Photothermal-responsive lignin-based polyurethane with mechanically robust, fast self-healing, solid-state plasticity and shape-memory performance.

In light of the depletion of petrochemical resources and increase in environmental pollution, there has been a significant focus on utilizing natural biomass, specifically lignin, to develop sustainable and functional materials. This research presents the development of a lignin-based polyurethane (DLPU) with photothermal-responsiveness by incorporating lignin and oxime-carbamate bonds into polyurethane network. The abundant hydrogen bonds between lignin and the polyurethane matrix, along with its cross-linked structure, contribute to DLPU's excellent mechanical strength (30.2 MPa) and toughness (118.7 MJ·m-3). Moreover, the excellent photothermal conversion ability of DLPU (54.4 %) activates dynamic reversible behavior of oxime-carbamate bonds and hydrogen bonds, thereby endowing DLPU with exceptional self-healing performance. After 15 min of near-infrared irradiation, DLPU achieves self-healing efficiencies of 96.0 % for tensile strength and 96.3 % for elongation at break. Additionally, DLPU exhibits photocontrolled solid-state plasticity as well as an excellent phototriggered shape-memory effect (70 s), with shape fixity and recovery ratios reaching 98.8 % and 95.3 %, respectively. By exploiting the spatial controllability and photothermal-responsiveness of DLPU, we demonstrate multi-dimensional responsive materials with self-healing and shape-shifting properties. This work not only promotes the development of multi-functional polyurethanes but also provides a pathway for the high-value utilization of lignin.

Chromatograms and Mass Spectra of High-Mannose and Paucimannose N-Glycans for Rapid Isomeric Identifications.

N-Linked glycosylation is one of the most essential post-translational modifications of proteins. However, N-glycan structural determination remains challenging because of the small differences in structures between isomers. In this study, we constructed a database containing collision-induced dissociation MSn mass spectra and chromatograms of high-performance liquid chromatography for the rapid identification of high-mannose and paucimannose N-glycan isomers. These N-glycans include isomers by breaking of arbitrary numbers of glycosidic bonds at arbitrary positions of canonical Man9GlcNAc2 N-glycans. In addition, some GlcMannGlcNAc2 N-glycan isomers were included in the database. This database is particularly useful for the identification of the N-glycans not in conventional N-glycan standards. This study demonstrated the application of the database to structural assignment for high-mannose N-glycans extracted from bovine whey proteins, soybean proteins, human mammary epithelial cells, and human breast carcinoma cells. We found many N-glycans that are not expected to be generated by conventional biosynthetic pathways of multicellular eukaryotes.

Cardiovascular safety of zoledronic acid in the treatment of primary osteoporosis: A meta-analysis and systematic review.

PURPOSE: Osteoporosis is intimately linked to cardiovascular disease and it has been uncertain that zoledronic acid is not correlated with cardiovascular disease. We intended to assess the cardiovascular safety of zoledronic acid in the treatment of primary osteoporosis. METHODS: We included only randomized controlled trials (RCTs) of patients with osteoporosis receiving zoledronic acid or a placebo. We systematically searched PubMed, Embase, Web of Science, Cochrane CENTRAL, Scopus, the Chinese National Knowledge Infrastructure, ClinicalTrials.gov, and ICTRP from the time of database creation to April 5, 2023. Two investigators extracted data independently on study characteristics, outcomes of interest, and risk of bias based on PRISMA guidelines. RESULTS: As of April 5, 2023, our search identified 32,361 records, and after excluding these records, 9 RCTs were included in the meta-analysis. The overall risk ratio for cardiovascular events with zoledronic acid for primary osteoporosis compared with placebo was 1.15 (95 % CI 1.05-1.26, I2=12 %, P = 0.002), while the risk of major adverse cardiovascular events with zoledronic acid (RR 1.03, 95 % CI 0. 89-1.18, I2=21 %, P = 0.71) was not significant, possibly due to atrial fibrillation (RR 1.21, 95 % CI 0.99-1.47, I2=0 %, P = 0.06) versus the increased relative risk of arrhythmia (RR 1.30, 95 % CI 1.11-1.52, I2=34 %, P = 0.001). Overall, the cardiovascular risk of zoledronic acid for the treatment of primary osteoporosis was not significant; however, the relative risk of elevated atrial fibrillation and arrhythmias remains to be further studied. CONCLUSIONS: In women with primary osteoporosis, zoledronic acid may increase the risk of atrial fibrillation (P = 0.06) and arrhythmias (P = 0.001) compared with placebo, independent of the risk of major adverse cardiovascular events, angina, and heart failure. However, the sample size of men with primary osteoporosis is small, and the cardiovascular risk of zoledronic acid in men with osteoporosis is uncertain.

