Stiffness measurement of nanosized liposomes using solid‐state nanopore sensor with automated recapturing platform

Abstract

This paper describes a method to gauge the stiffness of nanosized liposomes – a nanoscale vesicle – using a custom‐made recapture platform coupled to a solid‐state nanopore sensor. The recapture platform electrically profiles a given liposome vesicle multiple times through automated reversal of the voltage polarity immediately following a translocation instance to re‐translocate the same analyte through the nanopore – provides better statistical insight at the molecular level by analyzing the same particle multiple times compared to conventional nanopore platforms. The capture frequency depends on the applied voltage with lower voltages (i.e., 100 mV) permitting higher recapture instances than at higher voltages (>200 mV) since the probability of particles exiting the nanopore capture radius increases with voltage. The shape deformation was inferred by comparing the normalized relative current blockade (ΔI/I0̂false) at the two voltage polarities to that of a rigid particle, i.e., polystyrene beads. We found that liposomes deform to adopt a prolate shape at higher voltages. This platform can be further applied to investigate the stiffness of other types of soft matters, e.g., virus, exosomes, endosomes, and accelerate the potential studies in pharmaceutics for increasing the drug packing and unpacking mechanism by controlling the stiffness of the drug vesicles.

Mechanical characterization of vesicles and cells: A review

“…In recent years, a lot of interest is being directed toward SSN for nanovesicle characterization since optical detection technique used in traditional electrodeformation studies fail to detect nanosized vesicles. Nanopore technology has been widely used since its inception nearly two decades ago for DNA , proteins , glycans , viruses , liposomes , nanoparticles , and polymer profiling because of its high resolution (single‐molecule level), low‐cost, high throughput, minimal sample requirement (both volume and concentration).…”

“…(C) Multiple recapture protocol with time domains T delay (blue), T recapture (black), and T skip (red) shown in arrows and events highlighted by black dotted circles. Reprinted from with permission.…”

“…Recently, SSN assays were used to evaluate the electrodeformability of viruses and liposomes through a multiple recapture protocol . The multiple recapture protocol would evaluate the membrane mechanical properties of single‐vesicle multiple times (e.g., ∼25 times), thus, not only providing a statistically significant evaluation of the said properties of a single vesicle but also superseding conventional nanopore protocols which provide one value per translocating vesicle.…”

Fabrication of hexagonal boron nitride based 2D nanopore sensor for the assessment of electro‐chemical responsiveness of human serum transferrin protein

“…Since is independent of the applied voltage, it is a useful metric to measure the electric field induced molecular level changes of particles/biomolecules, such as deformation (e.g. soft particle) and conformational changes (e.g. protein unfolding) .…”

“…Nanopores are ostensibly simple, label‐free, low‐cost overhead, and high‐throughput sensors used to profile a plethora of biomolecules and particles such as DNA , proteins , polysaccharides,, liposomes , and viruses with a high resolution. In its early days, just over two decades ago , and to a large extent even today, the biological counterpart dictated terms due to its size reproducibility, low noise, and vast genetic engineering protocols, despite limitations in available pore size and chemical and physical working conditions.…”