Anticancer Effect of Alginate-Chitosan Hydrogel Loaded with Curcumin and Chrysin on Lung and Breast Cancer Cell Lines

Objective: We conducted the present study to investigate the anticancer effects of curcumin and chrysin loaded in the alginate-chitosan hydrogel on breast cancer (T47D) and lung cancer (A549). Background: Cancer, which is defined as abnormal cell growth, is one of the biggest public health problems in the world. Natural compounds, such as polyphenols, are used as chemo-preventive and chemotherapeutic agents in different types of cancer owing to their antioxidant, antineoplastic, and cytotoxic properties. To improve their bioavailability and releasing behavior, hydrogel systems with high drug loading and stability and hydrophilic nature have been designed. Methods: The curcumin-chrysin-loaded alginate-chitosan hydrogels were prepared through the ionic gelation mechanism utilizing CaCl2. The prepared hydrogels were studied by using the Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The MTT and DAPI staining assays were employed for cytotoxicity and apoptosis studies of curcumin-chrysin-loaded alginate-chitosan hydrogels. The effects of the curcumin-chrysin-loaded alginate-chitosan hydrogels on the cell cycle of cell lines T47D and A549 were also evaluated using the propidium iodide staining. Results: The FTIR indicated specific bands at 1607 and 1422 cm-1 (the carbonyl of alginate) at 834 cm-1 (sodium alginate), 1447 cm-1, and 1026 cm-1 (COOH and C-O stretching bands alginate and chitosan). The curcumin-chrysin-loaded alginate-chitosan hydrogels could significantly (p<0.05) reduce the viability and induce apoptosis, Morover, cause G2/M arrest of the cell cycle in both A549 and T47D cell lines. Conclusion: The alginate-chitosan hydrogels could work best as an enhanced anticancer drug delivery system.

Dynamic Gelation of Conductive Polymer Nanocomposites Consisting of Poly(3-hexylthiophene) and ZnO Nanowires

The sol–gel transition of conductive nanocomposites consisting of poly(3-hexylthiophene) (P3HT) and ZnO nanowires in o-dichlorobenzene (o-DCB) has been investigated rheologically. The physical gelation of P3HT in o-DCB spontaneously occurs upon adding the small amount of ZnO nanowires. The rheological properties of the P3HT/ZnO nanocomposite gels have been systematically studied by varying factors such as polymer concentration, nanowire loading, and temperature. The nanocomposite gel exhibits shear-thinning in the low shear rate range and shear-thickening in the high shear rate range. The elastic storage modulus of the nanocomposite gel gradually increases with gelation time and is consistently independent of frequency at all investigated ranges. The isothermal gelation kinetics has been analyzed by monitoring the storage modulus with gelation time, and the data are well fitted with a first-order rate law. The structural analysis data reveal that the polymer forms the crystalline layer coated on ZnO nanowires. A fringed micelle model is proposed to explain the possible gelation mechanism.

Thermo-Responsive Hydrogels: From Recent Progress to Biomedical Applications

Thermogels are also known as thermo-sensitive or thermo-responsive hydrogels and can undergo a sol–gel transition as the temperature increases. This thermogelling behavior is the result of combined action from multiscale thermo-responsive mechanisms. From micro to macro, these mechanisms can be attributed to LCST behavior, micellization, and micelle aggregation of thermogelling polymers. Due to its facile phase conversion properties, thermogels are injectable yet can form an in situ gel in the human body. Thermogels act as a useful platform biomaterial that operates at physiological body temperatures. The purpose of this review is to summarize the recent progress in thermogel research, including investigations on the thermogel gelation mechanism and its applications in drug delivery, 3D cell culture, and tissue engineering. The review also discusses emerging directions in the study of thermogels.

Influence of Glycerophosphate Salt Solubility on the Gelation Mechanism of Colloidal Chitosan Systems

Recently, thermosensitive chitosan systems have attracted the interest of many researchers due to their growing application potential. Nevertheless, the mechanism of the sol-gel phase transition is still being discussed, and the glycerophosphate salt role is ambiguous. The aim of the work is to analyze the possibility of the exclusive use of a non-sodium glycerophosphate salt and to determine its impact on the gelation conditions determined by rheological and turbidimetric measurements as well as the stability of the systems by measuring changes in the Zeta potential value. It was found that ensuring the same proportions of glycerophosphate ions differing in cation to amino groups present in chitosan chains, leads to obtaining systems significantly different in viscoelastic properties and phase transition conditions. It was clearly shown that the systems with the calcium glycerophosphate, the insoluble form of which may constitute additional aggregation nuclei, undergo the gelation the fastest. The use of magnesium glycerophosphate salt delays the gelation due to the heat-induced dissolution of the salt. Thus, it was unequivocally demonstrated that the formulation of the gelation mechanism of thermosensitive chitosan systems based solely on the concentration of glycerophosphate without discussing its type is incorrect.