Research Project: Engineering Extracellular Matrices for Controlling Structure and Dynamics of Lipid Bilayer Membranes
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Contributors
Funders
ID
EC.00132
Authors
Şenses, Erkan
Faculty Member
Publications
Liposomes under shear: structure, dynamics, and drug delivery applications
(Wiley-VCH, 2023) Karaz, Selcan; Şenses, Erkan; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; Yes; College of Engineering; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING
The targeted delivery to specific locations while not causing damage to healthy tissues efficiently remains a challenge in drug delivery systems. Through addressing this issue, stimuli-responsive materials have been under investigation. As one of the fundamental forces associated with blood flow, shear stress is taken as an advantage to design shear-sensitive drug carriers. Although blood flow is modeled as laminar flow under normal conditions, in case of constrictions caused by endothelial shear stress, cardiovascular diseases, or angiogenesis due to tumor formation, local shear stress can dramatically increase. To date, shear-sensitive materials have been investigated under two main categories: shear-disaggregated and shear-deformed nanoparticles based on their structural mechanism after exposure to high-shear stress. Among them, liposomes are promising materials with their soft and deformable structure, high biocompatibility, controlled-release properties, and sensitivity to shear stress. Herein, in this review, the effects of shear stress on liposomes in terms of their structural changes, flow regimes, rheological properties, and drug delivery applications are discussed. It is believed that this work provides a basis for designing more effective drug delivery systems considering the complexity of the human body.
Multiscale dynamics of lipid vesicles in polymeric microenvironment
(MDPI, 2022) Akay, Gizem; Han, Mertcan; Karaz, Selcan; Kızılel, Seda; Nizamoğlu, Sedat; Önal, Asım; Şenses, Erkan; Department of Electrical and Electronics Engineering; Department of Chemical and Biological Engineering; Graduate School of Sciences and Engineering; KUYTAM (Koç University Surface Science and Technology Center); Yes; College of Engineering; GRADUATE SCHOOL OF SCIENCES AND ENGINEERING; Research Center
Understanding dynamic and complex interaction of biological membranes with extracellular matrices plays a crucial role in controlling a variety of cell behavior and functions, from cell adhesion and growth to signaling and differentiation. Tremendous interest in tissue engineering has made it possible to design polymeric scaffolds mimicking the topology and mechanical properties of the native extracellular microenvironment; however, A fundamental question remains unanswered: that is, how the viscoelastic extracellular environment modifies the hierarchical dynamics of lipid membranes. in this work, we used aqueous solutions of poly(ethylene glycol) (PEG) with different molecular weights to mimic the viscous medium of cells and nearly monodisperse unilamellar DMPC/DMPG liposomes as a membrane model. Using small-angle X-ray scattering (SaXS), dynamic light scattering, temperature-modulated differential scanning calorimetry, bulk rheology, and fluorescence lifetime spectroscopy, we investigated the structural phase map and multiscale dynamics of the liposome-polymer mixtures. the results suggest an unprecedented dynamic coupling between polymer chains and phospholipid bilayers at different length/time scales. the microviscosity of the lipid bilayers is directly influenced by the relaxation of the whole chain, resulting in accelerated dynamics of lipids within the bilayers in the case of short chains compared to the polymer-free liposome case. at the macroscopic level, the gel-to-fluid transition of the bilayers results in a remarkable thermal-stiffening behavior of polymer-liposome solutions that can be modified by the concentration of the liposomes and the polymer chain length.
