Spin membrane immunoassay: Simplicity and specificity

Chan, S.W.; Tan, C. T.; Hsia, J.C.

doi:10.1016/0022-1759(78)90235-1

Cited by 28 publications

(2 citation statements)

References 7 publications

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“…We wish to investigate whether liposomes are also capable of delivering sufficient concentrations of nitroxides to cells for EPR imaging. Liposomes are an attractive vehicle for delivering EPR imaging probes to cells, as both nitroxides and fluorphores can be sequestered at high (mM) concentrations in the aqueous lumen of the liposome [15, 16]. Liposomally encapsulated nitroxides have been used previously to assess the stability of liposomes as drug carriers, [17, 18] and as a component in a system for in vitro cellular oxygen measurements [19].…”

Section: Introductionmentioning

confidence: 99%

Cellular uptake of electron paramagnetic resonance imaging probes through endocytosis of liposomes

Burks

Barth

Halpern

et al. 2009

Biochimica et Biophysica Acta (BBA) - Biomembranes

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Electron paramagnetic resonance imaging (EPRI) allows detection and localization of paramagnetic spin probes in vivo and in real time. We have shown that nitroxide spin probes entrapped in the intracellular milieu can be imaged by EPRI. Therefore, with the development of a tumor-targetable vehicle that can efficiently deliver nitroxides into cells, it should be possible to use nitroxide spin probes to label and image cells in a tumor. In this study, we assess the potential of liposomes as a delivery vehicle for imaging probes. We demonstrate that liposomes can stably encapsulate nitroxides at very high concentrations (> 100 mM), at which nitroxides exhibit concentration-dependent quenching of their EPR signal—a process analogous to the quenching of fluorescent molecules. The encapsulating liposomes thus appear spectroscopically “dark”. When the liposomes are endocytosed and degraded by cells, the encapsulated nitroxides are liberated and diluted into the much larger intracellular volume. The consequent relief of quenching generates a robust intracellular nitroxide signal that can be imaged. We show that through endocytosis of nitroxide-loaded liposomes, CV1 cells can achieve intracellular nitroxide concentrations of ~1 mM. By using tissue phantom models, we verify that this concentration is more than sufficient for in vivo EPR imaging.

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Section: Introductionmentioning

confidence: 99%

Cellular uptake of electron paramagnetic resonance imaging probes through endocytosis of liposomes

Burks

Barth

Halpern

et al. 2009

Biochimica et Biophysica Acta (BBA) - Biomembranes

View full text Add to dashboard Cite

show abstract

“…Containers such as a beaker are not needed; instead, a thin-layer space between the flat bottom of the ISE and the plate reference electrode is conveniently used for holding microliter amounts of immune sample solution. As an illustrative example of lipid antigen-antibody reactions, (e-dinitrophenylaminocaproyl)phosphatidylethanolamine (DNP-cap-PE) and its antiserum were chosen, because this particular system has been thoroughly studied in the liposome immune lysis process (15,16).…”

mentioning

confidence: 99%