Identification of the High Mannose N-Glycan Isomers Undescribed by Conventional Multicellular Eukaryotic Biosynthetic Pathways.

N-linked glycosylation is one of the most important post-translational modifications of proteins. Current knowledge of multicellular eukaryote N-glycan biosynthesis suggests high mannose N-glycans are generated in the endoplasmic reticulum and Golgi apparatus through conserved biosynthetic pathways. According to conventional biosynthetic pathways, four Man7GlcNAc2 isomers, three Man6GlcNAc2 isomers, and one Man5GlcNAc2 isomer are generated during this process. In this study, we applied our latest mass spectrometry method, logically derived sequence tandem mass spectrometry (LODES/MSn), to re-examine high mannose N-glycans extracted from various multicellular eukaryotes which are not glycosylation mutants. LODES/MSn identified many high mannose N-glycan isomers previously unreported in plantae, animalia, cancer cells, and fungi. A database consisting of retention time and CID MSn mass spectra was constructed for all possible MannGlcNAc2 (n = 5, 6, 7) isomers that include the isomers by removing arbitrary numbers and positions of mannose from canonical N-glycan, Man9GlcNAc2. Many N-glycans in this database are not found in current N-glycan mass spectrum libraries. The database is useful for rapid high mannose N-glycan isomeric identification.

Knowledge mapping of nano drug delivery systems across blood - Brain barrier from 1996 to 2022: A bibliometric analysis.

Background: The blood-brain barrier (BBB) is a natural physiological barrier that protects the central nervous system from foreign substances and limits the delivery of drugs to the brain. Nanotechnology has opened up new possibilities for drug delivery in the brain. Over several decades, various Nanoparticle Drug Delivery Systems (NDDS) that can cross the BBB have been developed for targeted delivery in the brain. To gain a comprehensive understanding of the current research hotspots and trends of NDDS across the BBB, this paper employs bibliometric analysis of articles published in the core database of Web of Science (WOS) from 1996 to 2022. Method: A search for relevant research literature on NDDS that can cross the BBB was conducted in the Web of Science database, covering the period from 1996 to 2022. The Bibliometrix R-4.0 software package was used to analyze data related to the countries of publication, research institutions, journals, citations, and keywords. The analysis aimed to identify the co-occurrence of keywords in the documents, including their titles and abstracts. Additionally, cooperative network analyses of authors, institutions, and countries of publication were conducted. Results: A total of 436 articles were analyzed, originating from 174 journals and 13 books, with the majority published in Q1 and Q2 journals. Contributors from 53 countries or regions participated in the publication of these articles, with China, the United States, and India having the highest number of articles by correspondent authors, and China, the United States, and Germany being the most cited countries. Fudan University, Hacettepe University, and Sichuan University were the top three institutions with the most publications. Among the 436 articles analyzed, 1337 keywords and 1450 keywords plus were identified. Factor analysis grouped the keywords plus into two categories: drug delivery systems, polymeric nanoparticles, gold nanoparticles, transferrin, and others, and drug, delivery, efficiency, expression, and mechanism. Conclusion: The research on NDDS that can cross the BBB is gradually receiving attention, and the recognition and cooperation in this field have increased.

Efficacy and safety of Gegen Qinlian decoction in the treatment of type II diabetes mellitus: a systematic review and meta-analysis of randomized clinical trials.

