Preparation and lectin binding characteristics of N-stearyl lactobionamide liposomes

Enhanced intracellular accumulation and cytotoxicity of bortezomib against liver cancer cells using N-stearyl lactobionamide surface modified solid lipid nanoparticles

Asialoglycoprotein receptors (ASGPRs) are highly expressed on hepatocytes and have been used for liver-targeted delivery and hepatocellular carcinoma (HCC) therapy. However, targeted delivery of bortezomib (BTZ) to HCC has not been reported. In this study, N-stearyl lactobionamide (N-SALB) with galactose (Gal) moiety was synthesized as a targeting agent and its structure was confirmed by FT-IR and NMR analyses. N-SALB surface-modified solid lipid nanoparticles (SLNs) loaded with BTZ (Gal-SLNs/BTZ) were developed to target BTZ delivery into HCC cancer cells. The Gal-SLNs/BTZ had an average particle size of 116.3 nm, polydispersity index (PDI) of 0.210, and zeta potential of -13.8 mV. TEM analysis showed their nanometer-sized spherical morphology. The encapsulation efficiency (EE) and drug loading (DL) capacity were 84.5 % and 1.16 %, respectively. Release studies showed that BTZ loaded inside the SLNs was slowly released over a period of 72 h at pH 7.4. Flow cytometry analysis showed significantly higher intracellular uptake of N-SALB-targeted nanoparticles than non-targeted nanoparticles in HepG2 cells. All lipid formulations showed good biocompatibility in the cytotoxicity study using MTT assay. Concentration-dependent cytotoxicity was observed for all formulations, with N-SALB-targeted nanoparticles demonstrating more cytotoxicity against HepG2 cells. The highest percentage of apoptosis was obtained for N-SALB-targeted nanoparticles compared to non-targeted nanoparticles (42.2 % and 8.70 %, respectively). Finally, biodistribution studies in HepG2 bearing nude mice showed that the accumulation of targeted nanoparticles in the tumor was significantly higher than non-targeted nanoparticles.

Polysaccharide conjugates surpass monosaccharide ligands in hepatospecific targeting - Synthesis and comparative in silico and in vitro assessment

Ligands with the polysaccharide headgroups have been recently reported by our group to possess enhanced interaction with asialoglycoprotein receptor (ASGPR) in silico as compared to ligands having galactose moieties. This enhanced interaction is a result of the polymer's backbone support in anchoring the ligand in a specific orientation within the bilayer. In this paper, we have attempted to provide an in vitro proof of concept by performing a comparative evaluation of polysaccharide and monosaccharide-based ligands. Docking was performed to understand interaction with ASGPR in silico. Agarose and galactose conjugates with behenic acid were synthesized, purified, and characterized to yield biocompatible hepatospecific ligands which were incorporated into nanoliposomes. Cellular internalization of these targeted liposomes was studied using confocal microscopy and flow cytometry. The toxicity potential was assessed in vivo. Results indicated that the polysaccharide-based ligand increased cellular uptake due to better interaction with the receptor as compared to ligand bearing a single galactose group. In addition to developing novel liver targeting ligands, the study also established proof of concept that has been suggested by earlier in silico investigations. The approach can be used to design targeting ligands and develop formulations with improved targeting efficacy.

Spontaneous transformation of lamellar structures from simple to more complex states

Spontaneous transformation of lamellar structures, such as multilamellar vesicles from micelles or unilamellar vesicles, is an important challenge in the field of amphiphile molecules, which may serve as models to understand biologically relevant bilayer membranes. Herein, we report a progressive self-assembly progress of N-tetradecyllactobionamide (C14G2) and tetraethylene glycol monododecyl ether (C12EO4) mixtures in aqueous solution. Increasing temperature or surfactant compositions causes spontaneous transformation from simple to high-level aggregates, i.e., from unilamellar vesicles, to coexisting multilamellar vesicles, terraced planar bilayers, and finally terraced planar bilayers. Deuterium nuclear magnetic resonance ((2)H NMR), freeze-fracture transmission electron microscopy (FF-TEM), and small-angle X-ray scattering (SAXS) measurements clearly demonstrate the spontaneously progressive self-assembly process. The interlamellar spacing (d) of the bilayers decreases from unilamellar vesicles to the terraced planar bilayers with an increase of the temperature or surfactant compositions. Lamellar samples consisting of terraced planar bilayers at higher temperature still show viscoelastic properties, being Bingham fluids, and both the viscoelasticity and yield stress increase with the composition and decrease with the temperature. The spontaneous transformation of the progressive self-assembly progress of C14G2 and C12EO4 aqueous mixtures is due to a balance of three driving forces, hydrophobic interactions, hydrogen bonding, and steric effects.

Preparation and characterization of galactose-modified liposomes by a nonaqueous enzymatic reaction

In this study, NOH (NOH = N-octadecyl-4-[(D-galactopyranosyl)oxy]-2,3,5,6-tetrahydroxy hexanamide) was enzymatically synthesized as a targeting molecule and incorporated into liposomes to prepare a liposome surface modified with galactose. Glycyrrhetinic-acid-loaded liposome (GA-LP) and glycyrrhetinic-acid-loaded liposome surface modified with galactose (NOH-GA-LP) were prepared by the ethanol-injection method. NOH-GA-LP was characterized by morphology, particle size, zeta potential, encapsulation efficiency, release in vitro, and stability. The size of spherical particles was in the range of 179-211 nm. Spherical particles exhibit a positive electrical charge (38.7 mV) and possess high encapsulation efficiency (91.3%) and show sustained release (72% over 48 hours) in vitro. This novel approach for the liposome surface modified with galactose by enzymatic synthesis is expected to provide potential application as a drug carrier for active targeted delivery to hepatocytes.

Breaking the barrier: methods for reversible permeabilization of cellular membranes

Plasma membrane constitutes a major barrier for the entry of hydrophilic molecules into the cell interior. Selective and reversible permeabilization of this barrier is a prerequisite for many biotechnological applications. This article reviews general principles of membrane permeabilization based on biological, chemical, and physical methods and mechanisms of the delivery of extrinsic substances to cell interior. The emphasis is given on the methods that have significantly contributed to our understanding of biological phenomena on membrane level or have been widely used in current biotechnology, such as delivery by membrane vehicles, electropermeabilization, microinjection, and biolistics. The mechanisms of the internalization of extrinsic substances and the advantages and drawbacks of individual techniques are discussed with respect to specific applications in biotechnology.