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1.
Article in English | MEDLINE | ID: mdl-39210609

ABSTRACT

PURPOSE: The objective of this study is to investigate the association between preoperative serum lipids levels and papillary thyroid cancer (PTC) patients' outcomes. METHODS: A retrospective cohort study including 3575 PTC patients from year 2012-2016 with follow-ups in our institute were enrolled. Preoperative serum lipids were divided into categorical variables by Receiver-operating curves. Univariable and multivariable cox regression models were developed and independent risk factors were used to construct a nomogram to predict disease-free survival (DFS) rate. RESULTS: Among the 3575 patients, the mean follow-up time was 56.7 months. Comparing with the patients with high level of triglycerides (TAG≥0.605 mmol/L) and high-density lipoprotein (HDL≥0.935 mmol/L), those with low level of TAG (hazard ratio [HR] 2.28 [95% CI, 1.35-3.83]) and HDL (HR 1.64, [1.02-2.62]) had a significantly higher risk of recurrence in PTCs. The 5-year DFS rate of patients with low level of TAG was 94.4%, which was much lower than that in the high level group (97.2%, P<0.001). While TC (P = 0.13), LDL (P = 0.07) and VLDL (P = 0.15) were not statistically correlated with PTCs' recurrence. The nomogram model showed clinical predictive value with the c-index of 0.80 (95% CI 0.73-0.87) and 0.82 (95% CI 0.73-0.90) for 3- and 4-year DFS in the training cohorts. CONCLUSION: In the present study, we provide initial evidence that low levels of TAG and HDL were independently associated with the recurrence of PTC, indicating that preoperative serum concentrations of lipids are helpful in predicting PTC patients' prognosis in clinical practice.

2.
Adv Mater ; : e2403728, 2024 Aug 04.
Article in English | MEDLINE | ID: mdl-39097946

ABSTRACT

Poly(ethylene terephthalate) (PET) is an important polymer with annual output second only to polyethylene. Due to its low biodegradability, a large amount of PET is recycled for sustainable development. However, current strategies for PET recycling are limited by low added value or small product scale. It is urgent to make a breakthrough on the principle of PET macromolecular reaction and efficiently prepare products with high added value and wide applications. Here, the catalyst- and solvent-free synthesis of biodegradable plastics are reported through novel carboxyl-ester transesterification between PET waste and bio-based hydrogenated dimer acid (HDA), which can directly substitute some terephthalic acid (TPA) units in PET chain by HDA unit. This macromolecular reaction can be facilely carried out on current equipment in the polyester industry without any additional catalyst and solvent, thus enabling low-cost and large-scale production. Furthermore, the product semi-bio-based copolyester shows excellent mechanical properties, regulable flexibility and good biodegradability, which is expected to substitute poly(butylene adipate-co-terephthalate) (PBAT) plastic as high value-added biodegradable materials. This work provides an environmental-friendly and economic strategy for the large-scale upcycling of PET waste.

3.
Biomacromolecules ; 25(7): 4545-4556, 2024 Jul 08.
Article in English | MEDLINE | ID: mdl-38902858

ABSTRACT

Copper (Cu) nanodrugs can be facilely prepared through atom transfer radical polymerization (ATRP) in an aqueous medium. However, it is difficult to control the morphology of Cu nanodrugs and thereby optimize their anticancer activity. In this work, aqueous ATRP was combined with polymerization-induced self-assembly (PISA) to prepare Cu nanodrugs with various morphologies. We mapped the relationship between polymerization condition and product morphology in which each morphology shows a wide preparation window. Decreasing the reaction temperature and feeding more Cu catalysts can improve the mobility of chains, facilitating the morphology evolution from sphere to other high-order morphologies. The resultant Cu nanodrugs with high monomer conversion and high Cu loading efficiency could be easily taken by cancer cells, showing excellent anticancer efficacy in vitro. This work proposed a potential strategy to prepare Cu nanodrugs with a specific morphology in batches, providing the method to optimize the anticancer efficacy through morphology control.


