Quantum dot-antibody and aptamer conjugates shift fluorescence upon binding bacteria

Dwarakanath, Sulatha; Bruno, John G.; Shastry, Anant; Phillips, Taylor; John, Ashely; Kumar, Ashok; Stephenson, L. D.

doi:10.1016/j.bbrc.2004.10.099

Cited by 143 publications

(58 citation statements)

References 6 publications

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“…Interestingly, more red shift was seen with E. coli than with B. subtilis, implying that different cell wall compositions are important. A recent study reported a blue shift of QD-DNA conjugates upon binding to bacteria (9), confirming that energy or electron transfer mechanisms are likely to play a role in observed spectra. Understanding the mechanism of the broadening could lead to the design of environmentally sensitive probes that cannot be created with overpassivated capped nanocrystals.…”

Section: Discussionmentioning

confidence: 52%

Uptake of CdSe and CdSe/ZnS Quantum Dots into Bacteria via Purine-Dependent Mechanisms

Kloepfer

Mielke

Nadeau

2005

Appl Environ Microbiol

221

158

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Quantum dots (QDs) rendered water soluble for biological applications are usually passivated by several inorganic and/or organic layers in order to increase fluorescence yield. However, these coatings greatly increase the size of the particle, making uptake by microorganisms impossible. We find that adenine-and AMPconjugated QDs are able to label bacteria only if the particles are <5 nm in diameter. Labeling is dependent upon purine-processing mechanisms, as mutants lacking single enzymes demonstrate a qualitatively different signal than do wild-type strains. This is shown for two example species, one gram negative and one gram positive. Wild-type Bacillus subtilis incubated with QDs conjugated to adenine are strongly fluorescent; very weak signal is seen in mutant cells lacking either adenine deaminase or adenosine phosphoribosyltransferase. Conversely, QD-AMP conjugates label mutant strains more efficiently than the wild type. In Escherichia coli, QD conjugates are taken up most strongly by adenine auxotrophs and are extruded from the cells over a time course of hours. No fluorescent labeling is seen in killed bacteria or in the presence of EDTA or an excess of unlabeled adenine, AMP, or hypoxanthine. Spectroscopy and electron microscopy suggest that QDs of <5 nm can enter the cells whole, probably by means of oxidative damage to the cell membrane which is aided by light.

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Section: Discussionmentioning

confidence: 52%

Uptake of CdSe and CdSe/ZnS Quantum Dots into Bacteria via Purine-Dependent Mechanisms

Kloepfer

Mielke

Nadeau

2005

Appl Environ Microbiol

221

158

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“…The results were impressive showing enhanced detection of bacterial cells, in this case E. coli, but through the use of alternative phages it could be possible to detect a range of different bacterium species. The technique showed an improvement in sensitivity, observed results were able to detect as little as 10 cells of E. coli per milliliter within approximately 1 hour [36]. The results highlight the potential of using a highly sensitive detection system that could be used in a clinical environment, such as hand-held device that would be able to quickly and effectively detect pathogenic bacteria.…”

Section: Quantum Dotsmentioning

confidence: 78%

“…The results highlight the potential of using a highly sensitive detection system that could be used in a clinical environment, such as hand-held device that would be able to quickly and effectively detect pathogenic bacteria. In another more novel way of using QDs as a bacterial diagnostic agents conducted by Dwarakanath, works on the basis of a notable change in the emission spectra of QDs when bound to a bacteria by either aptamers or antibodies [36]. In the experiments conducted to research the phenomena of change in emission wavelength, it was shown to be independent of aptamers or antibody size.…”

Section: Quantum Dotsmentioning

confidence: 99%

Applications of Nanomedicine in Antibacterial Medical Therapeutics and Diagnostics~!2009-08-26~!2009-11-25~!2010-02-24~!

Matthews¹,

Kanwar²,

Zhou³

et al. 2010

TOTMJ

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Abstract:The need for new and effective/efficient antibacterial therapeutics and diagnostics is necessary if we want to be able to maintain and improve the protection against pathogenic bacteria. Bacteria are becoming increasingly resistant to traditionally used antibiotics and as a result are a major health concern. The number of deaths and hospitalizations due to bacteria is increasing. Current methods of bacterial diagnostics are inefficient as they lack speed and ultra sensitivity and cannot be performed on site. This is where nanomedicine is playing a vital role. The discovery of new and innovative materials through the improvement in fabrication techniques has seen the establishment of an influx of novel antibacterial therapeutics and diagnostics. The goal of this review is to highlight the research that has been done through the implementation of nanomaterials and nanotechnologies for antibacterial medical therapeutic and diagnostic.

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“…[3][4][5][6] For instance, fluorescent QDs can be conjugated with bioactive moieties (eg, antibodies, peptide, aptamers, and small-molecule ligand) to target specific biologic events and cellular structures, such as labeling neoplastic cells, cell membrane receptors, DNA, and peroxisomes. [7][8][9][10] The increasingly widespread use of QDs in biomedical applications raises concerns about the potential risk of human exposure, interactions with biological systems, and toxicological implications. Nanomaterials with particular physicochemical properties may potentially enter tissues, cells, and organelles, and interact with functional biomolecular structures to induce toxicity.…”

Section: Introductionmentioning

confidence: 99%

Role of surface charge in determining the biological effects of CdSe/ZnS quantum dots

Liu¹,

Li²,

Xia³

et al. 2015

IJN

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The growing potential of quantum dots (QDs) in biomedical applications has provoked the urgent need to thoroughly address their interaction with biological systems. However, only limited studies have been performed to explore the effects of surface charge on the biological behaviors of QDs. In the present study, three commercially available QDs with different surface coatings were used to systematically evaluate the effects of surface charge on the cellular uptake, cytotoxicity, and in vivo biodistribution of QDs. Our results demonstrated that charged QDs entered both cancer cells and macrophages more efficiently than neutral ones, while negative QDs internalized mostly. Upon entry into cells, QDs were localized in different subcellular compartments (eg, cytoplasm and lysosomes) depending on the surface charge. Interestingly, inconsistent with the result of internalization, positive QDs but not negative QDs exhibited severe cytotoxicity, which was likely due to their disruption of cell membrane integrity, and production of reactive oxygen species. Biodistribution studies demonstrated that negative and neutral QDs preferentially distributed in the liver and the spleen, whereas positive QDs mainly deposited in the kidney with obvious uptake in the brain. In general, surface charge plays crucial roles in determining the biological interactions of QDs.

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Quantum dot-antibody and aptamer conjugates shift fluorescence upon binding bacteria

Cited by 143 publications

References 6 publications

Uptake of CdSe and CdSe/ZnS Quantum Dots into Bacteria via Purine-Dependent Mechanisms

Uptake of CdSe and CdSe/ZnS Quantum Dots into Bacteria via Purine-Dependent Mechanisms

Applications of Nanomedicine in Antibacterial Medical Therapeutics and Diagnostics~!2009-08-26~!2009-11-25~!2010-02-24~!

Role of surface charge in determining the biological effects of CdSe/ZnS quantum dots

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