eprintid: 36733
rev_number: 13
eprint_status: archive
userid: 9087
dir: disk0/00/03/67/33
datestamp: 2025-06-18 09:56:21
lastmod: 2025-06-18 09:56:36
status_changed: 2025-06-18 09:56:21
type: doctoralThesis
metadata_visibility: show
creators_name: Ebrahimi Pour, Bahareh
title: Structures and Functions of Synthetic and Native Biomembranes
subjects: ddc-540
divisions: i-120300
adv_faculty: af-12
cterms_swd: HEMT
cterms_swd: Biomembrane
cterms_swd: Biosensor
abstract: The main objective of this thesis is to quantitatively investigate the structure and function of a new class of artificial membrane models and two types of native biomembranes by the combination of unique physical techniques.
In chapter 4, the specific recognition of heavy metal ions by plant-inspired polymer (pAA-Cys5) mimicking plant phytochelatin protein was quantitatively detected by using
two experimental techniques. In section 4.1, the binding of Cd2+ to DOPE-pAACys5 was detected by using a high electron mobility transistor (HEMT) device based on GaN/AlGaN/GaN heterostructures. By precisely controlling the average intermolecular distance between pAA-Cys5 brushes, the sensitivity of the pAA-Cys5-functionalized device could be quantitatively assessed from the change in carrier mobility in the two-dimensional electron gas (2DEG) layer. In section 4.2, simultaneous grazing-incidence X-ray fluorescence (GIXF) and specular X-ray reflectivity (XRR) unraveled the spatial distribution of Cd2+ ions in the close proximity of the air/water interface, and the ion specificity of pAA-Cys5 was assessed by comparison with Ca2+ ions.
In chapter 5, the structures of native biomembranes in the direction perpendicular to the membrane surface were characterized using high-energy XRR, neutron reflectivity (NR), and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The direct spreading of native biomembranes enabled the maintenance of the amount, composition, and orientation of membrane proteins, which cannot be achieved by artificially reconstituted membrane systems. In this study, two types of membrane systems were investigated; sarcoplasmic reticulum membrane purified from rabbit muscle (section 5.1) and healthy and malaria-infected human erythrocyte ghost membranes (section 5.2). Ex-situ
combination of XRR and ATR-FTIR could unravel both structural features of membranes and spectroscopic fingerprints of membrane proteins in SR membranes. Moreover, NR of healthy and malaria-infected erythrocyte membranes can be attributed to the clusters of adhesion proteins. The obtained results demonstrate that the complementary combination of surface-sensitive techniques is a powerful tool for the characterization of structures and functions of artificial and native membranes.
date: 2025
id_scheme: DOI
id_number: 10.11588/heidok.00036733
own_urn: urn:nbn:de:bsz:16-heidok-367337
date_accepted: 2025-06-10
advisor: HASH(0x55ca98993100)
language: eng
bibsort: EBRAHIMIPOSTRUCTURES
full_text_status: public
place_of_pub: Heidelberg
citation:   Ebrahimi Pour, Bahareh  (2025) Structures and Functions of Synthetic and Native Biomembranes.  [Dissertation]     
document_url: https://archiv.ub.uni-heidelberg.de/volltextserver/36733/1/B.EbrahimiPour_Thesis.pdf