Bovine Serum Albumin Loaded Solid Lipid Nanoparticles Prepared by Double Emulsion Method

Solid lipid nanoparticles loaded with bovine serum albumin（BSA） were prepared by a double emulsion method. As the mass fraction of the model drug BSA increased from 0 to 15%, the particle size gradually increased. The physical stability of the nanoparticles was investigated by zeta potential measurement and they were shown to be quite stable. Fluorescence spectroscopy confirmed that the loaded position of BSA was on the interface between the inner aqueous phase and the solid lipid phase. Both Fourier-transform infrared spectroscopy and circular dichroism spectra indicate that BSA in the nanoparticles was not destroyed, but the secondary structure was disrupted slightly.

Influence of Emulsifiers on the Synthesis of Insulin-loaded Nanocapsules in Double Emulsion

Insulin entrapped nanocapsules to use polylactide （PLA） as the encapsulating material were prepared through a modified water-in-oil-in-water （W/O/W） emulsification and solvent evaporation method, The average particle size of PLA nanocapsules obtained was decreased to （181.5 ± 8.4） nm, and capably adjusted from 180 to 370 nm by using different types and content of nonionic emulsifiers. The influence of emulsifiers on property of nanocapsules was discussed in detail. The effects of spans and tweens to modify the size of the nanocapsules were different, which can be due to the distribution of the surfactants on the inner interface between the inner water and oil of the double emulsion. The encapsulation efficiency and drug release of nanocapsules were affected obviously by the content and type of emulsifiers.

Fabrication of Polymersomes with Controllable Morphologies through Dewetting w/o/w Double Emulsion Droplets

In this work, monodisperse giant polymersomes are fabricated by dewetting of water-in-oil-in-water double emulsion droplets which are assembled by amphiphilic block copolymer molecules in a microfluidic device. The dewetting process can be tuned by solvation between solvent and amphiphilic block copolymer to get polymersomes with controllable morphology. Good solvent （chloroform and toluene） hinders dewetting process of double emulsion droplets and gets acornlike polymersomes or patched polymersomes. On the other hand, poor solvent （hexane） accelerates the dewetting process and achieves complete separation of inner water phase from oil phase to form complete bilayer polymersomes. In addition, twin polymersomes with bilayer membrane structure are formed by this facile method. The formation mechanism for different polymersomes is discussed in detail.

Double Emulsion Droplets as Microreactors for Synthesis of Magnetic Macroporous Polymer Beads

An easy method is presented to fabricate monodisperse magnetic macroporous polymer beads（MMPBs）. Waterin-oil high internal phase emulsion（HIPE） is prepared by emulsifying aqueous iron ions solution in an oil phase containing monomers. The HIPE is introduced into a simple microfluidic device to fabricate monodisperse（water-in-oil）-in-water double emulsion droplets. The droplets serve as microreactors to synthesize Fe3O4 nanoparticles and are on-line polymerized to form MMPBs. The prepared MMPBs display uniform size, interconnected porous structure, superparamagnetic behavior and uniform distribution of Fe3O4 in polymer matrix. The MMPBs are characterized by scanning electron microscopy（SEM）, Fourier transform infrared spectroscopy（FTIR）, X-ray diffraction（XRD）, transmission electron microscopy（TEM）, vibrating sample magnetometry（VSM）. We believe that this method is a universal technique in preparing macroporous nanocomposite beads.

Regulating the Oil-Water Interface to Construct Double Emulsions:Current Understanding and Their Biomedical Applications

Double emulsions have been extensively used in scientific researches and industrial applications due to their attractive unique feature of multiple phases.However,constructing droplets with such a complex structure is not a simple task for all time.The simultaneous existence of two contradictory interfaces makes it hard to prepare stable double emulsions in principle and in practice.Over the past century,tremendous efforts have been devoted by myriads of scientists to make progresses in both theory and preparation of double emulsions.In this review,the current understanding of double emulsions is systematically revealed.In addition to emphasizing the corresponding pioneer and landmark works as many as possible,the state-of-the-art achievements will also be discussed.By regulating the oil-water interface with smartly designed interface-active agents in combination with varying the phase volume fractions,the basic theory framework based on the phase inversion from simple emulsions to double emulsions is also summarized.Technical preparation strategies of emulsification are introduced to show the building process of the two contradictory interfaces in one system.Furthermore,some specific biomedical applications of double emulsions are also discussed,which is expected to stimulate further innovation and utilization of double emulsions.

