This article presents the correlation of creep and viscoelastic properties to the cytoskeletal structure of both tumorigenic and non‐tumorigenic cells. Unique shear assay and strain mapping techniques were used to study the creep and viscoelastic properties of single non‐tumorigenic and tumorigenic cells. At least 20 individual cells, three locations per cell, were studied. From the results, lower densities in the volume of actin, and keratin 18 structures were observed with the progression of cancer and were correlated to the increased creep rates and reduced mechanical properties (Young's moduli and viscosities) of tumorigenic (MDA‐MB‐231) cells. The study reveals significant differences between the creep and viscoelastic properties of non‐tumorigenic breast cells versus tumorigenic cells. The variations in the creep strain rates are shown to be well characterized by lognormal distributions, while the statistical variations in the viscoelastic properties are well‐described by normal distributions. The implications of the results are discussed for the study of discrete cell behaviors, strain and viscoelastic responses of the cell, and the role of cell cytoskeleton in the onset and progression of cancers.
This article presents the release kinetics (RK) of a fungicidal antimicrobial agent (AMA), potassium sorbate (PS), that prolongs the shelf life of packaged food. The effects of PS release are explored on peanut and fresh bread to determine the effects of PS on Aspergillus niger (AN) microbe growth. The AN was cultured in a potato dextrose agar (PDA) medium to obtain AMA activity on the film. AMA activity of PS incorporated into cellulose acetate (CA) based film was tested on peanuts and fresh bread for an extended period of time. The RK of PS from the films was obtained by studying the de‐swelling properties of PS loaded film at room temperature (24°C) and at elevated temperature (37°C). The diffusion coefficients of PS released through the film network were obtained to be between 8.32 × 10−10 to 7.3 × 10−7 m2/s. The release exponents (n) of PS from the film occurred by anomalous transport with n‐values ranging from 0.13 to 0.16 at 24°C and 0.5 to 0.89 at 37°C. The average flux released from the CA film was consistent with the percentage PS release from the CA film showing that modeling the effective diffusion of PS from a porous media is feasible. The released PS was potent enough to inhibit the growth of AN for a week then over a period of 2 years. Thereafter, the implications of the results in designing smart food packaging for enhanced food preservation were discussed.
This article presents silica nanoparticles for the sustained release of AMACR antibody-conjugated and free doxorubicin (DOX) for the inhibition of prostate cancer cell growth. Inorganic MCM-41 silica nanoparticles were synthesized, functionalized with phenylboronic acid groups (MCM-B), and capped with dextran (MCM-B-D). The nanoparticles were then characterized using Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, zeta potential analysis, nitrogen sorption, X-ray diffraction, and thermogravimetric analysis, before exploring their potential for drug loading and controlled drug release. This was done using a model prostate cancer drug, DOX, and a targeted prostate cancer drug, α-Methyl Acyl-CoA racemase (AMACR) antibody-conjugated DOX, which attaches specifically to AMACR proteins that are overexpressed on the surfaces of prostate cancer cells. The kinetics of sustained drug release over 30 days was then studied using zeroth order, first order, second order, Higuchi, and the Korsmeyer-Peppas models, while the thermodynamics of drug release was elucidated by determining the entropy and enthalpy changes. The flux of the released DOX was also simulated using the COMSOL Multiphysics software package. Generally, the AMACR antibodyconjugated DOX drug-loaded nanoparticles were more effective than the free DOX drug-loaded formulations in inhibiting the growth of prostate cancer cells in vitro over a 96 h period. The implications of the results are then discussed for the development of drug-eluting structures for the localized and targeted treatment of prostate cancer.
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