Abstract
Background and Objectives
Platelet microparticles are microvesicles derived from platelets. Today, with the use of nanoparticles in cancer treatments, many limitations of traditional drug delivery methods are reduced. Doxorubicin, a chemotherapeutic drug available for the treatment of many cancers, has fluorescent properties and can be detected by fluorescent imaging in tissues. Aim of this study is to compare different drug loading methods into platelet microparticles.
 
Materials and Methods
In this experimental study, the platelet concentrates were taken on their fifth day from Iranian Blood Transfusion Organization. Then platelet microparticles were extracted from those concentrated platelets in several centrifugation stages.  Fluorescent microbeads with one-micrometer size and anti-CD41/61 antibody were used to determine the size and identity of microparticles, respectively. Doxorubicin was loaded at 10 µg/ml on platelet microparticles using three methods of incubation, cell-penetrating peptide, and Sonication. Using the auto-fluorescence property of Doxorubicin, the rate of drug loading on platelet microparticles was measured by flow cytometry method.
 
Results
In terms of size, 95% of the total population of microparticles was less than one micrometer. The expression levels of CD41 and CD61 were 92.39% and 80.03%, respectively. The average fluorescence light intensities calculated in each of the incubation, sonication, and CPP methods were determined to be 79.09% ± 11.37, 47.48% ± 25.12, and 56.69% ± 23.24, respectively.
 
Conclusions 
As the incubation method has higher loading percentage, it could be an effective method for loading drug in platelet microparticles. Furthermore, the use of this method can be considered for clinical studies.