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1. Rapid, Single-Step Protein Encapsulation via Flash NanoPrecipitation

   https://doi.org/10.3390/polym11091406  

   Levit, Shani L.; Walker, Rebecca C.; Tang, Christina (September 2019, Polymers)

   Flash NanoPrecipitation (FNP) is a rapid method for encapsulating hydrophobic materials in polymer nanoparticles with high loading capacity. Encapsulating biologics such as proteins remains a challenge due to their low hydrophobicity (logP < 6) and current methods require multiple processing steps. In this work, we report rapid, single-step protein encapsulation via FNP using bovine serum albumin (BSA) as a model protein. Nanoparticle formation involves complexation and precipitation of protein with tannic acid and stabilization with a cationic polyelectrolyte. Nanoparticle self-assembly is driven by hydrogen bonding and electrostatic interactions. Using this approach, high encapsulation efficiency (up to ~80%) of protein can be achieved. The resulting nanoparticles are stable at physiological pH and ionic strength. Overall, FNP is a rapid, efficient platform for encapsulating proteins for various applications. 

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2. Accelerated Reaction Rates within Self-Assembled Polymer Nanoreactors with Tunable Hydrophobic Microenvironments

   https://doi.org/10.3390/polym12081774  

   Harrison, Andrew; P. Zeevi, Michael; L. Vasey, Christopher; D. Nguyen, Matthew; Tang, Christina (August 2020, Polymers)

   null (Ed.)

   Performing reactions in the presence of self-assembled hierarchical structures of amphiphilic macromolecules can accelerate reactions while using water as the bulk solvent due to the hydrophobic effect. We leveraged non-covalent interactions to self-assemble filled-polymer micelle nanoreactors (NR) incorporating gold nanoparticle catalysts into various amphiphilic polymer nanostructures with comparable hydrodynamic nanoreactor size and gold concentration in the nanoreactor dispersion. We systematically studied the effect of the hydrophobic co-precipitant on self-assembly and catalytic performance. We observed that co-precipitants that interact with gold are beneficial for improving incorporation efficiency of the gold nanoparticles into the nanocomposite nanoreactor during self-assembly but decrease catalytic performance. Hierarchical assemblies with co-precipitants that leverage noncovalent interactions could enhance catalytic performance. For the co-precipitants that do not interact strongly with gold, the catalytic performance was strongly affected by the hydrophobic microenvironment of the co-precipitant. Specifically, the apparent reaction rate per surface area using castor oil (CO) was over 8-fold greater than polystyrene (750 g/mol, PS 750); the turnover frequency was higher than previously reported self-assembled polymer systems. The increase in apparent catalytic performance could be attributed to differences in reactant solubility rather than differences in mass transfer or intrinsic kinetics; higher reactant solubility enhances apparent reaction rates. Full conversion of 4-nitrophenol was achieved within three minutes for at least 10 sequential reactions demonstrating that the nanoreactors could be used for multiple reactions. 

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3. Real-time imaging of metallic supraparticle assembly during nanoparticle synthesis

   https://doi.org/10.1039/D1NR05416C  

   Wang, Mei; Park, Chiwoo; Woehl, Taylor J. (January 2022, Nanoscale)

   Observations of nanoparticle superlattice formation over minutes during colloidal nanoparticle synthesis elude description by conventional understanding of self-assembly, which theorizes superlattices require extended formation times to allow for diffusively driven annealing of packing defects. It remains unclear how nanoparticle position annealing occurs on such short time scales despite the rapid superlattice growth kinetics. Here we utilize liquid phase transmission electron microscopy to directly image the self-assembly of platinum nanoparticles into close packed supraparticles over tens of seconds during nanoparticle synthesis. Electron-beam induced reduction of an aqueous platinum precursor formed monodisperse 2–3 nm platinum nanoparticles that simultaneously self-assembled over tens of seconds into 3D supraparticles, some of which showed crystalline ordered domains. Experimentally varying the interparticle interactions ( e.g. , electrostatic, steric interactions) by changing precursor chemistry revealed that supraparticle formation was driven by weak attractive van der Waals forces balanced by short ranged repulsive steric interactions. Growth kinetic measurements and an interparticle interaction model demonstrated that nanoparticle surface diffusion rates on the supraparticles were orders of magnitude faster than nanoparticle attachment, enabling nanoparticles to find high coordination binding sites unimpeded by incoming particles. These results reconcile rapid self-assembly of supraparticles with the conventional self-assembly paradigm in which nanocrystal position annealing by surface diffusion occurs on a significantly shorter time scale than nanocrystal attachment. 

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4. From Frustration to Order: Role of Fluid–Fluid Interfaces in Precision Assembly of Nanoparticles

   https://doi.org/10.1021/acs.langmuir.4c03321  

   Zhou, Yilong; Çallıoǧlu, Şafak; Arya, Gaurav (December 2024, Langmuir)

   Fluid−fluid interfaces are an attractive platform for self-assembling nanoparticles into low-dimensional materials. In this Perspective, we review recent developments in the use of interfaces to direct the assembly of spherical and anisotropic nanoparticles into diverse and sophisticated architectures. We illustrate how nanoparticle clusters, strings, networks, superlattices, chiral lattices, and quasicrystals can be self-assembled by harnessing the frustration between interfacial and interparticle forces. We highlight the role of polymeric ligands attached to the surface of nanoparticles in modulating assembly behavior by directly altering particle−fluid and particle−particle interactions or by deforming at interfaces and junctions between particles. We conclude by providing a roadmap of key questions and opportunities in this exciting field of interfacial assembly. 

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5. Changing Self‐Assembly Through Degradation: Phenyl Vinyl Ketone Polymer Nanoparticles Under Light

   https://doi.org/10.1002/anie.202514545  

   Weerasinghe, M_A_Sachini_N; McBeth, Parker_Anthony; Mancini, Michelle_C; Konkolewicz, Dominik (September 2025, Angewandte Chemie International Edition)

   Abstract Photodegradable nanoparticles with sphere, worm, and vesicle morphologies were synthesized following polymerization induced self‐assembly (PISA), incorporating a photoresponsive phenyl vinyl ketone (PVK) block and a nonphoto responsive 2‐hydroxypropyl methacrylamide (HPMA) block. The photodegradation of nanoparticles under UV revealed that the initial shapes of sphere and vesicle particles are retained even until 7 h and after 24 h of photo‐induced degradation, respectively, despite a significant reduction in molecular weight (M_n). This could be due to the assembly of degraded PVK fragments in the hydrophobic region, maintaining the relative hydrophilic to hydrophobic ratio. However, worm nanoparticles exhibited a fast morphology reversal after 2 min of degradation, yielding sphere nanoparticles. Therefore, photo responsive PVK nanoparticles with morphology and conversion‐dependent degradation behavior were explored. Furthermore, undegraded and degraded nanoparticle coatings exhibited different surface properties, determined by contact angle measurements, with both morphology and degradation impacting the surface properties. Finally, the PVK nanoparticles could encapsulate molecules and release them upon degradation. Therefore, this study can ultimately be applied to numerous fields due to the potential uses of degradable polymers in various material systems, especially for the controlled release of agrochemicals, cleaning agents, or antifungal agents, as well as to enable surface modifications upon degradation. 

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