Investigation of Single‐Drug‐Encapsulating Liposomes using the Nano‐Impact Method

Abstract

Encapsulating liposomes are widely used for controlled drug delivery. We report the use of nano-impact experiments for the electrochemical attomolar quantification of the liposome load, uniquely at the single liposome level, using vitamin C encapsulated liposomes as a model. The size of the liposomes and their picomolar concentration are also determined in biological buffer in real time.

Characterizing the Catecholamine Content of Single Mammalian Vesicles by Collision–Adsorption Events at an Electrode

“…4 Furthermore, Cheng and Compton examined the electrochemistry of ascorbic acid-filled liposomes as they impact electrodes. 5 These are all examples of nanoparticles filled with electroactive molecules, their collisions at electrode surfaces, and the subsequent electrochemistry of the container contents. We show here that it is possible to combine these approaches to detect the contents of nanometer-sized vesicles from living systems following rupture on an electrode.…”

Electrochemical detection of a single cytomegalovirus at an ultramicroelectrode and its antibody anchoring

“…The interested reader can consult the references for a discussion on each of the techniques used to observe stochastic events electrochemically: blocking (9, 13), electrocatalytic amplification (1), open circuit potential (16), droplet blocking/reactor (13,14), and ECL (15,17,18). The simplest and most reproducible method of observing collisions is a technique termed blocking, which is so named because particles, which are brought to the electrode by a diffusion-limited flux and/or electrophoretic migration, irreversibly adsorb (1) to the electrode surface, blocking the flux of redox active species.…”

“…The electrochemical study of single collision events has been applied to a wide range of hard nanoparticles (NPs), which include metal, metal oxide, and organic NPs [platinum (1), silver (2), gold (3), nickel (4), copper (5), iridium oxide (6), cerium oxide (7), titanium oxide (8), silicon oxide (9), indigo (10), polystyrene (11), and relatively large aggregates of fullerene (12)]. Recently, collisions of soft particles have been investigated, such as toluene droplets (13) and liposomes (14). Also, collisions of toluene and tri-n-propylamine droplets were observed simultaneously by both electrochemical and electrogenerated chemiluminescent (ECL) measurements (15).…”

Diffusional impacts of nanoparticles on microdisc and microwire electrodes: The limit of detection and first passage statistics

“…This allows for the investigation of the electrocatalytic activity of the particle [6,12] and delivers information on the nanoparticle's Brownian motion at the electrode surface [13,14]. The nano-impact method has been used to identify various types of nanoparticles [15,5,10,16,17], and to provide fundamental insights into chemical mechanisms [18][19][20][21][22], agglomerations and aggregations [23,24], and the sensing at low nanoparticle concentrations for environmental studies [10].…”