Elucidating the Dependence of Size and Concentration of Gold Nanoparticles in Cellular Uptake

Nowadays, nanoscaled gold particles received a great deal of attention for biomedical applications especially in diagnostic imaging and therapeutics. In this review, recent progress in the elucidating on how size and concentration of gold nanoparticles (AuNPs) affect cellular uptake are discussed. Since AuNPs can be administered conveniently via intravenous injection due to its small size, its' ability to enter cells is one of the factors that determine the clinical utility of nanoparticles (NPs). The size of AuNPs is one of the limitations in the potential use of gold markers for medical imaging or tracking of elusive tumors. Most work showed that at the size range of 10-100 nm, AuNPs of diameter 50 nm demonstrate the highest uptake while high efficacy in AuNPs accumulation in cells are achieved at higher concentration. The fewer AuNPs are in the solution, the lesser chance for a receptor to receive gold nanoparticle; "membrane wrapping" time is longer, resulting to lower uptake by the cell, which is turn had significant effect on endocytosis and exocytosis pathways on AuNP uptake in cell. These findings provide useful information in the design consideration and optimization of the NP-uptake at cell level for effective applications in imaging, diagnosis, therapeutics, and targeting.