Surface-active solid lipid nanoparticles as Pickering stabilizers for oil-in-water emulsions

The preparation and properties of water-in-oil (W/O) emulsions stabilised solely by adsorbed surface-active solid lipid nanoparticles (SLNs) at the oil-water interface were studied. Monostearin-based SLNs were prepared using food-grade micoremulsions as nanoscle 'reactors'. Hot oil-in-water (O/W) microemulsions (70°C) consisting of monostearin, Tween 20, ethanol and water were crash-cooled to 4°C to promote the liquid-solid transition of the monostearin and thus develop sub-micron solid lipid particles. SLNs obtained from the cooled microemulsions were partially stabilised with addition to lecithin (0.5% w/w) to the microemulsion system. With 2% (w/w) added monstearin, the W/O emulsion was stable for the 14 days of study. The microstructure of the emulsions revealed the presence of two stabilisation mechanisms, namely Pickering-type and continuous phase crystal network stabilisation, which both contributed to slowing dispersed droplet coalescence. Overall, this study demonstrated that surface-active SLNs developed using a microemulsion technique could effectively kinetically stabilise model W/O emulsions.

Download Full-text

Microemulsion-Based Solid Lipid Nanoparticles As Emulsion Stabilisers

10.32920/ryerson.14662881.v1 ◽

2021 ◽

Author(s):

Elham H. Hazfi

Keyword(s):

Solid Lipid Nanoparticles ◽

Lipid Nanoparticles ◽

Continuous Phase ◽

Tween 20 ◽

Microemulsion System ◽

Solid Lipid ◽

Oil In Water ◽

Phase Crystal ◽

Surface Active ◽

Oil Water

The preparation and properties of water-in-oil (W/O) emulsions stabilised solely by adsorbed surface-active solid lipid nanoparticles (SLNs) at the oil-water interface were studied. Monostearin-based SLNs were prepared using food-grade micoremulsions as nanoscle 'reactors'. Hot oil-in-water (O/W) microemulsions (70°C) consisting of monostearin, Tween 20, ethanol and water were crash-cooled to 4°C to promote the liquid-solid transition of the monostearin and thus develop sub-micron solid lipid particles. SLNs obtained from the cooled microemulsions were partially stabilised with addition to lecithin (0.5% w/w) to the microemulsion system. With 2% (w/w) added monstearin, the W/O emulsion was stable for the 14 days of study. The microstructure of the emulsions revealed the presence of two stabilisation mechanisms, namely Pickering-type and continuous phase crystal network stabilisation, which both contributed to slowing dispersed droplet coalescence. Overall, this study demonstrated that surface-active SLNs developed using a microemulsion technique could effectively kinetically stabilise model W/O emulsions.

Download Full-text

Interfacial and colloidal characterization of oil-in-water emulsions stabilized by interface-tunable solid lipid nanoparticles

Food Chemistry ◽

10.1016/j.foodchem.2019.125619 ◽

2020 ◽

Vol 306 ◽

pp. 125619 ◽

Cited By ~ 3

Author(s):

Honggu Lim ◽

Myeongsu Jo ◽

Choongjin Ban ◽

Young Jin Choi

Keyword(s):

Solid Lipid Nanoparticles ◽

Lipid Nanoparticles ◽

Solid Lipid ◽

Oil In Water

Download Full-text

Surface-active solid lipid nanoparticles for emulsion stabilization

10.32920/ryerson.14648505.v1 ◽

2021 ◽

Author(s):

Renuka Tanmay Gupta

Keyword(s):

