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1.
Anal Chem ; 95(2): 1402-1408, 2023 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-36595555

RESUMO

This work presented an alternative approach for studying bacteria-cell interactions in three-dimensional (3D) hydrogel microspheres formed by the cross-linking reaction of alginate and calcium-ethylenediaminetetraacetic acid (EDTA-Ca) produced in a microfluidic chip. During the co-culture process of hepatocytes (HepG2) and Escherichia coli (E. coli) 25922, we concluded that the content change of tryptophan metabolites detected via ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was related to the cell damage level and the change of interleukin (IL-22) detected by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) was related to the ways of co-cultivation. Compared to the two-dimensional (2D) adherent cell culture process in a Petri dish (2D), the co-culture process of HepG2 and E. coli 25922 in hydrogel microspheres indicated more information about metabolism such as the appearance of indole-3-propionic acid (IPA) and possibly IL-22. The method provides a new perspective to investigate the bacteria-cell interaction and it could be a promising tool in the study of gut microbiota and human health.


Assuntos
Escherichia coli , Triptofano , Humanos , Bactérias , Comunicação Celular , Cromatografia Líquida/métodos , Escherichia coli/química , Hidrogéis , Microesferas , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Espectrometria de Massas em Tandem/métodos , Células Hep G2
2.
Sensors (Basel) ; 23(2)2023 Jan 08.
Artigo em Inglês | MEDLINE | ID: mdl-36679514

RESUMO

In recent years, the use of optical methods for temperature measurements has been attracting increased attention. High-performance miniature sensors can be based on glass microspheres with whispering gallery modes (WGMs), as their resonant frequencies shift in response to the ambient parameter variations. In this work, we present a systematic comprehensive numerical analysis of temperature microsensors with a realistic design based on standard silica fibers, as well as commercially available special soft glass fibers (GeO2, tellurite, As2S3, and As2Se3). Possible experimental implementation and some practical recommendations are discussed in detail. We developed a realistic numerical model that takes into account the spectral and temperature dependence of basic glass characteristics in a wide parameter range. To the best of our knowledge, spherical temperature microsensors based on the majority of the considered glass fibers have been investigated for the first time. The highest sensitivity dλ/dT was obtained for the chalcogenide As2Se3 and As2S3 microspheres: for measurements at room temperature conditions at a wavelength of λ = 1.55 µm, it was as high as 57 pm/K and 36 pm/K, correspondingly, which is several times larger than for common silica glass (9.4 pm/K). Importantly, dλ/dT was almost independent of microresonator size, WGM polarization and structure; this is a practically crucial feature showing the robustness of the sensing devices of the proposed design.


Assuntos
Dióxido de Silício , Dióxido de Silício/química , Temperatura , Microesferas
3.
Int J Nanomedicine ; 18: 307-322, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36700146

RESUMO

Background: Successful treatment of infectious bone defect remains a major challenge in the orthopaedic field. At present, the conventional treatment for infectious bone defects is surgical debridement and long-term systemic antibiotic use. It is necessary to develop a new strategy to achieve effective bone regeneration and local anti-infection for infectious bone defects. Methods: Firstly, vancomycin / poly (lactic acid-glycolic acid) sustained release microspheres (VAN/PLGA-MS) were prepared. Then, through the dual-nozzle 3D printing technology, VAN/PLGA-MS was uniformly loaded into the pores of nano-hydroxyapatite (n-HA) and polylactic acid (PLA) scaffolds printed in a certain proportion, and a composite scaffold (VAN/MS-PLA/n-HA) was designed, which can not only promote bone repair but also resist local infection. Finally, the performance of the composite scaffold was evaluated by in vivo and in vitro biological evaluation. Results: The in vitro release test of microspheres showed that the release of VAN/PLGA-MS was relatively stable from the second day, and the average daily release concentration was about 15.75 µg/mL, which was higher than the minimum concentration specified in the guidelines. The bacteriostatic test in vitro showed that VAN/PLGA-MS had obvious inhibitory effect on Staphylococcus aureus ATCC-29213. Biological evaluation of VAN/MS-PLA/n-HA scaffolds in vitro showed that it can promote the proliferation of adipose stem cells. In vivo biological evaluation showed that VAN/MS-PLA/n-HA scaffold could significantly promote bone regeneration. Conclusion: Our research shows that VAN/MS-PLA/n-HA scaffolds have satisfying biomechanical properties, effectively inhibit the growth of Staphylococcus aureus, with good biocompatibility, and effectiveness on repairing bone defects. The VAN/MS-PLA/n-HA scaffold provide the clinic with an application prospect in bone tissue engineering.


