Naphthol Blue Black and 99mTc-Labeled Mannosylated Human Serum Albumin (99mTc-MSA) Conjugate as a Multimodal Lymph Node Mapping Nanocarrier

Ji Youn Lee,Ho Young Kim,Yun-Sang Lee,Jae Min Jeong

doi:10.1038/s41598-018-31933-1

Abstract

99mTc-labeled mannosylated human serum albumin (MSA) has been reported as a sentinel lymph node (SLN)-imaging agent by binding to macrophages in the LNs. By conjugating it with blue dye, we developed a new multimodal radio-nanocarrier by visual investigation, fluorescence imaging, and single photon emission computed tomography (SPECT)/computed tomography (CT). Binding affinities of seven blue dyes to MSA were tested. According to the spectroscopic study and visual inspection of MSA-bound dyes, naphthol blue black (NBB) was selected as the best candidate of multimodal agent. Thus, 99mTc-MSA-NBB conjugate was prepared and further investigated using mice. After footpad injection, it showed high popliteal LN accumulation at 1 h. SPECT/CT also showed high popliteal as well as inguinal LN uptakes at 10 min that sustained until 2 h. In conclusion, we prepared a multimodal SLN imaging radio-nanocarrier, 99mTc-MSA-NBB conjugate, and confirmed its excellency as a multimodal probe for SLN mapping.

Highlights

Blue dyes[1,2] or radiotracers[5,6,7] have been used for the detection of sentinel lymph node (SLN); both of these methods have limitations
Various blue dyes that bind to albumin and mannosylated human serum albumin (MSA) with high affinity and exhibit a strong dark blue color, such as naphthol blue black (NBB), patent blue VF (PBVF), reactive blue 4 (RB4), nitrazine yellow (NY), indocyanine green (ICG), brilliant blue R (BR), and brilliant blue G (BG) (Fig. 1), were tested and NBB showing the highest binding was selected as the best candidate
The results of dynamic light scattering (DLS) analysis showed that the particle size of MSA (6.34 ± 0.49 nm) was larger than Human serum albumin (HSA) (5.58 ± 0.16 nm) due to conjugated mannose groups, and it increased to 9.32 ± 0.34 nm after 99mTc-labeling due to the reduction of disulfide bonds (Supplementary Figure S3)

Summary

Introduction

Blue dyes[1,2] or radiotracers[5,6,7] have been used for the detection of SLN; both of these methods have limitations. Blue dyes rapidly diffuse to LNs adjacent to SLN due to small size (

Objectives

Methods

Results

Conclusion