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1.
Artigo em Inglês | MEDLINE | ID: mdl-31994305

RESUMO

The two-dimensional (2D) vanadium carbide (V 2 C) MXene has shown great potential as a photothermal agent (PTA) for photothermal therapy (PTT). However, the use of V 2 C in PTT is limited by the harsh synthesis condition and low photothermal conversion efficiency (PTCE). Herein, to address such an issue, we report a completely different green delamination method using algae extraction to intercalate and delaminate V 2 AlC to produce mass V 2 C nanosheets (NSs) with a high yield (90%). The resulting V 2 C NSs demonstrated good structural integrity and remarkably high absorption in near-infrared (NIR) region with a PTCE as high as 48% under an 808-laser irradiation. It is superior to the previously reported MXene photothermal agents, including Mo 2 C (42.9%), Nb 2 C (36.4% at NIR-I and 45.65% at NIR-II), Ta 4 C 3 (44.7%), and even comparable to the cutting-edge photo absorption agents, such as gold-based materials, and carbon-based nanostructures. Systemic in vitro and in vivo studies demonstrate the V 2 C NSs severe as efficient PTA for photoacoustic (PA) and magnetic resonance imaging (MRI)-guided photothermal hyperthermia of cancer. This work provides a cost-effectively, environment-friendly, and high-yield disassembly approach of MAX, opening a new avenue to develop MXenes with desirable properties for a myriad of applications.

2.
Adv Healthc Mater ; 9(2): e1901528, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31820854

RESUMO

Bimetallic nanoparticles have received considerable attention owing to synergistic effect and their multifunctionality. Herein, new multifunctional Pd@Au bimetallic nanoplates decorated hollow mesoporous MnO2 nanoplates (H-MnO2 ) are demonstrated for achieving not only nucleus-targeted NIR-II photothermal therapy (PTT), but also tumor microenvironment (TME) hypoxia relief enhanced photodynamic therapy (PDT). The Pd@Au nanoplates present a photothermal conversion efficiency (PTCE) as high as 56.9%, superior to those PTAs activated in the NIR-II region such as Cu9 S5 nanoparticles (37%), Cu3 BiS3 nanorods (40.7%), and Au/Cu2- x S nanocrystals (43.2%). They further functionalize with transactivator of transcription (TAT) moiety for cell nuclear-targeting and biodegradable hollow mesoporous MnO2 (≈100 nm) loaded with photosensitizer Ce6 (TAT-Pd@Au/Ce6/PAH/H-MnO2 ) to construct a hierarchical targeting nanoplatform. The as-made TAT-Pd@Au/Ce6/PAH/H-MnO2 demonstrates good premature renal clearance escape ability and increased tumor tissue accumulation. It can be degraded in acidic TME and generate O2 by reacting to endogenous H2 O2 to relieve the hypoxia for enhanced PDT, while the released small TAT-Pd@Au nanoplates can effectively enter into the nucleus to mediate PTT. As a result, a remarkable therapeutic effect is achieved owing to the synergistic PTT/PDT therapy. This hierarchical targeting, TME-responsive, cytoplasm hypoxia relief PDT, and nuclear NIR-II PTT synergistic therapy can pave a new avenue for nanomaterials-based cancer therapy.

3.
Chemosphere ; 215: 693-702, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30347364

RESUMO

Ionic silver is a potential hazard to aquatic life forms because of the increasing usage of silver based materials. The need for developing a sustainable and ecofriendly process to minimize the toxic effects of the free ions burden is now a scientific consensus. Therefore, we report the latest results in cyanobacterium Leptolyngbya JSC-1 investigating the tolerance towards toxic doses of silver, its extracellular biomineralization and silver nano-deposits formation inside the cells, and speculate about potential environmental impacts. In this study, scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) analysis reveal the extracellular biomineralization of soluble silver (1-100 µM) into corresponding nanoparticles (50-100 nm in diameter) by JSC-1, while X-ray photoelectron spectroscopy (XPS) examination divulged the presence of both Ag+ and Ag0 in extracellularly biomineralized silver, depicting a mixture of both AgxO and elemental Ag. The scanning transmission electron microscopy (STEM), EDS and elemental mapping visualized the formation of intracellular silver nanoparticles. Moreover, this feature of silver tolerance in JSC-1 was further exploited and a novel protocol was developed for isolation and maintenance of axenic culture of this filamentous cyanobacterium. Consequently, this capability of silver biomineralization by JSC-1, both extra- and intra-cellularly might be useful for modeling the Ag resistance mechanism in cyanobacteria and also might be a sustainable alternative for heavy metals bioremediation in aquatic environments.


