ABSTRACT
Silver nanoparticles (AgNPs) are potent antimicrobial agents, but their utility is limited due to their relatively high cytotoxicity. In this work, we used trehalose as the ligand to reduce the cytotoxicity of AgNPs without affecting their antimicrobial activities. Trehalose is a disaccharide that is unique to mycobacteria. We showed that trehalose-functionalized AgNPs, AgNP-Tre, drastically increased the viability of A549 cells, especially at high concentrations, for example, from 4% for AgNPs to 67% for AgNP-Tre at 64 µg/mL. The trehalose ligand slowed down the release of silver, and the amount of silver released from AgNP-Tre was less than half of that from AgNPs in the culture medium. Intriguingly, while the maltose (Mal) or tri(ethylene glycol) (TEG) ligand reduced the antibacterial activity of AgNPs against M. smegmatis (minimal inhibitory concentration (MIC) of AgNP-Mal and AgNP-TEG: 4 µg/mL for 7 nm AgNPs), the activity of AgNP-Tre was similar to that of AgNPs (MIC of AgNP-Tre: 1 µg/mL for 7 nm AgNPs). Uptake experiments revealed that the intracellular concentration of AgNP-Tre was 87 and 114% higher than those of AuNP-Mal and AgNP-TEG, respectively. The increased uptake was attributed to the enhanced interactions of AgNP-Tre with mycobacteria promoted by the trehalose ligand.
ABSTRACT
We report the preparation of stable micelles from random copolymers of 2-hydroxyethyl methacrylate (HEMA) and perfluorophenyl azide (PFPA)-derivatized HEMA (HEMA-PFPA). The copolymers were synthesized by RAFT polymerization at room temperature under mild conditions without affecting the azide functionality. Upon addition of water to the copolymer solution in DMSO, the random copolymers self-assembled into micelles even at the percentage of HEMA-PFPA as low as 4.5%. The size of the micelles can be controlled by the molecular weight and the concentration of the copolymer, and the percentage of HEMA-PFPA in the copolymer. In addition, iron oxide nanoparticles and quantum dots were successfully encapsulated into the micelles with high encapsulation efficiency (â¼80%). These nanoparticles, which were hydrophobic and formed agglomerates in water, became fully dispersed after encapsulating into the micelles. The micelles were stable and the size remained unchanged for at least 6months.
ABSTRACT
A multivalent trehalose-grafted poly(lactic acid) is synthesized and encapsulated with iron oxide magnetic nanoparticles. The magnetic micelles interact with Mycobacterium smegmatis to form orange clusters. Very little particle interaction is found on Staphylococcus epidermidis 35984 or Escherichia coli ORN 208. The presented new approach to the detection of mycobacteria does not require molecular biology reagents or sophisticated instruments.
Subject(s)
Bacterial Typing Techniques/methods , Magnetite Nanoparticles/chemistry , Mycobacterium smegmatis/classification , Trehalose/chemistry , Escherichia coli/classification , Staphylococcus epidermidis/classificationABSTRACT
Mesoporous silica nanomaterials of different shapes (film, platelet, sphere, rod) were synthesized simply by tuning the mole ratio of dual cationic surfactant templates, cetyltrimethylammonium bromide (CTAB) and tetrabutylammonium iodine (TBAI). The film showed the most potent antibacterial activity against mycobacteria.
Subject(s)
Anti-Bacterial Agents/chemical synthesis , Anti-Bacterial Agents/pharmacology , Cetrimonium Compounds/chemical synthesis , Cetrimonium Compounds/pharmacology , Mycobacterium/drug effects , Nanostructures/chemistry , Quaternary Ammonium Compounds/chemical synthesis , Quaternary Ammonium Compounds/pharmacology , Silicon Dioxide/chemistry , Surface-Active Agents/chemistry , Anti-Bacterial Agents/chemistry , Cetrimonium , Cetrimonium Compounds/chemistry , Mycobacterium/chemistry , Porosity , Quaternary Ammonium Compounds/chemistryABSTRACT
Fluorescein-doped silica nanoparticles (FSNPs) functionalized with D-arabinose (Ara) showed strong interactions with Mycobacterium smegmatis (M. smegmatis) and caused the bacteria to aggregate. This aggregate formation was used as a means to detect M. smegmatis at the concentration of 10(4) CFU per mL.
Subject(s)
Arabinose/analogs & derivatives , Cell Aggregation/physiology , Mycobacterium smegmatis/isolation & purification , Nanoparticles/chemistry , Silicon Dioxide/chemistry , Arabinose/metabolism , Fluoresceins/chemistry , Microscopy, Fluorescence , Mycobacterium smegmatis/metabolism , Silicon Dioxide/chemical synthesisABSTRACT
Silica and iron oxide nanoparticles with sizes ranging from 6 to 40 nm were functionalized with trehalose. The trehalose-conjugated nanoparticles showed strong interactions with Mycobacterium smegmatis (M. smegmatis) and minimal interactions with macrophage (RAW 264.7) or A549 cells. In addition, trehalose-conjugated silica nanoparticles selectively interacted with M. smegmatis on M. smegmatis-treated A549 cells, demonstrating high potential of trehalose in developing targeted therapy for treating mycobacterial infection.
Subject(s)
Mycobacterium Infections, Nontuberculous/microbiology , Mycobacterium smegmatis/metabolism , Nanoparticles/metabolism , Trehalose/metabolism , Animals , Cell Line , Humans , Mice , Molecular Targeted Therapy , Mycobacterium smegmatis/isolation & purification , Nanoparticles/ultrastructureABSTRACT
In this study, amine-functionalized hollow mesoporous silica nanoparticles with an average diameter of â¼100 nm and shell thickness of â¼20 nm were prepared by an one-step process. This new nanoparticulate system exhibited excellent killing efficiency against mycobacterial (M. smegmatis strain mc(2) 651) and cancer cells (A549).
Subject(s)
Amines/chemistry , Anti-Bacterial Agents/pharmacology , Antineoplastic Agents/pharmacology , Drug Carriers/chemistry , Drug Delivery Systems/instrumentation , Nanoparticles/chemistry , Silicon Dioxide/chemistry , Anti-Bacterial Agents/chemistry , Antineoplastic Agents/chemistry , Cell Line, Tumor , Cell Proliferation/drug effects , Doxorubicin/chemistry , Doxorubicin/pharmacology , Drug Carriers/chemical synthesis , Humans , Mycobacterium smegmatis/drug effects , Porosity , Silicon Dioxide/chemical synthesisABSTRACT
We describe a simple and general approach to conjugate nanoparticles on pristine graphene. The method takes advantage of the high reactivity of perfluorophenyl nitrene towards the C[double bond, length as m-dash]C bonds in graphene, where perfluorophenyl azide-functionalized nanoparticles are conjugated to pristine graphene through the [2+1] cycloaddition reaction by a fast photoactivation.
ABSTRACT
Glyconanoparticle carriers have been synthesized and efficiently delivered into mycobacteria. Mesoporous silica nanoparticles were functionalized with α,α-trehalose through azide-mediated surface photoligation, and loaded with the antitubercular drug isoniazid. The glyconanoparticles showed high isoniazid loading capacity and higher antimicrobial activity than the free drug.
ABSTRACT
Nanoparticles conjugated with d-maltoheptaose (G7) showed a striking increase in the internalization by Escherichia coli. This applies to strains with and without the maltodextrin transport channel and particles ranging from a few to a hundred nanometers.