Assuntos
Durapatita , Vancomicina , Durapatita/farmacologia , Vancomicina/farmacologia , Tecidos Suporte , Microesferas , Preparações de Ação Retardada/farmacologia , Regeneração Óssea , Poliésteres/farmacologia , Impressão Tridimensional , Osteogênese
4.
Methods Mol Biol ; 2623: 187-200, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36602687

RESUMO

Optical trapping of organelles inside cells is a powerful technique for directly measuring the forces generated by motor proteins when they are transporting the organelle in the form of a "cargo". Such experiments provide an understanding of how multiple motors (similar or dissimilar) function in their endogenous environment. Here we describe the use of latex bead phagosomes ingested by macrophage cells as a model cargo for optical trap-based force measurements. A protocol for quantitative force measurements of microtubule-based motors (dynein and kinesins) inside macrophage cells is provided.


Assuntos
Cinesinas , Fagossomos , Microesferas , Cinesinas/metabolismo , Fagossomos/metabolismo , Dineínas/metabolismo , Transporte Biológico , Microtúbulos/metabolismo
5.
Carbohydr Polym ; 302: 120422, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36604084

RESUMO

The purpose of this study was to develop an oral paediatric formulation of budesonide (BUD) for the treatment of inflammatory bowel disease. A formulation realized as microspheres using the prilling/vibration technique is proposed as an innovative drug delivery system ensuring BUD-specific colonic release in response to different triggers, such as pH, transit time, and resident microbiota. BUD, or the inclusion complex BUD/hydroxypropyl-ß-cyclodextrin, was loaded into microspheres consisting of different ratios of alginate, Eudragit® FS 30D, with or without inulin. Sixteen formulations are produced that show high yields and encapsulation efficiencies, ensuring a homogenous distribution of BUD into the matrix. Microsphere diameters of <655 µm and promising flow properties make these systems suitable for oral administration to children. Swelling and drug release studies in simulated gastrointestinal fluid are used to demonstrate the response of microspheres to time and pH triggers. Studies in faecal medium highlight that drug release from microspheres with inulin is also influenced by microbiota.


Assuntos
Budesonida , Inulina , Humanos , Criança , Microesferas , Sistemas de Liberação de Medicamentos/métodos , Ácidos Polimetacrílicos/química , Colo , Concentração de Íons de Hidrogênio , Tamanho da Partícula
6.
Food Res Int ; 163: 112212, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36596140

RESUMO

Rapid and sensitive quantitative detection methods are required to monitor and detect Salmonella throughout the food supply chain and early prevention of foodborne disease outbreaks. In this study, a magnetic microbead enzyme-linked immunoassay (MELISA) based on phage receptor binding protein was developed for rapid enrichment and detection of Salmonella in complex food matrices. RBP 41 from phage T102 acted as a species-specific recognition element for Salmonella by exploiting its strong binding capacity to Salmonella surface receptors. RBP 41-MBs were prepared by coupling recombinant RBP 41 with MBs and used to separate and enrich Salmonella cells from spiked food samples. The captured complexes were further integrated with ELISA procedures by HRP-labeled anti-Salmonella antibody for rapid and accurate detection of Salmonella. The whole method took <1.5 h and the detection limit was 10 CFU/mL. Therefore, MELISA was successfully developed for the detection of Salmonella in various spiked food samples (skim milk, lettuce, and chicken breast). The ELISA reaction process of this method was carried out on magnetic beads. It simplified the process of the traditional ELISA method and reduces the reaction time. This study expanded the use of phage-associated proteins and demonstrated the promising prospects for practical applications in the detection of foodborne pathogens.


