title: Suppression of the reticuloendothelial system using λ-carrageenan to prolong the circulation of gold nanoparticles.
abstract: OBJECTIVE
  Gold nanoparticles are employed for imaging and treatment of surgically inaccessible tumors owing to their inherent optical absorption and ability to extravasate through intravenous distribution. These nanoparticles are cleared from the blood by the reticuloendothelial system (RES) as expected given their size.
  
  
  METHODS
  This study demonstrates the effects of RES blockade through the intravenous administration of λ-carrageenan, resulting in a decrease in the median clearance rate from 18.9 (95% CrI: 15.9-22.6) to 11.2 (95% CrI: 8.8-13.9) μl/min and an increase in nanoparticle circulation half-life t(½)( = 264 ± 73 vs 160 ± 22 min; p < 0.01).
  
  
  RESULTS
  This 59.3% decrease in clearance is greater than the 15% previously reported for liposomes [ 1 ].
  
  
  CONCLUSIONS
  The primary benefit of nontoxic RES blockade is to increase the circulation time, where traditional particle modification is ineffective or impractical.
authors.affiliation: Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA.
authors.forename: Isidro B
authors.initials: IB
authors.lastname: Magaña
authors.affiliation: School of Biological Sciences, Louisiana Tech University, Ruston, LA 71272, USA.
authors.forename: Raghuvara B
authors.initials: RB
authors.lastname: Yendluri
authors.affiliation: Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA.
authors.forename: Pratik
authors.initials: P
authors.lastname: Adhikari
authors.affiliation: Nanospectra Biosciences, Inc., Houston, TX 77054, USA.
authors.forename: Glenn P
authors.initials: GP
authors.lastname: Goodrich
authors.affiliation: Nanospectra Biosciences, Inc., Houston, TX 77054, USA.
authors.forename: Jon A
authors.initials: JA
authors.lastname: Schwartz
authors.affiliation: Department of Chemical Engineering, Louisiana Tech University, Ruston, LA 71272, USA.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Sherer
authors.affiliation: Department of Biomedical Engineering, Louisiana Tech University, Ruston, LA 71272, USA.
authors.forename: Dennis Patrick
authors.initials: DP
authors.lastname: O'Neal
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002351:Carrageenan / Q000008:administration & dosage*; D002626:Chemistry, Pharmaceutical; D005260:Female; D006046:Gold / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D006207:Half-Life; D007275:Injections, Intravenous; D008657:Metabolic Clearance Rate; D053768:Metal Nanoparticles; D008807:Mice, Inbred BALB C; D008954:Models, Biological; D012157:Mononuclear Phagocyte System / Q000187:drug effects* / Q000378:metabolism; D036103:Nanotechnology; D010316:Particle Size; D017156:Photoplethysmography; D013678:Technology, Pharmaceutical / Q000379:methods
chemical_list: D000970:Antineoplastic Agents; D006046:Gold; D002351:Carrageenan
keywords: RES clearance; accelerated blood clearance; gold nanoparticles; gold nanorods; gold nanoshells; pharmacokinetics; reticuloendothelial system blockade; λ-carrageenan