Subject(s)
Antineoplastic Agents , Copper , Polymerization , Copper/chemistry , Humans , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Metal Nanoparticles/chemistry , Water/chemistry , Cell Line, Tumor
4.
Heliyon ; 10(9): e30505, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38726194

ABSTRACT

FERMT2 has been identified as a participant in integrin-linked kinase signaling pathways, influencing epithelial-mesenchymal transition and thereby affecting tumor initiation, progression, and invasion. While the character of FERMT2 in the tumor microenvironment (TME) as well as its implications for immunotherapy remain unclear. Thus, we conducted a comprehensive analysis to assess the prognostic significance of FERMT2 using Kaplan-Meier analysis. In addition, we employed enrichment analysis to uncover potential underlying molecular mechanisms. Using "Immunedeconv" package, we evaluated the immune characteristics of FERMT2 within TME. Furthermore, we determined the expression levels of FERMT2 in various cell types within TME, based on single-cell sequencing data. To confirm the co-expression of FERMT2 and markers of cancer-associated fibroblasts (CAFs), we performed multiplex immunofluorescence staining on tissue paraffin sections across various cancer types. Our analysis disclosed a significant correlation between elevated FERMT2 expression and unfavorable prognosis in specific cancer types. Furthermore, we identified a strong correlation between FERMT2 expression and diverse immune-related factors, including immune checkpoint molecules, immune cell infiltration, microsatellite instability (MSI), and tumor mutational burden (TMB). Additionally, there was a significant correlation between FERMT2 expression and immune-related pathways, particularly those associated with activating, migrating, and promoting the growth of fibroblasts in diverse cancer types. Interestingly, we observed consistent co-expression of FERMT2 in both malignant tumor cells and stromal cells, particularly within CAFs. Notably, our findings also indicated that FERMT2, in particular, exhibited elevated expression levels within tumor tissues and co-expressed with α-SMA in CAFs based on the multiplex immunofluorescence staining results.

5.
J Control Release ; 368: 676-690, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38458572

ABSTRACT

Barrier membranes play a pivotal role in the success of guided periodontal tissue regeneration. The biodegradable barriers predominantly used in clinical practice often lack sufficient barrier strength, antibacterial properties, and bioactivity, frequently leading to suboptimal regeneration outcomes. Although with advantages in mechanical strength, biodegradability and plasticity, bioinert aliphatic polyesters as barrier materials are usually polymerized via toxic catalysts, hard to be functionalized and lack of antibacterial properties. To address these challenges, we propose a new concept that controlled release of bioactive substance on the whole degradation course can give a bioinert aliphatic polyester bioactivity. Thus, a Zn-based catalytic system for polycondensation of dicarboxylic acids and diols is created to prepare zinc covalent hybrid polyester (PBS/ZnO). The atomically-dispersed Zn2+ ions entering main chain of polyester molecules endow PBS/ZnO barrier with antibacterial properties, barrier strength, excellent biocompatibility and histocompatibility. Further studies reveal that relying on long-term controlled release of Zn2+ ions, the PBS/ZnO membrane greatly expedites osteogenetic effect in guided tissue regeneration (GTR) by enhancing the mitochondrial function of macrophages to induce M2 polarization. These findings show a novel preparation strategy of bioactive polyester biomaterials based on long term controlled release of bioactive substance that integrates catalysis, material structures and function customization.


Subject(s)
Guided Tissue Regeneration , Zinc Oxide , Zinc , Polyesters/chemistry , Delayed-Action Preparations , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Ions , Bone Regeneration
6.
Angew Chem Int Ed Engl ; 63(20): e202402747, 2024 05 13.
Article in English | MEDLINE | ID: mdl-38488767

ABSTRACT

In this study, some copper catalysts used for atom transfer radical polymerization (ATRP) were explored as efficient anti-tumor agents. The aqueous solution of copper-containing nanoparticles with uniform spheric morphology was in situ prepared through a copper-catalyzed activator generated by electron transfer (AGET) ATRP in water. Nanoparticles were then directly injected into tumor-bearing mice for antitumor chemotherapy. The copper nanodrugs had prolonged blood circulation time and enhanced accumulation at tumor sites, thus showing potent antitumor activity. This work provides a novel strategy for precise and large-scale preparation of copper nanodrugs with high antitumor activity.


