Interaction and cellular uptake of surface-modified carbon dot nanoparticles by J774.1 macrophages

Abstract

Carbon dot (Cdot) nanoparticles are an emerging class of carbon nanomaterials with a promising potential for drug delivery and bio imaging applications. Although the interaction between Cdots and non-immune cell types has been well studied, Cdot interactions with macrophages have not been investigated. Exposure of Cdot nanoparticles to J774.1 cells, a murine macrophage cell line, resulted in minimal toxicity, where notable toxicity was only seen with Cdot concentrations higher than 0.5 mg/ml. Flow cytometric analysis revealed that Cdots prepared from citric acid were internalized at significantly higher levels by macrophages compared with those prepared from bamboo leaves. Interestingly, macrophages preferentially took up phenylboronic acid (PB)-modified nanoparticles. By fluorescence microscopy, strong blue light-specific punctate Cdot fluorescence resembling Cdot structures in the cytosolic space was mostly observed in J774.1 macrophages exposed to PB-modified nanoparticles and not unmodified Cdot nanoparticles. PB binds to sialic acid residues that are overexpressed on diseased cell surfaces. Our findings demonstrate that PB-conjugated Cdots can be taken up by macrophages with low toxicity and high efficiency. These modified Cdots can be used to deliver drugs to suppress or eliminate aberrant immune cells such as macrophages associated with tumors such as tumor-associated macrophages.

Cellular Toxicity and Immunological Effects of Carbon-based Nanomaterials

“…Another study demonstrated that phenylboronic acid (PB)-modified carbon dot nanoparticles could be taken up by macrophages with low toxicity and high efficiency compared to unmodified nanoparticles. The findings suggested that these modified nanoparticles are good candidates for delivering drugs to suppress or eliminate aberrant immune cells, such as tumour-associated macrophages [ 94 ].…”

Immunotoxicity of Carbon-Based Nanomaterials, Starring Phagocytes

“…In the case of CDs, several studies have highlighted the importance of the carbon source and the synthesis method. For example, the CDs prepared using citric acid are usually internalized at higher levels by macrophages compared to CDs from different source [ 94 , 95 ]. Additional modifications influence uptake as well.…”

Nanotechnology and sialic acid biology

“…Carbon dot (Cdot) NPs offer promising potential for drug delivery and bioimaging applications. J774.1 macrophages have been shown to take up phenylboronic acid (PBA)-modified NPs as PB binds to sialic acid residues overexpressed on diseased cell surfaces and finds application in drug targeting to macrophages associated with tumors [67].…”