Alessio Caciagli,Mykolas Zupkauskas,Aviad Levin,Tuomas P. J. Knowles,Clément Mugemana,Nico Bruns,Thomas O’Neill,William J. Frith,Erika Eiser
Many industrial soft materials include oil-in-water (O/W) emulsions at the core of their formulations. By using tuneable interface stabilizing agents, such emulsions can self-assemble into complex structures. DNA has been used for decades as a thermoresponsive, highly specific binding agent between hard and, recently, soft colloids. Up until now, emulsion droplets functionalized with DNA had relatively low coating densities and were expensive to scale up. Here, a general O/W DNA-coating method using functional nonionic amphiphilic block copolymers, both diblock and triblock, is presented. The hydrophilic poly(ethylene glycol) ends of the surfactants are functionalized with azides, allowing for efficient, dense, and controlled coupling of dibenzocyclooctane-functionalized DNA to the polymers through a strain-promoted alkyne–azide click reaction. The protocol is readily scalable due to the triblock’s commercial availability. Different production methods (ultrasonication, microfluidics, and membrane emulsification) are used with different oils (hexadecane and silicone oil) to produce functional droplets in various size ranges (submicron, ∼20 and >50 μm), showcasing the generality of the protocol. Thermoreversible submicron emulsion gels, hierarchical “raspberry” droplets, and controlled droplet release from a flat DNA-coated surface are demonstrated. The emulsion stability and polydispersity is evaluated using dynamic light scattering and optical microscopy. The generality and simplicity of the method opens up new applications in soft matter, biotechnological research, and industrial advances.
Zein particles are potential for the encapsulation of bioactive compounds . Deoxyribonucleic acid (DNA) shows good pH stability and can complex with antioxidants. In this study, DNA and DNA-quercetin complexes was used as the coating layer of zein particles. Zein particles had a size of 85.10 nm and ζ-potential of −30.73 mV at 1 mg/mL DNA. Zein/DNA particles were stable at pH 4–9. Encapsulation efficiency of kaempferol and α-tocopherol in complex particles reached 92.90% and 97.02%, respectively. The potential use of zein/DNA particles was evaluated for protecting kaempferol. Moreover, DNA-quercetin complex coating was investigated to discuss the protection of α-tocopherol in zein particles. The DNA coating improved the storage stability of kaempferol or α-tocopherol by strengthening physical barrier. DNA-quercetin complexes further improved the stability of α-tocopherol by acting as antioxidant barrier. The retention of kaempferol and α-tocopherol was about 58% in zein/DNA and zein/DNA-quercetin particles at 45 °C after 28 days.