Aim: The study aims to systematically assess the efficacy and safety of Gegen Qinlian decoction in the treatment of type 2 diabetes mellitus. Methods: We systematically searched a total of nine databases from the time of creation to 20 March 2023. The quality of the literature was assessed using the risk of bias assessment tool in the Cochrane Handbook. RevMan 5. 3 and Stata 14.0 were applied to conduct meta-analysis. Results: A total of 17 studies, encompassing 1,476 patients, were included in the study. Gegen Qinlian decoction combined with conventional treatment was found to significantly reduce FBG (MD = -0.69 mmol/L, 95% CI -0.84 to -0.55, p < 0.01; I2 = 67%, p<0.01), 2hPG (MD = -0.97 mmol/L, 95% CI -1.13 to -0.81, p < 0.01; I2 = 37%, p=0.09), HbA1c (MD = -0.65%, 95% CI -0.78 to -0.53, p < 0.01; I2 = 71%, p<0.01), TC (MD = -0.51 mmol/L, 95% CI -0.62 to -0.41, p < 0.01; I2 = 45%, p=0.09), TG (MD = -0.17mmol/L, 95% CI -0.29 to -0.05, p < 0.01; I2 = 78%, p<0.01), LDL-C (MD = -0.38mmol/L, 95% CI -0.53 to -0.23, p < 0.01; I2 = 87%, p<0.01), HOMA-IR (SMD = -1.43, 95% CI -2.32 to -0.54, p < 0.01; I2 = 94%, p<0.01), and improved HDL-C (MD = 0.13 mmol/L, 95% CI 0.09-0.17, p < 0.01; I2 = 30%, p=0.24). Only three studies explored the differences in efficacy between GQD alone and conventional treatment in improving glucose-lipid metabolism and insulin resistance, and some of the outcome indicators, such as 2hPG and HDL-C, were examined in only one study. Therefore, the effect of GQD alone on glucose-lipid metabolism and insulin resistance cannot be fully determined, and more high-quality studies are needed to verify it. Publication bias analysis revealed no bias in the included studies. Conclusion: Gegen Qinlian Decoction has certain efficacy and safety in enhancing glycolipid metabolism and alleviating insulin resistance, potentially serving as a complementary therapy for type 2 diabetes mellitus. Rigorous, large-sample, multicenter RCTs are needed to verify this. Systematic review registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023413758, PROSPERO CRD42023413758.

3D printed heterogeneous hybrid hydrogel scaffolds for sequential tumor photothermal-chemotherapy and wound healing.

Surgical resection remains the mainstay of melanoma treatment. However, due to the difficulties in controlling tumor recurrence and wound healing simultaneously, high postoperative recurrence rates and wound reconstruction remain the most significant challenges. As a result, a heterogeneous hybrid hydrogel scaffold was designed in this work to achieve sequential photothermal therapy and chemotherapy for melanoma recurrence inhibition and wound healing. A 3D printing platform was used to create a SA-GG@PDA hybrid hydrogel scaffold, which was prepared from a hybrid bioink consisting of sodium alginate (SA), gellan gum (GG), and polydopamine nanoparticles (PDA NPs). The printability, biocompatibility, and mechanical qualities of the hybrid bioink were all satisfactory. PDA NPs were generated in situ in the hybrid bioink, providing superior photothermal effects to the scaffold. After coating with a thermosensitive gelatin hydrogel loaded with the chemotherapeutic drug doxorubicin (DOX), the heterogeneous hydrogel scaffold could accelerate drug release under photothermal triggering and achieve photothermal-chemotherapy to suppress tumor cell proliferation and recurrence after surgical resection. Subsequently, the printed porous hybrid hydrogel scaffold enhanced HUVEC proliferation and migration, as well as tissue ingrowth, promoting wound healing following surgery. In the same mouse model, the sequential treatment with the heterogeneous SA-GG@PDA + DOX hydrogel scaffold was tested. The fabrication of the heterogeneous SA-GG@PDA + DOX hydrogel scaffold with multifunctional capabilities seemed to be a potential technique for preventing tumor recurrence and promoting wound healing following surgery.

