Mitra, H. | bioRxiv Science

bioRxiv2025

Effects of arginine on the interfacial behavior of proteins

HypothesisProtein adsorption at fluid-fluid interfaces can induce conformational rearrangements and promote aggregation. Arginine, as an amino acid is known to attenuate protein-protein interactions and lower the viscosity of protein formulations. Given its surface-active properties, we hypothesize that arginine may be effective in limiting aggregation at fluid-fluid interfaces. ExperimentsInterfacial rheology of Etanercept (Enbrel), Immunoglobulin G1 (IgG1), and Bovine Serum Albumin (BSA) was characterized across a range of concentrations, with and without L-arginine Hydrochloride. The interfacial response was examined in both linear and nonlinear regimes.{zeta} -potential was also measured for selected formulations to evaluate the relationship between electrostatic characteristics and the rheological outcomes. FindingsBased on both linear and nonlinear interfacial rheology results, arginine generally weakened protein-protein interactions; however, the effect depends on protein identity and concentration. In arginine-containing formulations, Enbrel and BSA displayed only minor variation in interfacial viscoelasticity between 0.01 and 1 mg/mL, particularly during prolonged aging; in contrast, IgG1 showed larger concentration-dependent differences. These results strengthen predictive frameworks for interfacial stability and guide the rational design of protein-amino acid biopharmaceutical formulations. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=147 SRC="FIGDIR/small/674647v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@10a0bc8org.highwire.dtl.DTLVardef@8b9be7org.highwire.dtl.DTLVardef@1a88e43org.highwire.dtl.DTLVardef@113d5a9_HPS_FORMAT_FIGEXP M_FIG C_FIG

biophysics↗

bioRxiv2024

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 skins 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. It reports on how viscoelastic properties change with frequency, time, and strain, noting strain-stiffening and shear-thinning at high strain amplitudes. Human male and female abdominal tissues are also compared to minipig tissues, highlighting distinct viscoelastic traits and lipids role in them. The findings suggest the existence of species, anatomical location, tissue depth, and sex-based rheological differences. We also concluded the minipig male tissue is a more accurate model for human male subcutaneous tissue than for females.

biophysics↗