Synthesis of Oil-Laden Poly(ethylene glycol) Diacrylate Hydrogel Nanocapsules from Double Nanoemulsions

Abstract

Multiple emulsions have received great interest due to their ability to be used as templates for the production of multi-compartment particles for a variety of applications.However, scaling these complex droplets to nanoscale dimensions has been a challenge due to limitations on their fabrication methods. Here, we report the development of oil-in-water-in-oil (O1/W/O2) double nanoemulsions via a two-step high-energy method, and their use as templates for complex nanogels comprised of inner oil droplets encapsulated within a hydrogel matrix.Using a combination of characterization methods, we determine how the properties of the nanogels are controlled by the size, stability, internal morphology, and chemical composition of the nanoemulsion templates from which they are formed. This allows for identification of 2 compositional and emulsification parameters that can be used to optimize the size and oil encapsulation efficiency of the nanogels. Our templating method produces oil-laden nanogels with high oil encapsulation efficiencies and average diameters of 200-300 nm. In addition, we demonstrate the versatility of the system by varying the types of inner oil, the hydrogel chemistry, the amount of inner oil, and the hydrogel network crosslink density. These non-toxic oil-laden nanogels have potential applications in food, pharmaceutical, and cosmetic formulations.

Toward the Formulation of Stable Micro and Nano Double Emulsions through a Silica Coating on Internal Water Droplets

“…On the contrary, in the two-step processes (which we followed), the internal water may be different from the external water, which makes them more suited for optimizing the encapsulation efficiency. [13][14][15] The primary w 1 /O emulsion must be of very small size, preferably a nano-emulsion stabilized by a low HLB surfactant. Reverse emulsion is generally obtained by a high-energy method, using a high-pressure homogenizer or ultrasounds.…”

“…For example, such a co-encapsulation of drugs is critical for optimizing targeted therapies by the simultaneous co-delivery of anticancer species with another complementary cytotoxic molecule, anti-inflammatory agent or adjuvant. Double emulsion formulations at the nanoscale were already reported, [12][13][14][15]17,18 but always by turning one of the liquid phase, i.e. internal water or oil, into a polymerized matrix.…”

Preparation of α-Linolenic-Acid-Loaded Water-in-Oil-in-Water Microemulsion and Its Potential as a Fluorescent Delivery Carrier with a Free Label

“…The two-step heterotherm method, a novel attempt to form stable W/O/W microemulsion, achieves the span from micro- to nanosize via using only a single surfactant to control the balance of the lowest free energy at multiple interfaces. The surfactant consisting of hydrophilic and hydrophobic groups has effective functional effects on reducing interfacial tension and generating strong interfacial films. , In most cases, both a surfactant and co-surfactant are employed to further increase the extent of emulsification and stabilize the oil droplets in aqueous media …”

Low temperature flow lithography

“…Flow lithography (FL), a microfluidic technique that synthesizes hydrogel particles via photolithography, has been gaining popularity because of its ability to assign complex geometrical and chemical designs to microparticles. 1 Such particles have demonstrated extended functionalities over homogenous spherical particles produced by conventional methods, such as emulsion polymerization 2,3 and droplet-based microfluidics. [4][5][6] For example, non-spherical particles of specific geometry 7,8 have been utilized in photonics, 9 self-assembly, 10 microelectromechanical systems (MEMS), 11 and biomimicry systems, in which particles that structurally resemble biological elements, such as red blood cells, have been synthesized.…”