Assuntos
Bacteriófagos , Microesferas , Imunoensaio/métodos , Salmonella , Fenômenos Magnéticos
7.
Toxins (Basel) ; 15(1)2023 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-36668898

RESUMO

Lateral flow immunoassay (LFIA) based on fluorescent microbeads has attracted much attention for its use in rapid and accurate food safety monitoring. However, conventional fluorescent microbeads are limited by the aggregation-caused quenching effect of the loaded fluorophores, thus resulting in low signal intensity and insufficient sensitivity of fluorescent LFIA. In this study, a green-emitting fluorophore with an aggregation-induced emission (AIE) characteristic was encapsulated in polymer nanoparticles via an emulsification technique to form ultrabright fluorescent microbeads (denoted as AIEMBs). The prepared AIEMBs were then applied in a competitive LFIA (AIE-LFIA) as signal reporters for the rapid and highly sensitive screening of fumonisin B1 (FB1) in real corn samples. High sensitivity with a detection limit of 0.024 ng/mL for FB1 was achieved by the developed AIE-LFIA. Excellent selectivity, good accuracy, and high reliability of the AIE-LFIA were demonstrated, indicating a promising platform for FB1 screening.


Assuntos
Ouro , Nanopartículas Metálicas , Reprodutibilidade dos Testes , Microesferas , Imunoensaio/métodos , Limite de Detecção
8.
Nano Lett ; 23(2): 588-596, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36607826

RESUMO

Microcantilevers are widely employed as mass sensors for biological samples, from single molecules to single cells. However, the accurate mass quantification of living adherent cells is impaired by the microcantilever's mass sensitivity and cell migration, both of which can lead to detect masses mismatching by ≫50%. Here, we design photothermally actuated microcantilevers to optimize the accuracy of cell mass measurements. By reducing the inertial mass of the microcantilever using a focused ion beam, we considerably increase its mass sensitivity, which is validated by finite element analysis and experimentally by gelatin microbeads. The improved microcantilevers allow us to instantly monitor at much improved accuracy the mass of both living HeLa cells and mouse fibroblasts adhering to different substrates. Finally, we show that the improved cantilever design favorably restricts cell migration and thus reduces the large measurement errors associated with this effect.


Assuntos
Células HeLa , Animais , Camundongos , Humanos , Microesferas
9.
Anal Chim Acta ; 1239: 340724, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36628724

RESUMO

This study developed a flexible and wearable paper-based chemoresistive sensor (FWPCS) by modifying a SWCNT-PdNP-polystyrene microsphere (SPPM) composite (SPPM/FWPCS) for the low-cost and online determination of fruit ripeness and corruption. A new method for the batch and low-cost fabrication of SPPM/FWPCSs based on laser direct writing was proposed. The sensing mechanism of FWPCS relies on the electron depletion layer in the sensing composite created by the Schottky barriers among SWCNTs, PdNPs, and the adsorbed oxygen, along with the construction of O2-. When the SPPM sensing film is exposed to ethylene, trapped electrons are released into the conduction band through oxidation and cleavage of ethylene, causing a decrease in resistance. The properties and morphology of the synthesized SPPM composite were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. Additionally, the key parameters for the fabrication of SPPMs/FWPCS related to the sensing performance were optimized. The concentration of C2H4 can be detected down to 100 ppb using the SPPMs/FWPCS at 25 °C. Finally, the real-time determination of banana ripeness and corruption verified the feasibility of the sensor, indicating that the SPPMs/FWPCS has prospects in monitoring fruit ripeness and corruption during storage and transportation.


