Erratum to: Enzymatic- and temperature-sensitive controlled release of ultrasmall superparamagnetic iron oxides (USPIOs)

Yu, Shann S.; Scherer, Randy L.; Ortega, Ryan A.; Bell, Charleson S; O’Neil, Conlin P.; Hubbell, Jeffrey A.; Giorgio, Todd D.

doi:10.1186/1477-3155-9-51

Cited by 7 publications

(9 citation statements)

References 1 publication

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“…In three similar examples, the formation of a superparamagnetic MRI contrast agent can be generated when dextranase, MMP‐2 or MMP‐9 protease cleaves the hydrophilic coating of a SPION, causing the nanoparticles to aggregate and decrease the T 2 * relaxation time constant of the system . Using the same concept, but in the opposite sense, aggregated SPIONs linked via complimentary stands of DNA can be used to detect the activity of the restriction enzyme EcoRV, which cleaves the DNA and irreversibly disaggregates the SPIONs, resulting in an increase in the T 2 * relaxation time constant of the system . A similar example also generated a change in T 2 * relaxation following disaggregation of DNA‐linked SPIONs during in vitro studies, when secreted alkaline phosphatase de‐phosphorylates 2′‐AMP to create adenosine, which then disrupts a DNA duplex that links the SPIONs .…”

Section: Examples Of Responsive Mri Contrast Agentsmentioning

confidence: 99%

A review of responsive MRI contrast agents: 2005–2014

Hingorani

Bernstein

Pagel

2014

Contrast Media & Molecular

178

184

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This review focuses on MRI contrast agents that are responsive to a change in a physiological biomarker. The response mechanisms are dependent on six physicochemical characteristics, including the accessibility of water to the agent, tumbling time, proton exchange rate, electron spin state, MR frequency, or superparamagnetism of the agent. These characteristics can be affected by changes in concentrations or activities of enzymes, proteins, nucleic acids, metabolites, or metal ions, or changes in redox state, pH, temperature, or light. A total of 117 examples are presented, including examples that employ nuclei other than 1H, which attests to the creativity of multidisciplinary research efforts to develop responsive MRI contrast agents.

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Section: Examples Of Responsive Mri Contrast Agentsmentioning

confidence: 99%

A review of responsive MRI contrast agents: 2005–2014

Hingorani

Bernstein

Pagel

2014

Contrast Media & Molecular

178

184

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“…16 In brief, USPIO cores of predictable diameters were first synthesized through thermal decomposition, by controlling the molar ratios of iron precursor to oleic acid introduced in the reaction feed (Supplementary Figure S1). A 1:2 mass ratio of dried hydrophobic USPIO cores to PEG-PPS polymers were then dissolved in toluene, vortexed to mix, sonicated for 5 seconds to break apart clumps, and then dried by rotary evaporation for 20 minutes.…”

Section: Encapsulation Of Uspios In Peg-pps Copolymersmentioning

confidence: 99%

“…This phenomenon can be explained by previous observations that aggregated or clustered superparamagnetic nanoparticles result in higher R 2 versus fully dispersed, singlet nanoparticles. 16,31 Others have demonstrated via TEM that following endocytosis of iron oxide nanoparticles, macrophages can process the particles into lysosomes, where dense clusters of particles can usually be observed. Taken together, these other observations help explain how even a small amount of nanoparticle uptake results in a marked change in T 2 contrast in the system.…”

mentioning

confidence: 99%

Size- and charge-dependent non-specific uptake of PEGylated nanoparticles by macrophages

Yu¹,

Lau²,

Thomas³

et al. 2012

IJN

130

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Abstract:The assessment of macrophage response to nanoparticles is a central component in the evaluation of new nanoparticle designs for future in vivo application. This work investigates which feature, nanoparticle size or charge, is more predictive of non-specific uptake of nanoparticles by macrophages. This was investigated by synthesizing a library of polymer-coated iron oxide micelles, spanning a range of 30-100 nm in diameter and −23 mV to +9 mV, and measuring internalization into macrophages in vitro. Nanoparticle size and charge both contributed towards non-specific uptake, but within the ranges investigated, size appears to be a more dominant predictor of uptake. Based on these results, a protease-responsive nanoparticle was synthesized, displaying a matrix metalloproteinase-9 (MMP-9)-cleavable polymeric corona. These nanoparticles are able to respond to MMP-9 activity through the shedding of 10-20 nm of hydrodynamic diameter. This MMP-9-triggered decrease in nanoparticle size also led to up to a six-fold decrease in nanoparticle internalization by macrophages and is observable by T 2 -weighted magnetic resonance imaging. These findings guide the design of imaging or therapeutic nanoparticles for in vivo targeting of macrophage activity in pathologic states.

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“…The restriction enzyme EcoRV can cleave DNA duplexes that link SPIONs, which allows the SPIONs to irreversibly disaggregate. [48] A more complicated example detects the activity of secreted alkaline phosphatase, which can dephosphorylate 2’-AMP to create adenosine, which in turn can disrupt a DNA duplex that aggregates SPIONs, thereby separating the SPIONs and reduce their collective superparamagnetism. [49] As an exception to this behavior, a highly aggregated system of SPIONs in a hydrogel becomes less aggregated after trypsin digestion, which increased superparamagnetism and decreased the T2* relaxation time of the SPIONs.…”

Section: Introductionmentioning

confidence: 99%

Detecting Enzyme Activities with Exogenous MRI Contrast Agents

Hingorani¹,

Yoo²,

Bernstein³

et al. 2014

Chemistry A European J

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This review focuses on exogenous MRI contrast agents that are responsive to enzyme activity. Enzymes can catalyze a change in water access, rotational tumbling time, the proximity of a 19F-labeled ligand, the aggregation state, the proton chemical exchange rate between the agent and water, or the chemical shift of 19F, 31P, 13C or a labile 1H of an agent, which can be used to detect enzyme activity. The variety of agents attests to the creativity in developing enzyme-responsive MRI contrast agents.

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Erratum to: Enzymatic- and temperature-sensitive controlled release of ultrasmall superparamagnetic iron oxides (USPIOs)

Cited by 7 publications

References 1 publication

A review of responsive MRI contrast agents: 2005–2014

A review of responsive MRI contrast agents: 2005–2014

Size- and charge-dependent non-specific uptake of PEGylated nanoparticles by macrophages

Detecting Enzyme Activities with Exogenous MRI Contrast Agents

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