CAJ | 학술논문

单个分子实验有很重要的意义,一方面,对于非均相体系,单个分子实验可得到分子性质分布信息;另一方面,对于均相和非均相体系,单个分子轨迹直接记录了分子性质的涨落,包含了丰富的动力学信息.在诸多单个分子检测技术中,单分子光学检测技术具有快速、无损、可探测到凝聚相内部单个分子的能力.进行单分子检测的关键是消除拉曼和瑞利散射以及杂质荧光等背景的干扰,利用共焦、近场和隐失场激发减少激发体积和检测体积,可以降低背底,提高信噪比.本实验利用共焦荧光显微镜观测单个罗丹明标记的磷脂分子在亲水玻璃表面的扩散、脱附,及其荧光闪烁的行为.实验表明,除由表面的平均力场阻碍分子运动外,还有一些特殊位点会造成长时间的特异性吸附,并得到特异性吸附的分子的脱附速率,(5.9±0.2)s-1.用穿越时间分布函数测得分子在表面的扩散速率为(3.3±0.1)×10-8cm2@s-1,与分子在磷脂膜中的扩散速率相当.观测到了一些吸附的分子出现了荧光闪烁的现象,并对其产生原因进行了一些分析.
단개분자실험유흔중요적의의,일방면,대우비균상체계,단개분자실험가득도분자성질분포신식;령일방면,대우균상화비균상체계,단개분자궤적직접기록료분자성질적창락,포함료봉부적동역학신식.재제다단개분자검측기술중,단분자광학검측기술구유쾌속、무손、가탐측도응취상내부단개분자적능력.진행단분자검측적관건시소제랍만화서리산사이급잡질형광등배경적간우,이용공초、근장화은실장격발감소격발체적화검측체적,가이강저배저,제고신조비.본실험이용공초형광현미경관측단개라단명표기적린지분자재친수파리표면적확산、탈부,급기형광섬삭적행위.실험표명,제유표면적평균력장조애분자운동외,환유일사특수위점회조성장시간적특이성흡부,병득도특이성흡부적분자적탈부속솔,(5.9±0.2)s-1.용천월시간분포함수측득분자재표면적확산속솔위(3.3±0.1)×10-8cm2@s-1,여분자재린지막중적확산속솔상당.관측도료일사흡부적분자출현료형광섬삭적현상,병대기산생원인진행료일사분석.
We report an investigation on the surface behaviors, including diffusion,desorption and fluorescence blinking, of rhodamine-labeled phospholipid molecules at single-molecule level by confocal fluorescence microscopy. It was found that besides an average force field on the hydrophilic glass surface there exist special sites which strongly adsorb rhodamine-labeled phospholipid molecules. The desorption rate of the strongly adsorbed molecules is determined to be (5.9± 0.2) s- 1. The diffusion coefficient of the molecules on the surface, (3.3± 0.1)× 10- 8 cm2@ s- 1, is much smaller than that in aqueous solution, (2.3± 0.1)× 10- 6 cm2@ s- 1, but is in the same order as that in a fluid phospholipid membrane. Fluorescence blinking was observed in some of the strongly adsorbed molecules, which may be attributed to reversible quantum jumps to dark states induced by the strong interaction between the molecule and adsorption sites.