Assuntos
Poliestirenos , Dispositivos Eletrônicos Vestíveis , Microesferas , Frutas , Oxigênio , Etilenos
10.
J Orthop Surg Res ; 18(1): 17, 2023 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-36609253

RESUMO

BACKGROUND: Cervical and lumbar pain is usually caused by degeneration of the nucleus pulposus (NP). As a powerful therapeutic strategy, tissue engineering can effectively restore the normal biological properties of the spinal unit. Previous studies suggested that poly(lactic-co-glycolic acid) (PLGA) microspheres are effective carriers of cells and biomolecules in NP tissue engineering. This study aims to explore the therapeutic effect of PLGA microspheres coloaded with transforming growth factor-ß1 (TGF-ß1) and anti-miR-141 on intervertebral disc degeneration (IDD). METHODS: PLGA microspheres were characterized by scanning electron microscopy, a laser particle size analyzer, and laser confocal microscopy. The in vitro release rate of biomolecules from the microspheres was analyzed by reversed-phase high-performance liquid chromatography and agarose gel electrophoresis. The rat NP cells (NPCs) treated with the solutions released from microspheres for different lengths of time were assigned to a control group (Ctrl), an empty PLGA microsphere group (Mock microsphere, MS), a TGF-ß1-loaded PLGA microsphere group (TMS), an anti-miR-141-loaded PLGA microsphere group (AMS), and an anti-miR-141 + TGF-ß1-loaded PLGA microsphere group (ATMS). The proliferation and apoptosis of NPCs were observed by alamar blue and flow cytometry. The gene and protein expression of cartilage markers COL2A1 and ACAN were observed by RT-qPCR and Western blot. The rat model of IDD was established by tail puncture. Rats were divided into a control group (Ctrl), a mock operation group (Mock), a TGF-ß1 microsphere group (TMS), an anti-miR-141 microsphere group (AMS), and an anti-miR-141 + TGF-ß1 microsphere group (ATMS). The degree of rat tail IDD was assessed in each group through magnetic resonance imaging (MRI), safranin O-fast green staining, immunohistochemistry, and Western blotting. RESULTS: PLGA microspheres were stably coloaded and could sustainably release TGF-ß1 and anti-miR-141. The results of in vitro cell experiments showed that the release solution of PLGA microspheres significantly enhanced the proliferation of NPCs without inducing their apoptosis and significantly upregulated cartilage markers in NPCs. The effect of microspheres was greater in the ATMS group than that in the TMS group and AMS group. In vivo experiments showed that IDD could be effectively inhibited and reversed by adding microspheres coloaded with TGF-ß1 and/or anti-miR-141, and the effect was greatest in the ATMS group. CONCLUSION: PLGA microspheres coloaded with TGF-ß1 and anti-miR-141 can reverse IDD by inhibiting the degeneration of NPCs.


Assuntos
Degeneração do Disco Intervertebral , Disco Intervertebral , MicroRNAs , Animais , Ratos , Antagomirs/metabolismo , Cartilagem/metabolismo , Disco Intervertebral/metabolismo , Degeneração do Disco Intervertebral/patologia , MicroRNAs/metabolismo , Microesferas , Fator de Crescimento Transformador beta1/metabolismo , Poliglactina 910
11.
Artigo em Inglês | MEDLINE | ID: mdl-36508900

RESUMO

To study the effect of acute-phase reaction (APR) of inflammation on the release of octreotide acetate microsphere (Sandostatin®, SLAR) at a clinical dose, a more sensitive liquid chromatography coupled to tandem mass spectrometry analysis method needs to be developed because of the low plasma concentrations of octreotide. Solid-phase microextraction with an Oasis® HLB µElution plate was adopted for sample preparation. Extraction recovery ranged from 65.7 % to 73.2 %, and the matrix effect was negligible. High sensitivity and an intense chromatographic peak were acquired by optimizing the chromatography and mass spectrometry conditions. The lower limit of quantitation (LLOQ) was 0.01 ng/mL based on 100 µL of plasma, and linearity ranged from 0.01 to 5.0 ng/mL. The coefficients of variations for intraday and interday precision were less than 4.4 %, and the relative error of accuracy was within 5.7 %. The validated method was successfully applied to pharmacokinetics studies of SLAR in a seven-day inflammation model of rabbits, indicating that the APR did not affected the release and pharmacokinetics of the octreotide microspheres.