Injectable thermo-sensitive and wide-crack self-healing hydrogel loaded with antibacterial anti-inflammatory dipotassium glycyrrhizate for full-thickness skin wound repair.

Severe skin injuries are hard to repair and susceptible to bacterial infection. Development of a versatile antimicrobial anti-inflammatory hydrogel dressing that eliminates concern over antibiotic resistance is urgently needed but remains an elusive goal. Our research, described herein, the design and fabrication of a new family of supramolecular hydrogels based on hydroxypropyl chitosan (HPCS) and poly(N-isopropylacrylamide) (PNIPAM) may prove to be that goal. Employing the reversible cross-linking by ß-cyclodextrin (ß-CD) and adamantyl (AD) pre-assembly, the hydrogels can be formed in a facile one-pot method. Additionally, the structure and performance of the hydrogels can be controlled by a simple adjustment of the AD content. The obtained hydrogels exhibit an abundance of desired properties; they are injectable, thermosensitive, highly ductile, self-healable (will self-heal recurring damage to the hydrogel bandage of up to several millimeters wide), biocompatible, and have antimicrobial activity against Staphylococcus aureus when infused with dipotassium glycyrrhizinate (DG). Using a mouse full-thickness skin defect model, in vivo wound healing evaluations revealed that the DG-loaded hydrogels (HP-3/DG10) applied to the wound resulted in rapid wound closure. The hydrogels promoted efficient tissue remolding, collagen deposition, decreased inflammation and performed better than the control groups of commercial TegadermTM film and 3M dressing. Given their multifunctionality and in vivo efficacy, the DG-loaded HP hydrogels hold great potential as a wound dressing for full-thickness skin repair. STATEMENT OF SIGNIFICANCE: Injectable hydrogels are receiving increasing attention as an ideal wound dressing. To the best of our knowledge, however, injectable and wide-crack self-healing hydrogel dressings have been hardly studied. A versatile antimicrobial hydrogel without drug resistance or cytotoxicity is also highly required. Therefore, in the present study, we constructed injectable thermosensitive and wide-crack self-healing hydrogels with antibacterial and anti-inflammatory properties. These hydrogels were developed through novel strategies of the wide-crack self-healing design and the loading of the bioactive antibacterial and anti-inflammatory agent dipotassium glycyrrhizinate. The simple preparation method and multifunctionality of the studied hydrogel composites may provide important insights for the development of future biomaterials for wound dressings and other biomedical applications.

The effect of joint distraction osteogenesis combined with platelet-rich plasma injections on traumatic ankle arthritis.

OBJECTIVE: To study effect of joint distraction osteogenesis combined with platelet-rich plasma injections on traumatic ankle arthritis (TAA). METHODS: 106 patients with TAA admitted to our hospital (from January 2018 to January 2020) were recruited as the study cohort and randomly divided into a surgical group and a combined group. The surgical group was treated with simple joint retraction surgery, and the combined group was treated with platelet-rich plasma injections in addition to the surgery administered to the operation group. After 6 months of treatment, the clinical efficacy of the two groups was evaluated, and the changes in the ankle joint function, the serum related factors, and the quality of life before and at six months after the treatment were observed. The incidences of adverse reactions (ARS) in the two groups were counted to evaluate the treatment safety. RESULTS: The total effective rate was 98.11% in the combined group and 77.36% in the operation group. The overall curative effect of the combined group was better than it was in the operation group (P<0.05). After the treatment, the ankle joint movement angles, the joint function, the serum factor levels, and the quality of life of the patients in combined group were better than they were in the operation group (P<0.05). No significant difference was found in the incidence of ARs (P>0.05). CONCLUSION: Arthroplasty with platelet-rich plasma injections can improve joint function recovery, inhibit the inflammatory factor expression levels, and enhance TAA patients' quality of life.

Fabrication of Au Nanoparticle Arrays on Flexible Substrate for Tunable Localized Surface Plasmon Resonance.

