Facile Morphology Control during Rapid Fabrication of Nanosized Organosilica Particles

Preparation of Golf Ball-like Polymer Particles Bearing Site-Selective Functional Groups

Golf ball-like particles have emerged as interesting materials in the fields of therapeutics, diagnostics, chemical sensing, etc. because of their unique shapes (with concave and convex moieties) and physical properties. Despite their uniqueness, their surfaces are generally covered with single components lacking functional groups, and a well-established functionalization method for a specific area of these particles, such as their concave or convex surface, is lacking. Thus, we proposed a seeded-dispersion polymerization (SDP)-based method for preparing anionic- and cationic-group-bearing golf ball-like polymer particles mainly on their convex surface. Briefly, we prepared golf ball-like particles with site-selective functional groups by subjecting n-butyl methacrylate (nBMA) to SDP in the presence of polystyrene-seed particles and dodecane using 2,2'-azobis(isobutyronitrile) as an initiator; this yielded a poly(nBMA), PnBMA, concave phase. The shape of the golf ball-like particles was also controlled by adjusting the nBMA amount and solvent composition. Further, the results revealed that the functional groups were introduced onto the convex surface of the golf ball-like particles, and the position of the ionic groups on the particles was confirmed based on metal-nanoparticle adsorption. Thus, we demonstrated the feasibility of preparing convex surfaces of golf ball-like particles to impart such surfaces with anionic or cationic functional groups, thereby expanding the application scope of these heteromorphic particles.

Continuous-Flow Nanoprecipitation Method to Synthesize Degradable Hollow Mesoporous Organosilica Nanoparticles for Insecticide Delivery

Degradable mesoporous organosilica nanoparticles (MONPs) are attracting significant attention in the area of designing smart drug carriers mainly due to their excellent stability and multiple functions. However, the efficient, controllable, and large-scale production of MONPs still faces huge challenges. Herein, a novel and facile continuous-flow nanoprecipitation strategy was reported to synthesize hollow MONPs with highly uniform and tailored properties. The synthesized hollow MONPs possessed a large surface area (SBET > 1070.1 m2 g-1), narrow size distribution, large hollow cavity, and thin shell. Interestingly, the incorporation of organic moieties into silica cross-linked networks led to the timely degradation of nanocarriers with the desired responsiveness. Moreover, the applicability of the as-obtained hollow MONPs has been demonstrated in the loading and pH-responsive release of thiamethoxam (THI). The resultant THI-loaded MONPs possessed long-term storage stability at a low temperature and showed release behaviors in response to a basic environment. Benefiting from the shielding property of MONPs, THI-loaded MONPs manifested superior stability against the photolysis as compared to that of the THI technical. This work provides a new consideration for promoting the advancement of nanotechnology in agricultural fields.

Organosilica-based deformable nanopesticides with enhanced insecticidal activity prepared by flash nanoprecipitation

A flash nanoprecipitation technique was developed for the construction of a novel type of deformable hollow organosilica nanoparticle for pesticide delivery.

Scalable Manufacture of Curcumin-Loaded Chitosan Nanocomplex for pH-Responsive Delivery by Coordination-Driven Flash Nanocomplexation

Metal coordination-driven nanocomplexes are known to be responsive to physiologically relevant stimuli such as pH, redox, temperature or light, making them well-suited for antitumor drug delivery. The ever-growing demand for such nanocomplexes necessitates the design of a scalable approach for their production. In this study, we demonstrate a novel coordination self-assembly strategy, termed flash nanocomplexation (FNC), which is rapid and efficient for the fabrication of drug-loaded nanoparticles (NPs) in a continuous manner. Based on this strategy, biocompatible chitosan (CS) and Cu2+ can be regarded anchors to moor the antitumor drug (curcumin, Cur) through coordination, resulting in curcumin-loaded chitosan nanocomplex (Cur-loaded CS nanocomplex) with a narrow size distribution (PDI < 0.124) and high drug loading (up to 41.75%). Owing to the excellent stability of Cur-loaded CS nanocomplex at neutral conditions (>50 days), premature Cur leakage was limited to lower than 1.5%, and pH-responsive drug release behavior was realized in acidic tumor microenvironments. An upscaled manufacture of Cur-loaded CS nanocomplex is demonstrated with continuous FNC, which shows an unprecedented method toward practical applications of nanomedicine for tumor therapy. Furthermore, intracellular uptake study and cytotoxicity experiments toward H1299 cells demonstrates the satisfied anticancer efficacy of the Cur-loaded CS nanocomplex. These results confirm that coordination-driven FNC is an effective method that enables the rapid and scalable fabrication of antitumor drugs.

