Maltoheptaose Promotes Nanoparticle Internalization by Escherichia coli

Nanoparticles conjugated with D-maltoheptaose (G7) showed a striking increase in the surface adherence and internalization by E. coli. This applies to silica nanoparticles (SNP), magnetic nanoparticles (MNP), silica-coated magnetic nanoparticles (SMNP) and silica-coated quantum dots (SQDs) ranging from a few to over a hundred nanometers in size, as well as wild type E. coli ATCC 33456, ORN 178, ORN 208 with the maltodextrin transport channel and the LamB mutant JW 3392-1 (Fig. 1). TEM images including the thin section samples revealed the uptake of nanoparticles in cell walls and inside the cytoplasm (Fig. 2). Unfunctionalized nanoparticles and nanoparticles functionalized with β-cyclodextrin (CD) showed little or no binding to the E. coli cell surface, and no obvious internalization of the nanoparticles was observed. D-Mannose-functionalized nanoparticles bound to the pili of E. coli ORN 178 through the well-known Man-binding lectin (FimH) rather than cell internalization. Surface ligands that can improve the uptake of nanomaterials to bacterial cells should provide a powerful means of targeting a payload delivery to a potential disease causing strain. Work is underway to develop nanomaterial delivery systems for multidrug resistance bacteria

Glyconanoparticle Uptake Profile in Lung Carcinoma Cells

Non-small cell lung carcinoma (NSCLC) is responsible for nearly 85% of lung cancer, and early diagnosis and treatment of lung cancer can circumvent possible death. We focus on glyconanoparticles with a magnetic or a fluorescent core that act as multivalent glyco-scaffold to study cell surface interaction and internalization. The glyconanoparticles were synthesized by conjugating various carbohydrates on magnetic nanoparticles and fluorescent silica nanoparticles by a photocoupling technique developed in our laboratory. The size of nanoparticles used varies from 6 nm to 60 nm. The resulting glyconanoparticles were treated with human adenocarcinoma non-small lung epithelial cells (A549) and the primary small airway epithelial cells (PCS-301-010). The cellular uptake was studied and quantified by confocal fluorescence microscopy, flow cytometry, thin section TEM, and prussian blue staining. We found that the extent of cellular uptake was dependent on the type of carbohydrate ligands and the nature of the nanoparticles used. Experiments were conducted to investigate the mechanism of the uptake, and results will be discussed

Interactions of Carbohydrate-conjugated Nanoparticles with Mycobacterium Smegmatis

Mycobacterium smegmatis is a non-pathogenic microorganism and has been widely used as a model organism to study infections caused by M. tuberculosis and other mycobacterial pathogens. We report that nanoparticles conjugated with selected carbohydrate show a striking increase in the surface adherence by M. smegmatis. This applies to silica nanoparticles and magnetic nanoparticles ranging from 100 nm to 5 nm. Under the same experimental conditions, minimum adhesion was observed for unfunctionalized nanoparticles. The synthesis and characterization of the glyconanoparticles will be presented. The finding is applied to imaging M. smegmatis infected lung epithelial cells, and the results will be discussed

Enhancing Antibiotic Activity Using Nanomaterial-Antibiotic Conjugates

We demonstrate that streptomycin conjugated on silica nanoparticles (SNP-Str) can be used to effectively target streptomycin-resistant Escherichia coli (E. coli) bacteria by lowering the minimum inhibitory concentration (MIC) of streptomycin up to 2 log folds. Silica nanoparticles were synthesized with an average diameter of 80, 50 and 30 nm, respectively. Streptomycin was then covalently conjugated to SNP using efficient photocoupling chemistry. The MIC for free streptomycin sulfate was recorded as a high 2.0 mg/mL for an engineered Strr mutant E. coli ORN 208. Conjugating the streptomycin to SNP resulted in the decrease in MIC to 161 μg/mL, 63 μg/mL, and 19 μg/mL for SNP of 80, 50 and 30 nm, respectively. In this poster, the synthesis, characterization, and evaluation of SNP-Str will be presented and discussed

One-Step Synthesis of Amine-Functionalized Hollow Mesoporous Silica Nanoparticles as Efficient Antibacterial and Anticancer Materials

In this study, amine-functionalized hollow mesoporous silica nanoparticles with an average diameter of ∼100 nm and shell thickness of ∼20 nm were prepared by an one-step process. This new nanoparticulate system exhibited excellent killing efficiency against mycobacterial (<i>M. smegmatis</i> strain mc² 651) and cancer cells (A549)

Magnetic Multivalent Trehalose Glycopolymer Nanoparticles for the Detection of Mycobacteria

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

Trehalose-Conjugated, Photofunctionalized Mesoporous Silica Nanoparticles for Efficient Delivery of Isoniazid into Mycobacteria

Glyconanoparticle carriers have been synthesized and efficiently delivered into mycobacteria. Mesoporous silica nanoparticles were functionalized with <i>α,α</i>-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