Assuntos
Octreotida , Espectrometria de Massas em Tandem , Animais , Coelhos , Espectrometria de Massas em Tandem/métodos , Microesferas , Cromatografia Líquida/métodos , Inflamação , Cromatografia Líquida de Alta Pressão/métodos , Reprodutibilidade dos Testes
12.
Chemosphere ; 313: 137539, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36521750

RESUMO

Excessive copper (Cu) concentrations pose significant health risks to both plants and humans. In this study, sodium alginate (SA)-gelatin (GEL)-polyvinyl pyrrolidone (PVP)- embedded dinotefuran (DIN) microspheres were prepared using spray-drying technology. The loading content and encapsulation efficiency of optimal microspheres determined by physical modifications were 19.77% and 99.32%, respectively. In addition, the microspheres showed variable stimuli-responsive controlled release capacities in different temperatures and types of soil, as well as showed better control efficiency of larvae of Protaetia brevitarsis at pesticide application in the early stage, with the potential ability to control pest outbreaks at high temperatures. In addition, blank microspheres improved the growth and physiological activity of cucumber seedlings, reduced copper content in leaves, increased soil nutrient content, and prevented soil acidification. Further, the use of blank microspheres increased the relative abundance of soil beneficial functional bacteria communities, which mediate heavy metal (HM) immobilization/tolerance and promote plant growth. Redundancy analysis (RDA) and Spearman correlation analysis showed that these beneficial functional bacteria were mainly positively correlated with soil EC, A-N, and N-N. In summary, this study showed that the technique of combining physically modified carrier materials with pesticides has the potential to reduce Cu contamination in the surrounding agricultural soil during pesticide application, thereby reducing Cu uptake by crops.


Assuntos
Praguicidas , Poluentes do Solo , Humanos , Cobre/toxicidade , Praguicidas/toxicidade , Solo , Microesferas , Preparações de Ação Retardada , Poluentes do Solo/toxicidade , Alginatos
13.
Langmuir ; 39(1): 638-646, 2023 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-36542801

RESUMO

Although paraquat is a widely used herbicide, it is toxic to humans if ingested or absorbed through an open wound. To improve the safety of paraquat, a new formulation of paraquat based on photoresponsive polymers was exploited. Photoresponsive ß-cyclodextrin polymer microspheres (AZO-CD) were synthesized via a host-guest interaction between ß-cyclodextrin and azobenzene. AZO-CD were characterized by Fourier transform infrared spectrometry, circular dichroism, ultraviolet (UV) spectrophotometry, and thermogravimetric analysis, and their photoresponsiveness was also evaluated. AZO-CD were used to load paraquat, which yielded photoresponsive paraquat-loaded microspheres. For the paraquat-loaded microspheres, irradiation with UV light or sunlight induced the isomerization of azobenzene into the cis form. Then, the cis-azobenzene was liberated from the cavities of the ß-cyclodextrin. The paraquat-loaded microspheres released paraquat continuously over time. Furthermore, under UV light, the herbicidal capacity of the paraquat-loaded microspheres against barnyard grass was comparable to that of free paraquat at the same dose. Our findings show that loading paraquat into AZO-CD provides a safe and environmentally friendly herbicide formulation.


