DataSheet1_Microfluidic production of polyacrylic acid functionalized PEG microgels for efficient biomolecular conjugation.PDF

We present a double emulsion drop-based microfluidic approach to produce uniform polyacrylic acid functionalized polyethylene glycol (PAA-PEG) microgels. By utilizing double emulsion drops as templates, we produce monodisperse microgels by rapid photopolymerization of the inner prepolymer drop consisting of polyacrylic acid (PAA) and polyethylene glycol diacrylate (PEGDA), followed by dewetting the oil layer when they disperse into an aqueous media. The size control of the PAA-PEG microgels with a broad range is achieved by tuning the flow rate of each phase; the uniformity of the microgels is maintained even when the flow rate changes. The results show rapid R-phycoerythrin (R-PE) coupling with the microgels’ carboxylate with minimal non-specific adsorption, demonstrating highly efficient and reliable biomolecular conjugation within PAA-PEG microgels.</p

Solvent-Free Fabrication of Anisotropic Microparticles with Precise 3D Shape Control Using Dipping-Based Micromolding

We present an innovative solvent-free micromolding technique for rapidly fabricating complex polymer microparticles with three-dimensional (3D) shapes utilizing a surface tension-induced dipping process. Our fabrication process involves loading a photocurable solution into micromolds through mold dipping. The loaded solution, induced by surface tension, undergoes spatial deformation upon mold removal caused by surface forces, ultimately acquiring an anisotropic shape before photopolymerization. Results show that the amount of photocurable solution loaded depends on the degree of capillary penetration, which can be adjusted by varying the dipping time and mold height. It enables the production of polymer particles with precisely controlled 3D shapes without diluting them with volatile organic solvents. Sequential micromolding enables the spatial stacking of the polymer domain through a bottom-up approach, facilitating the creation of complex multicompartmental microparticles with independently controlled compartments. Finally, we demonstrated the successful simultaneous conjugation of multiple model-fluorescent proteins through the biofunctionalization of microparticles, indicating functional stability and effective conjugation of hydrophilic molecules such as proteins. We also extend our capacity to create bicompartmental microparticles with distinct functionalities in each compartment, revealing spatially controlled functional structures. In summary, these findings demonstrate a straightforward, rapid, and reliable method for producing highly uniform complex particles with precise control over the 3D shape and compartmentalization, all accomplished without the use of organic solvents

A Facile Synthesis–Fabrication Strategy for Integration of Catalytically Active Viral-Palladium Nanostructures into Polymeric Hydrogel Microparticles <i>via</i> Replica Molding

The synthesis of small, uniform, well-dispersed and active Pd nanocatalysts under mild conditions in a predictable and controlled manner is an unmet challenge. Viral nanomaterials are attractive biotemplates for the controlled synthesis of nanoparticles due to their well-defined and monodisperse structure along with abundant surface functionalities. Here, we demonstrate spontaneous formation of small (1–2 nm), uniform and highly crystalline palladium (Pd) nanoparticles along genetically modified tobacco mosaic virus (TMV1cys) biotemplates without external reducing agents. The ratio between TMV and Pd precursor plays an important role in the exclusive formation of well-dispersed Pd nanoparticles along TMV biotemplates. The as-prepared Pd–TMV complexes are then integrated into the poly(ethylene glycol) (PEG)-based microparticles <i>via</i> replica molding (RM) technique in a simple, robust and highly reproducible manner. High catalytic activity, recyclability and stability of the hybrid Pd–TMV–PEG microparticles are further demonstrated through dichromate reduction as a model reaction. Taken together, these findings demonstrate a significant step toward simple, robust, and scalable synthesis and fabrication of efficient biotemplate-supported Pd nanocatalysts in readily deployable polymeric scaffolds with high capacity in a controlled manner

Controlled Fabrication of Multicompartmental Polymeric Microparticles by Sequential Micromolding via Surface-Tension-Induced Droplet Formation