Subject(s)
Antineoplastic Agents , Copper , Polymerization , Copper/chemistry , Animals , Mice , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Humans , Catalysis , Metal Nanoparticles/chemistry , Cell Line, Tumor , Free Radicals/chemistry , Nanoparticles/chemistry
7.
J Mater Chem B ; 11(14): 3136-3150, 2023 04 05.
Article in English | MEDLINE | ID: mdl-36896831

ABSTRACT

Craniomaxillofacial bone defects result in physical and psychological dual injuries making the promotion or acceleration of bone regeneration imperative. In this work, a fully biodegradable hydrogel is facilely prepared via thiol-ene "click" reactions under human physiological conditions using multifunctional poly(ethylene glycol) (PEG) derivatives as precursors. This hydrogel shows excellent biological compatibility, enough mechanical strength, a low swelling rate and an appropriate degradation rate. Rat bone marrow mesenchymal stem cells (rBMSCs) can survive and proliferate on/in the PEG hydrogel and differentiate into osteogenic cells. The PEG hydrogel can also effectively load rhBMP-2 through the above "click" reaction. Under the physical barrier of the chemically crosslinked hydrogel network, the spatiotemporal release of rhBMP-2 effectively promotes the proliferation and osteogenic differentiation of rBMSCs at a loading concentration of 1 µg ml-1. Finally, based on a rat calvarial critical-size defect model, the rhBMP-2 immobilized hydrogel loaded with rBMSCs basically accomplishes the repair and regeneration within 4 weeks featured by remarkably enhanced osteogenesis and angiogenesis. The click-based injectable bioactive PEG hydrogel developed in the present study is a new type of bone substitute with great expectations in future clinical applications.


Subject(s)
Bone Regeneration , Osteogenesis , Animals , Humans , Rats , Biocompatible Materials/pharmacology , Hydrogels/pharmacology , Polyethylene Glycols/pharmacology , Recombinant Proteins/pharmacology , Bone Morphogenetic Protein 2/pharmacology
8.
Adv Mater ; 35(20): e2210758, 2023 May.
Article in English | MEDLINE | ID: mdl-36809549

ABSTRACT

Poly(ethylene terephthalate) (PET) is an important polymer with an annual output second only to polyethylene. The development of PET recycling technologies is therefore necessary to not only eliminate the harm associated with white pollution and microplastics, but also to reduce carbon emissions. Antibacterial PET, one of the most high-value advanced materials, has improved the ability to treat bacterial infections. However, current methods of manufacturing commercial antibacterial PET require blending with an excess of metal-based antibacterial agents, which leads to biotoxicity and a nonpersistent antibacterial activity. In addition, high-efficiency organic antibacterial agents have yet to be employed in antibacterial PET due to their poor thermal stabilities. Herein, a solid-state reaction for the upcycling of PET waste using a novel hyperthermostable antibacterial monomer is described. This reaction is catalyzed by the residual catalyst present in the PET waste. It is found that a catalytic amount of the antibacterial monomer enabled the low-cost upcycling of PET waste to produce high-value recycled PET with a strong and persistent antibacterial activity, as well as similar thermal properties to the virgin PET. This work provides a feasible and economic strategy for the large-scale upcycling of PET waste and exhibits potential for application in the polymer industry.


Subject(s)
Plastics , Polyethylene Terephthalates , Polymers , Catalysis , Ethylenes
9.
J Mater Chem B ; 11(2): 335-344, 2023 01 04.
Article in English | MEDLINE | ID: mdl-36412982

ABSTRACT

Dentin bonding is the most common form of human tissue repair among tissue-biomaterial adhesions, concerning billions of people's oral health worldwide. However, insufficient adhesive infiltration in the demineralized dentin matrix (DDM) always produces numerous defects in the bonding interface termed the hybrid layer, which causes high levels of bacteria-related secondary dental diseases, and less than 50% of the bonding lasts more than 5 years. Therefore, it is urgent and vital to construct an antibacterial low-defect hybrid layer to solve the durability-related problems. A DDM with a hydrogel-like surface formed by the hydration of highly-anionic non-collagenous proteins (NCPs) is firstly used as a template to electrostatically assemble polyethyleneimine (PEI). The formation of a stable antibacterial polyelectrolyte complex of PEI/NCPs rapidly eliminates NCP hydration capacity and significantly improves the infiltration of various adhesives. Simultaneously, both the PEI during the assembly and the PEI-assembled DDM can directly destroy a biofilm of S. Mutans on the DDM. Consequently, a long-term antibacterial and low-defect hybrid layer is successfully created, which greatly improves the bonding effectiveness. This helps to improve the clinical treatment of bacteria-based dental diseases and the tooth-restoration repair effect and prevent secondary dental diseases, having significance in clinical dentistry and providing insights for other tissue-biomaterial adhesions.