Particle Size ◽

Solid Lipid Nanoparticles ◽

Lipid Nanoparticles ◽

Laser Diffraction ◽

Cooling Curve ◽

Weighted Mean ◽

Ζ Potential ◽

Mean Particle Size ◽

Solid Lipid ◽

Oil In Water

Solid lipid nanoparticles (SLNs) consisting of the food grade surfactant lipid glyceryl stearate citrate (GSC) were prepared using hot melt emulsification and high-pressure homogenization. Flash-cooling of the resultant oil-in-water nanoemulsions led to the formation of GSC SLNs. The effective mean particle size of the SLNs was ~180 nm by dynamic light scattering and the volume-weighted mean particle size was ~152 nm by laser diffraction, with a zeta (ζ) potential of ~-49 mV. Effective mean particle size and ζ potential were stable for 24 wk. An equilibrium contact angle of ~108.7⁰ measured through oil phase was obtained, suggesting a wettable lipid surface. The melting curve of the SLNs obtained by differential scanning calorimetry showed a significantly lower melting point and broader peak as compared to the bulk GSC, which was attributed to the nano-scale particle size. Unusually, the cooling curve showed an identical crystallization temperature as that for the bulk GSC, which suggested surface heterogeneous crystallization of the SLNs. Subsequent heating-cooling cycles confirmed the existence of nanosized particles in the sample during thermal analysis. Transmission electron (TEM) and atomic force microscopy (AFM) both revealed anisometric, flattened SLNs with circular or elliptical shapes. SLNs were studied for their effectiveness as colloidal emulsifiers in oil-in-water (o/w) emulsions. The generated o/w emulsions had a volume-weighted mean droplet size of ~459 nm by laser diffraction and ζ potential of ~-43 mV. The emulsions were stable for up to 12 wk. as observed for macroscopic changes by inverted light microscopy. TEM images pointed to the presence of a Pickering-type network stabilizing the emulsions. With time, desorption of the SLNs from the oil droplet surface into the continuous aqueous environment, coupled with Ostwald ripening, resulted in destabilization of the emulsions. Overall, these results demonstrated that stabilization of o/w emulsions was achievable using SLNs as the sole emulsifiers.

Download Full-text

Tailored rigidity of W/O Pickering emulsions using diacylglycerol-based surface-active solid lipid nanoparticles

Food & Function ◽

10.1039/d1fo01883c ◽

2021 ◽

Author(s):

Guoyan Li ◽

Wan Jun Lee ◽

Chin Ping Tan ◽

Oi-Ming Lai ◽

Yong Wang ◽

...

Keyword(s):

Solid Lipid Nanoparticles ◽

Colloidal Stability ◽

Lipid Nanoparticles ◽

Pickering Emulsions ◽

Solid Lipid ◽

Surface Active ◽

Long Chain

Pickering water-in-oil (W/O) emulsions were fabricated by using medium-long chain diacylglycerol (MLCD)-based solid lipid nanoparticles (SLNs) and the connection between the characteristics of the SLNs and the colloidal stability of...

Download Full-text

Surface-active solid lipid nanoparticles for emulsion stabilization

10.32920/ryerson.14648505 ◽

2021 ◽

Author(s):

Renuka Tanmay Gupta

Keyword(s):

Particle Size ◽

Solid Lipid Nanoparticles ◽

Lipid Nanoparticles ◽

Laser Diffraction ◽

Cooling Curve ◽

Weighted Mean ◽

Ζ Potential ◽

Mean Particle Size ◽

Solid Lipid ◽

Oil In Water

Solid lipid nanoparticles (SLNs) consisting of the food grade surfactant lipid glyceryl stearate citrate (GSC) were prepared using hot melt emulsification and high-pressure homogenization. Flash-cooling of the resultant oil-in-water nanoemulsions led to the formation of GSC SLNs. The effective mean particle size of the SLNs was ~180 nm by dynamic light scattering and the volume-weighted mean particle size was ~152 nm by laser diffraction, with a zeta (ζ) potential of ~-49 mV. Effective mean particle size and ζ potential were stable for 24 wk. An equilibrium contact angle of ~108.7⁰ measured through oil phase was obtained, suggesting a wettable lipid surface. The melting curve of the SLNs obtained by differential scanning calorimetry showed a significantly lower melting point and broader peak as compared to the bulk GSC, which was attributed to the nano-scale particle size. Unusually, the cooling curve showed an identical crystallization temperature as that for the bulk GSC, which suggested surface heterogeneous crystallization of the SLNs. Subsequent heating-cooling cycles confirmed the existence of nanosized particles in the sample during thermal analysis. Transmission electron (TEM) and atomic force microscopy (AFM) both revealed anisometric, flattened SLNs with circular or elliptical shapes. SLNs were studied for their effectiveness as colloidal emulsifiers in oil-in-water (o/w) emulsions. The generated o/w emulsions had a volume-weighted mean droplet size of ~459 nm by laser diffraction and ζ potential of ~-43 mV. The emulsions were stable for up to 12 wk. as observed for macroscopic changes by inverted light microscopy. TEM images pointed to the presence of a Pickering-type network stabilizing the emulsions. With time, desorption of the SLNs from the oil droplet surface into the continuous aqueous environment, coupled with Ostwald ripening, resulted in destabilization of the emulsions. Overall, these results demonstrated that stabilization of o/w emulsions was achievable using SLNs as the sole emulsifiers.

Download Full-text