AFM and TEM characterization of siRNAs lipoplexes: A combinatory tools to predict the efficacy of complexation

Belletti, Daniela; Tonelli, Massimo; Forni, Flavio; Tosi, Giovanni; Vandelli, Maria Angela; Ruozi, Barbara

doi:10.1016/j.colsurfa.2013.07.021

Cited by 12 publications

(13 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…On the contrary, microscopic techniques, particularly TEM, can be usefully applied for the evaluation of the nanosystem morphology (Anabousi et al, 2005;Belletti et al, 2013;Ruozi et al, 2007). The image from NS-TEM of LPs revealed a homogeneous population of vesicles (Figure 1a) ranging from 100 to 200 nm in agreement with the results obtained by PCS.…”

Section: Resultssupporting

confidence: 77%

“…Generally, lipidic systems can be considered as amorphous structures in which the bright/dark contrast observed in TEM images can be related to the Z number of the atoms and to the thickness of the samples. As an example, the dense areas and the fraction containing heavy elements appeared dark owing to the electron scattering of the atoms (Belletti et al, 2013;Egerton, 2005). However, the contrast can be easily realized by staining, i.e.…”

Section: Resultsmentioning

confidence: 97%

See 1 more Smart Citation

Functionalization of liposomes: microscopical methods for preformulative screening

Belletti

Vandelli

Tonelli

et al. 2014

Journal of Liposome Research

Self Cite

View full text Add to dashboard Cite

The development of smart delivery systems able to deliver and target a drug to the site of action is one of the major challenges in the field of pharmaceutical technology. The surface modification of nanocarriers, such as liposomes, is widely investigated either for increasing the blood circulation time (by pegylation) or for interacting with specific tissues or cells (by conjugation of a selective ligand as a monoclonal antibody, mAb). Microscopical analysis thereby is a useful approach to evaluate the morphology and the size owing to resolution and versatility in defining either surface modification or the architecture and the internal structure of liposomes. This contribution aims to connect the outputs obtained by transmission electron (TEM) and atomic force (AFM) microscopical techniques for identifying the modifications on the liposomal surface. To reach this objective, we prepared liposomes applying two different pegylation technologies and further modifying the surface by mAb conjugation. This work demonstrates the feasibility to apply the combined approach (TEM and AFM analysis) in the evaluation of the efficacy of a surface engineering process.

show abstract

Section: Resultssupporting

confidence: 77%

Section: Resultsmentioning

confidence: 97%

Functionalization of liposomes: microscopical methods for preformulative screening

Belletti

Vandelli

Tonelli

et al. 2014

Journal of Liposome Research

Self Cite

View full text Add to dashboard Cite

show abstract

“…These size distributions were confirmed by fluorescence microscopy (Fig. 10) and negative staining transmission electron microscopy after Belletti et al (2013) (Fig. 11).…”

Section: Fluorescence and Uv/vis Spectroscopysupporting

confidence: 74%

Supramolecular Langmuir monolayers and multilayered vesicles of self-assembling DNA–lipid surface structures and their further implications in polyelectrolyte-based cell transfections

2015

View full text Add to dashboard Cite

The basic interfacial characteristics of DNA-lipid recognitions have been studied. The complex structures of individual unbound DNA molecules and their binary and ternary complexes with zwitterionic lipids and divalent cations were followed by employing lipid monolayers at the air-liquid interfaces, as well as by performing various microscopic, spectroscopic, and thermodynamic measurements with multilayered vesicles. The pressure-area isotherms depicted that Mg 2? -ions increase the surface pressure of lipid films and thus give rise to electrostatic and hydrophobic lipid-DNA interactions in terms of DNA adsorption, adhesion, and compaction. These features were further approached by using multilamellar vesicles with a mean diameter of 850 nm, where a metal ion-directed nucleic acid compaction and condensation effects were shown. The data obtained show the effectiveness of Langmuir monolayers and lipid multilayers in studying nucleic acid-lipid recognitions. The data provide with further details and support previous reports on mainly structural features of these recognitions. Biomolecular surface recognition events were presented in direct link with spectral and thermodynamic features of lipid vesicle-polynucleotide complex formations. The results serve to build a theoretical model considering the use of neutral lipids in lipoplex designs as a polyelectrolyte alternatives to the currently employed cytotoxic cationic liposomes. The supramolecular structures formed and their possible roles in interfacial electrostatic and hydrophobic mechanisms of endosomal escape in relevant cell transfection assays are particularly emphasized.

show abstract

“…(4) Complexes formed by electrostatic interactions between cationic liposomes and siRNA, called lipoplexes, are considered to be the most suitable carriers for the intracellular delivery of nucleic acids, particularly for siRNA. (5,6) In addition, they are versatile systems whose surfaces can be modified to increase their circulation time and improve their interaction with the target. (7) One of the key factors influencing siRNA delivery is the macromolecular shape of the lipoplex.…”

Section: Introductionmentioning

confidence: 99%

Supramolecular Organization and siRNA Binding of Hyaluronic Acid-Coated Lipoplexes for Targeted Delivery to the CD44 Receptor

et al. 2015

View full text Add to dashboard Cite

Original Citation:Supramolecular organization and siRNA binding of hyaluronic acid-coated lipoplexes for targeted delivery to the CD44 receptor. Published version:DOI:10.1021/acs.langmuir.5b01979 Terms of use:Open Access (Article begins on next page) Anyone can freely access the full text of works made available as "Open Access". Works made available under a Creative Commons license can be used according to the terms and conditions of said license. Use of all other works requires consent of the right holder (author or publisher) if not exempted from copyright protection by the applicable law. Availability: This is the author's manuscript AbstractThe dynamics of the formation of siRNA-lipoplexes coated with hyaluronic acid (HA) and the parameters influencing their supramolecular organization were studied. The insertion of a HAdioleylphosphatidylethanolamine (DOPE) conjugate in the liposome structure as well as subsequent complexation with siRNA increased the liposome size. Lipoplexes were around 110 nm at high ± charge ratios with a zeta potential around +50 mV and around 230 nm at low ± ratios, with a zeta potential that decreased to negative values, reaching −45 mV. The addition of the conjugate did not compromise siRNA binding to liposomes, although these nucleic acids induced a displacement of part of the HA-DOPE conjugate upon lipoplex formation, as confirmed by capillary electrophoresis. Isothermal titration calorimetry, X-ray diffraction studies, and cryo-TEM microscopy demonstrated that in addition to electrostatic interactions with siRNA a rearrangement of the lipid bilayers takes place, resulting in condensed oligolamellar vesicles. This phenomenon is dependent on the number of siRNA molecules and the degree of modification with HA. Finally, the suitable positioning of HA on the lipoplex surface and its ability to bind specifically to the CD44 receptors in a concentrationdependent manner was demonstrated by surface plasmon resonance analysis.

show abstract

AFM and TEM characterization of siRNAs lipoplexes: A combinatory tools to predict the efficacy of complexation

Cited by 12 publications

References 23 publications

Functionalization of liposomes: microscopical methods for preformulative screening

Functionalization of liposomes: microscopical methods for preformulative screening

Supramolecular Langmuir monolayers and multilayered vesicles of self-assembling DNA–lipid surface structures and their further implications in polyelectrolyte-based cell transfections

Supramolecular Organization and siRNA Binding of Hyaluronic Acid-Coated Lipoplexes for Targeted Delivery to the CD44 Receptor

Contact Info

Product

Resources

About