A Co-Encapsulation of Coenzyme Q10 and Curcumin in Liposomes Coated with Chitosan (Q10-Cur-Lip-Chi) with Enhanced Solubility and Stability for Good Release Performance and Antioxidative Activity.

BACKGROUND: Coenzyme Q10 (Q10) is a powerful lipophilic antioxidant with poor solubility in aqueous media. Curcumin (Cur) is a natural polyphenolic phytochemical molecule with poor aqueous solubility. The liposome is an improved administration of drugs because it is biocompatible and permeable for nutraceutical delivery. Chitosan, a hydrophilic polymer, is often used as a polymer coating for its good biocompatible and biodegradable properties, and its relatively low toxicity level. METHODS: Q10 and Cur co-loaded liposomes coated with chitosan (Q10-Cur-Lip-Chi) were constructed. The co-encapsulation of Q10 and Cur in liposomes coated with chitosan was verified by TEM, DLS, DSC, FT-IR, and XRPD. The release profile and antioxidant activity of Q10-Cur-Lip-Chi were accessed. RESULTS: The particle size of Q10-Cur-Lip-Chi was about 1440 nm with narrow particle distribution. A satisfactory encapsulation efficiency (EE) of Q10 was about 98%, and 25% for that of Cur. Q10-Cur- Lip-Chi showed higher solubility and better pH resistance with 98.5% of Q10 and Cur retention at pH 7.0 - 9.0. Q10-Cur-Lip also showed great salt stability with a vesicle size change of less than 5%. PSof Q10-Cur-Lip-Chi changed less than 10% at 4°C of storage. Q10-Cur-Lip-Chi also exhibited a good controlled release profile with its accumulative release of less than 34% for Q10 and 30% for curcumin after 24 h. The Q10-Cur-Lip-Chi performed a synergistic effect on antioxidant activity reaching 41.86±1.84%, which was 5.9 times higher than that of Q10, 2.5 times higher than that of Cur, and 1.7 times higher than that of the mixture. CONCLUSION: The co-encapsulation Q10-Cur-Lip-Chi improves the solubility and stability of Q10 and Cur for good release performance and antioxidative activity.

Fluorescent enzyme-linked immunoassay based on silane-doped carbon dots for sensitive detection of microcystin-LR in water and crucian samples.

In this work, a fluorescent nanoparticles labeling-free fluorescence enzyme-linked immunoassay (FELISA) has been established for the ultrasensitive detection of microcystin-LR (MC-LR) in water and fish samples. Polyclonal antibody against MC-LR was labeled with horseradish peroxidase (HRP) and used as signal probe for binding with analyte in sample or for coating antigen. After washing of the unbound antibody, the substrate system (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS)/H2O2) was added. The oxidation product of ABTS (ox-ABTS) catalyzed by HRP effectively caused the fluorescence quenching of subsequently added silane-doped carbon dots (Si-CDs), and the change in fluorescence intensity of Si-CDs was used to realize the quantitative detection of MC-LR. Under the optimum conditions, the Si-CDs based FELISA method showed a good linear relationship from 0.001 to 3.20 µg L-1 (R2 = 0.994) and provided a low detection limit of 0.6 ng L-1, which was approximately 30-fold lower than that of traditional indirect competitive ELISA. Average recovery values from 79.9% to 109.2% was obtained from spiked water and crucian samples, suggesting its potential application on the monitoring of MR-LR at a trace level.