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Foster Leach posted an update 6 months, 3 weeks ago
Biomaterials play a crucial role in tissue engineering as a functional replacement, regenerative medicines, supportive scaffold for guided tissue growth, and drug delivery devices. The term biomaterial refers to metals, ceramics, and polymers account for the vast majority. In the case of polymers, hydrogels have emerged as active materials for an immense variety of applications. Epoxy-based hydrogels possess a unique network structure that enables very high levels of hydrophilicity and biocompatibility. Hydrogel such as Medipacs Epoxy Polymers (MEPs) models were constructed to understand water’s behavior at the water/hydrogel interface and hydrogel network. We computed the Gibbs dividing surface (GDS) to define the MEP/water interface, and all the physicochemical properties were computed based on GDS. We calculated the radial distribution function (RDF), the 2D surface roughness of the immersed MEPs. RDF analysis confirmed that the first hydration shell is at a distance of 1.86 Å, and most of the water molecules are near the hydroxyl group of the MEPs network. Hydrogen bonds (H-bonds) analysis was performed, and the observation suggested that the disruption of the H-bonds between MEP chains leads to an increase in the polymer matrix’s void spaces. These void spaces are filled with diffused water molecules, leading to swelling of the MEP hydrogel. PD184352 swelling parameter was estimated from the fitted curve of the yz-lattice of the simulation cell. The MEP/water interface simulation results provide insightful information regarding the design strategy of epoxy-based hydrogel and other hydrogels vital for biomedical applications.Herein, we report the fabrication of a nanotherapeutic platform integrating near-infrared (NIR) imaging with combined therapeutic potential through photodynamic (PDT) and photothermal therapies (PTT) and recognition functionality against ovarian cancer. Owing to its NIR fluorescence, singlet oxygen generation and heating capacity, IR780 iodide is exploited to construct a multifunctional nanosystem for single-wavelength NIR laser imaging-assisted dual-modal phototherapy. We opted for loading IR780 into polymeric Pluronic-F127-chitosan nanoformulation in order to overcome its hydrophobicity and toxicity and to allow functionalization with folic acid. The obtained nanocapsules show temperature-dependent swelling and spectroscopic behavior with favorable size distribution for cellular uptake at physiological temperatures, improved fluorescence properties and good stability. The fabricated nanocapsules can efficiently generate singlet oxygen in solution and are able to produce considerable temperature increase (46 °C) upon NIR laser irradiation. Viability assays on NIH-OVCAR-3 cells confirm the successful biocompatibilization of IR780 by encapsulating in Pluronic and chitosan polymers. NIR fluorescence imaging assays reveal the ability of folic-acid functionalized nanocapsules to serve as intracellular contrast agents and demonstrate their active targeting capacity against folate receptor expressing ovarian cancer cells (NIH-OVCAR-3). Consequently, the targeted nanocapsules show improved NIR laser induced phototherapeutic performance against NIH-OVCAR-3 cells compared to free IR780. We anticipate that this class of nanocapsules holds great promise as theranostic agents for application in image-guided dual PDT-PTT and imaging assisted surgery of ovarian cancer.
Biosurfactants are surface-active molecules produced by different microorganisms and display a promising alternative to synthetically derived food emulsifiers. One of these biosurfactants, synthesized by Bacillus subtilis, is the lipopeptide surfactin, which composes a linear fatty acid and cyclic peptide moiety. This study explores the interfacial and emulsion forming properties of surfactin to further characterize its suitability as an O/W emulsifier in food formulations.
Surfactin revealed a high interfacial activity with a reduction of interfacial tension of 83.26 % to 4.21 ± 0.11 mN/m. O/W emulsions (c
= 10 % w/w) were prepared by high-pressure homogenization, which yielded volume-based mean particle sizes below 1 μm already at low emulsifier concentrations of 0.01 % (w/w). Environmental stress experiments revealed that emulsions were stable between pH 6 to pH 9. #link# Furthermore, neither phase separation nor extensive emulsion instability was observed with NaCl addition up to 0.5 M. However, CaCl
addition (> 3 mM) destabilized surfactin mediated emulsions. Finally, the main emulsion forming and stabilization effect of surfactin was related to its high interfacial activity and the high degree of electrostatic repulsion between the oil droplets (i.e. zeta-potential of up to -100 mV).
In comparison to other natural and synthetic emulsifiers, the results showed that surfactin is a strong candidate to form and stabilize O/W emulsions under the reported conditions.
In comparison to other natural and synthetic emulsifiers, the results showed that surfactin is a strong candidate to form and stabilize O/W emulsions under the reported conditions.Doxorubicin is a broad-spectrum antineoplastic drug used in tumor therapy, its clinical application is limited by side effects on normal tissues. In this article, a pH-responsive drug delivery system (NPs(DOX/AFc)) with co-delivers doxorubicin (DOX) and aminoferrocene (AFc) was prepared by a two-step synthesis method including the oxidation of hyaluronic acid and Schiff base reaction. NPs(DOX/AFc) can be used in combination therapy of chemodynamic therapy (CDT) and chemotherapy (CT), thus the dosage of the chemotherapeutic drug DOX was reduced. The drug release behavior of NPs(DOX/AFc) in vitro showed that acid-responsive drug releases under the endosomal/lysosomal environment were 56.5 % of DOX and 61.8 % of AFc. In vitro toxicity experiments showed that DOX and AFc had synergistic effects (CI = 0.878). The results of intracellular ROS measurement and the mitochondrial membrane potential analysis showed that in tumor cells NPs(DOX4/AFc) induced more production of reactive oxygen species and more loss of the mitochondrial membrane potential.