Analiza membranske difuzibilnosti čestica liganada uz prisutnost difuzibilnih receptora

master's thesis

• Title (english): Analysis of ligand particle membrane diffusibility in presence of diffusible receptors
• Author: Bruno Buljan
• Mentor: Ana-Sunčana Smith (mentor)
• Mentor: Denis Sunko (mentor)
• Committee member: Denis Sunko (predsjednik povjerenstva)
• Committee member: Ana-Sunčana Smith (član povjerenstva)
• Committee member: Mario Basletić (član povjerenstva)
• Committee member: Nenad Pavin (član povjerenstva)
• Committee member: Mihael Grbić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2018-12-21, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics

Abstract

U ovome diplomskom radu je analitički i pomoću računalnih simulacija proučena difuzija čestica u membrani. Čestice su razmještene u dvije paralelno postavljene membrane i mogu difundirati po svakoj membrani te stvarati premošćujuće veze koje imobiliziraju čestice u vezi. Izvedeni su izrazi koji opisuju gustoću premošćujućih veza i efektivni difuzijski koeficijent čestica. Kroz Monte Carlo simulacije je proučena ovisnost tih dviju veličina o intrinzičnom slobodnom difuzijskom koeficijentu čestica na jednoj odnosno drugoj membrani, o energiji vezanja pri stvaranju čestičnog intermembranskog kompleksa i o koncentraciji čestica na jednoj odnosno drugoj membrani. Najzanimljiviji rezultat simulacija je porast efektivnog difuzijskog koeficijenta čestica na membrani s porastom koncentracije čestica na istoj membrani. Sličan fenomen je opažen u simulacijama i analitički proučen u analognom sustavu s nepomičnim česticama na jednoj od membrana [1]. Ispitani teorijski modeli za efektivni difuzijski koeficijent pokazuju zadovoljavajuće slaganje u područjima niskih koncentracija čestica. Analiza slaganja simulacija s teorijskim modelima na visokim koncentracijama čestica upućuje na buduće pristupe pri teorijskom razmatranju efektivne difuzije u biološkim sustavima.

Abstract (english)

In this master thesis we study diffusion of particles in a membrane by means of numerical simulations and theoretical analysis. The particles are randomly distributed in two membranes set parallel to each other and are able to diffuse within membrane as well as make bridging complexes spanning the two membranes which make the particles in a complex immobile. We proposed expressions for the density of bridging complexes and for the effective diffusion coefficient of the particles. Using Monte Carlo simulations we investigated the dependence of the aforementioned physical quantities on the physical parameters of the system. These are intrinsic mobility of particles on both membranes, binding energy of the formation of the bridging complex and the concentration of particles on both membranes. As a notable result we report the increase in effective diffusion coefficient with the increase of the concentration of diffusing particles on the same membrane. A similar phenomenon has already been detected in simulations and studied analytically in an analogous system with imobilized particles on one of the membranes [1]. The analytical expressions for the diffusion coefficient we proposed here are in agreement with simulation data for low particle concentrations. Disagreement of the simulation data and analytical models at high particle concentrations hints on possible future approaches to modelling membrane diffusion in biological systems.

• Keywords: difuzija; anomalna difuzija; difuzija u membrani; ligand; receptor
• Keywords (english): diffusion; anomalous diffusion; diffusion in membranes; ligand; receptor
• Language: croatian
• URN:NBN: urn:nbn:hr:217:060703
• Study programme: Title: Physics; specializations in: Research; Course: Research; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: magistar/magistra fizike (magistar/magistra fizike)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-01-23 13:51:12