In this work, Au nanoparticle (AuNP) arrays on shape memory polyurethane (SMPU) substrates serve as flexible materials for tunable localized surface plasmon resonance (LSPR). AuNP arrays prepared by diblock copolymer self-assembly are transferred from rigid silicon wafers onto flexible SMPU substrates with ultrasonic treatment rather than peeling off directly. The resultant AuNP array SMPU films have excellent mechanical properties and stable thermodynamic properties. The LSPR arising from AuNP arrays is increased by negative bending on SMPU substrates, whereas the LSPR is decreased by positive bending. Besides, upon uniaxial tension, the vertical LSPR is increased first then decreased, whereas the parallel LSPR is similar, resulting in the overall LSPR of AuNP arrays being increased first and then decreased with the mechanical uniaxial tension of SMPU. Moreover, the resultant AuNP array SMPU films exhibit excellent flexibility, stability, and homogeneity in practical surface-enhanced Raman scattering (SERS) application. This approach of incorporating AuNP arrays on SMPU substrates for tuning plasmonic properties have great potential applications in SERS, fluorescence enhancement, and newly optoelectronic materials.

Impact of the numbers of injections of platelet rich plasma on the clinical outcomes in patients with knee osteoarthritis: A protocol for an updated network meta-analysis.

BACKGROUND: Two published meta-analyses have investigated the effects of the number of injections of platelet rich plasma (PRP) on clinical outcomes in knee osteoarthritis patients, however conflicting findings were generated. METHODS: We will systematically search PubMed, Embase, and China National Knowledgement Infrastructure (CNKI) to capture additional eligible studies. After screening citations, extracting essential data, assessing the risk of bias, we will use RevMan software and Open BUGS to perform head-to-head and network meta-analysis of pain alleviation and improvement of joint functionality, respectively. DISCUSSION: Knee joint osteoarthritis (KOA) is the main cause of joint degeneration in elderly, which seriously reduces patients quality of life. Although intra-articular PRP has been extensively prescribed to treat KOA, a definitive conclusion about the appropriate number of injections has not yet been generated in published meta-analyses. The present updated network meta-analysis will comprehensively answer this question. ETHICS AND DISSEMINATION: We will communicate our findings through participating in academic conferences or submiting it to be considered for publication in peer reviewed scholar journal. INPLASY REGISTRATION NUMBER: We registered this protocol in International Plateform of Registered Systematic Review and Meta-Analysis Protocols (INPLASY) platform and obtained an identifier of INPLASY2020110043 (https://inplasy.com/inplasy-2020-11-0043/).

Mesoscopic simulations of drug-loaded diselenide crosslinked micelles: Stability, drug loading and release properties.

Intelligent reversible crosslinked micelles that have a good balance of structure stability in normal tissue and controlled drug release responded to the tumor microenvironment are highly promising novel drug delivery systems. However, to date, there have been very few reports about mesoscale simulations of drug-loaded polymeric reversible crosslinked micelles. Here, dissipative particle dynamics (DPD) simulation, the nearest-neighbor bonding principle, and the nearest media-bead bond breaking principle were used to investigate the influence of physiological environment along with low tumor pH and reduction microenvironment on the stability and doxorubicin (DOX) distribution of the star polymer [PCL-b-P(HEMA-Se-Se˜)-b-PPEGMA]6 diselenide crosslinked micelles with different diselenide crosslinking levels (CLs). The self-assembly process results obtained by DPD simulations reveal the formation of three-layer spherical micelles with the loaded DOX mainly distributed at the interfacial regions of the inner PCL core and middle HEMA layer. The structural stability and DOX loading capacity of the micelles can be improved by appropriately increasing the CL based on the nearest-neighbor bonding principle due to the effect of the pressure exerted by the crosslink that squeezes the loaded drugs from the intermediate and interfacial layers into the micelle core. Furthermore, the effect of breaking of the diselenide bond on the drug release properties was investigated through the use of the nearest media-bead bond breaking principle. A low CL gives rise to intense drug release, increasing the toxic side effects on the system. With the increase in the CL, the micelles show the transformation from local crosslinking to compact crosslinking, leading to slower drug release. Therefore, this work can provide some guidance on the mesoscale for the structural design and controlled construction of reversible crosslinked micelles for smart drug delivery systems.

