Liposome-Enveloped Molecular Nanogels

Abstract

Novel hydrogel@liposome particles were prepared by pHtriggered molecular gel formation inside of liposomes loaded with a lowmolecular weight gelator derived from L-valine (1). Liposome formation was carried out using L-α-phosphatidylcholine (PC) and cholesterol as components of the lipid bilayer. Molecular hydrogelator 1 and pyranine, a ratiometric fluorescent pH probe, were entrapped in the liposomes at pH 9 and posterior acidification with D-glucono-1,5-lactone to pH 5−6 provoked intraliposomal gel formation. Removal of the lipid bilayer with sodium dodecyl sulfate yielded naked nanogel particles. The systems were characterized by transmission electron microscopy and dynamic light scattering. The hydrogel@liposomes were loaded with doxorubicin, showing a similar release than that observed for liposomes. The hybrid particles described here are the first case of nonpolymeric hydrogel@liposome systems reported. This type of nanocarriers merges the benefits of liposomal vehicles with the inherent stimuli responsiveness and enhanced biocompatibility of hydrogels formed by low-molecular weight molecules, foretelling a potential use in environmentally sensitive drug release.

Nanoscale Drug Delivery Systems in Glioblastoma

“…The construction of nanogel is based on physical crosslinks (van der Waals, electrostatic interactions and hydrogen bonding) and/or chemical covalent bonds, endowing nanogel with the conformational changeability property against environmental stimuli [ 175 ]. Nanogel particles can be synthesized in an initiated [ 176 ] or self-assembly [ 177 ] manner, through which initiator/gelator is required or not respectively. Unlike micelle, the amphiphilic associations between nanogel polymers exhibited superior stability, which is attributed to the plentiful cross-link points in nanogel instead of di-/tri-blocks structure in micelles.…”

Development of Gelled-Oil Nanoparticles for the Encapsulation and Release of Berberine

“…20,21 Bulk organogels from LMWGs can be easily downsized to aqueous colloidal dispersions of gelled-oil nanoparticles (GNPs) via a two-step process in which emulsified oil droplets are typically generated via a hot emulsification process followed by cooling. 24−27 Although GNPs have exhibited the potential for the encapsulation, protection, and delivery of a variety of bioactives with low water solubility (i.e., nile red and efavirenz, 28 rose bengal and hypericine, 29 rhodamine 123, 30 curcumin, 31,32 curcuminaldehyde, 33 sunscreen, 34 indomethacin and ketoconazole, 35 metallophthalocyanine, 36 flurbiprofen, 37 β-carotene, 38 coumarin, 39 paclitaxel, 40,41 and doxorubicin 42 ), they are still relatively seldom used. The commercially available 12-hydroxystearic acid (HSA) is the most commonly used LMWG for GNPs, 25,28,[34][35][36][37]40,41 and thus the development of new custom LWMGs offers the opportunity to form gels with a wider variety of organic liquids 43,44 as well as introduce other interesting properties to trigger different types of stimuliresponsive systems that could enable tunable release characteristics.…”

Self-assembled low-molecular-weight gelator injectable microgel beads for delivery of bioactive agents

“…50 nm) from LMWGs within a stabilising liposome shell that was subsequently removed. 11 These nanoparticle LMWGs are very small, and it is difficult to fully understand their internal structuring and stability.…”