We present a preliminary study concerning the feasibility of the production of magnetic lipid nanoparticles for biomedical applications. Magnetic nanoparticles (MN) were obtained by a precipitation method; afterwards, different experimental protocols and lipid mixtures were used to produce MN-containing lipid nanoparticles. Two types of lipid nanoparticles were obtained, namely solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). SLN of stearic acid were produced by emulsion followed by dilution method while NLC, alternatively composed of a mixture of tristearin/tricaprylin or tristearin/labrasol/ phosphatidylcholine, were produced by homogenization followed by ultrasonication method. MN (with a 5 % relative mass concentration) were added to the lipid phase before the emulsion formation. The samples were characterized using photon correlation spectroscopy (PCS) and X-ray diffraction (XRD). Magnetization loops and magnetization vs. T curves, in the zero field cooling (ZFC) and field cooling (FC) modes [1], were collected in the 6 K – 300 K temperature (T) range with a SQUID magnetometer. MN were also analyzed using transmission Mössbauer spectroscopy in the 25 K – 300 K temperature range with a 57 Co in Rh source; the spectrometer was calibrated using an α-Fe foil. The 25 K Mössbauer spectrum shows just one sextet with a hyperfine field of ~ 50 T; this result, and the absence of the sextet asymmetries expected even for small size magnetite nanoparticles, suggest that MN are possibly made of maghemite [3]. At T = 6 K, the saturation magnetization of the as-prepared MN is ~ 33 emu/g, about 40 % of the value of bulk maghemite. This effect may be due to the presence of crystalline disorder [2] or to the canting of surface spins [1]. The size analysis showed that MN-containing SLN are larger than MN-containing NLC, being their average size equal to 500 nm and 200 nm, respectively, but monodispersed and stable up to ten months. The XRD spectra indicated that the NM nanocrystalline structure did not change upon their inclusion in lipid nanoparticles. The magnetic properties of both the MN-containing SLN and the MN-containing NLC dispersions do not substantially differ compared to those of the as-prepared MN, indicating that the magnetic interparticle interactions are still present. This suggests that the MN may form agglomerates within the lipid nanoparticles. This study confirms the possibility to incorporate MN in lipid nanoparticles; their magnetic and physicochemical properties suggest their possible use both in therapy and in diagnostics. References 1) L. Del Bianco, I. G. Lesci, G. Fracasso, G. Barucca, F. Spizzo, M. Tamisari, R. Scotti, L. Ciocca, Mater. Res. Express. 2, 065002 (2015). 2) F. Assa, H. Jafarizadeh-Malmiri, H. Ajamein, N. Anarjan, H. Vaghari, Z. Sayyar, A. Berenjian, Nano Res. 9(8), 2203 (2016). (3) J. Tuček, R. Zboril, D. Petridis, J. Nanosci. Nanotechnol. 6, 926 (2006). I. Dézsi, Cs. Fetzer, Á. Gombkötő, I. Szűcs, J. Gubicza, T. Ungár, J. Appl. Phys. 103, 104312 (2008)
Magnetic lipid nanoparticles for drug delivery: a preliminary study.
Spizzo F.;Del Bianco L.;SGUIZZATO, Maddalena;Esposito E.;Cortesi R.
2017
Abstract
We present a preliminary study concerning the feasibility of the production of magnetic lipid nanoparticles for biomedical applications. Magnetic nanoparticles (MN) were obtained by a precipitation method; afterwards, different experimental protocols and lipid mixtures were used to produce MN-containing lipid nanoparticles. Two types of lipid nanoparticles were obtained, namely solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). SLN of stearic acid were produced by emulsion followed by dilution method while NLC, alternatively composed of a mixture of tristearin/tricaprylin or tristearin/labrasol/ phosphatidylcholine, were produced by homogenization followed by ultrasonication method. MN (with a 5 % relative mass concentration) were added to the lipid phase before the emulsion formation. The samples were characterized using photon correlation spectroscopy (PCS) and X-ray diffraction (XRD). Magnetization loops and magnetization vs. T curves, in the zero field cooling (ZFC) and field cooling (FC) modes [1], were collected in the 6 K – 300 K temperature (T) range with a SQUID magnetometer. MN were also analyzed using transmission Mössbauer spectroscopy in the 25 K – 300 K temperature range with a 57 Co in Rh source; the spectrometer was calibrated using an α-Fe foil. The 25 K Mössbauer spectrum shows just one sextet with a hyperfine field of ~ 50 T; this result, and the absence of the sextet asymmetries expected even for small size magnetite nanoparticles, suggest that MN are possibly made of maghemite [3]. At T = 6 K, the saturation magnetization of the as-prepared MN is ~ 33 emu/g, about 40 % of the value of bulk maghemite. This effect may be due to the presence of crystalline disorder [2] or to the canting of surface spins [1]. The size analysis showed that MN-containing SLN are larger than MN-containing NLC, being their average size equal to 500 nm and 200 nm, respectively, but monodispersed and stable up to ten months. The XRD spectra indicated that the NM nanocrystalline structure did not change upon their inclusion in lipid nanoparticles. The magnetic properties of both the MN-containing SLN and the MN-containing NLC dispersions do not substantially differ compared to those of the as-prepared MN, indicating that the magnetic interparticle interactions are still present. This suggests that the MN may form agglomerates within the lipid nanoparticles. This study confirms the possibility to incorporate MN in lipid nanoparticles; their magnetic and physicochemical properties suggest their possible use both in therapy and in diagnostics. References 1) L. Del Bianco, I. G. Lesci, G. Fracasso, G. Barucca, F. Spizzo, M. Tamisari, R. Scotti, L. Ciocca, Mater. Res. Express. 2, 065002 (2015). 2) F. Assa, H. Jafarizadeh-Malmiri, H. Ajamein, N. Anarjan, H. Vaghari, Z. Sayyar, A. Berenjian, Nano Res. 9(8), 2203 (2016). (3) J. Tuček, R. Zboril, D. Petridis, J. Nanosci. Nanotechnol. 6, 926 (2006). I. Dézsi, Cs. Fetzer, Á. Gombkötő, I. Szűcs, J. Gubicza, T. Ungár, J. Appl. Phys. 103, 104312 (2008)I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
