RESUMO
Gold nanorods (GNRs) with exceptional photothermal properties have held promising potential for application in the biomedical field. In this study, the authors achieved photothermal ablation by polyethylene glycol (PEG)-functionalised GNRs. Well-dispersed and uniform GNRs were produced through a seed-mediated growth method. A thermal camera was used to scrutinise the temperature distribution and efficiency of the photothermal properties of the GNRs, which were irradiated by an 808â nm laser on a silicon chip. They observed that the GNRs provided about a 5°C temperature increase and produced hyperthermia efficiently. Since GNRs need to be surface tailored with a biocompatible material rather than cetyltrimethylammonium bromide (CTAB), they chose methoxyl PEG thiol to modify the GNRs. By taking advantage of the alkaline environment that assists this functionalisation, they accomplished about 89% removal of CTAB and identified a PEG layer on the surface of the GNRs. The GNR biocompatibility was considerably improved without any shift of the optical properties. Hepatocellular carcinoma cells were incubated with GNRs for 24â h and then were irradiated with a near-infrared laser for 3â min. Few cells remained alive, which demonstrated the photothermal ablation ability of the GNRs.
Assuntos
Carcinoma Hepatocelular/terapia , Ouro/química , Neoplasias Hepáticas/terapia , Nanopartículas Metálicas/uso terapêutico , Fototerapia/métodos , Polietilenoglicóis/química , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Materiais Revestidos Biocompatíveis/síntese química , Materiais Revestidos Biocompatíveis/química , Materiais Revestidos Biocompatíveis/uso terapêutico , Ensaios de Seleção de Medicamentos Antitumorais , Temperatura Alta , Humanos , Neoplasias Hepáticas/patologia , Teste de Materiais , Nanopartículas Metálicas/química , Nanotubos/químicaRESUMO
Focal infections that are caused by antibiotic-resistant bacteria are becoming an ever-growing challenge to human health. To address this challenge, a pH-responsive amphiphilic polymer of polyaniline-conjugated glycol chitosan (PANI-GCS) that can self-assemble into nanoparticles (NPs) in situ is developed. The PANI-GCS NPs undergo a unique surface charge conversion that is induced by their local pH, favoring bacterium-specific aggregation without direct contact with host cells. Following conjugation onto GCS, the optical-absorbance peak of PANI is red-shifted toward the near-infrared (NIR) region, enabling PANI-GCS NPs to generate a substantial amount of heat, which is emitted to their neighborhood. The local temperature of the NIR-irradiated PANI-GCS NPs is estimated to be approximately 5 °C higher than their ambient tissue temperature, ensuring specific and direct heating of their aggregated bacteria; hence, damage to tissue is reduced and wound healing is accelerated. The above results demonstrate that PANI-GCS NPs are practical for use in the photothermal ablation of focal infections.
Assuntos
Infecções Bacterianas/terapia , Fenômenos Fisiológicos Bacterianos/efeitos da radiação , Hipertermia Induzida/métodos , Nanopartículas/administração & dosagem , Nanopartículas/química , Fototerapia/métodos , Animais , Infecções Bacterianas/patologia , Sobrevivência Celular/efeitos da radiação , Temperatura Alta , Concentração de Íons de Hidrogênio , Luz , Camundongos , Camundongos Endogâmicos BALB C , Eletricidade Estática , Resultado do TratamentoRESUMO
This work develops a composite system of reduced graphene oxide (rGO)-iron oxide nanoparticles (rGO-IONP) that can synergistically induce physical and chemical damage to methicillin-resistant Staphylococcus aureus (MRSA) that are present in subcutaneous abscesses. rGO-IONP was synthesized by the chemical deposition of Fe(2+)/Fe(3+) ions on nanosheets of rGO in aqueous ammonia. The antibacterial efficacy of the as-prepared rGO-IONP was evaluated in a mouse model with MRSA-infected subcutaneous abscesses. Upon exposure to a near-infrared laser in vitro, rGO-IONP synergistically generated localized heat and large amounts of hydroxyl radicals, which inactivated MRSA. The in vivo results reveal that combined treatment with localized heat and oxidative stress that is caused by hydroxyl radicals accelerated the healing of wounds associated with MRSA-infected abscesses. The above results demonstrate that an rGO-IONP nanocomposite system that can effectively inactivate multiple-drug-resistant bacteria in subcutaneous infections was successfully developed. FROM THE CLINICAL EDITOR: The emergence of methicillin-resistant S. aureus (MRSA) has posed a significant problem in the clinical setting. Thus, it is imperative to develop new treatment strategies against this. In this study, the authors described the use of reduced graphene oxide (rGO)-iron oxide nanoparticles (rGO-IONP) to induce heat and chemical damage to MRSA. This approach may provide a platform the design of other treatment modalities against multiple-drug-resistant bacteria.
Assuntos
Antibacterianos/uso terapêutico , Compostos Férricos/uso terapêutico , Grafite/uso terapêutico , Radical Hidroxila/metabolismo , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Nanocompostos/uso terapêutico , Infecções Estafilocócicas/terapia , Animais , Antibacterianos/química , Feminino , Compostos Férricos/química , Grafite/química , Temperatura Alta , Hipertermia Induzida/métodos , Raios Infravermelhos , Camundongos Endogâmicos BALB C , Nanocompostos/química , Nanocompostos/ultraestrutura , Estresse Oxidativo/efeitos dos fármacos , Fototerapia/métodos , Infecções Estafilocócicas/metabolismoRESUMO
Bioassay-guided chromatographic separation of the cytotoxic MeOH extract of Phaius mishmensis led to the isolation of two known and six new indoloquinazolinones, phaitanthrins A-E (1-5) and methylisatoid (6). The structures of the new compounds were elucidated by spectroscopic analysis. Phaitanthrin A (1) and tryptanthrin (7) showed moderate cytotoxicity against MCF-7, NCI-H460, and SF-268 cell lines. A series of ketone adducts of tryptanthrin were prepared and tested initially for anticancer activity in vitro against MCF-7, NCI-H460, and SF-268 human cancer cell lines. The 3-pentanone adduct 13 showed activity similar to tryptanthrin.