title: Multistability in platelets and their response to gold nanoparticles.
abstract: The nanoparticle (NP) response of platelets is shown to be critically dependent on extent of preactivation of platelets by an agonist like ADP. A transition from de-aggregatory to aggregatory state is triggered in the presence of gold NPs (AuNP) only in such critical conditions. Adhered and suspended platelets respond differentially to NPs. Preactivation in the adhered state induced by shear force explains such observation. The NP effect is associated with enhanced release reaction, tyrosine phosphorylation and CD62P expression level. Unlike cancer cells, whose response is maximal when NP size is optimal (within the range 50 - 70 nm), the platelet response monotonically increases with reduction of the AuNP size. The uptake study, using quenching of quinacrine hydrochloride fluorescence by AuNP, indicates that accumulation 18 nm AuNP is several-fold higher than the 68 nm AuNP. It is further shown that AuNP response can provide a simple measure for thrombotic risk associated with nano-drugs.
  
  
  BACKGROUND
  Platelet aggregation can be triggered in the presence of gold nanoparticles (AuNP). Platelet response monotonically increases with reduction of the AuNP size. AuNP response can provide a simple measure for thrombotic risk associated with nano-drugs.
authors.affiliation: Department of Biochemistry, University of Calcutta, Kolkata, India.
authors.forename: Suryyani
authors.initials: S
authors.lastname: Deb
authors.forename: Hirak K
authors.initials: HK
authors.lastname: Patra
authors.forename: Prabir
authors.initials: P
authors.lastname: Lahiri
authors.forename: Anjan Kr
authors.initials: AK
authors.lastname: Dasgupta
authors.forename: Kuntal
authors.initials: K
authors.lastname: Chakrabarti
authors.forename: Utpal
authors.initials: U
authors.lastname: Chaudhuri
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D006046:Gold / Q000737:chemistry*; D006801:Humans; D053768:Metal Nanoparticles / Q000008:administration & dosage / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010766:Phosphorylation / Q000187:drug effects; D010974:Platelet Aggregation / Q000187:drug effects; D014443:Tyrosine / Q000378:metabolism
chemical_list: D014443:Tyrosine; D006046:Gold; D000255:Adenosine Triphosphate