Reflux-precipitation Polymerization Research Articles

A Visual Distance-Based Capillary Immunoassay Using Biomimetic Polymer Nanoparticles for Highly Sensitive and Specific C-Reactive Protein Quantification.

The low-cost daily monitoring of C-reactive protein (CRP) levels is crucial for screening acute inflammation or infections as well as managing chronic inflammatory diseases. In this study, we synthesized novel 2-Methacryloyloxy ethyl phosphorylcholine (MPC)-based biomimetic nanoparticles with a large surface area to develop a visual CRP-quantification assay using affordable glass capillaries. The PMPC nanoparticles, synthesized via reflux precipitation polymerization, demonstrated multivalent binding capabilities, enabling rapid and specific CRP capture. In the presence of CRP, PMPC nanoparticles formed sandwich structures with magnetic nanoparticles functionalized with CRP antibodies, thereby enhancing detection sensitivity and specificity. These sandwich complexes were magnetically accumulated into visible and quantifiable stacks within the glass capillaries, allowing for the rapid, sensitive, and specific quantification of CRP concentrations with a detection limit of 57.5 pg/mL and a range spanning from 0 to 5000 ng/mL. The proposed visual distance-based capillary biosensor shows great potential in routine clinical diagnosis as well as point-of-care testing (POCT) in resource-limited settings.

Preparation of poly(acrylonitrile-co-styrene) microspheres by reflux precipitation polymerization

Poly(acrylonitrile-co-styrene) microspheres are utilized in several applications due to their superior mechanical properties, excellent chemical stability, and tunable surface modification. In this work, poly(acrylonitrile-co-styrene) microspheres were synthesized in ethyl acetate usingreflux precipitation polymerization. The average particle size and morphology of microspheres were carefully measured to investigate the responding influencing factors. In the growth process of these microspheres, the average particle size of poly(AN-co-St) microspheres changed a little after 180 min. However, the yield of the microspheres continued to increase until 420 min. The properties of the solvents had a significant impact on both the average particle size and the morphology of the poly(AN-co-St) microspheres. The concentrations of the initiator and the cross-linker have minimal effect on the average particle size of poly(AN-co-St) microspheres. By controlling the monomer content at 25 wt%, the yield of these microspheres could reach 82%. The method is straightforward to operate andthe prepared microspheres exhibithigh sphericity and uniformity. As a result, it shows great promise for thepreparation of submicron poly(AN-co-St) microspheres.

Facile preparation of zwitterionic core-shell nanogels for dual-functional coatings: Combining antifouling and antibacterial features in silicon implant model surface modification

To develop surface-coating technology for fabricating functionalized biomedical implant and overcome implant-associated bacterial infections, this study presented an innovative antifouling and antibacterial dual-functional nanogel coating methodology for engineering silicon-based biomedical implants/biochips. Firstly, zwitterionic core-shell PAA@(GMA/SBMA) nanogels were designed and prepared via reflux-precipitation polymerization and were characterized through NMR, FTIR, DLS, AFM and TEM. The nanogels exhibited uniform and spherical morphology, salt-ion responsiveness, and high lysozyme loading capability. Subsequently, the PAA@(GMA/SBMA) nanogels were covalently grafted onto the surface of silicon wafers, via an epoxy-amine ring-opening reaction, to prepare nanogel-coated silicon wafers (Si@nanogels). A comprehensive array of characterization techniques, including SEM-EDS, contact angle measurements, and XPS, validated the effective nanogel-coating. These coatings demonstrated notable resistance to protein adsorption, highlighting their robust antifouling properties. Upon loading with the antibacterial agent lysozyme, the nanogel coating displayed remarkable antibacterial efficacy against both Gram-negative (E. coli) and Grampositive (S. aureus) bacteria and effectively inhibited biofilm formation. Furthermore, the nanogel coatings exhibited good biocompatibility and dynamic stability, thus facilitating the surface-mediated adhesion and growth of fibroblast 3T3 cells. Significantly, this work provided a facile, economic and efficient surface modification approach to fabricate nanogel-coated antifouling/antibacterial dual-functional biomedical implant model towards potential clinical applications.

