Stimuli-Responsive Lyotropic Liquid Crystalline Nanosystems with Incorporated Poly(2-Dimethylamino Ethyl Methacrylate)-b-Poly(Lauryl Methacrylate) Amphiphilic Block Copolymer

Abstract

There is an emerging need to evolve the conventional lyotropic liquid crystalline nanoparticles to advanced stimuli-responsive, therapeutic nanosystems with upgraded functionality. Towards this effort, typically used stabilizers, such as Pluronics®, can be combined or replaced by smart, stimuli-responsive block copolymers. The aim of this study is to incorporate the stimuli-responsive amphiphilic block copolymer poly(2-(dimethylamino)ethyl methacrylate)-b-poly(lauryl methacrylate) (PDMAEMA-b-PLMA) as a stabilizer in lipidic liquid crystalline nanoparticles, in order to provide steric stabilization and simultaneous stimuli-responsiveness. The physicochemical and morphological characteristics of the prepared nanosystems were investigated by light scattering techniques, cryogenic-transmission electron microscopy (cryo-TEM), X-ray diffraction (XRD) and fluorescence spectroscopy. The PDMAEMA-b-PLMA, either individually or combined with Poloxamer 407, exhibited different modes of stabilization depending on the lipid used. Due to the protonation ability of PDMAEMA blocks in acidic pH, the nanoparticles exhibited high positive charge, as well as pH-responsive charge conversion, which can be exploited towards pharmaceutical applications. The ionic strength, temperature and serum proteins influenced the physicochemical behavior of the nanoparticles, while the polymer concentration differentiated their morphology; their micropolarity and microfluidity were also evaluated. The proposed liquid crystalline nanosystems can be considered as novel and attractive pH-responsive drug and gene delivery nanocarriers due to their polycationic content.

Aqueous Heat Method for the Preparation of Hybrid Lipid–Polymer Structures: From Preformulation Studies to Protein Delivery

“…The population of the particles became more homogenous with the increasing weight ratio of PLMA-b-PDMAEMA ( Figure S1 ). The ζ-potential values increased but not significantly ( Figure 2 b), probably due to the partially protonated amino groups of PDMAEMA block at the pH 5.5 of HPLC-grade water [ 21 ]. The scattering-intensity value of DDA:TDB:PLMA-b-PDMAEMA 1:0.2:0.5 increased significantly in comparison to the scattering-intensity value of the pure liposomes (from ≈80 KCps to ≈140 KCps).…”

“…The raw materials are: lipids with adjuvant properties: DDA and TDB; and amphiphilic block copolymer poly(2-(dimethylamino)ethyl methacrylate)-b-poly(lauryl methacrylate) (PLMA-b-PDMAEMA). This amphiphilic block copolymer has been already used for the formulation of stimuli-responsive lyotropic liquid crystalline nanosystems and stimuli-responsive polymer-grafted liposomes for the delivery of hydrophobic anti-glioma agents [ 21 , 22 , 23 ]. For comparison reasons, we also used PAMAM G4.…”

Advances in the Design of pH-Sensitive Cubosome Liquid Crystalline Nanocarriers for Drug Delivery Applications

“…Chountoulesi et al [78] combined poly(2-dimethylamino ethyl) methacrylate (PDMAEMA), a cationic polyelectrolyte, in a conjunction with the hydrophobic poly(lauryl methacrylate) (PLMA), to produce a pH-responsive cubosome in association with monoolein or phytantriol. The cationic polyelectrolyte bears an ionizable tertiary amino group, which is protonated under acidic conditions.…”

Engineering nanotheranostic strategies for liver cancer

“…Compared with viral vector gene delivery, nonviral delivery of nanomaterials has superior efficiency, specificity, biosafety, and multifunction design[ 58 - 60 ] (Figure 6 ). Common nonviral gene delivery vectors include many cationic nanocarriers that were developed to adsorb nucleic acids by electrostatic interactions, such as cationic liposomes and polymers with positively charged blocks[ 61 , 62 ].…”