Enhanced reduction in cell viability by hyperthermia induced by magnetic nanoparticles

Colloidal suspensions of iron oxide magnetic nanoparticles are known to dissipate energy when exposed to an oscillating magnetic field. Such energy dissipation can be employed to locally raise temperature inside a tumor between 41°C and 45°C (hyperthermia) to promote cell death, a treatment known as magnetic fluid hyperthermia (MFH). This work seeks to quantify differences between MFH and hot-water hyperthermia (HWH) in terms of reduction in cell viability using two cancer cell culture models, Caco-2 (human epithelial colorectal adenocarcinoma) and MCF-7 (human breast cancer). Magnetite nanoparticles were synthesized via the co-precipitation method and functionalized with adsorbed carboxymethyl dextran. Cytotoxicity studies indicated that in the absence of an oscillating magnetic field, cell viability was not affected at concentrations of up to 0.6 mg iron oxide/mL. MFH resulted in a significant decrease in cell viability when exposed to a magnetic field for 120 minutes and allowed to rest for 48 hours, compared with similar field applications, but with shorter resting time. The results presented here suggest that MFH most likely induces apoptosis in both cell types. When compared with HWH, MFH produced a significant reduction in cell viability, and these effects appear to be cell-type related

Physicochemical behavior and cellular interactions of novel oral calcitonin delivery systems

The attractive properties of peptides and proteins as therapeutic agents and the challenges faced by the oral delivery of such agents have been the primary motivation for the design and development of novel oral delivery systems that could circumvent biological barriers. In this work, salmon calcitonin, a 32 amino acid polypeptide hormone used in the treatment of bone diseases, such as Paget\u27s disease, hypercalcemia and osteoporosis, was employed as the model protein. The main goal of this work was the creation of pH-sensititive hydrogel microspheres composed of Poly(methacrylic acid-grafted-polyethylene glycol)) (PMAA-g-EG), their primary characterization, and the examination of their performance as a transport enhancer for salmon calcitonin. For this purpose, a gastrointestinal cell culture model, the Caco-2 cell line, was employed to investigate the cytotoxic effects of the polymeric carrier, its effects on the cell monolayer integrity, and its ability to enhance the transport of salmon calcitonin. Microsphere carriers composed of P(MAA-g-EG) hydrogels were successfully created by dispersion polymerization utilizing deionize water as the solvent. The characterization of these systems was performed by FTIR revealed that microspheres created by dispersion polymerization possessed similar infrared spectral characteristics to hydrogel films prepared with the same monomer ratio. These hydrogels also possessed narrow particle size distribution and spherical shape as evidenced by PCS and SEM analysis. The examination of the physicochemical interactions of the P(MAA-g-EG) microsphere system with Caco-2 cell monolayers revealed that these systems possessed low cytotoxicity and were capable of opening the tight junctions between epithelial cells by significantly reducing the transepithelial electrical resistance. The presence of P(MAA-g-EG) microspheres significantly increased the transport of paracellularly transported molecules such as 14C-mannitol and fluorescein isothiocyanate dextran when compared to controls. Fluorescein sodium salt solutions were also investigated as an actively transported molecule. The transport of fluorescein was highly affected by PEG chains. Salmon calcitonin transport was significantly enhanced in the presence of the microspheres. The main transport mechanism for salmon calcitonin through epithelial cell monolayers was found to be mainly paracellular

Synthetic Thermo-Responsive Terpolymers as Tunable Scaffolds for Cell Culture Applications

The use of tailored synthetic hydrogels for in vitro tissue culture and biomanufacturing provides the advantage of mimicking the cell microenvironment without issues of batch-to-batch variability. To that end, this work focused on the design, characterization, and preliminary evaluation of thermo-responsive, transparent synthetic terpolymers based on N-isopropylacrylamide, vinylphenylboronic acid, and polyethylene glycol for cell manufacturing and in vitro culture applications. Polymer physical properties were characterized by FT-IR, 1H-NMR, DLS, rheology, and thermal-gravimetric analysis. Tested combinations provided polymers with a lower critical solution temperature (LCST) between 30 and 45 °C. Terpolymer elastic/shear modulus varied between 0.3 and 19.1 kPa at 37 °C. Cellular characterization indicated low cell cytotoxicity on NIH-3T3. Experiments with the ovarian cancer model SKOV-3 and Jurkat T cells showed the terpolymers’ capacity for cell encapsulation without interfering with staining or imaging protocols. In addition, cell growth and high levels of pluripotency demonstrated the capability of terpolymer to culture iPSCs. Characterization results confirmed a promising use of terpolymers as a tunable scaffold for cell culture applications