Temperature/pH/reduction-sensitive multiple stimulus-responsive nanogels synthesized by one-pot method for design as curcumin carriers

Curcumin (Cur) is of interest due to its widely reported pharmacology, which is limited by its low water solubility and low bioavailability of clinical use. Here, we report the characterization and application of a multiple stimulus-responsive nanogel loaded with Cur. Sensitive P(AM-co-NIPAM) nanogels for pH, temperature, and reduction stimuli were prepared by reflux precipitation polymerization method using AM and NIPAM as raw materials. DLS and SEM analyses showed that the fabricated nanogels had a uniform size distribution with spherical and nucleated-shell structures. By adjusting the feeding amounts of reactive monomers, cross-linkers, and initiators, a series of monodisperse nanogels with different particle sizes could be obtained. The representative nanogels have different Cur-loaded behaviors at different temperatures, times, and initial concentrations of the drug, as well as a sensitive release to changes in pH, temperature, or reducing conditions. Cur-P(AM-co-NIPAM) nanogels showed superior antioxidant activity over the free Cur in vitro. Meanwhile, it inhibited LPS and H2O2-induced oxidative stress, which could effectively inhibit the cellular production of excessive reactive oxygen species and had a protective effect against LPS-induced cellular damage. This nanogel controlled release system significantly improved the safety limit of Cur without hemolytic behavior and had good cytocompatibility. The successful development of such Cur nanogels will lead to advanced materials that can be functionalized and optimized for the controlled delivery of small molecules or biomolecules for targeted therapeutic and biomedical applications.

Facile and fast fabrication of magnetic molecularly imprinted polymer for extraction of carbamazepine from environmental samples and fish tissues followed by UHPLC-MS/MS detection

A rapid synthesis of carbamazepine (CBZ) magnetic molecularly imprinted polymer (MMIP) was proposed based on reflux precipitation polymerization method. The synthesis time for the formation of MIP coating on MMIP was shortened to less than 4 h. The characterization of MMIP demonstrates the successful synthesis of the imprinted layer. The adsorption selectivity of MMIP was systematically evaluated and showed fast selective recognition for CBZ. The MMIP based magnetic solid-phase extraction (MSPE) combined with UHPLC-MS/MS was developed, and its feasibility was validated in four complex matrices of environmental water, sediment, fish muscle and liver. It was successfully applied for the analysis of environmental water, sediment, and different fish tissues. Four environmental water samples from different sampling sites were found to contain CBZ at concentrations < LOD or LOQ, while the sediment samples collected at the same location did not contain CBZ. Two out of three wild snakeheads were found to contain CBZ, and the liver showed the highest residue. The study of drug exposed snakeheads indicate CBZ tends to accumulate in liver, followed by brain, heart and kidneys, and finally muscle and gills. The proposed method displays high potential for analyzing CBZ in complex environmental and biological samples.

Molecularly imprinted polymers by reflux precipitation polymerization for selective solid-phase extraction of quinolone antibiotics from urine

Molecularly imprinted polymers (MIPs) possess high specific cavities towards the template molecules, thus solid-phase extraction (SPE) based on MIPs using the target as the template has been widely used for selective extraction. However, the performance of SPE depends strongly on the shape and the distribution of the MIP sorbents, and rapid synthesis of MIPs with uniform particles remains a challenge. Our previous studies have shown that reflux precipitation polymerization (RPP) was a simple and rapid method for the synthesis of uniform MIPs. However, synthesis of MIPs by RPP for a group of targets using only one of the targets as the template has rarely been reported. In this work, MIPs with specific recognition capability for a group of quinolone antibiotics were synthesized for the first time via RPP with only ofloxacin as the template. The synthesized MIPs displayed good adsorption performance and selectivity (IF > 3.5) towards five quinolones, and subsequently were used as SPE adsorbents. Based on this MIPs-SPE, after systematic optimization of the SPE operation parameters during loading, washing and elution, an efficient and sensitive enough SPE method for separation and enrichment of the five quinolones in urine was developed and evaluated in combination with LC-MS/MS. The results showed that MIPs-SPE-LC-MS/MS has a good correlation (R2 ≥ 0.9961) in the linear range of 1–500 μg L−1. The limit of detection (LOD) and limit of quantification (LOQ) for the five quinolones were 0.10–0.14 μg L−1 and 0.32–0.48 μg L−1, respectively. In addition, the proposed method demonstrated good reproducibility (≤ 13 %) and high accuracy (92 %–113 %). We are confident that this method holds significant promise for the analysis of quinolones within the contexts of forensic medicine, epidemiology, and environmental chemistry.