Rapid Construction of Green Nanopesticide Delivery Systems Using Sophorolipids as Surfactants by Flash Nanoprecipitation

Green delivery carriers of nanopesticides, like sophorolipid biosurfactants, are of great significance to reduce environmental pollution and promote sustainable agricultural development. However, the molecular diversity of an unisolated sophorolipid mixture with almost unpredictable self-assembly properties has limited the in-depth study of its structure-activity relationship and hindered the development of green pesticide delivery systems. In this work, the acidic and lactonic sophorolipids were successfully separated from the sophorolipid mixture through silica gel column chromatography. A series of cost-effective green nanopesticides loaded with lambda-cyhalothrin (LC) were rapidly fabricated based on a combination of the acidic and lactonic sophorolipids as surfactants by flash nanoprecipitation. The effects of the acidic-to-lactonic ratio on particle size, drug loading capacity, and biological activity against Hyphantria cunea of LC-loaded nanoparticles were systematically investigated. The resultant nanopesticides exhibited a better insecticidal efficacy than a commercial emulsifiable concentrate formulation. This work opens up a novel strategy to construct scalable, cost-effective, and environmentally friendly nanopesticide systems.

Recent advanced development of metal-loaded mesoporous organosilicas as catalytic nanoreactors

Ordered periodic mesoporous organosilicas have been widely applied in adsorption/separation/sensor technologies and the fields of biomedicine/biotechnology as well as catalysis. Crucially, surface modification with functional groups and metal complexes or nanoparticle loading has ensured high efficacy and efficiency. This review will highlight the current state of design and catalytic application of transition metal-loaded mesoporous organosilica nanoreactors. It will outline prominent synthesis approaches for the grafting of metal complexes, metal salt adsorption and in situ preparation of metal nanoparticles, and summarize the catalytic performance of the resulting mesoporous organosilica hybrid materials. Finally, the potential prospects and challenges of metal-loaded mesoporous organosilica nanoreactors are addressed.

Control and Preparation of Quaternized Chitosan and Carboxymethyl Chitosan Nanoscale Polyelectrolyte Complexes Based on Reactive Flash Nanoprecipitation

Nanoscale polyelectrolyte complex materials have been extensively investigated for their promising application in protocell, drug carriers, imaging, and catalysis. However, the conventional preparation approach involving positive and negative polyelectrolytes leads to large size, wide size distribution, instability, and aggregation due to the nonhomogeneous mixing process. Herein, we employ reactive flash nanoprecipitation (RFNP) to control the mixing and preparation of the nanoscale polyelectrolyte complex. With RFNP, homogeneous mixing complexation between oppositely charged chitosan derivatives could be achieved, resulting in stable nanoscale complexes (NCs) with controllable size and narrow size distribution. The smallest size of NCs is found at specific pH due to the maximum attraction of positive and negative molecules of chitosan. The size can be modulated by altering the volumetric flow rates of inlet streams, concentration, and charge molar ratio of two oppositely charged chitosan derivatives. The charge molar ratio is also tuned to create NCs with positive and negative shells. There is no significant variation in the size of NCs produced at different intervals of time. This method allows continuous and tunable NC production and could have the potential for fast, practical translation.

A Cost-Effective Nano-Sized Curcumin Delivery System with High Drug Loading Capacity Prepared via Flash Nanoprecipitation

Flash nanoprecipitation (FNP) is an efficient technique for encapsulating drugs in particulate carriers assembled by amphiphilic polymers. In this study, a novel nanoparticular system of a model drug curcumin (CUR) based on FNP technique was developed by using cheap and commercially available amphiphilic poly(vinyl pyrrolidone) (PVP) as stabilizer and natural polymer chitosan (CS) as trapping agent. Using this strategy, high encapsulation efficiency (EE > 95%) and drug loading capacity (DLC > 40%) of CUR were achieved. The resulting CUR-loaded nanoparticles (NPs) showed a long-term stability (at least 2 months) and pH-responsive release behavior. This work offers a new strategy to prepare cost-effective drug-loaded NPs with high drug loading capacity and opens a unique opportunity for industrial scale-up.

Flash Technology-Based Self-Assembly in Nanoformulation: From Fabrication to Biomedical Applications

Advances in nanoformulation have driven progress in biomedicine by producing nanoscale tools for biosensing, imaging, and drug delivery. Flash-based technology, the combination of rapid mixing technique with the self-assembly of macromolecules, is a new engine for the translational nanomedicine. Here, we review the state-of-the-art in flash-based self-assembly including theoretical and experimental principles, mixing device design, and applications. We highlight the fields of flash nanocomplexation (FNC) and flash nanoprecipitation (FNP), with an emphasis on biomedical applications of FNC, and discuss challenges and future directions for flash-based nanoformulation in biomedicine.