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Nanocolloidal albumin-IRDye 800CW: a near-infrared fluorescent tracer with optimal retention in the sentinel lymph node.

Heuveling DA, Visser GW, de Groot M, de Boer JF, Baclayon M, Roos WH, Wuite GJ, Leemans CR, de Bree R, van Dongen GA - Eur. J. Nucl. Med. Mol. Imaging (2012)

Bottom Line: Conjugation of IRDye 800CW to nanocolloidal albumin was always about 50% efficient and resulted in a stable and pure product without affecting the particle size of the nanocolloidal albumin.No decrease in the fluorescence signal from SN was observed 24 h after injection of the nanocolloidal albumin-IRDye 800CW, while a strong decrease or complete disappearance of the fluorescence signal was seen 24 h after injection of ICG/HSA.Nanocolloidal albumin-IRDye 800CW is a promising fluorescent tracer with optimal kinetic features for SN detection.

View Article: PubMed Central - PubMed

Affiliation: Department of Otolaryngology/Head and Neck Surgery, VU University Medical Center, Amsterdam, The Netherlands.

ABSTRACT

Purpose: At present, the only approved fluorescent tracer for clinical near-infrared fluorescence-guided sentinel node (SN) detection is indocyanine green (ICG), but the use of this tracer is limited due to its poor retention in the SN resulting in the detection of higher tier nodes. We describe the development and characterization of a next-generation fluorescent tracer, nanocolloidal albumin-IRDye 800CW that has optimal properties for clinical SN detection.

Methods: The fluorescent dye IRDye 800CW was covalently coupled to colloidal human serum albumin (HSA) particles present in the labelling kit Nanocoll in a manner compliant with current Good Manufacturing Practice. Characterization of nanocolloidal albumin-IRDye 800CW included determination of conjugation efficiency, purity, stability and particle size. Quantum yield was determined in serum and compared to that of ICG. For in vivo evaluation a lymphogenic metastatic tumour model in rabbits was used. Fluorescence imaging was performed directly after peritumoral injection of nanocolloidal albumin-IRDye 800CW or the reference ICG/HSA (i.e. ICG mixed with HSA), and was repeated after 24 h, after which fluorescent lymph nodes were excised.

Results: Conjugation of IRDye 800CW to nanocolloidal albumin was always about 50% efficient and resulted in a stable and pure product without affecting the particle size of the nanocolloidal albumin. The quantum yield of nanocolloidal albumin-IRDye 800CW was similar to that of ICG. In vivo evaluation revealed noninvasive detection of the SN within 5 min of injection of either nanocolloidal albumin-IRDye 800CW or ICG/HSA. No decrease in the fluorescence signal from SN was observed 24 h after injection of the nanocolloidal albumin-IRDye 800CW, while a strong decrease or complete disappearance of the fluorescence signal was seen 24 h after injection of ICG/HSA. Fluorescence-guided SN biopsy was very easy.

Conclusion: Nanocolloidal albumin-IRDye 800CW is a promising fluorescent tracer with optimal kinetic features for SN detection.

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Size distribution of nanocolloidal albumin-IRDye 800CW and native nanocolloidal albumin as assessed by AFM imaging. AFM measured the height of a particle, which represents particle size
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Fig3: Size distribution of nanocolloidal albumin-IRDye 800CW and native nanocolloidal albumin as assessed by AFM imaging. AFM measured the height of a particle, which represents particle size

Mentions: Coupling of IRDye 800CW to nanocolloidal albumin as well as native HSA resulted in a conjugation yield of about 50% as determined by a fluorescence spectrophotometer (precipitation method) and/or HPLC. As a result, on average 1.4 IRDye 800CW molecules were coupled per HSA molecule (about 67 kDa) in the nanocolloidal albumin particles. Buckle et al. [24] estimated the molecular weight of a nanocolloidal albumin particle to be about 670 kDa, and this means that a nanocolloidal albumin particle contained on average 14 covalently bound dye molecules. The presence of Tween-80 in the reaction mixture as well as in the PD10 column eluent minimized the amount of associated noncovalently bound dye in the end product, as was shown by control reactions with hydrolysed IRDye 800CW and nanocolloidal albumin (<3%). In general, nanocolloidal albumin-IRDye 800CW appeared to contain <2% of free IRDye 800CW after purification, and this percentage did not change during 120 h of storage. The particle size distributions are shown in Fig. 3. The average size of the nanocolloidal albumin-IRDye 800CW was similar to the average size of native nanocolloidal albumin: 14.6 ± 0.4 nm and 14.1 ± 1.5 nm, respectively. In serum, the relative quantum yields of nanocolloidal albumin-IRDye 800CW and ICG were 0.96 and 1.0, respectively. Absolute quantum yields of nanocolloidal albumin-IRDye 800CW and ICG in TCB were 8.0 ± 0.2% and 8.6 ± 0.1%, respectively.Fig. 3


Nanocolloidal albumin-IRDye 800CW: a near-infrared fluorescent tracer with optimal retention in the sentinel lymph node.