A versatile strategy to construct surface functionalized pH/redox dual stimuli‐responsive nanogels for targeted drug delivery

AbstractDeveloping facile, green, and efficient synthetic methodology for preparing surface‐functionalized nanogels has attracted tremendous attention in the field of polymer chemistry and biomaterials engineering. Herein, a series of “clickable” P(MAA‐PMA) nanogels with reactive alkyne groups were conveniently prepared by “one‐pot” reflux‐precipitation polymerization (RPP), their particle sizes and zeta potentials are solid content‐dependent. Using P(MAA‐PMA)‐1 nanogels as the model, the physicochemical properties including particle size, surface potential, morphology, solution stability, and pH/redox responsiveness were characterized in detail. Moreover, the pH/redox dual‐responsive drug release feature/kinetics and parameters were analyzed using Korsmeyer–Peppas model and Gallagher–Corrigan model. Then the surface of nanogels was facilely modified with various thiol‐containing functional ligands via thiol‐yne photo click reaction. As targeted drug carriers, doxorubicin (DOX)‐loaded folic acid (FA)‐functionalized nanogels (FA@Nanogels/DOX) demonstrated higher tumor cell proliferation inhibition effect in B16F10 cancer cells than that in CHO‐K1 normal cells, while the non‐FA‐functionalized counterparts (Nanogels/DOX) do not show similar effect. This work provides a versatile “one‐pot RPP‐photo Click functionalization” strategy to construct surface‐functionalized pH/redox dual responsive nanogels for efficient and targeted drug delivery.

Construction of magnetically recyclable Fe3O4/hTiO2/g-C3N4 composites for solar photocatalytic degradation of organic pollutants: Study on the performance and mechanism insight

Magnetically separable Fe3O4/hTiO2/g-C3N4 composites were successfully constructed through coating polymethylacrylic acid sacrificial interlayer by the reflux-precipitation polymerization and subsequent TiO2 outer layer by sol–gel method over magnetic Fe3O4 nanospheres, calcining process and forming composites with g-C3N4 in sequence. The formation mechanism of unique composites was proved by TEM, XPS, VSM, XRD and EDX mapping characterization. Their photocatalytic activity was investigated by the solar photodegradation of organic dyes. The results revealed the photocatalytic performance of Fe3O4/hTiO2/g-C3N4 for degrading methylene blue (95.0 %, 120 min) under simulated sunlight irradiation (Xe lamp, 500 W) was much better than g-C3N4 (71.1 %, 120 min) and Fe3O4/hTiO2 (40.3 %, 120 min). The boosted property is presumably ascribed to the synergetic interaction of multiple components and effective separation of the photoproduced electron-hole pairs between g-C3N4 and TiO2, which was verified using photocurrent and EIS analysis. On the basis of the scavenging studies of radicals (h+, •O2– and •OH), the mechanism of the boosted photocatalytic performance was put forward. The degradation pathways of methylene blue were also proposed by identifying reaction intermediates produced during photocatalysis. More significantly, the composites presented excellent magnetic responsive property owing to the magnetic Fe3O4. The superior recyclability was confirmed by cyclical photocatalytic experiments with the help of an external magnet, which is crucial for the sustainable and green application of photocatalysts.

Carboxybetaine-Based Zwitterionic Polymer Nanogels with Long Blood Circulation for Cancer Therapy.