Assuntos
Cultura Axênica/métodos , Cianobactérias/metabolismo , Prata/química , Biodegradação Ambiental , Cianobactérias/citologia , Íons/química , Íons/toxicidade , Nanopartículas Metálicas/química , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Espectroscopia Fotoeletrônica , Prata/toxicidade , Espectrometria por Raios X
4.
Artif Cells Nanomed Biotechnol ; 46(sup3): S471-S480, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30198334

RESUMO

Utilizing novel approaches for the green synthesis of metal nanoparticles are of great importance. Therefore, we reported biogenic synthesis of silver nanoparticles (AgNPs) using extracts of Leptolyngbya strain JSC-1, and their significant applications against pathogenic bacteria and cancerous HeLa cell line. The biofabricated AgNPs were characterized by UV-visible spectroscopy, FTIR, SEM, TEM, DLS and zeta-potential. The as prepared AgNPs were assessed for inhibition of bacterial growth and induction of apoptosis in HeLa cells by different doses of AgNPs was evaluated. UV-visible spectroscopy and FTIR of AgNPs demonstrated the surface plasmon resonance at 413 nm and interaction among extract and nanoparticles, respectively. Electron microscopy revealed the morphology and DLS demonstrated size distribution of the particles (10-100 nm). Zeta potential values were between -47 and 0 mV, indicating stability of the particles. Proliferation of HeLa cells was significantly inhibited and severe cytotoxicity with higher intracellular uptake were observed after applying high concentration of AgNPs. Efficient inhibition zones (17 ± 2 and 21 ± 2 mm) were produced at maximum concentration (100 µl from 1 mg ml-1 stock of AgNPs) for Staphylococcus aureus and Escherichia coli, respectively. These findings reveal that the biofabricated AgNPs possess strong antibacterial activity and ability to induce apoptosis in cancer cell line (HeLa).


Assuntos
Antibacterianos , Apoptose/efeitos dos fármacos , Misturas Complexas/química , Cianobactérias/química , Escherichia coli/crescimento & desenvolvimento , Nanopartículas Metálicas/química , Prata , Staphylococcus aureus/crescimento & desenvolvimento , Antibacterianos/química , Antibacterianos/farmacologia , Células HeLa , Humanos , Prata/química , Prata/farmacologia
5.
Microb Pathog ; 125: 150-157, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30217515

RESUMO

Low cost and an easy technique for the synthesis of palladium nanoparticles (PdNPs) was developed. Glucosamine was used to stabilize palladium precursor (PdCl2) into palladium nanoparticles. Several analytical techniques were used for the determination of morphology, crystalline structure; size, capping, and composition of synthesize palladium nanoparticles. The UV-visible spectroscopy SPR peak (Surface Plasmon Resonance) at 284 nm revealed synthesis of PdNPs. Energy dispersive X-ray (EDX) and X-ray diffraction (XRD) studies proved the elemental composition and crystalline structure of the synthesized palladium nanoparticles respectively. The average particle sizes (5.5 nm) were obtained by using the 1 M glucosamine solution, with a fixed amount of PdCl2 (4 mM). Moreover, the as synthesized PdNPs was evaluated against Gram negative bacterial E. which shows tremendous antibacterial activity as compare to tobramycin standard antibiotics. It's mechanistically found that PdNPs damage cell membrane and caused imbalance of metabolism system of the cell as a result production of reactive oxygen species (ROS). Thus, these finding revealed that cells become leaky and all organelles come out from cells, finally caused death of the E. coli. Addition, the as prepared PdNPs also showed excellent catalytic activities toward reduction of methylene blue and 4-nitrophenol.Thus, glucosamine mediated PdNPs having dual functions biomedical as well as intoxicating catalyst for industries.