Assuntos
Herbicidas , beta-Ciclodextrinas , Humanos , Paraquat/toxicidade , Microesferas , beta-Ciclodextrinas/química , Compostos Azo/química , Polímeros/química
14.
J Colloid Interface Sci ; 633: 1012-1021, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36516677

RESUMO

HYPOTHESIS: Classical (solid particles stabilized) Pickering emulsions have been widely studied due to the irreversible adsorption of solid particles at the oil-water interface. Mesoporous hollow silica microspheres (MHSMs) are promising stabilizers for Pickering emulsion owing to its larger specific surface area and lower apparent density. However, this type of Pickering emulsion has not attracted enough attention. The stabilization mechanism of Pickering emulsion by MHSMs has not been studied in detail yet. EXPERIMENTS: Herein, stable Pickering emulsions were prepared using only MHSMs as stabilizers. In order to investigate its stabilization mechanism, the effect factors of size, shell thickness, wettability and concentration of MHSMs, and oil/water ratio on the stability of Pickering emulsions were analyzed deeply. FINDINGS: As a result, the stability of Pickering emulsion can be improved by MHSMs with smaller particle size and shell thickness. Also, MHSMs with the intermediate hydrophobicity and suitable oil/water ratio actually do favour for the stability of Pickering emulsion. As expected, the stability of Pickering emulsion can be enhanced by increasing the concentration of MHSMs in a certain range. The Pickering emulsions tend to achieve excellent stable state when the concentration of MHSMs is 1.25 mg/mL. All those results suggested that the stability of Pickering emulsions correlates directly to particle size, shell thickness, wettability and concentration of MHSMs, and oil/water ratio. This research paves a way for the fabrication of functional materials via Pickering emulsions.


Assuntos
Dióxido de Silício , Emulsões , Microesferas , Molhabilidade , Interações Hidrofóbicas e Hidrofílicas , Tamanho da Partícula
15.
Int J Biol Macromol ; 226: 485-495, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36521695

RESUMO

Microsphere with sphere-in-capsule structure is a multi-drugs delivery system to achieve the purpose of combination therapy. In this paper, we have prepared gelatin/alginate-based microspheres with sphere-in-capsule structure by a relatively fast, simple, and easily large-scale industrialized emulsification method for spatiotemporal manipulative drug release in gastrointestinal tract. Calcium alginate microspheres encapsulated with bovine serum albumin (BSA) were first prepared as inner microspheres, and then inner microspheres and ranitidine hydrochloride (RH) were co-encapsulated by gelatin microspheres to form double-layer microspheres with sphere-in-capsule structure. The size and distribution of microspheres can be easily controlled by emulsifying conditions. The microspheres with sphere-in-capsule structure displayed desirable encapsulation efficiency of BSA (61.52 %) and RH (56.07 %). The in vitro simulated drug release showed the spatiotemporal release feature of microspheres with sphere-in-capsule structure. In the specific simulated fluid, the release behavior and cumulative release of RH (sustainedly released 95 % in simulated gastric fluid) and BSA (rapidly released 73 % in simulated intestinal fluid) were different. The drug release mechanisms were analyzed to determine RH and BSA's release behavior. Overall, the microspheres with sphere-in-capsule structure have the potential application of spatiotemporal manipulative drug delivery in the gastrointestinal tract.


Assuntos
Alginatos , Gelatina , Microesferas , Gelatina/química , Alginatos/química , Liberação Controlada de Fármacos , Trato Gastrointestinal , Soroalbumina Bovina/química , Tamanho da Partícula
16.
Enzyme Microb Technol ; 164: 110169, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36508943

