Nanoscale vesicles form the structural framework of organelles such as lysosomes, endosomes, exosomes,endocytic and exocytic vesicles, as well as the lipid envelope for viruses. These physiological or pathologicalnanocarriers are nature?s delivery systems for molecules and therefore represent prototypes for developingnovel drug/gene delivery systems for pharmaceutical applications. An important aspect of vesicles is that theirmechanical properties allow them to achieve seemingly diametrical tasks: 1- to deform and merge with targetmembranes to deliver their cargos, and 2- to maintain physical integrity without rupturing in dynamic biologicalenvironments. Pure synthetic vesicles (i.e. liposomes), for example, do not possess sufficient mechanicalintegrity to effectively withstand harsh perturbations present in biological environments (e.g. large fluctuationsin static pressure), but reinforcement by more complex structural features, such as membrane proteins andprotein-lipid complexes, can provide structural integrity, while maintaining the ability to deform and to fuse withtarget membranes. Hence, studying the mechanical properties of vesicles, and understanding the mechanismsof reinforcement, as well as the effect of soluble effectors on vesicles? mechanics at the nanoscale, is of greatsignificance for both fundamental and applied purposes. Not only can it help us understand the fundamentalbiological transport phenomena, but also can lead to new solutions for bio-inspired drug/gene delivery systems.Force spectroscopy of liposomes is the most direct way to understand mechanical properties of vesicles,however, with the current technologies it is very challenging to do force spectroscopy on nanoscale liposomesin solution. The current state-of-the-art technique, atomic force spectroscopy (AFM) is expensive and time-consuming, is low-throughput, and requires highly-trained operators and complex sample preparation.Furthermore, there is currently no method that can separate and sort vesicles based on their mechanicalproperties, limiting our ability to directly compare mechanical properties with functional characteristics. In this project we will develop a nanopore based force spectroscopy method, that overcomes limitations ofAFM, to characterize the mechanical properties of nanoscale liposomes and can sort liposomes based on theirmechanical properties.
Two specific aims of this are Aim 1: to detect and measure varied mechanicalproperties of nanoscale vesicles using resistive pulse sensing in solid-state nanopores, and Aim 2: to developan automated feedback-controlled system that can sort nanovesicles based on their mechanical properties. The proposed nanopore force spectroscopy can be used to characterize mechanical properties of naturally-occurring nanovesicals such as viruses, exosomes, etc. In addition, an automated feedback-controlled systemwill be developed that can separate samples of desired mechanical properties (e.g. rigidity) out of a mixedpopulation of vesicles with varied properties. Such a platform can be used to sort heterogeneous biologicalsamples based on their mechanical behavior and study the functional role of biomechanics at the nanoscale.
Deformable soft nanoparticles with thin biological membranes are central themes in biology for intracellularvesicular trafficking and virus infection of cells; and are also used as artificial transporters for drug delivery. Inthis proposed research project; a novel nanotechnology-based instrument will be developed that enables us toovercome current limitations in sorting nanoparticles based on their deformability in real-time and with high-throughput capacity. This in turn will open up possible approaches to enhance our understanding ofbiomechanics and mechanobiology at nanoscale.
| Lee, Jung Soo; Peng, Bin; Sabuncu, Ahmet C et al. (2018) Multiple consecutive recapture of rigid nanoparticles using a solid-state nanopore sensor. Electrophoresis 39:833-843 |
| Freedman, Kevin J; Goyal, Gaurav; Ahn, Chi Won et al. (2017) Substrate Dependent Ad-Atom Migration on Graphene and the Impact on Electron-Beam Sculpting Functional Nanopores. Sensors (Basel) 17: |