Heuveling DA, Visser GW, de Groot M, de Boer JF, Baclayon M, Roos WH, Wuite GJ, Leemans CR, de Bree R, van Dongen GA - Eur. J. Nucl. Med. Mol. Imaging (2012)

Size distribution of nanocolloidal albumin-IRDye 800CW and native nanocolloidal albumin as assessed by AFM imaging. AFM measured the height of a particle, which represents particle size
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369133&req=5

Fig3: Size distribution of nanocolloidal albumin-IRDye 800CW and native nanocolloidal albumin as assessed by AFM imaging. AFM measured the height of a particle, which represents particle size
Mentions: Coupling of IRDye 800CW to nanocolloidal albumin as well as native HSA resulted in a conjugation yield of about 50% as determined by a fluorescence spectrophotometer (precipitation method) and/or HPLC. As a result, on average 1.4 IRDye 800CW molecules were coupled per HSA molecule (about 67 kDa) in the nanocolloidal albumin particles. Buckle et al. [24] estimated the molecular weight of a nanocolloidal albumin particle to be about 670 kDa, and this means that a nanocolloidal albumin particle contained on average 14 covalently bound dye molecules. The presence of Tween-80 in the reaction mixture as well as in the PD10 column eluent minimized the amount of associated noncovalently bound dye in the end product, as was shown by control reactions with hydrolysed IRDye 800CW and nanocolloidal albumin (<3%). In general, nanocolloidal albumin-IRDye 800CW appeared to contain <2% of free IRDye 800CW after purification, and this percentage did not change during 120 h of storage. The particle size distributions are shown in Fig. 3. The average size of the nanocolloidal albumin-IRDye 800CW was similar to the average size of native nanocolloidal albumin: 14.6 ± 0.4 nm and 14.1 ± 1.5 nm, respectively. In serum, the relative quantum yields of nanocolloidal albumin-IRDye 800CW and ICG were 0.96 and 1.0, respectively. Absolute quantum yields of nanocolloidal albumin-IRDye 800CW and ICG in TCB were 8.0 ± 0.2% and 8.6 ± 0.1%, respectively.Fig. 3

Bottom Line: Conjugation of IRDye 800CW to nanocolloidal albumin was always about 50% efficient and resulted in a stable and pure product without affecting the particle size of the nanocolloidal albumin.No decrease in the fluorescence signal from SN was observed 24 h after injection of the nanocolloidal albumin-IRDye 800CW, while a strong decrease or complete disappearance of the fluorescence signal was seen 24 h after injection of ICG/HSA.Nanocolloidal albumin-IRDye 800CW is a promising fluorescent tracer with optimal kinetic features for SN detection.

View Article: PubMed Central - PubMed

Affiliation: Department of Otolaryngology/Head and Neck Surgery, VU University Medical Center, Amsterdam, The Netherlands.

ABSTRACT

Purpose: At present, the only approved fluorescent tracer for clinical near-infrared fluorescence-guided sentinel node (SN) detection is indocyanine green (ICG), but the use of this tracer is limited due to its poor retention in the SN resulting in the detection of higher tier nodes. We describe the development and characterization of a next-generation fluorescent tracer, nanocolloidal albumin-IRDye 800CW that has optimal properties for clinical SN detection.

Methods: The fluorescent dye IRDye 800CW was covalently coupled to colloidal human serum albumin (HSA) particles present in the labelling kit Nanocoll in a manner compliant with current Good Manufacturing Practice. Characterization of nanocolloidal albumin-IRDye 800CW included determination of conjugation efficiency, purity, stability and particle size. Quantum yield was determined in serum and compared to that of ICG. For in vivo evaluation a lymphogenic metastatic tumour model in rabbits was used. Fluorescence imaging was performed directly after peritumoral injection of nanocolloidal albumin-IRDye 800CW or the reference ICG/HSA (i.e. ICG mixed with HSA), and was repeated after 24 h, after which fluorescent lymph nodes were excised.

Results: Conjugation of IRDye 800CW to nanocolloidal albumin was always about 50% efficient and resulted in a stable and pure product without affecting the particle size of the nanocolloidal albumin. The quantum yield of nanocolloidal albumin-IRDye 800CW was similar to that of ICG. In vivo evaluation revealed noninvasive detection of the SN within 5 min of injection of either nanocolloidal albumin-IRDye 800CW or ICG/HSA. No decrease in the fluorescence signal from SN was observed 24 h after injection of the nanocolloidal albumin-IRDye 800CW, while a strong decrease or complete disappearance of the fluorescence signal was seen 24 h after injection of ICG/HSA. Fluorescence-guided SN biopsy was very easy.

Conclusion: Nanocolloidal albumin-IRDye 800CW is a promising fluorescent tracer with optimal kinetic features for SN detection.

Show MeSH
Related in: MedlinePlus