A. Anitha a, N. Fletcher b,c, Z. H. Houston b,c,  K. J. Thurecht b,c, L. Grøndahl a,c*

 

a School of Chemistry and Molecular Biosciences
  b Centre for Advanced Imaging
c Australian Institute for Bioengineering and Nanotechnology
The University of Queensland, Brisbane, Queensland, Australia

 

Alginate; an anionic biocompatible and nontoxic natural co-polymer of (1, 4)-linked β-D-mannuronate (M) and α-L-guluronate (G) has been comprehensively studied for use in various biomedical applications1. Mammals lack alginase enzyme which is required for the biodegradation of the polymer alginate. The in vivo fate of alginate has not been explored in much detail, except one study which investigated the biodistribution of radiolabelled chemically modified alginate (propylene glycol alginate-tyrosinamide) 2 for 24 hours in Wistar rats. Thus, the present study investigates the biodistribution of ultrapure alginate for a prolonged time.

Ultrapure alginate was tested for its biodistribution in the early and prolonged time points with Positron Emission Tomography (PET) and fluorescent imaging, respectively. 64Cu labelled alginate samples were administrated in to BALB/c mice (n=4) and PET imaging was done for the initial 48 hours. All scans were co-registered to a computed tomography (CT) image taken immediately after each PET image for anatomical reference. Similarly, cyanine 5-amine conjugated alginate was administered to BALB/c mice through the tail vein, and imaged using a fluorescent imaging system co-regsitered with an X-ray for anatomical reference (Bruker MsFx pro) at 2, 7 and 14 days post-injection.

The time activity curves from the PET data for the first 2 hours showed the expected uptake into the bloodstream followed by initial clearance through the renal system, alginate then remained in circulation over the 48 hours, quickly equilibrating their uptake in the liver and spleen. The results from in vivo bio-distribution and ex vivo FACS studies showed the clearance of cyanine 5-amine-alginate conjugate through the kidneys over two weeks whereas the liver clears a little faster. Accumulation in the spleen is also seen from 2 hours after injection which does not decrease within the time frame observed. Overall, the present investigation will form the foundation for future research in the translation of alginate-based materials for biomedical applications.

References

  1. Lee, KY; Mooney, DJ. Progress in Polymer Science 2012, 37, 106-126. 
  2. Al-Shamkhani, A; Duncan, R. Journal of Bioactive and Compatible Polymers 1995, 10, 4-13.

Biographic Details

Name: Anitha A (Anitha Sudheesh Kumar)

Title: Dr

Affiliation, Country: School of Chemistry and Molecular Biosciences, The University of Queensland, Australia; Phone: +61 7 336 54257,  E-mail: a.sudheeshkumar@uq.edu.au

Research interests: Biopolymers, Drug Delivery, Nanoparticles, Cancer therapy

Venue

Room: 
Hawken N201