Given the advantages of antifouling capacity and good biocompatibility, zwitterionic polymers have been profoundly applied for drug delivery to improve the pharmacokinetics profile. Here, a zwitterionic polymer (poly (carboxybetaine methacrylate) (PCBMA)) nanogel was fabricated by one-step reflux precipitation polymerization for doxorubicin (DOX) loading. The obtained nanogels display favorable long blood circulation without priming immune responses as a result of the introduction of the zwitterionic group. Meanwhile, the disulfide bonds deriving from the crosslinker endow nanogels with excellent glutathione-responsive degradation and sufficient drug release under a reduction environment. The carboxylate groups originating from carboxybetaine provide modification sites to conjugate with fluorescent dye to achieve labeling and biodistribution tracking. Overall, under the significantly prolonging circulation and enhanced tumor accumulation through passive targeting, DOX-loaded PCBMA nanogels show a noticeable tumor inhibition effect in mouse colorectal cancer models, which may provide a delivery vehicle with great promise in cancer therapy.

Synthesis of molecularly-imprinted polymers towards a group of amphetamine-type stimulants by reflux precipitation polymerization with a pseudo template

Determination of amphetamine-type drugs (ATSs) in urine and wastewater is a simplified approach for the widespread monitoring of ATSs abuse. To improve the sensitivity of the analytical methods, molecularly imprinted polymers (MIPs) based solid-phase extraction (SPE) pretreatment attracted great attention in this field. Generally, smaller particle sizes and more uniform morphology of the MIPs could provide higher detection sensitivity. Our previous works showed reflux precipitation polymerization (RPP) is a method for synthesizing monodispersed MIPs with small particle size. However, synthesis of uniform spherical MIPs towards a group of targets has never been reported. Therefore, in the present work, MIPs towards a group of ATSs were synthesized via RPP with a pseudo template for the first time. After screening potential pseudo-templates, N-methylphenylethylamine (MPEA) was selected as the optimal pseudo-template. MPEA-MIPs were characterized by scanning electron microscope (SEM), FT-IR spectroscopy and X-ray photoelectron spectroscopy (XPS) spectra. Adsorption isotherms, adsorption kinetics and selectivity were evaluated, and the experimental results indicated that the MPEA-MIPs possessed good selectivity and adsorption property towards ATSs. After optimization of the MIP-SPE procedure, the MIP-SPE cartridges were then coupled with liquid chromatography and tandem mass spectrometry (LC-MS/MS) for determination of ATSs. The evaluation results showed that MIP-SPE-LC-MS/MS displayed good linearity (R2 >0.991) in the linear range (1.0–50.0 µg/L for urine and 0.5–50.0 µg/L for wastewater), and low matrix effect (85–112%). The limit of detection (LOD) was 0.05 -0.29 µg/L, and the accuracy (85–115%) and repeatability (RSD ≤ 15%) were satisfactory at low, medium and high concentrations. To the best of our knowledge, this is the first time that dummy MIPs towards a group of ATSs were synthesized by RPP polymerization, which showed great potential for the detection of ATSs in urine and wastewater.

Precipitation Polymerization: A Powerful Tool for Preparation of Uniform Polymer Particles.

Precipitation polymerization (PP) is a powerful tool to prepare various types of uniform polymer particles owing to its outstanding advantages of easy operation and the absence of any surfactant. Several PP approaches have been developed up to now, including traditional thermo-induced precipitation polymerization (TRPP), distillation precipitation polymerization (DPP), reflux precipitation polymerization (RPP), photoinduced precipitation polymerization (PPP), solvothermal precipitation polymerization (SPP), controlled/‘‘living’’ radical precipitation polymerization (CRPP) and self-stabilized precipitation polymerization (2SPP). In this review, a general introduction to the categories, mechanisms, and applications of precipitation polymerization and the recent developments are presented, proving that PP has great potential to become one of the most attractive polymerization techniques in materials science and bio-medical areas.

Novel Contact Lenses Embedded with Drug-Loaded Zwitterionic Nanogels for Extended Ophthalmic Drug Delivery.