Controlled construction of gold nanoparticles in situ from ß-cyclodextrin based unimolecular micelles for in vitro computed tomography imaging.

The development of nanomaterials as highly efficient contrast agents for tumor computed tomography (CT) imaging still remains a huge challenge. In this study, a novel and facile approach to fabricate unimolecular micelles-stablized gold nanoparticles (AuNPs) without external reductant for in vitro targeted CT imaging was described. Amphiphilic 21-arm star-like polymers ß-cyclodextrin-g-{poly(2-(dimethylamino)ethyl methacrylate)-poly(2-hydroxyethyl methacrylate)-poly[poly(ethylene glycol) methyl ether methacrylate]} [ß-CD-g-(PDMA-b-PHEMA-b-PPEGMA)] was firstly synthesized and proved to form unimolecular core-middle layer-shell-type micelles in water through experimental and computer simulation results. Taking advantage of the reducing groups of PDMA block, AuNPs were decorated in the micellar PDMA block because of the in situ reduction of gold ions, which were absorbed by the PDMA chains in the core layer with a narrow nanoparticle size distribution. This strategy could prevent aggregation of AuNPs, which were capable of being employing as a highly effective probe for specific CT imaging in vitro. Importantly, the ß-CD-g-(PDMA-b-PHEMA-b-PPEGMA)/AuNPs incubated with HepG2 cells, displayed more intense X-ray attenuation property (>37%) than conventional iodine-based CT imaging agent (Omnipaque) and also possessed a satisfying cytocompatibility in the given concentration range. The facile fabrication procedures and the efficiency of CT imaging render the novel hybrid unimolecular micelles to become potent candidates for applications in tumor-targeted CT imaging.

Synergistic effects of boron-doped silicone resin and a layered double hydroxide modified with sodium dodecyl benzenesulfonate for enhancing the flame retardancy of polycarbonate.

To improve the flame retardancy of polycarbonate (PC), a novel and environmentally friendly flame retardant was synthesized by combining boron-doped silicone resin (BSR) with a layered double hydroxide (LDH) modified with sodium dodecyl benzenesulfonate (SDBS) which was denoted as DBS-LDH/BSR. The structure of the hybrid was characterized by Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS), which indicated that BSR was successfully combined with DBS-LDH. X-ray diffraction (XRD) studies showed that the reaction of BSR occurred only on the surface of DBS-LDH. In addition, scanning electron microscopy (SEM) was used to further verify the combination of DBS-LDH with BSR. PC exhibited the optimum flame retardancy following the incorporation of 10 wt% DBS-LDH/BSR (5 wt% DBS-LDH and 5 wt% BSR). Based on thermogravimetric analysis, the char residue of this PC composite in air at 750 °C increased to 3.60 wt%. Mechanical test showed that the DBS-LDH/BSR could affect the mechanical properties after incorporation into PC. According to the UL-94 vertical burning test, the flame retardant rating of the PC composite improved to V-0. Furthermore, the limiting oxygen index (LOI) value of the PC composite increased to 34%. According to the cone calorimeter test, the peak heat release rate (PHRR) dramatically decreased by 44%. The morphology of the PC composite after combustion was characterized by SEM, which revealed that the pores of the composite were smaller than those of pure PC. This result was attributed to the limited spread of oxygen and heat permeation. Thus, both DBS-LDH and BSR contributed to the synergistic effects of reducing the fire hazard of PC.

Aligned Chemically Etched Silver Nanowire Monolayer as Surface-Enhanced Raman Scattering Substrates.

