Folate/NIR 797-conjugated albumin magnetic nanospheres: synthesis, characterisation, and in vitro and in vivo targeting evaluation

PLoS One. 2014 Sep 4;9(9):e106483. doi: 10.1371/journal.pone.0106483. eCollection 2014.


A practical and effective strategy for synthesis of Folate-NIR 797-conjugated Magnetic Albumin Nanospheres (FA-NIR 797-MAN) was developed. For this strategy, Magnetic Albumin Nanospheres (MAN), composed of superparamagnetic iron oxide nanoparticles (SPIONs) and bovine serum albumin (BSA), were covalently conjugated with folic acid (FA) ligands to enhance the targeting capability of the particles to folate receptor (FR) over-expressing tumours. Subsequently, a near-infrared (NIR) fluorescent dye NIR 797 was conjugated with FA-conjugated MAN for in vivo fluorescence imaging. The FA-NIR 797-MAN exhibited low toxicity to a human nasopharyngeal epidermal carcinoma cell line (KB cells). Additionally, in vitro and in vivo evaluation of the dynamic behaviour and targeting ability of FA-NIR 797-MAN to KB tumours validated the highly selective affinity of FA-NIR 797-MAN for FR-positive tumours. In summary, the FA-NIR 797-MAN prepared here exhibited great potential for tumour imaging, since the near-infrared fluorescence contrast agents target cells via FR-mediated endocytosis. The high fluorescence intensity together with the targeting effect makes FA-NIR 797-MAN a promising candidate for imaging, monitoring, and early diagnosis of cancer at the molecular and cellular levels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cattle
  • Contrast Media / chemistry*
  • Diagnostic Imaging / methods
  • Folic Acid / chemistry*
  • Humans
  • KB Cells
  • Nanospheres / chemistry*
  • Serum Albumin, Bovine / chemistry


  • Contrast Media
  • Serum Albumin, Bovine
  • Folic Acid

Grant support

This work was supported by the National Key Basic Research Program of China (973 Program) (Grant No. 2013 CB933904, 2013 CB733803), National Natural Science Foundation of China (81271635, 81071881, 81301270, 81101139). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.