NIR-dye Based Heat Generation System for Studying Thermodynamic Response of Lipid-Bilayers
Ladda ner
Typ
Examensarbete för masterexamen
Program
Nanotechnology (MPNAT), MSc
Publicerad
2019
Författare
Xue, Lin
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
In this study, we develop a local heat generation system utilizing the photothermal
effect on the micro-scale. Organic dye molecules are hosted in a polymer matrix
to construct an NIR-absorbing medium, and it is proved to be an alternative candidate
to plasmonic nanoparticles for creating a system with high absorption in the
NIR regime and high transmission at visible wavelengths.
We carry out optical and thermal simulations to optimize the heat generation
of such a system. The transfer matrix method is used to calculate the system
absorption dependence on the NIR-absorber thickness and NIR dye concentration.
It is shown that for a concentration of 5 mg/ml a 20 m thick absorbing layer
can provide 30% of absorption at 1064 nm, which is sufficient for generating an
effective heat source density. In COMSOL multiphysics we obtain a simulation of
the heat generation system in two configurations, indicating that the illumination
with a NIR laser can provide sufficient heating.
It is valuable to study the micro-scale thermal migration and manipulation of
biological particles in a temperature gradient, since it can provide the information
on the interaction between the molecules and the solvent. Therefore, based on our
NIR-absorbing system, we present several experiments investigating the thermodynamic
response of lipid-bilayers. It is found that the local heating can facilitate
the formation of lipid-bilayers from fluidic phase adsorbed vesicles. This might
result from the promotion of vesicle rupture and the consequent fusion between
lipids leading to the formation of a bilayer. Another study utilizing the lipid phase
transition demonstrates that a photobleached spot within a gel phase lipid-bilayer
can only recover in the presence of NIR-laser heating causing the local temperature
to increase above the transition threshold. Adopted from this observation, we
establish a reversible gel phase lipid lithography system, which utilizes a visible
laser and NIR laser as a pen and eraser, respectively, to be able to optically print a
desired pattern on the canvas made of lipid materials and then thermally remove
it.
Beskrivning
Ämne/nyckelord
NIR dye , optical absorption , photothermal effect , lipid-bilayers , lipid phase transition