Author(s)

Soon Ki Sung^1,2*, Hyuk Kyu Pak^3*, Jong Hyeok Kwak⁴, Sang Weon Lee¹, Young Ha Kim¹, Beong Ik Hur⁵, Seong Jin Jin⁶, Gyeong Rip Kim^1,2

¹Department of Neurosurgery, Pusan National University Yang-san Hospital, Yang-san, Korea.
²Research Institute for Convergence of Biomedical Science and Technology, Yang-san, Korea.
³Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, Korea.
⁴Department of Radiology, Pusan National University Yang-san Hospital, Yang-san, Korea.
⁵Department of Neurosurgery, Pusan National University Hospital, Busan, Korea.
⁶Haeundae Paik Hospital, Busan, Korea.

We studied the quantum dot-liposome complex (QLC), which is the giant unilamellar vesicle with quantum dots (QDs) incorporated in its lipid bilayer. A spin coating method in conjunction with the electroformation technique yielded vesicles with highly homogeneous unilamellar structure. We observed QD size dependence of the QLC formation: QLCs form with blue, green and yellow-emission QD (core radius ~1.05 nm, 1.25 nm and 1.65 nm) but not with red-emission QD (core radius ~2.5 nm). In order to explain this size dependence, we made a simple model explaining the QD size effect on QLC formation in terms of the molecular packing parameter and the lipid conformational change. This model predicts that QDs below a certain critical size (radius ≈ 1.8 nm) can stably reside in a lipid bilayer of 4 - 5 nm in thickness for Egg-PC lipids. This is consistent with our previous experimental results. In the case of red-emission QD, QD-aggregations are only observed on the fluorescent microscopy instead of QLC. We expected that the reduction of packing parameter (P) would lead to the change of specific QD radius. This prediction could be verified by our experimental observation of the shift of the specific QD size by mixing DOPG.

Quantum Dot-Liposome Complexes (QLCs), The Interface Energy at Optical Head Area, Packing Parameter, DOPC/DOPG QLC

Sung, S. , Pak, H. , Kwak, J. , Lee, S. , Kim, Y. , Hur, B. , Jin, S. and Kim, G. (2018) Specific Radius Change of Quantum Dot inside the Lipid Bilayer by Charge Effect of Lipid Head-Group. Open Journal of Biophysics, 8, 163-175. doi: 10.4236/ojbiphy.2018.83012.