Quantum dot probes for bacteria distinguish Escherichia coli mutants and permit in vivo imaging

Leevy, W. Matthew; Lambert, Timothy N.; Johnson, James R.; Morris, J. D.; Smith, Bradley D.

doi:10.1039/b803590c

Cited by 56 publications

(39 citation statements)

References 27 publications

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“…However, for bacterial gene therapy applications the size of the QD can inhibit binding of the probe to its target on the bacterial surface. 88 Although autofluorescence is decreased with NIR emission wavelengths, tissue absorption and scattering still impede the amount of excitation light that reaches the fluorophore. To address this 'self-illuminating' QDs have been developed which couple QDs with the Renilla luciferase.…”

Section: Instrumentation For Oimentioning

confidence: 99%

Bacterial vectors for imaging and cancer gene therapy: a review

et al. 2012

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The significant burden of resistance to conventional anticancer treatments in patients with advanced disease has prompted the need to explore alternative therapeutic strategies. The challenge for oncology researchers is to identify a therapy which is selective for tumors with limited toxicity to normal tissue. Engineered bacteria have the unique potential to overcome traditional therapies' limitations by specifically targeting tumors. It has been shown that bacteria are naturally capable of homing to tumors when systemically administered resulting in high levels of replication locally, either external to (non-invasive species) or within tumor cells (pathogens). Pre-clinical and clinical investigations involving bacterial vectors require relevant means of monitoring vector trafficking and levels over time, and development of bacterial-specific real-time imaging modalities are key for successful development of clinical bacterial gene delivery. This review discusses the currently available imaging technologies and the progress to date exploiting these for monitoring of bacterial gene delivery in vivo.Cancer Gene Therapy ( INTRODUCTIONAlthough the potential anti-cancer effects of acquired bacterial infection have been evident for over 120 years and the presence of bacteria in excised tumors has been noted for over 60 years, 1 it is only in more recent times that the tumor-specific growth of bacteria has been considered for therapeutic purposes. While the precise mechanism(s) behind preferential bacterial tumor colonization remain poorly understood, this phenomenon must relate to unique tumor attributes that separate them from healthy tissues. Factors such as the irregular blood supply; local immune suppression; inflammation; and unique nutrient supply (e.g., purines) in tumors have been proposed to play a role. 2 Bacterial entry into the tumor environment is proposed to be facilitated by the leaky vasculature. Cancer cells are characterized by an aberrantly accelerated metabolism and proliferation leading to an imbalance of oxygen supply and consumption which is a major causative factor of tumor hypoxia. 3 The hypoxic nature of solid tumors enhances the growth of anaerobic and facultatively anaerobic bacteria. In addition, these areas with low oxygen and high interstitial pressure are considered to be an immunological sanctuary, where bacterial clearance mechanisms are greatly inhibited. 4 Necrotic regions are also rich in nutrients favoured by bacteria due to tumor cell turnover. However, tumor selective bacterial colonization now appears to be both bacterial species and tumor origin independent, since aerobic bacteria are also capable of colonising tumors, and even small tumors lacking an anaerobic center are colonised. See Figure 1 for proposed mechanisms.Invasive bacteria can internalize and replicate within tumor cells, while non-invasive bacteria grow externally to tumor cells, within the tumor micro-environment. 5 The tumor selective growth of bacteria has made them an attractive vehicle for the delivery of ...

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Section: Instrumentation For Oimentioning

confidence: 99%

Bacterial vectors for imaging and cancer gene therapy: a review

et al. 2012

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“…Additional strategies have been explored to further improve the sensitivity of QD-based bacterial detection systems. For example, the binding affinity of QDs coated with zinc(II)-dipicolylamine coordination complexes, a bacterial ligand, has been shown to correlate to the size of the QDs 156 . Based on this observation, QDs with tailored sizes have been developed to distinguish different mutants of the same bacterial species.…”

Section: Nanoparticle-based Bacterial Detectionmentioning

confidence: 99%

Nanoparticle approaches against bacterial infections

Gao

Thamphiwatana

Angsantikul

et al. 2014

WIREs Nanomed Nanobiotechnol

281

162

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Despite the wide success of antibiotics, the treatment of bacterial infection still faces significant challenges, particularly the emergence of antibiotic resistance. As a result, nanoparticle drug delivery platforms including liposomes, polymeric nanoparticles, dendrimers, and various inorganic nanoparticles have been increasingly exploited to enhance the therapeutic effectiveness of existing antibiotics. This review focuses on areas where nanoparticle approaches hold significant potential to advance the treatment of bacterial infection. These areas include targeted antibiotic delivery, environmentally responsive antibiotic delivery, combinatorial antibiotic delivery, nanoparticle-enabled antibacterial vaccination, and nanoparticle-based bacterial detection. In each area we highlight the innovative antimicrobial nanoparticle platforms and review their progress made against bacterial infections.

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“…The potential of these probes as reporters of cell surface structure was raised by an early bacterial imaging study using CdSe/ZnS core/shell quantum dots coated with PSVue-Biotin . 128 Bacterial staining with these extremely bright fluorescent imaging probes was observed to be sensitive to the cell surface topology. For example, there was no staining of smooth E. coli strains with wild type LPS and extended O-antigen polysaccharides which prevented access of the relatively large nanoparticles to the phosphorylated lipid A buried in the outer membrane.…”

Section: Molecular Imaging Of Bacteriamentioning

confidence: 99%

Imaging and therapeutic applications of zinc(ii)-dipicolylamine molecular probes for anionic biomembranes

2016

Self Cite

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This feature article describes the development of synthetic zinc(II)-dipicolylamine (ZnDPA) receptors as selective targeting agents for anionic membranes in cell culture and living subjects. There is a strong connection between anionic cell surface charge and disease, and ZnDPA probes have been employed extensively for molecular imaging and targeted therapeutics. Fluorescence and nuclear imaging applications include detection of diseases such as cancer, neurodegeneration, arthritis, and microbial infection, and also quantification of cell death caused by therapy. Therapeutic applications include selective targeting of cytotoxic agents and drug delivery systems, photodynamic inactivation, and modulation of the immune system. The article concludes with a summary of expected future directions.

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Quantum dot probes for bacteria distinguish Escherichia coli mutants and permit in vivo imaging

Abstract: Fluorescent quantum dots coated with zinc(ii)-dipicolylamine coordination complexes can selectively stain a rough Escherichia coli mutant that lacks an O-antigen element and permit optical detection in a living mouse leg infection model.

Cited by 56 publications

References 27 publications

Bacterial vectors for imaging and cancer gene therapy: a review

Bacterial vectors for imaging and cancer gene therapy: a review

Nanoparticle approaches against bacterial infections

Imaging and therapeutic applications of zinc(ii)-dipicolylamine molecular probes for anionic biomembranes

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