RESUMO

Surface functioned magnetic silica particles are efficient carriers to achieve facilitated separation and recycling of biocatalysts. However, traditional methods of modifying magnetic silica particles required time-costly sequential coating and surface modification steps and toxic solvents. Herein, a green and efficient routine was proposed to prepare the surface modified silica-coated magnetic microspheres (SCEs@SiO2 @Fe3O4) in one-pot. The elastin-like polypeptides (ELPs)-SpyCatcher chimera (SCEs) were purified by inverse transition cycling with high yield (275 mg/L) and incorporated into the magnetic silica spheres based on the biomimetic silicification capability of ELPs as proved by the EDS and SEM mapping. No SCEs leaked was observed within 48 h, indicating excellent stability in buffer. Then, the biofunctionalized carriers were used to purify and immobilize the target dual enzymes (xylanase-linker-SpyTag-linker-lichenase, bienzymes) directly from the crude cell lysis solution by the spontaneous isopeptide bond reaction between SpyCatcher and SpyTag. The immobilized bienzymes were sphere-like magnetic silica particles with uniform size, which had good magnetic responsiveness. The immobilization yield, immobilization efficiency and activity recovery for xylanase were 86%, 84 % and 72 %, while for lichenase was 92 %, 86 % and 79 %, respectively. Besides, the immobilized bienzymes showed good reusability (>60 %, 10 times for xylanase, >95 %, 8 times for lichenase). The SCEs modified silica-coated magnetic microspheres are expected to provide versatile platforms for single-step of purification and immobilization of multienzymes, offering great potentials in the field of biocatalysis.


Assuntos
Enzimas Imobilizadas , Dióxido de Silício , Enzimas Imobilizadas/química , Dióxido de Silício/química , Biomimética , Microesferas , Fenômenos Magnéticos
17.
Int J Biol Macromol ; 228: 13-22, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36549620

RESUMO

In this study, carbon dots (CDs) were prepared by a one-pot hydrothermal method using tempo-oxidized cellulose nanocrystals (TOCNC) and polyethylenimine (PEI). The CDs were self-assembled with a microsphere adsorbent prepared using TOCNC and sodium alginate (SA). CDs-TOCNC/SA-an environmentally friendly, fluorescent-sensitive, and recyclable microsphere adsorbent-was obtained. FTIR analysis showed that PEI successfully modified the CDs. In addition, the fluorescence quenching of CDs was observed when the concentration of Pb2+ was 0.0001-100 mg/L, indicating that CDs can dynamically monitor Pb2+. CDs-TOCNC/SA can produce blue fluorescence under 365 nm UV light and selectively and efficiently adsorb Pb2+. When the concentration of Pb2+ was 0.0001-100 mg/L, fluorescence quenching of the adsorbent was observed, indicating that CDs-TOCNC/SA could visually adsorb Pb2+. The adsorption isotherm and kinetic parameters show that the adsorption process conforms to the Langmuir isotherm model at 298 K, and the maximum adsorption capacity of Pb2+ was 190.1 mg/g at pH = 5. Moreover, CDs-TOCNC/SA could still obtain 78.99 % Pb2+ after five sorption-desorption cycles. The adsorption mechanism may involve ion exchange, electrostatic attraction, intra-particle diffusion, and chemical complexation.


Assuntos
Chumbo , Poluentes Químicos da Água , Microesferas , Adsorção , Fluorescência , Carbono , Alginatos/química , Poluentes Químicos da Água/química , Cinética , Concentração de Íons de Hidrogênio
18.
ACS Appl Mater Interfaces ; 15(1): 391-406, 2023 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-36562459

