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This paper explains the wrinkling behavior of a bilayer system comprised of a soft, thick hydrogel on a hard thin skin in which the hydrogel has viscoelastic properties. The role of external stress and viscoelastic properties on the morphology of nanoscale wrinkles is discussed in a time-dependent mechanical and thermomechanical framework and compared with the corresponding results from a linear elastic treatment of the hydrogel. Our results show that the strain rate and magnitude of strain have substantial impact on nanoscale wrinkle morphology when viscoelasticity of the substrate is included in the model. As such, engineering the relaxation time through the material synthesis process or material selection plays an important role. This is important to modeling an autoregulatory humidity sensing device that was previously developed by our group and others, where the formation of humidity-dependent nanoscale wrinkles tunes the transmission or scattering of light through the substrate, thereby enabling a plasmonic nanoparticle array to switch on or off plasmonic heating of the system that generates or removes the nanoscale wrinkles. Three different lumped viscoelastic models are applied: generalized Maxwell (GM), generalized Kelvin–Voigt (GK), and Burger (BR) models. Time evolution analysis of these models, including comparison with the validated linear elastic model at high relaxation time and with experimental data, shows best agreement with the GK result. Finally, we quantitatively demonstrate how the morphology of nanoscale wrinkles that is accessible to viscoelastic models can adjust the light transmission across the substrate by amounts that are useful for the autoregulatory device. This viscoelastic modeling will enable more quantitative predictions and design principles for taking advantage of responsive materials such as for pressure or humidity sensors or thermal-responsive drug delivery systems. [ABSTRACT FROM AUTHOR]

Accurate cancer detection and diagnosis is of utmost importance for reliable drug-response prediction. Successful cancer characterization relies on both genetic analysis and histological scans from tumor biopsies. It is known that the cytoskeleton is significantly altered in cancer, as cellular structure dynamically remodels to promote proliferation, migration, and metastasis. We exploited these structural differences with supervised feature extraction methods to introduce an algorithm that could distinguish cancer from non-cancer cells presented in high-resolution, single cell images. In this paper, we successfully identified the features with the most discriminatory power to successfully predict cell type with as few as 100 cells per cell line. This trait overcomes a key barrier of machine learning methodologies: insufficient data. Furthermore, normalizing cell shape via microcontact printing on self-assembled monolayers enabled better discrimination of cell lines with difficult-to-distinguish phenotypes. Classification accuracy remained robust as we tested dissimilar cell lines across various tissue origins, which supports the generalizability of our algorithm. [ABSTRACT FROM AUTHOR]

Biologic products are large molecules such as proteins, peptides, nucleic acids, etc., which have already produced many new drugs for clinical use in the last decades. Due to the inherent challenges faced by biologics after oral administration ( e.g., acidic stomach pH, digestive enzymes, and limited permeation through the gastrointestinal tract), several alternative routes of administration have been investigated to enable sufficient drug absorption into systemic circulation. This review describes the buccal, sublingual, pulmonary, and transdermal routes of administration for biologics with relevant details of the respective barriers. While all these routes avoid transit through the gastrointestinal tract, each has its own strengths and weaknesses that may be optimal for specific classes of compounds. Buccal and sublingual delivery enable rapid drug uptake through a relatively permeable barrier but are limited by small epithelial surface area, stratified epithelia, and the practical complexities of maintaining a drug delivery system in the mouth. Pulmonary delivery accesses the highly permeable and large surface area of the alveolar epithelium but must overcome the complexities of safe and effective delivery to the alveoli deep in the lung. Transdermal delivery offers convenient access to the body for extended-release delivery via the skin surface but requires the use of novel devices and formulations to overcome the skin's formidable stratum corneum barrier. New technologies and strategies advanced to overcome these challenges are reviewed, and critical views in future developments of each route are given. [ABSTRACT FROM AUTHOR]