Assuntos
Antibacterianos/metabolismo , Glucosamina/metabolismo , Nanopartículas Metálicas/ultraestrutura , Paládio/metabolismo , Substâncias Redutoras/metabolismo , Membrana Celular/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Excipientes/metabolismo , Redes e Vias Metabólicas/efeitos dos fármacos , Nanopartículas Metálicas/química , Espécies Reativas de Oxigênio/metabolismo , Espectrometria por Raios X , Análise Espectral , Ressonância de Plasmônio de Superfície , Difração de Raios X
6.
Microb Pathog ; 114: 116-123, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29174698

RESUMO

This study describes the first ever utilization of cell free aqueous extract of cyanobacterium Leptolyngbya JSC-1 as a source of strong reducing and stabilizing agents for the optimal biofabrication of gold nanoparticles (AuNPs) through an eco-friendly synthetic route. Well dispersed crystalline AuNPs of spherical morphology with a particle size of 100-200 nm were prepared. FTIR spectral analysis was then performed to characterize the possible functionalities of JSC-1 extract, mainly involved in stabilizing and formation of AuNPs. Based on the redox potential of JSC-1 extract, it was further confirmed that the extract provide a strong reducing environment in the reaction medium and causes reduction of gold ions. The resultant AuNPs were then explored to find out their photo-catalytic activity for methylene blue and antibacterial activities against E. coli (18 ± 2 mm) and S. aureus (14 ± 2 mm). It has been mechanistically identified that AuNPs caused bacterial membrane damage and cell disruption by inducing the production of intracellular reactive oxygen species (ROS). Together, these finding reveals that biochemically capped AuNPs are the promising antibacterial agents that induce oxidative stress in the two bacterial species evaluated and cause their membrane disruption leading to cell leakage and death.


Assuntos
Antibacterianos/farmacologia , Cianobactérias/metabolismo , Excipientes/farmacologia , Ouro/química , Nanopartículas Metálicas/química , Antibacterianos/química , Bactérias/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Excipientes/química , Ouro/farmacologia , Química Verde , Testes de Sensibilidade Microbiana , Nanotecnologia/métodos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Tamanho da Partícula , Espécies Reativas de Oxigênio/metabolismo , Staphylococcus aureus/efeitos dos fármacos
7.
Comput Biol Chem ; 71: 10-19, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28957725

RESUMO

Growing resistance in malarial parasites, particularly in Plasmodium falciparum needs a serious search for the discovery of novel drug targets. Inosine monophosphate dehydrogenase (IMPDH) is an important target for antimalarial drug discovery process in P. falciparum for the treatment of malaria. In the absence of x-ray crystal structure of this enzyme, homology modeling proved to be a reasonable alternate to study substrate binding mechanisms of this enzyme. In this study, a 3-D homology model for P. falciparum IMPDH was constructed taking human IMPDH (PDB code 1NF7) as template. Furthermore, an in-silico combinatorial library of ribavirin (RVP) derivatives (1347 molecules) was designed and virtually screened for ligands having selectively greater binding affinity with Plasmodium falciparum IMPDH relative to human IMPDH II. A total of five Ribavirin derivatives were identified as having greater binding affinity (-126 to -108Kcal/mol and -9.4 to -8.6Kcal/mol) with Plasmodium falciparum IMPDH. These five inhibitors should be used as selective and potent for Plasmodium falciparum IMPDH. Such type of study will provide information to synthetic medicinal chemist to enhance the potential of compounds (RVP derivatives) as chemotherapeutic agents to fight against the increasing burden of malarial infections.


Assuntos
Simulação por Computador , IMP Desidrogenase/antagonistas & inibidores , IMP Desidrogenase/química , Simulação de Acoplamento Molecular , Plasmodium falciparum/enzimologia , Avaliação Pré-Clínica de Medicamentos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , IMP Desidrogenase/metabolismo , Estrutura Molecular , Ribavirina/análogos & derivados , Ribavirina/química , Ribavirina/farmacologia , Relação Estrutura-Atividade
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