In situ precipitation: a novel approach for preparation of iron-oxide magnetoliposomes

Abstract

Background Conventional methods of preparing magnetoliposomes are complicated and inefficient. A novel approach for magnetoliposomes preparation was investigated in the study reported here. Methods FeCl 3 /FeCl 2 solutions were hydrated with lipid films to obtain liposome-encapsulated iron ions by ultrasonic dispersion. Non-encapsulated iron ions were removed by dialysis. NH 3 · H 2 O was added to the system to adjust the pH to a critical value. Four different systems were prepared. Each was incubated at a different temperature for a different length of time to facilitate the permeation of NH 3 · H 2 O into the inner phase of the liposomes and the in situ formation of magnetic iron-oxide cores in the liposomes. Single-factor analysis and orthogonal-design experiments were applied to determinate the effects of alkalization pH, temperature, duration, and initial Fe concentration on encapsulation efficiency and drug loading. Results The magnetoliposomes prepared by in situ precipitation had an average particle size of 168±14 nm, zeta potential of −26.2±1.9 mV and polydispersity index of 0.23±0.06. The iron-oxide cores were confirmed as Fe 3 O 4 by X-ray diffraction and demonstrated a superparamagnetic response. Encapsulation efficiency ranged from 3% to 22%, while drug loading ranged from 0.2 to 1.58 mol Fe/mol lipid. The optimal conditions for in situ precipitation were found to be an alkalization pH of 12, temperature of 60°C, time of 60 minutes, and initial Fe concentration of 100 mM Fe 3+ + 50 mM Fe 2+ . Conclusion In situ precipitation could be a simple and efficient approach for the preparation of iron-oxide magnetoliposomes.

Effective elimination of liver cancer stem-like cells by CD90 antibody targeted thermosensitive magnetoliposomes

“…Fe 3 O 4 was clustered with a diameter of 10­­­-20 nm. Lipids layer of CD90@TMs was visible in correlative TEM image [21]. The average particle size in water was 130±4.6 nm (Figure 1B) and zeta potentials were negative (Figure 1C).…”