Subject(s)
Polyethyleneimine , Stomatognathic Diseases , Humans , Static Electricity , Materials Testing , Anti-Bacterial Agents/pharmacology , Biocompatible Materials , Dentin
10.
ACS Appl Mater Interfaces ; 13(16): 19387-19397, 2021 Apr 28.
Article in English | MEDLINE | ID: mdl-33876927

ABSTRACT

Poly(ethylene glycol) (PEG) is applied extensively in biomedical fields because of its nontoxic, nonimmunogenic, and protein resistance properties. However, the strong hydrophilicity of PEG prevents it from self-assembling into an amphiphilic micelle in water, making it a challenge to fabricate a full-PEG carrier to deliver hydrophobic anticancer drugs. Herein, a paclitaxel (PTX)-loaded nanodrug was readily prepared through self-assembly of PTX and an amphiphilic PEG derivative, which was synthesized via melt polycondensation of two PEG diols (i.e., PEG200 and PEG10k) and mercaptosuccinic acid. The full PEG component endows the nanocarrier with good biocompatibility. Furthermore, because of the core cross-linked structure via the oxidation of mercapto groups, the nanodrug can be selectively disassociated under an intratumor reductive microenvironment through the reduction of disulfide bonds to release the loaded PTX and kill the cancer cells while maintaining high stability under the extratumor physiological condition. Additionally, it was confirmed that the nanodrug not only prolongs the biocirculation time of PTX but also possesses excellent in vivo antitumor efficacy while avoiding side effects of free PTX, for example, liver damage, which is promising for delivering clinical hydrophobic drugs to treat a variety of malignant tumors.


Subject(s)
Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Drug Carriers/chemistry , Nanomedicine , Polyethylene Glycols/chemistry , Cell Line, Tumor , Humans , Hydrophobic and Hydrophilic Interactions , Materials Testing , Oxidation-Reduction
11.
Biomater Sci ; 9(3): 960-972, 2021 Feb 09.
Article in English | MEDLINE | ID: mdl-33559657

ABSTRACT

Numerous efforts have been made to prepare hydrogels with injectability, adhesivity and osteogenic activity for bone regeneration. However, current hydrogels with these characteristics have limited application in clinical translation due to their complex chemical compositions, which causes difficulty in batch production. In this study, a multifunctional hydrogel with a binary component is prepared for bone regeneration. Dopamine (DA) is first grafted to alginate (Alg) by amidation reaction to give Alg-DA. Then an injectable hydrogel is facilely prepared by mixing strontium ions with the Alg-DA aqueous solution, utilizing the dynamic ionic bonds between the strontium ions and carboxyl groups of Alg-DA. Under the simulated oxidation conditions in vivo, the injectable hydrogel can form stable chemical crosslinkages owing to the presence of catechol groups on Alg-DA. In addition, the catechol groups endow the hydrogel with significant tissue adhesivity. More importantly, the strontium ions endow the hydrogel with osteogenic activity. As indicated by animal experiments, the strontium containing hydrogel scaffolds help to treat rat bone defects within 8 weeks compared to hydrogels without strontium and control groups. This simple hydrogel constructed by using a binary component has achieved several necessary functions, and is expected to be used as a scaffold for bone tissue engineering in clinical applications.


Subject(s)
Adhesives , Hydrogels , Alginates , Animals , Bone Regeneration , Osteogenesis , Rats , Tissue Engineering , Tissue Scaffolds
12.
ACS Appl Mater Interfaces ; 12(33): 37549-37560, 2020 Aug 19.
Article in English | MEDLINE | ID: mdl-32702232

ABSTRACT

Energy dissipation is a common mechanism to improve the ductility of polymeric hydrogels. However, for poly(ethylene glycol) (PEG) hydrogels, it is not easy to dissipate energy, as polymer chains are dispersed in water without strong interchain interactions or decent entanglement. The brittleness limits the real applications of PEG hydrogels, although they are promising candidates in biomedical fields, as PEG has been approved by the U.S. Food and Drug Administration. Herein, we chemically introduced a center for energy dissipation in the PEG hydrogel system. Amphiphilic segmented PEG derivatives were designed through the melt polycondensation of triethylene glycol (PEG150) and high molecular weight PEG in the presence of succinic acid and mercaptosuccinic acid as dicarboxylic acids. Full PEG hydrogels with elastic nanospheres as giant cross-linkers were facilely prepared by the self-assembly of esterified PEG150 segments and the oxidation of mercapto groups. The resultant full PEG hydrogels can dissipate energy by the deformation of elastic nanospheres with outstanding ductility and self-recoverability while maintaining the excellent biocompatibility owing to their full PEG components. This work provides an original strategy to fabricate full PEG hydrogels with high ductility and self-recoverability, potentially applicable in biomedical fields.