Therapeutic ophthalmic contact lenses with prolonged drug release and improved bioavailability have been developed to circumvent tedious eye drop instillation. In this work, zwitterionic nanogels based on poly(sulfobetaine methacrylate) (PSBMA) were easily fabricated by one-step reflux-precipitation polymerization, with the advantages of being surfactant-free and morphology controlled. Then, the ophthalmic drug levofloxacin (LEV) was encapsulated into the nanogels. A set of contact lenses with varied nanogel-loading content was fabricated by the cast molding method, with the drug-loaded nanogels dispersed in pre-monomer solutions composed of 2-hydroxyethyl methacrylate (HEMA) and N-vinyl-2-pyrrolidone (NVP). The structure, surface morphology, water contact angle (WCA), equilibrium water content (EWC), transmittance, and mechanical properties of the contact lenses were subsequently investigated, and in vitro drug release and biocompatibility were further evaluated. As a result, the optimized contact lens with nanogel-loading content of 8 wt% could sustainably deliver LEV for ten days, with critical lens properties within the range of recommended values for commercial contact lenses. Moreover, cell viability assays revealed that the prepared contact lenses were cytocompatible, suggesting their significant potential as an alternative to traditional eye drops or ointment formulations for long-term oculopathy treatment.

Preparation of Fe3O4@PMAA@Ni Microspheres towards the Efficient and Selective Enrichment of Histidine-Rich Proteins.

Magnetic material is considered to as a major concern material for the enrichment of histidine-rich proteins (His-proteins) via metal-ion affinity. In this work, magnetic polymer microspheres with core-shell structure (Fe3O4@PMAA@Ni) were successfully prepared via reflux-precipitation polymerization followed by in situ reduction and growth of Ni2+. The obtained Ni nanofoams with flower-like structure and uniform pore size (3.34 nm) provided numerous binding sites for His-proteins. The adsorption performance of Fe3O4@PMAA@Ni microspheres for His-proteins was estimated via selectively separating bovine hemoglobin (BHb) and bovine serum albumin (BSA) from a matrix composed of BHb, BSA, and lysozyme (LYZ). The results indicated that Fe3O4@PMAA@Ni microspheres could efficiently and selectively separate His-proteins from the matrix, with a maximum adsorption capacity of ∼2660 mg/g for BHb. Moreover, Fe3O4@PMAA@Ni microspheres exhibited good stability and recyclability for BHb separation over seven cycles. Therefore, this work reported a novel and facile strategy to prepare core-shell Fe3O4@PMAA@Ni microspheres, which was promising for practical applications of His-protein separation and purification in proteomics.

Temperature-responsive iron nanozymes based on poly(N-vinylcaprolactam) with multi-enzyme activity.

Iron (Fe)-based nanozymes are widely applied in the biomedical field due to their enzyme-like catalytic activity. Herein, Fe(ii)-based coordination polymer nanohydrogels (FeCPNGs) have been conveniently prepared as a new type of nanozyme by the chelation reaction between ferrous iron and polymer nanohydrogels. The P(VCL-co-NMAM) nanohydrogels prepared by a reflux precipitation polymerization method using N-vinylcaprolactam (VCL) and N-methylol acrylamide (NMAM) as monomers and N,N-methylenebisacrylamide (MBA) as a crosslinker were esterified using P2O5 and then chelated with Fe(ii) ions to form nanozymes with peroxidase and superoxide dismutase (SOD) activity. It was found by dynamic light scattering (DLS) and transmission electron microscopy (TEM) that the nanohydrogels prepared with a monomer concentration of 4% and mass ratio of 1 : 1 (VCL : NMAM) had more uniform particle size, better dispersion and a distinct temperature response. The results of Fourier transform infrared (FTIR), DLS, TEM, X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) indicated the successful preparation of the esterified nanohydrogel and FeCPNGs. Of particular importance is that such FeCPNGs can functionally mimic two antioxidant enzymes (peroxidase and superoxide dismutase) by UV analysis of catalytic oxidation between 3,3,5,5-tetramethylbenzidine (TMB) and H2O2 and the kit analysis of SOD-like activity.

