ABSTRACT
Molecularly imprinted polymers (MIPs) have garnered the interest of researchers in the drug delivery due to their advantages, such as exceptional durability, stability, and selectivity. In this study, a biocompatible MIP drug adsorption and delivery system with high loading capacity and controlled release, was prepared based on chitosan (CS) and graphene quantum dots (GQDs) as the matrix, and the anticancer drug oxaliplatin (OXAL) as the template. Additionally, samples without the drug (non-imprinted polymers, NIPs) were created for comparison. GQDs were produced using the hydrothermal method, and samples underwent characterization through FTIR, XRD, FESEM, and TGA. Various experiments were conducted to determine the optimal pH for drug adsorption, along with kinetic and isotherm studies, selectivity assessments, in vitro drug release and kinetic evaluations. The highest drug binding capacity was observed at pH 6.5. The results indicated the Lagergren-first-order kinetic model (with rate constant of 0.038 min-1) and the Langmuir isotherm (with maximum adsorption capacity of 17.15 mg g-1) exhibited better alignment with the experimental data. The developed MIPs displayed significant selectivity towards OXAL, by an imprinting factor of 2.88, in comparison to two similar drugs (cisplatin and carboplatin). Furthermore, the analysis of the drug release profile showed a burst release for CS-Drug (87% within 3 h) at pH 7.4, where the release from the CS-GQD-Drug did not occur at pH 7.4 and 10; instead, the release was observed at pH 1.2 in a controlled manner (100% within 28 h). Consequently, this specific OXAL adsorption and delivery system holds promise for cancer treatment.
ABSTRACT
AIM: This study was conducted to utilise the effective self-healing system to regain the mechanical properties of the cementitious materials containing micro-cracks. METHODS: Storing epoxy and calcium nitrate as healing agents was performed by microencapsulation in the urea-formaldehyde shell. The microcapsules were characterised by Fourier transform infrared, thermogravimetric analysis, differential scanning calorimetric, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Cementitious samples were prepared by mortar mixing with various amounts of microcapsules (0, 1, 3 and 6% w/w). The healing potential of microcapsules was analysed based on the recovery rate of the mechanical properties. RESULTS: The obtained microcapsules have an outer rough surface, suitable diameter (1-100 µm) and shell thickness (0.2-0.6 µm), and remarkable thermal stability (up to 260 °C). Mechanical test results exhibit that created micro-cracks were healed completely and regained the recovery rates over 100%. CONCLUSION: The prepared microcapsules besides enhancing thermal stability, demonstrate a high performance in microcracks sealing to improve durability of cementitious materials.
Subject(s)
Calcium Compounds/chemistry , Capsules/chemistry , Epoxy Compounds/chemistry , Nitrates/chemistry , Calorimetry, Differential Scanning , Materials Testing , Microscopy, Electron, Scanning , Spectrum Analysis/methodsABSTRACT
Final purpose of tissue engineering is to regenerate or repair damaged tissues or organs. Desired repair efficacy necessitates proper physicochemical performances of scaffolds, among which adequate mechanical properties are crucial. Therefore, reinforcing tissue engineering scaffolds has been a hot research trend in recent years. In this regard, the use of some biomaterials as reinforcing materials is a longstanding area of interest. This article introduces the most popular reinforcing materials and focuses on recent advances in the use of these materials for reinforcing mechanical properties of tissue engineering scaffolds. A classification based on materials nature, for example, bioceramics, clays, carbon-based materials, and metal oxides, is provided, followed by their effects on scaffolds properties. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1560-1575, 2019.