13.
Biomater Sci ; 8(8): 2234-2244, 2020 Apr 15.
Article in English | MEDLINE | ID: mdl-32129324

ABSTRACT

In the present study, low molecular weight poly(propylene carbonate) (PPC, Mn = 3500), a biodegradable liquid polymer easily prepared from carbon dioxide (CO2), was modified into poly(propylene carbonate)diacrylate (PPC-DA) by acylation, and methoxy poly(ethylene glycol) (mPEG) was modified into methoxy poly(ethylene glycol) acrylate (mPEG-A). Using PPC-DA as the dispersant to dissolve hydrophobic doxorubicin (DOX) and the initiator, and with mPEG-A as the co-monomer and polymerisable surfactant, a biodegradable nanodrug with excellent biocompatibility was prepared by shear emulsification polymerization without surfactants or organic solvent residues. The nanodrug can be efficiently endocytosed by tumor cells and can rapidly release doxorubicin triggered by the acidic endosomal pH. As evidenced by experiments in tumor-bearing mice, such a nanodrug is stealthy during blood circulation, and targets tumor sites with high efficiency. Moreover, this nanodrug is more effective and less toxic than free doxorubicin. This study provides a green and versatile approach for preparing biodegradable nanodrugs via a simple and efficient process. Moreover, this study extends the applications of CO2 based polymers in the biomedical field, promoting the development of CO2 polymerization fixation.


Subject(s)
Antineoplastic Agents/administration & dosage , Carbon Dioxide/chemistry , Doxorubicin/administration & dosage , Nanoparticles/administration & dosage , Polyethylene Glycols/administration & dosage , Polypropylenes/administration & dosage , Animals , Antineoplastic Agents/chemistry , Cell Survival/drug effects , Doxorubicin/chemistry , Drug Liberation , Emulsions , Endocytosis , HeLa Cells , Hep G2 Cells , Humans , Mice, Inbred BALB C , Mice, Nude , Nanoparticles/chemistry , Neoplasms/drug therapy , Neoplasms/pathology , Polyethylene Glycols/chemistry , Polypropylenes/chemistry , Solvents , Surface-Active Agents , Tumor Burden/drug effects
14.
Biomater Sci ; 8(5): 1394-1404, 2020 Mar 07.
Article in English | MEDLINE | ID: mdl-31922160

ABSTRACT

Injectable shear-thinning hydrogels can be prepared by the non-covalent interactions between hydrophilic polymers. Although electrostatic force is a typical non-covalent interaction, direct mixing of two oppositely charged polyelectrolytes usually leads to a complex coacervate rather than an injectable hydrogel. Herein, a facile approach is proposed to prepare a shear-thinning hydrogel by nanoengineering of polyelectrolytes. Nanosized cationic micelles with electroneutral shells were prepared by mixing methoxyl poly(ethylene glycol)-block-poly(ε-caprolactone) and poly(ε-caprolactone)-block-poly(hexamethylene guanidine) hydrochloride-block-poly(ε-caprolactone) in an aqueous solution. When sodium carboxymethyl cellulose was added into the micellar solution, the outer poly(ethylene glycol) shell of mixed micelles prevented the instant electrostatic interaction between poly(hexamethylene guanidine) hydrochloride segments and sodium carboxymethyl cellulose, resulting in a homogenous shear-thinning electrostatic (STES) hydrogel. Because of the cationic poly(hexamethylene guanidine) hydrochloride segments, this hydrogel exhibits strong antibacterial activity against both Gram-positive and Gram-negative bacteria. Furthermore, the poly(ε-caprolactone) core of the mixed micelles can efficiently encapsulate a hydrophobic drug. In this work, curcumin-loaded STES hydrogel prepared by this method was used as wound dressing material that can promote wound healing even in infected wounds by further reducing bacterial infection via releasing curcumin. The present study provides a facile strategy to prepare shear-thinning antibacterial hydrogels from polyelectrolytes, which has great potential in biomedical application.