Polymeric multicompartmental microparticles have significant potential in many applications due to the capability to hold various functions in discrete domains within a single particle. Despite recent progress in microfluidic techniques, simple and scalable fabrication methods for multicompartmental particles remain challenging. This study reports a simple sequential micromolding method to produce monodisperse multicompartmental particles with precisely controllable size, shape, and compartmentalization. Specifically, our fabrication procedure involves sequential formation of primary and secondary compartments in micromolds via surface-tension-induced droplet formation coupled with simple photopolymerization. Results show that monodisperse bicompartmental particles with precisely controllable size, shape, and chemistry can be readily fabricated without sophisticated control or equipment. This technique is then extended to produce multicompartmental particles with controllable number of compartments and their size ratios through simple design of mold geometry. Also, core–shell particles with controlled number of cores for primary compartments can be readily produced by simple tuning of wettability. Finally, we demonstrate that the as-prepared multicompartmental particles can exhibit controlled release of multiple payloads based on design of particle compositions. Combined, these results illustrate a simple, robust, and scalable fabrication of highly monodisperse and complex multicompartmental particles in a controlled manner based on sequential micromolding

Controllable Preparation of Monodisperse Microspheres Using Geometrically Mediated Droplet Formation in a Single Mold

We present a surfactant-free fabrication method for simultaneous generation of monodisperse microspheres with controllable size manner. Droplets that become microspheres by solidification processes are made in a two-step process: capillary rising-induced fluid division and wetting of immiscible fluid in a micromold. Design of the mold geometry and the monomer concentration primarily determines the microsphere size and the size distribution. Furthermore, the synergistic effect of two parameters is able to efficiently manipulate the microsphere sizes from submicrometers to a few hundred micrometers

Double Hydrophilic Janus Cylinders at an Air–Water Interface

Colloidal particles spontaneously attach to the interface between two immiscible fluids to minimize the interfacial area between the two phases. The shape and wettability of particles have a strong influence on their configuration and interactions at fluid–fluid interfaces. In this study, we investigate the behavior of asymmetrically hydrophilic Janus cylinders (or double hydrophilic Janus cylinders with two different hydrophilic regions) trapped at an air–water interface. We find that these double hydrophilic Janus cylinders with aspect ratios of 0.9, 1.2, and 2.4 adopt both end-on and tilted configurations with respect to the interface. Our numerical calculations show that the coexistence of these configurations is a result of multiple energy minima present in the attachment energy profile that can be represented as a complex energy landscape. Double hydrophilic Janus cylinders with tilted orientations induce hexapolar interface deformation, which accounts for the pair interactions between the particles as well as the nondeterministic assembly behaviors of these particles at the interface

A Rapid One-Step Fabrication of Patternable Superhydrophobic Surfaces Driven by Marangoni Instability

We present a facile and inexpensive approach without any fluorinated chemistry to create superhydrophobic surface with exceptional liquid repellency, transportation of oil, selective capture of oil, optical bar code, and self-cleaning. Here we show experimentally that the control of evaporation is important and can be used to form superhydrophobic surface driven by Marangoni instability: the method involves in-situ photopolymerization in the presence of a volatile solvent and porous PDMS cover to afford superhydrophobic surfaces with the desired combination of micro- and nanoscale roughness. The porous PDMS cover significantly affects Marangoni convection of coating fluid, inducing composition gradients at the same time. In addition, the change of concentration of ethanol is able to produce versatile surfaces from hydrophilic to superhydrophobic and as a consequence to determine contact angles as well as roughness factors. In conclusion, the control of evaporation under the polymerization provides a convenient parameter to fabricate the superhydrophobic surface, without application of fluorinated chemistry and the elegant nanofabrication technique

Palladium Nanocatalysts Immobilized on Functionalized Resin for the Direct Synthesis of Hydrogen Peroxide from Hydrogen and Oxygen

The direct synthesis of hydrogen peroxide (DSHP) from H₂ and O₂ is conceptually the most ideal and straightforward reaction for producing H₂O₂ in industry. However, precisely tailored catalysts are still in progress for large scale production. Here, we report highly efficient and industrially relevant catalysts for the direct synthesis of H₂O₂ from H₂ and O₂ prepared by the immobilization of Pd nanocatalysts onto a functionalized resin. The continuous production of 8.9 wt % H₂O₂ and high productivity (180 g of H₂O₂ (g of Pd)⁻¹ h^–1) is achieved under intrinsically safe and less-corrosive conditions without any loss of activity. We expect this approach is a substantial improvement of nanocatalysts for direct synthesis of hydrogen peroxide from hydrogen and oxygen and will greatly accelerate the industrially relevant process of on site production of hydrogen peroxide soon