Highly stable, active and recyclable solid acid catalyst based on polymer-coated magnetic composite particles

A facile approach has been adopted for coating cross-linked polystyrene (PS) shells on the surface of Fe3O4 magnetic clusters using reflux-precipitation polymerization (RPP). Treating the PS shell with chlorosulfonic acid yields magnetic composite particles with acid functionality. By adjusting the amount and proportion of monomers (styrene and divinylbenzene), the obtained magnetic composite particle solid acid (MPM-5S) exhibits a saturation magnetization value of 18 emu/g, a specific surface area of 243 m2/g and an acid density of 2.113 mmol/g. The MPM-5S magnetic solid acid catalyst was evaluated for esterification of oleic acid with methanol to prepare biodiesel. Under mild conditions, the conversion of oleic acid reached 91%, which was much higher than the catalytic activity of Amberlyst-15 and close to the catalytic activity of concentrated H2SO4. The solid acid catalyst can be recovered by magnetic separation and reused three times maintaining over 95% of its initial catalytic activity. Additionally, the solid acid can be used to catalyze the dehydration of fructose to 5-hydroxymethylfurfural.

Versatile functionalization of surface-tailorable polymer nanohydrogels for drug delivery systems.

Surface decoration of nanohydrogels with functional molecules as well as nanomaterials offers a facile approach for developing multifunctional drug nanocarriers. Herein, the surface-tailorable polymer nanohydrogels, with the catechol groups as a universal anchor, were prepared by simple reflux-precipitation polymerization for versatile functionalization as drug delivery systems. The resultant polymer nanohydrogels were not only capable of delivering doxorubicin (DOX) through electrostatic interactions, but also exhibited facile conjugation with magnetic Fe3O4 nanoparticles and anticancer drug bortezomib (BTZ) via the versatile catechol-based coupling chemistry. The DOX and Fe3O4 loaded nanohydrogels (DOX-Fe3O4@NG) exhibited high DOX loading capability and triggered drug release behaviors in the acidic and redox environment. Furthermore, the DOX-Fe3O4@NG achieved improved cellular uptake in the presence of external magnetic field due to the active magnetic targeting properties. As for the dual drug delivery system (DOX-BTZ@NG), the DOX-BTZ@NG also released the drugs in response to the external stimuli including low pH and GSH presence, indicating their intelligent drug delivery properties. In particular, the DOX-BTZ@NG showed higher antiproliferation efficacy to cancer cells in comparison with the single drug loaded nanohydrogels, suggesting a synergistic effect of the dual drug combination therapy. The degradable poly(AA-co-DMA) nanohydrogels with surface-tailorable functionalities are thus a promising versatile platform for conjugation with both nanomaterials and drug molecules.

Biodegradable phosphorylcholine-based zwitterionic polymer nanogels with smart charge-conversion ability for efficient inhibition of tumor cells

Zwitterionic polymer nanocarriers have attracted much attention in recent years due to their desirable biocompatibility and anti-fouling properties. However, the super-hydrophilic and neutral charge of zwitterionic polymer results in weak interactions with negatively charged cell membranes, which leads to suboptimal uptake by tumor cells. Herein, a series of biodegradable poly(2-methacryloyloxyethyl phosphorylcholine-s-s-vinylimidazole) (PMV) nanogels with uniform spherical shape was fabricated by one-step reflux precipitation polymerization, which was clean and efficient. The PMV nanogels remained in zwitterionic state at physiological pH (pH 7.4) and were converted rapidly to positive charged state at tumor extracellular pH (pH 6.5). Proton nuclear magnetic resonance spectra and acid-base titration experiment proved that the charge-conversion ability of PMV nanogels was attributed to protonation of the imidazole ring in an acidic environment. Protein stability experiment showed that PMV nanogels exhibited a protein-adsorption resistance at pH 7.4 for as long as 7 days while adsorbed protein rapidly at pH 6.5. Moreover, PMV nanogels showed a reducing-labile property, which was able to degrade into short linear polymer chains in the presence of reduction agents. Therefore, the doxorubicin (DOX) release profile was controlled finely with a low DOX leakage under physiological conditions (7.8% in 48 h) and a rapid DOX release in 10 mM glutathione at pH 7.4 (78.9% in 48 h). Confocal laser scanning microscope and flow cytometry showed that the PMV nanogels exhibit an enhanced cellular uptake by tumor cells at pH 6.5 compared with pH 7.4, which allows for a severe cytotoxic effect of DOX-loaded PMV nanogels against tumor cells.