Subject(s)
Anti-Bacterial Agents/pharmacology , Hydrogels/pharmacology , Nanotechnology , Polyelectrolytes/pharmacology , Animals , Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/chemistry , Cell Line , Curcumin/chemistry , Escherichia coli/drug effects , Healthy Volunteers , Humans , Hydrogels/chemical synthesis , Hydrogels/chemistry , Male , Mice , Micelles , Osteoblasts/drug effects , Osteoblasts/pathology , Polyelectrolytes/chemical synthesis , Polyelectrolytes/chemistry , Rats , Rats, Sprague-Dawley , Staphylococcus aureus/drug effects , Static Electricity , Wound Healing/drug effects
15.
ACS Appl Mater Interfaces ; 10(44): 38506-38516, 2018 Nov 07.
Article in English | MEDLINE | ID: mdl-30360113

ABSTRACT

Natural fibers with functionalities have attracted considerable attention. However, developing facile and versatile strategies to modify natural fibers is still a challenge. In this study, cotton fibers, the most widely used natural fibers, were partially oxidized by sodium periodate in aqueous solution, to give oxidized cotton fibers containing multiple aldehyde groups on their surface. Then poly(hexamethylene guanidine) was chemically grafted onto the oxidized cotton fibers forming Schiff bases between the terminal amines of poly(hexamethylene guanidine) and the aldehyde groups of oxidized cotton fibers. Finally, carbon-nitrogen double bonds were reduced by sodium cyanoborohydride, to bound poly(hexamethylene guanidine) covalently to the surface of cotton fibers. These functionalized fibers show strong and persistent antibacterial activity: complete inhibition against Escherichia coli and Staphylococcus aureus was maintained even after 1000 consecutive washing in distilled water. On the other hand, cotton fibers with only physically adsorbed poly(hexamethylene guanidine) lost their antibacterial activity entirely after a few washes. According to Cell Counting Kit-8 assay and hemolytic analysis, toxicity did not significantly increase after chemical modification. Attributing to the hydrophilicity of poly(hexamethylene guanidine) coatings, the modified cotton fibers were also more hygroscopic compared to untreated cotton fibers, which can improve the comfort of the fabrics made of modified cotton fibers. This study provides a facile and versatile strategy to prepare modified polysaccharide natural fibers with durable antibacterial activity, biosecurity, and comfortable touch.


Subject(s)
Anti-Bacterial Agents/pharmacology , Cotton Fiber/microbiology , Textiles , Amines/chemistry , Anti-Bacterial Agents/chemistry , Escherichia coli/drug effects , Escherichia coli/pathogenicity , Guanidine/chemistry , Hydrophobic and Hydrophilic Interactions/drug effects , Periodic Acid/chemistry , Staphylococcus aureus/drug effects , Staphylococcus aureus/pathogenicity , Wettability/drug effects
16.
Macromolecules ; 51(2): 289-296, 2018 Jan 23.
Article in English | MEDLINE | ID: mdl-29983451

ABSTRACT

Various hydrophobic supports have been used for lipase immobilization since the active site of lipase can be opened in a hydrophobic environment. Nevertheless, the increase of lipase activity is still limited. This study demonstrates a hyperactivation-protection strategy of lipase after immobilization on poly(n-butyl acrylate)-polyaldehyde dextran (PBA-PAD) core-shell nanoparticles. The inner hydrophobic PBA domain helps to rearrange lipase conformation to a more active form after immobilization into the PAD shell. More importantly, the outer PAD shell with dense polysaccharide chains prevents the immobilized lipase from contact with outside aqueous medium and revert its conformation back to an inactive form. As a result, under optimal conditions the activity of lipase immobilized in PBA-PAD nanoparticles was enhanced 40 times over the free one, much higher than in any previous report. Furthermore, the immobilized lipase retained more than 80 % of its activity after 10 reaction cycles.