RESUMO

The effective treatment for periodontitis is to completely and sustainedly eradicate the bacterial pathogens from the complex periodontal pockets. Local sustained-release antibiotics as a complementary treatment after scaling and root planning can sustainedly combat bacterial pathogens in the periodontal pockets to help treat the disease, but the increasing concern of bacterial resistance limits its future use. Here, we reported a local antibacterial system based on microsized multifunctional Ag-TiO2-x encapsulated in alginate (ATA) microspheres. We confirmed that ATA displayed strong photothermally enhanced dual enzyme-mimicking (peroxidase-like and catalase-like) activities and weak photocatalytic activity under 808 nm near-infrared (NIR) irradiation, which could boost the generation of reactive oxygen species (ROS) and O2 in the presence of low-level H2O2. As a result, the ATA/H2O2/NIR system exhibited efficient antibacterial activity against Porphyromonas gingivalis and Streptococcus gordonii in both planktonic and biofilm forms. With the help of ROS, ATA could release Ag+ in concentrations sufficient to inhibit periodontal pathogens as well. Moreover, the in situ-generated oxygen was supposed to alleviate the local hypoxic environment and would help downregulate the lipopolysaccharide-mediated inflammatory response of periodontal stem cells. The in vivo rat periodontitis treatment results demonstrated that the ATA/H2O2/NIR system reduced the bacterial load, relieved inflammation, and improved tissue healing. Our work developed a new local prolonged bactericidal and oxygenation system for enhanced periodontitis. Avoiding the usage of antibiotics and nanomaterials, this strategy showed great promise in adjunctive periodontitis treatment and also in other biomedical applications.


Assuntos
Alginatos , Periodontite , Ratos , Animais , Alginatos/farmacologia , Bolsa Periodontal/tratamento farmacológico , Espécies Reativas de Oxigênio/farmacologia , Peróxido de Hidrogênio/farmacologia , Microesferas , Periodontite/tratamento farmacológico , Periodontite/microbiologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Porphyromonas gingivalis
19.
J Colloid Interface Sci ; 634: 481-494, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36542977

RESUMO

Recently, electromagnetic radiation is a serious threat to equipment accuracy, military safety and human health. The combination with different materials to fabricate absorber composites with well-designed morphology is expected to ameliorate this issue. In here, CuS/Fe3O4@polypyrrole (CuS/Fe3O4@PPy) flower-like composites are constructed by the combination of hydrothermal method, solvothermal method and in-situ polymerization. CuS with flower-like structure consisting of nanosheets can provide a conductive backbone and large specific surface area. Hollow Fe3O4 microspheres play a key role in deciding magnetic loss, and electromagnetic waves can penetrate their hollow structure, result in multiple reflection and refraction. PPy coating can enhance the combined strength of composite, and effectively consume microwaves by scattering and multiple refraction in the intercalated structure. As expected, the minimum reflection loss (RLmin) of CuS/Fe3O4@PPy composites is -74.12 dB at 8.16 GHz with a thickness of 2.96 mm, and the effective absorption bandwidth (EAB) is 4.6 GHz (13.4-18.0 GHz) at 1.68 mm. The excellent electromagnetic wave absorption performances are attributed to the synergy effect of different components. This work provides a unique strategy for the structural design of flower-like microspheres in the field of electromagnetic wave absorption.


Assuntos
Polímeros , Pirróis , Humanos , Condutividade Elétrica , Microesferas
20.
J Colloid Interface Sci ; 634: 730-736, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36563429

RESUMO

Electrocatalytic water splitting is a promising technology for sustainable hydrogen (H2) production; however, it is restricted by the kinetically sluggish anodic oxygen evolution reaction (OER). Replacing OER with urea oxidation reaction (UOR) with low thermodynamic potential can simultaneously improve the energy efficiency of H2 production and purify urea-containing wastewater. Here we report a facile assembly-calcination two-step method to synthesize heterogeneous Ni-MoN nanosheet-assembled microspheres (Ni-MoN NAMs). The nanosheet-assembled structure and the synergistic metallic Ni-MoN heterogeneous interface endow the Ni-MoN NAMs with good OER (1.52 V@10 mA cm-2), UOR (1.28 V@10 mA cm-2), and hydrogen evolution reaction (HER, 0.16 V@10 mA cm-2) activity. The two-electrode urea electrolysis cell with Ni-MoN NAMs as both the cathode and anode requires an extremely low cell voltage of 1.41 V to afford 20 mA cm-2, which is 0.3 V lower than that of the water electrolyzer, paving the way for energy-saving H2 production.


Assuntos
Hidrogênio , Oxigênio , Microesferas , Ureia , Água
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