CaCO3-Assisted Preparation of pH-Responsive Immune-Modulating Nanoparticles for Augmented Chemo-Immunotherapy

Due to the negative roles of tumor microenvironment(TME)in compromising therapeutic responses of various cancer therapies,it is expected that modulation of TME may be able to enhance the therapeutic responses during cancer treatment.Herein,we develop a concise strategy to prepare pH-responsive nanoparticles via the CaCO3-assisted double emulsion method,thereby enabling effective co-encapsulation of both doxorubicin(DOX),an immunogenic cell death(ICD)inducer,and alkylated NLG919(aNLG919),an inhibitor of indoleamine 2,3-dioxygenase 1(IDO1).The obtained DOX/aNLG919-loaded CaCO3 nanoparticles(DNCaNPs)are able to cause effective ICD of cancer cells and at the same time restrict the production of immunosuppressive kynurenine by inhibiting IDO1.Upon intravenous injection,such DNCaNPs show efficient tumor accumulation,improved tumor penetration of therapeutics and neutralization of acidic TME.As a result,those DNCaNPs can elicit effective anti-tumor immune responses featured in increased density of tumor-infiltrating CD8+cytotoxic T cells as well as depletion of immunosuppressive regulatory T cells(Tregs),thus effectively suppressing the growth of subcutaneous CT26 and orthotopic 4T1 tumors on the Balb/c mice through combined chemotherapy&immunotherapy.This study presents a compendious strategy for construction of pH-responsive nanoparticles,endowing significantly enhanced chemo-immunotherapy of cancer by overcoming the immunosuppressive TME.

Reaction-controlled microgel-lipase co-stabilized compartmentalized emulsion for recyclable biodiesel production

Pickering emulsions have been widely used for biphasic catalysis in the past decade.However,it remains a great challenge to achieve simple product collection and enzyme recovery.Poly(N-isopropylacrylamide)(PNIPAM)-based microgels can endow Pickering emulsions with stimuli-responsiveness,while most microgelstabilized emulsions are oil-in-water(O/W)type and not ideal for interfacial catalysis.Besides,altering temperature or pH value for demulsification is time-and energy-consuming and may cause irreversible deactivation of enzymes.In this work,inverse water-in-oil(W/O)Pickering emulsions were formed using hexanoic acidswollen microgels as the sole emulsifiers.When lipase was added in the water phase,stable oil-in-water-in-oil(O/W/O)Pickering double emulsions could be formed through one-step emulsification,owing to the synergistic effect of the hydrophobic microgels and hydrophilic lipase at the interface.Compared with other biphasic systems,such double emulsion systems represent a desirable platform for highly efficient biodiesel production because of the ultra-high interfacial areas and fast mass transport between two phases.More importantly,the switchable transition between hydrophobicity/hydrophilicity of microgels is controlled by the catalytic reaction.Therefore,double emulsions demulsify spontaneously when substrates are used up without the need for energy input or loss of enzymatic activity,enabling the facile collection of products and demonstrating the excellent recyclability of the biphasic catalysis system.

Supramolecular Polymer Emulsifiers for One-step Complex Emulsions

Complex emulsions, such as double emulsions and high-internal-phase emulsions, have shown great applications in the fields of drug delivery, sensing, catalysis, oil-water separation and self-healing materials. Their controllable preparation is at the forefront of interface and material science. Surfactants and polymers have been widely used as emulsifiers for building complex emulsions. Yet some inherent disadvantages exist including multi-step emulsifications and low production efficiency. Alternatively, supramolecular polymer emulsifier for complex emulsions via one-step emulsification is rising as a new strategy due to the ease of preparation. In this feature article, we review our recent progresses in using supramolecular polymer emulsifiers for the preparation of complex emulsions. Double emulsions and high-internal-phase emulsions are successfully prepared via one-step emulsification with the help of different supramolecular interactions including electrostatic, hydrogen bond, coordination interaction and dynamic covalent bond, which will be particularly emphasized in detail. In the end, a comprehensive prospect is given for the future development of this field. This article is expected to provide new inspirations for preparing complex emulsions via supramolecular routes.

Hydrophilic surface modification of PDMS for droplet microfluidics using a simple,quick,and robust method via PVA deposition

Polydimethylsiloxane(PDMS)is a dominant material in the fabrication of microfluidic devices to generate water-in-oil droplets,particularly lipid-stabilized droplets,because of its highly hydrophobic nature.However,its key property of hydrophobicity has hindered its use in the microfluidic generation of oil-in-water droplets,which requires channels to have hydrophilic surface properties.In this article,we developed,optimized,and characterized a method to produce PDMS with a hydrophilic surface via the deposition of polyvinyl alcohol following plasma treatment and demonstrated its suitability for droplet generation.The proposed method is simple,quick,effective,and low cost and is versatile with respect to surfactants,with droplets being successfully generated using both anionic surfactants and more biologically relevant phospholipids.This method also allows the device to be selectively patterned with both hydrophilic and hydrophobic regions,leading to the generation of double emulsions and inverted double emulsions.