RESUMO
Cadmium (Cd) removal from soil is crucial as Cd enters the food chain and affect food safety, thus impose severe threaten to human health. We developed PPC@PC-Fe, a dual-functional core-shell sphere for efficient soil Cd reduction. The shell (PPC) was composed of encapsulated citric acid (CA) in a polylactic acid (PLA) and polyethylene glycol (PEG) network, which endows a function of activating Cd; and the core (PC-Fe) consisted of a polyacrylic acid/carboxymethyl chitosan (PAA/CMC) hydrogel with Fe3O4 nanoparticles to adsorb adjacent activated Cd. Upon water contact, the shell dissolved, releasing CA to activate soil Cd. Simultaneously, the swellable PC-Fe core absorbed water and expanded in size, promoting the disintegration of PLA in the shell, which triggered the automatic separation of core from shell, enabling the exposed PC-Fe core to rapidly adsorb Cd. Furthermore, the PC-Fe core can be magnetically removed after adsorption of Cd. Soil culture tests showed that 2 % PPC@PC-Fe reduced soil Cd from 6.009 mg/kg to 4.834 mg/kg in 10 days, with the acid-soluble Cd being the predominantly target to be activated and remove. This study demonstrates an effective stepwise activation and adsorption mechanism by a single carrier, with simple magnetic collection minimizing secondary pollution. It offers an innovative approach to the remediation of cadmium-contaminated sites in the field.
RESUMO
Antibiotic abuse is increasing the present rate of drug-resistant bacterial wound infections, producing a significant healthcare burden globally. Herein, we prepared a pH-responsive CMCS/PVP/TA (CPT) multifunctional hydrogel dressing by embedding the natural plant extract TA as a nonantibiotic and cross-linking agent in carboxymethyl chitosan (CMCS) and polyvinylpyrrolidone (PVP) to prompt wound healing. The CPT hydrogel demonstrated excellent self-healing, self-adaptive, and adhesion properties to match different wound requirements. Importantly, this hydrogel showed pH sensitivity and exhibited good activity against resistant bacteria and antioxidant activity by releasing TA in case of bacterial infection (alkaline). Furthermore, the CPT hydrogel exhibited coagulant ability and could rapidly stop bleeding within 30 s. The biocompatible hydrogel effectively accelerated wound healing in a full-thickness skin defect model by thickening granulation tissue, increasing collagen deposition, vascular proliferation, and M2-type macrophage polarization. In conclusion, this study demonstrates that multifunctional CPT hydrogel offers a candidate material with potential applications for infected skin wound healing.
Assuntos
Antibacterianos , Bandagens , Quitosana , Hidrogéis , Cicatrização , Quitosana/química , Quitosana/análogos & derivados , Quitosana/farmacologia , Quitosana/síntese química , Cicatrização/efeitos dos fármacos , Hidrogéis/química , Hidrogéis/farmacologia , Hidrogéis/síntese química , Animais , Concentração de Íons de Hidrogênio , Camundongos , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/síntese química , Povidona/química , Masculino , Staphylococcus aureus/efeitos dos fármacos , Materiais Biocompatíveis/farmacologia , Materiais Biocompatíveis/química , Materiais Biocompatíveis/síntese química , Pele/efeitos dos fármacos , Pele/patologiaRESUMO
Practical application of powder photocatalysts is far from satisfying due to their low photon utilization, inconvenient recovery and potential environmental risk. In this study, an easily recoverable, environmentally friendly and highly transparent floatable magnetic photocatalyst carrier was prepared based on biopolymer alginate and Fe3O4 particles. Further, three different types of photocatalysts were chosen as model semiconductor photocatalysts and loaded on the shell of the carriers. The freeze process facilitated the formation of internal cavities that enhanced floating ability and transparency of the spheres. Meanwhile, the excellent floating performance offered massive reaction sites for pollutants reacting with photocatalysts, O2 and photons on the air/water interface. Photodegradation results showed all three floatable hybrid photocatalysts exhibited enhanced photocatalytic efficiencies compared to the virgin photocatalysts. In short, the carrier can integrate excellent floating ability, environmental friendliness and full recycling with good stability, and it can greatly improve the photocatalytic efficiency of various powder semiconductor photocatalysts.
RESUMO
Bone related-bacterial diseases including wound infections and osteomyelitis (OM) remain a serious problem accompanied with amputation in most severe cases. In this work, we report an exceptional effective antibacterial alginate aerogel, which consists of tigecycline (TGC) and octahedral Cu crystal as an organo-inorganic synergy platform for antibacterial and local infection therapy applications. The alginate aerogel could greatly prolong the release of copper ions and maintain effective antibacterial concentration over 18 days. The result of in-vitro experiments demonstrated that the alginate aerogel has an exceptional effective function on antibacterial activity. Cytotoxicity tests indicated that the alginate aerogel has low biological toxicity (average cell viability >75%). These remarkable results suggested that the alginate aerogel exhibits great potential for the treatment of OM, and has a prosperous future of application in bone tissue engineering.
Assuntos
Alginatos/química , Antibacterianos/química , Osso e Ossos/efeitos dos fármacos , Cobre/química , Escherichia coli/efeitos dos fármacos , Géis/química , Alginatos/síntese química , Alginatos/toxicidade , Antibacterianos/farmacologia , Infecções Bacterianas/tratamento farmacológico , Osso e Ossos/microbiologia , Proliferação de Células/efeitos dos fármacos , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacologia , Géis/síntese química , Géis/toxicidade , Células Endoteliais da Veia Umbilical Humana , Humanos , Íons/química , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Tigeciclina/químicaRESUMO
The application of iron oxide nanoparticles (IONs) is often limited by agglomeration and low loading. Here, we presented a facile phase change material (PCM) -based sol-gel strategy for the fabrication of α-Fe2O3 nanoparticles. Rosin was used as the PCM in the sol-gel process and the carbon-based substrate of α-Fe2O3 nanoparticles in the thermal process. The α-Fe2O3 nanoparticle embedded rosin-derived biochar(α-Fe2O3@HrBc)were highly dispersed. The dispersity of α-Fe2O3 nanoparticle could be regulated by the weight ratios of rosin to FeCl3·6H2O during the preparation, as evidenced by the scanning electron microscope (SEM) spectrum and the sorption capacity results. Among a series of α-Fe2O3@HrBc nanocomposites, the one with the weight ratios of 1/1.5 rosin/FeCl3·6H2O had the highest capacity for hexavalent chromium (Cr(VI)) sorption. This phenomenon can be ascribed to a remarkably enhanced interfacial reactivity due to an increase in the dispersity of α-Fe2O3 nanoparticle. In addition, SEM showed that the majority of α-Fe2O3 nanoparticles was dispersed on and inside the biochar substrate. Batch adsorption experiments revealed that the α-Fe2O3@HrBc adsorbed 90% Cr(VI) within one minute, and the maximum capacity was up to 166â¯mg·g-1 based on the Langmuir model. The FTIR and XPS spectra revealed that the adsorbed Cr(VI) species were partially reduced to less toxic Cr(III). Considering that α-Fe2O3 nanoparticles provided important sorption sites, the newly formed Cr(III) and the remaining Cr(VI) ions could be adsorbed on α-Fe2O3@HrBc via the formation of FeCr coprecipitation.