Silver nanowires (AgNWs) were chemically etched to significantly increase the surface roughness and then self-assembled on the liquid/gas interfaces via the interfacial assembly method to obtain aligned chemically etched silver nanowire films. The as-fabricated silver nanowire films were used as novel surface-enhanced Raman scattering (SERS) substrates. The morphologies and plasmon characteristics of the substrates were investigated using multiple measurement methods. The performance of as-fabricated substrates was measured using rhodamine B as a probe. The detection limitation can be as low as 10-11 M. The greatly improved plasmonic properties are attributed to the efficient light coupling and larger electromagnetic field enhancement. The novel set of SERS substrates of aligned chemically etched AgNWs is believed to be important for efficient, homogeneous, and ultrasensitive SERS sensing applications.

Fabrication of Ordered Nanopattern by using ABC Triblock Copolymer with Salt in Toluene.

Ordered nanopatterns of triblock copolymer polystyrene-block-poly(2-vinylpyridine)-block- poly (ethylene oxide)(PS-b-P2VP-b-PEO) have been achieved by the addition of lithium chloride (LiCl). The morphological and structural evolution of PS-b-P2VP-b-PEO/LiCl thin films were systematically investigated by varying different experimental parameters, including the treatment for polymer solution after the addition of LiCl, the time scale of ultrasonic treatment and the molar ratio of Li+ ions to the total number of oxygen atoms (O) in PEO block and the nitrogen atoms (N) in P2VP block. When toluene was used as the solvent for LiCl, ordered nanopattern with cylinders or nanostripes could be obtained after spin-coating. The mechanism of nanopattern transformation was related to the loading of LiCl in different microdomains.

Superparamagnetic-oil-filled nanocapsules of a ternary graft copolymer.

Stearic and oleic acid-coated Fe3O4 nanoparticles were dispersed in decahydronaphthalene (DN). This oil phase was dispersed in water using ternary graft copolymer poly(glycidyl methacrylate)-graft-[polystyrene-ran-(methoxy polyethylene glycol)-ran-poly(2-cinnamoyloxyethyl methacrylate)] or PGMA-g-(PS-r-MPEG-r-PCEMA) to yield capsules. The walls of these capsules were composed of PCEMA chains that were soluble in neither water nor DN, and the DN-soluble PS chains stretched into the droplet phase and the water-soluble MPEG chains extended into the aqueous phase. Structurally stable capsules were prepared by photolyzing the capsules with UV light to cross-link the PCEMA layer. Both the magnetite particles and the magnetite-containing capsules were superparamagnetic. The sizes of the capsules increased as they were loaded with more magnetite nanoparticles, reaching a maximal loading of ~0.5 mg of ligated magnetite nanoparticles per mg of copolymer. But the radii of the capsules were always <100 nm. Thus, a novel nanomaterial--superparamagnetic-oil-filled polymer nanocapsules--was prepared. The more heavily loaded capsules were readily captured by a magnet and could be redispersed via shaking. Although the cross-linked capsules survived this capturing and redispersing treatment many times, the un-cross-linked capsules ruptured after four cycles. These results suggest the potential to tailor-make capsules with tunable wall stability for magnetically controlled release applications.

Metal ion induced-assembly of amylose in aqueous solution.

Cu(2+)/amylose assemblies of various sizes were prepared through the Cu(2+) ion induced-assembly of amylose. These assembly structures were characterized via transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), dynamic light scattering (DLS), (1)H NMR analysis, fluorescence spectroscopy (FL) and UV-vis absorption spectroscopy (UV-vis). The results from these characterizations revealed the existence of a complexation effect and/or a bridging effect between the hydroxyl groups of amylose and Cu(2+) ions, and that the formation of the hydrophobic domains promoted the formation of Cu(2+)/amylose assemblies. The use of other metal ions to induce the formation of spherical, flower- and wire-like amylose assemblies was investigated as well. A preliminary investigation on the ability of amylose to capture various metal ions was also performed, and the results of this work demonstrated that amylose could bind quantitatively metal ions that were at low concentrations. This work provided an alternative strategy for the recovery of precious metals from metal ion-containing aqueous solutions and the reduction of water pollution.