Rheological and Lipid Characterization of Minipig and Human Skin Tissue: A Comparative Study Across Different Locations and Depths.

Understanding the rheology of minipig and human skin is crucial for enhancing drug delivery methods, particularly for injections. Despite many studies on skin's viscoelasticity, especially the subcutaneous layer, comparative analyses across different clinical sites are scarce, as is data on the impact of hydration or lipid levels. This study employs shear rheology and lipid analysis to evaluate viscoelasticity and lipid content across three anatomical locations-breast, belly, and neck and three different depth layers in Yucatan minipigs.

Effects of shear-induced crystallization on the complex viscosity of lamellar-structured concentrated surfactant solutions.

Material relationships at low temperatures were determined for concentrated surfactant solutions using a combination of rheological experiments, cross-polarized microscopy, calorimetry, and small angle X-ray scattering. A lamellar structured 70 wt% solution of sodium laureth sulfate in water was used as a model system. At cold temperatures (5 °C and 10 °C), the formation of surfactant crystals resulted in extremely high viscosity.

Rheology of bi-disperse dense fiber suspensions.

While significant progress has been made in the modeling and simulation of uniform fiber suspensions, no existing model has been validated for industrially-relevant concentrated suspensions containing fibers of multiple aspect ratios. In the present work, we investigate bi-disperse suspensions with two fiber populations in varying aspect ratios in a steady shear flow using direct numerical simulations. Moreover, we measure the suspension viscosity by creating a controlled length bidispersity for nylon fibers suspended in a Newtonian fluid.

Linear and nonlinear rheology of liberase-treated breast cancer tumors.

Extracellular matrix (ECM) rigidity has been shown to increase the invasive properties of breast cancer cells, promoting transformation and metastasis through mechanotransduction. Reducing ECM stiffness enzymatic digestion could be a promising approach to slowing breast cancer development by de-differentiation of breast cancer cells to less aggressive phenotypes and enhancing the effectiveness of existing chemotherapeutics improved drug penetrance throughout the tumor. In this study, we examine the effects of injectable liberase (a blend of collagenase and thermolysin enzymes) treatments on the linear and nonlinear rheology of allograft 4T1 mouse mammary tumors.

Rheology of 3D printable ceramic suspensions: effects of non-adsorbing polymer on discontinuous shear thickening.

Concentrated suspensions of particles at volume fractions () ≥ 0.5 often exhibit complex rheological behavior, transitioning from shear thinning to shear thickening as the shear stress or shear rate is increased. These suspensions can be extruded to form 3D structures, with non-adsorbing polymers often added as rheology modifiers to improve printability.

Guar Gel Binders for Silicon Nanoparticle Anodes: Relating Binder Rheology to Electrode Performance.

Binding agents are a critical component of Si-based anodes for lithium-ion batteries. Herein, we introduce a composite hydrogel binder consisting of carbon black (CB) and guar, which is chemically cross-linked with glutaraldehyde as a means to reinforce the electrode structure during lithiation and improve electronic conductivity. Dynamic rheological measurements are used to monitor the cross-linking reaction and show that rheology plays a significant role in binder performance.

Using rheology to quantify the effects of localized collagenase treatments on uterine fibroid digestion.

Uterine fibroids are stiff, benign tumors containing excessive, disordered collagens that occur in 70-80% of women before age 50 and cause bleeding and pain. Collagenase Clostridium histolyticum (CCH) is a bacterial enzyme capable of digesting the collagens present in fibroids. By combining CCH with injectable drug delivery systems to enhance effectiveness, a new class of treatments could be developed to reduce the stiffness of fibroids, preventing the need for surgical removal and preserving fertility.

Cellulose nanocrystals for gelation and percolation-induced reinforcement of a photocurable poly(vinyl alcohol) derivative.

Nanomaterials are regularly added to crosslinkable polymers to enhance mechanical properties; however, important effects related to gelation behavior and crosslinking kinetics are often overlooked. In this study, we combine cellulose nanocrystals (CNCs) with a photoactive poly(vinyl alcohol) derivative, PVA-SbQ, to form photocrosslinked nanocomposite hydrogels. We investigate the rheology of PVA-SbQ with and without CNCs to decipher the role of each component in final property development and identify a critical CNC concentration (1.

Core-Shell Microneedle Gel for Self-Regulated Insulin Delivery.

A bioinspired glucose-responsive insulin delivery system for self-regulation of blood glucose levels is desirable for improving health and quality of life outcomes for patients with type 1 and advanced type 2 diabetes. Here we describe a painless core-shell microneedle array patch consisting of degradable cross-linked gel for smart insulin delivery with rapid responsiveness and excellent biocompatibility. This gel-based device can partially dissociate and subsequently release insulin when triggered by hydrogen peroxide (HO) generated during the oxidation of glucose by a glucose-specific enzyme covalently attached inside the gel.