Development of water-compatible molecularly imprinted solid-phase extraction coupled with high performance liquid chromatography–tandem mass spectrometry for the detection of six sulfonamides in animal-derived foods

A water-compatible molecularly imprinted polymer (MIP) was prepared by combining reversible addition-fragmentation chain transfer (RAFT) with reflux precipitation polymerization (RPP) for solid-phase extraction (SPE) coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC–MS/MS) to detect six sulfonamides (SAs) in animal-derived foods and water samples. The SEM images indicated the spherical structure of MIP materials. In water medium, MIPs still performed good specific adsorption for SAs. Under the optimized detection conditions, the proposed method offered good linearity (R2 > 0.996) for the six SAs with relative standard deviation (RSD) for ten replicate extractions of 1.64%–4.68%, limits of detection (S/N = 3) of 0.02 μg L−1-0.1 μg L−1 and recoveries of 63.49%–115.72%. Besides, the whole extract process avoided organic solvent consumption, and trace sulfadiazine residues were found in the pork sample at similar concentration of 3.57 and 3.79 μg kg-1 using the MIP-SPE method and commercial Oasis HLB cartridge, respectively. It is confirmed the method could be applied to quantitative detect the trace residue sulfonamides in animal-derived samples and water samples.

Biodegradable Zwitterionic Nanogels with Long Circulation for Antitumor Drug Delivery.

Zwitterionic nanocarriers have emerged as a new class of biocompatible nanomaterials with outstanding stealth capability in blood circulation. In this work, a novel biodegradable zwitterionic nanogel based on poly(sulfobetaine methacrylate) (PSBMA) was developed for reduction-responsive drug delivery to tumors. PSBMA nanogels were facilely fabricated by one-step reflux precipitation polymerization with the advantage of being surfactant-free and time-saving. The disulfide bond not only endowed the nanogels degradability in a reduction environment but also be modified with a fluorescent group after partial reduction. In vitro release experiments disclosed that doxorubicin (DOX)-loaded PSBMA nanogels could hold the drugs firmly in physiological conditions (only 7% release in 24 h) and release the drugs rapidly and sufficiently in 10 mM glutathione (85% in 8 h). More interestingly, PSBMA nanogels displayed long circulation in blood after intravenous injection, and small change was found in half-life of nanogels between the first (34.1 h) and the second injection (30.5 h), indicating that there was no accelerated blood clearance phenomenon for these nanogels. Meanwhile, no obvious immunogenic response was detected after PSBMA nanogels were injected into BALB/c mice. Furthermore, PSBMA nanogels showed a high accumulation of 9.5 and 10.7% of injected dose per gram of tissue in tumors at 24 and 48 h post intravenous injection, respectively. With outstanding long circulation time, high tumor accumulation, and sufficient drug release in a reduction environment, DOX-loaded PSBMA nanogels demonstrated the strongest tumor growth inhibition effect among all of the treatment groups in human hypopharyngeal carcinoma-bearing mouse models. Therefore, our study provided a facile drug delivery platform based on biodegradable zwitterionic nanogels and may have great potential in tumor drug delivery.

Reflux Precipitation Polymerization: A New Platform for the Preparation of Uniform Polymeric Nanogels for Biomedical Applications.

Reflux precipitation polymerization (RPP) represents an effective approach that enables to prepare various types of polymeric nanogels with precise control over the morphology and structure. Owing to facile loading or modification by a variety of functional moieties, rationally designed nanogels pose the possibility to attain a platform for tailoring functional properties that could be widely used for various biomedical applications, such as multifunctional drug delivery, enrichment of functional peptides, separation of specific proteins, as well as detection of circulating tumor cells. This feature article highlights RPP as a promising polymerization strategy that provides access to facile generation of modular nanostructures or multifunctional properties in a diverse range of biomedical applications, proving that RPP has great potential to become one of the most attractive polymerization techniques in polymer chemistry.