title: Engineered atherosclerosis-specific zinc ferrite nanocomplex-based MRI contrast agents.
abstract: BACKGROUND
  Cardiovascular diseases are the most prevalent cause of morbidity and mortality affecting millions of people globally. The most effective way to counter cardiovascular complications is early diagnosis and the safest non-invasive diagnostic approach is magnetic resonance imaging (MRI). In this study, superparamagnetic ferrite nanoparticles doped with zinc, exhibiting highly enhanced saturation magnetization and T2 and computed tomography (CT) contrast were synthesized. These nanoparticles have been strategically engineered using bovine lactoferrin (Lf), polyethylene glycol (PEG), and heat shock protein (Hsp)-70 antibody specifically targeting atherosclerosis with potential therapeutic value. The nanocomplexes were further validated in vitro to assess their cytotoxicity, internalization efficiency, effects on cellular proliferation and were assessed for MRI as well as X-ray CT in ex vivo Psammomys obesus rat model.
  
  
  RESULTS
  Optimized zinc doped ferrite nanoparticles (Zn0.4Fe2.6O4) with enhanced value of maximum saturation magnetization value on 108.4 emu/g and an average diameter of 24 ± 2 nm were successfully synthesized. Successfully incorporation with bovine lactoferrin, PEG and Hsp-70 (70 kDa) antibody led to synthesis of spherical nanocomplexes (size 224.8 nm, PDI 0.398). A significantly higher enhancement in T2 (p < 0.05, 1.22-fold) and slightly higher T1 (1.09-fold) and CT (1.08-fold) contrast compared to commercial ferrite nanoparticles was observed. The nanocomplexes exhibited effective cellular internalization within 2 h in both THP-1 and Jurkat cells. MRI scans of contrast agent injected animal revealed significant arterial narrowing and a significantly higher T2 (p < 0.05, 1.71-fold) contrast in adult animals when compared to juvenile and control animals. The excised heart and aorta agar phantoms exhibited weak MRI contrast enhancement in juvenile animal but significant contrast enhancement in adult animal specifically at the aortic arch, descending thoracic aorta and iliac bifurcation region with X-ray CT scan. Histological investigation of the contrast agent injected aorta and heart confirmed site target-specific accumulation at the atherosclerotic aortic arch and descending thoracic aorta of the adult animal with severely damaged intima full of ruptured microatheromas.
  
  
  CONCLUSIONS
  Overall, the study demonstrates the strategic development of nanocomplex based bimodal MRI and CT contrast agents and its validation on Psammomys obesus for atherosclerosis diagnostics.
authors.affiliation: Nanomedicine-Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Faculty of Health, Centre for Molecular and Medical Research (C-MMR), Deakin University, Pigdons Road, Waurn Ponds, Geelong, VIC, 3217, Australia.
authors.forename: Rajneesh
authors.initials: R
authors.lastname: Chaudhary
authors.affiliation: Nanomedicine-Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Faculty of Health, Centre for Molecular and Medical Research (C-MMR), Deakin University, Pigdons Road, Waurn Ponds, Geelong, VIC, 3217, Australia.
authors.forename: Kislay
authors.initials: K
authors.lastname: Roy
authors.affiliation: Nanomedicine-Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Faculty of Health, Centre for Molecular and Medical Research (C-MMR), Deakin University, Pigdons Road, Waurn Ponds, Geelong, VIC, 3217, Australia.
authors.forename: Rupinder Kaur
authors.initials: RK
authors.lastname: Kanwar
authors.affiliation: Metabolic Research Unit, School of Medicine (SoM), Faculty of Health, Centre for Molecular and Medical Research (C-MMR), Deakin University, Pigdons Road, Waurn Ponds, Geelong, VIC, 3217, Australia.
authors.forename: Ken
authors.initials: K
authors.lastname: Walder
authors.affiliation: Nanomedicine-Laboratory of Immunology and Molecular Biomedical Research (NLIMBR), School of Medicine (SoM), Faculty of Health, Centre for Molecular and Medical Research (C-MMR), Deakin University, Pigdons Road, Waurn Ponds, Geelong, VIC, 3217, Australia. jagat.kanwar@deakin.edu.au.
authors.forename: Jagat Rakesh
authors.initials: JR
authors.lastname: Kanwar
mesh_terms: D000818:Animals; D050197:Atherosclerosis / Q000175:diagnosis*; D002460:Cell Line; D045744:Cell Line, Tumor; D003287:Contrast Media / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006801:Humans; D019169:Jurkat Cells; D008279:Magnetic Resonance Imaging / Q000379:methods; D058185:Magnetite Nanoparticles / Q000737:chemistry*; D010316:Particle Size; D019047:Phantoms, Imaging; D011092:Polyethylene Glycols / Q000737:chemistry; D051381:Rats; D014057:Tomography, X-Ray Computed / Q000379:methods; D015032:Zinc / Q000737:chemistry*
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; D058185:Magnetite Nanoparticles; C001215:ferrite; D011092:Polyethylene Glycols; D015032:Zinc