Nanoparticles’ Size and Chemical Modification have Detrimental Role on the Interaction of Nano Gold with Brain: Extent of Accumulation and Toxicity
Blood brain barrier (BBB) is a very selective barrier that protects the brain and the central nervous system (CNS) from the entry of harmful substances and helps regulate the exchange of different molecules and nutrients from and into the brain and the CNS. This selectivity makes delivering therapeutic and diagnostic materials across the BBB very challenging. In this study, different shapes and sizes of gold nanoparticles (GNP) were synthesized and functionalized with five different thiolated ligands to acquire GNP with various surface chemistries. The potential of GNP of different properties to be accumulated into the brain through BBB and into other organs was investigated in mouse model using qualitative and quantitative approaches. Gold nanorods (GNR) functionalized with 4-mercaptophenol (Mph) showed the highest penetration ability across the BBB into the brain with no significant deposition into other organs. Interestingly, increasing the size of GNR retarded their delivery into the brain, while enhanced their accumulation into other organs. On the other hand, gold nanospheres (GNS) demonstrated high deposition percentages into the brain and other organs with possible toxic effect. The properties of GNP have a crucial role in their interaction with BBB and accumulation into the brain and other organs. GNP could be considered as a promising nano-platform for drug delivery into the brain and as a photothermal-induced agent against brain cancer.