan (CS) to form Ber-loaded CS/FD-Tau complex nanoparticles with high drug loading efficiency. Berberine release from the nanoparticles had fast release in simulated intestinal fluid (SIF, pH 7.4), while the release was slow in simulated gastric fluid (SGF, pH 2.0). The effect of the berberine-loaded nanoparticles in protecting intestinal tight-junction barrier function against nitric oxide and inflammatory cytokines released from LPS-stimulated macrophage was evaluated by determining the transepithelial electrical resistance (TEER) and paracellular permeability of a model macromolecule fluorescein isothiocyanate-dextran (FITC-dextran) in a Caco-2 cells/RAW264.7 cells co-culture system. Inhibition of redistribution of tight junction ZO-1 protein by the nanoparticles was visualized using confocal laser scanning microscopy (CLSM). The results suggest that the nanoparticles may be useful for local delivery of berberine to ameliorate LPS-induced intestinal epithelia tight junction disruption, and that the released berberine can restore barrier function in inflammatory and injured intestinal epithelial.

In this study, fed-batch fermentation of Haloferax mediterranei using glucose and yeast extract as carbon and nitrogen source, respectively, was carried out to produce poly(hydroxyalkanoate) (PHA). After fermentation for 117 h, the concentration of H. mediterranei and PHA content reached 85.8 g/l and 48.6%, respectively. 1H- and 13C-NMR spectra proved that the produced PHA was poly(3-hydroxybutyrate-co-3-hydroxyvalerate) P(3HB-co-3HV) co-polymer. However, further fractionation using chloroform/acetone revealed that the produced PHA consisted of at least two compositionally different co-polymers (P1 and P2). One P(3HB-co-3HV) co-polymer (P1, 93.4 wt%) contains 10.7 mol% of 3-HV unit in the chain structure and has a high molecular weight of 569.5 kg/mol. The other one (P2, 6.6 wt%) has a slightly higher 3-HV content, ca. 12.3 mol%, but its molecular weight is relatively low, 78.2 kg/mol. Both fractions exhibit two overlapped melting peaks measured by differential scanning calorimetry when the heating rate is at and below 20 degrees C/min. For example, at a heating rate of 10 degrees C/min, the two melting peaks occur at 134.8 degrees C and 144.3 degrees C for P1, and 131.1 degrees C and 140.6 degrees C for P2. Through observing the variation of relative intensity of these two melting peaks by changing the heating rate, it was proven that the phenomenon is caused by a melt/recrystallization process. Glass-transition temperature, crystallization temperature and thermal degradation behavior of these co-polymers were also discussed.

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