17.
RSC Adv ; 8(71): 40701-40711, 2018 Dec 04.
Article in English | MEDLINE | ID: mdl-35557897

ABSTRACT

The phase separation behavior of poly(methyl methacrylate) (PMMA)/poly(styrene-co-maleic anhydride) (SMA) blends with and without one-dimensional hollow silica nanotubes (HSNTs) was investigated using time-resolved small-angle laser light scattering. During isothermal annealing over a range of 100 °C above the glass transition temperature, the Arrhenius equation is applicable to describe the temperature dependence of phase separation behavior at the early and late stages of spinodal decomposition (SD) for unfilled and filled PMMA/SMA systems. The mechanical barrier effect of HSNTs on the macromolecular chain diffusion of the blend matrix may retard the concentration fluctuation at the early stage and slow down the domain coarsening at the late stage of SD phase separation for the blend matrix to result in the decrease of apparent diffusion coefficient D app, the postponement of the relaxation time and the decline of temperature sensitivity for the phase separation rate.

18.
Chem Commun (Camb) ; 51(78): 14644-7, 2015 Oct 07.
Article in English | MEDLINE | ID: mdl-26290273

ABSTRACT

We reported a novel injectable doxorubicin-loaded hydrogel based on host-guest interaction and Schiff's base reaction. A supramolecular polymeric prodrug was prepared through the inclusion of adamantane-modified doxorubicin into the ß-cyclodextrin cavity on the polyaldehyde dextran chain, which was in situ crosslinked by carboxymethyl chitosan.


Subject(s)
Hydrogels , Polymers/chemistry , Prodrugs/chemistry , beta-Cyclodextrins/chemistry , Doxorubicin/administration & dosage , Drug Carriers
19.
J Mater Chem B ; 3(5): 784-795, 2015 Feb 07.
Article in English | MEDLINE | ID: mdl-32262169

ABSTRACT

After nearly half a century of development under the guidance of the osseointegration theory, the major dilemmas for current implant dentistry are the implant associated infection and insufficient osseointegration. Moreover, biological aging of titanium (Ti) implants also brings great uncertainty to clinical results. In the present study, a novel nano-micro-hierarchical topography pattern is created by sandblasting and dual acid-etching on a Ti surface. The physico-chemical properties of the surfaces were characterized by scanning electron microscopy, contact angle measurement, X-ray photoelectron spectroscopy and X-ray diffraction. The effects of the hierarchical surfaces on osteoprogenitor cell growth and bacterial activities were separately evaluated. The optimized nano-micro-hierarchical Ti surface exhibits surprisingly topography-dependent antibacterial capacity via inhibiting bacterial adhesion of several species in the early stage and better osteogenesis ability than the microscaled surface. Aging studies demonstrate that, compared with the surface with a microscale structure, the nano-micro-hierarchical Ti surface has greater anti-aging ability manifested as being more capable to retain hydrophilicity and bioactivity during aging. Furthermore, the present study reveals that the biological aging of the Ti implant is attributed to two decisive factors during the aging period: the progressively thickened amorphous TiO2 layer by autoxidation and the unavoidable accumulation of hydrocarbons on the Ti implant surface.

20.
J Mater Chem B ; 3(15): 3024-3031, 2015 Apr 21.
Article in English | MEDLINE | ID: mdl-32262502

ABSTRACT

Paclitaxel-loaded reduction-responsive core-crosslinked micelles were prepared in situ in aqueous media via"click" chemistry. An amphiphilic block copolymer with multiple pendant azide groups was first synthesized through the controlled ring-opening copolymerization of ε-caprolactone (CL) and 5,5-dibromomethyl trimethylene carbonate (DBTC) in the presence of methoxy poly(ethylene glycol) (mPEG) as a macroinitiator, followed by azidation. This amphiphilic block copolymer could self-assemble into micelles and paclitaxel (PTX) could be encapsulated into the micellar core to form PTX-loaded micelles, which were core-crosslinked in situ by propargyl dithiopropionate via"click" chemistry, to develop a reduction-responsive polymeric drug delivery system. The in vitro release studies revealed the minimized release of PTX under physiological conditions, whereas a burst release of PTX was observed in response to reductive conditions. The core-crosslinked micelles displayed efficient cell-uptake and reduction-responsive drug release due to the nanoscale diameter and splitting of disulfide bonds under a reductive environment, which was confirmed by confocal laser scanning microscopy using Nile red as a fluorescent probe. This kind of polymeric nano-carrier with excellent biocompatibility and quick reduction-response opens a new avenue to intracellular anticancer drug delivery.

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