Chitosan functionalisation of gold nanoparticles encourages particle uptake and induces cytotoxicity and pro-inflammatory conditions in phagocytic cells, as well as enhancing particle interactions with serum components

Abstract

Background Gold nanoparticles (AuNPs) are a popular choice for use in medical and biomedical research applications. With suitable functionalisation AuNPs can be applied in drug delivery systems, or can aid in disease diagnosis. One such functionalisation is with chitosan, which enables efficient interaction and permeation of cellular membranes, providing an effective adjuvant. As both AuNPs and chitosan have been shown to have low toxicity and high biocompatibility their proposed use in nanomedicine, either individually or combined, is expanding. However, further toxicological and immunological assessments of AuNP-chitosan conjugates are still needed. Therefore, we have evaluated how AuNP functionalisation with chitosan can affect uptake, cytotoxicity, and immunological responses within mononuclear cells, and influence the interaction of AuNPs with biomolecules within a complex biofluid. The AuNPs used were negatively charged through citrate-coating, or presented either low or high positive charge through chitosan-functionalisation. Uptake by THP-1 cells was assessed via transmission electron microscopy and electron energy loss spectroscopy, pro-inflammatory responses by ELISA and qRT-PCR, and cell death and viability via lactate dehydrogenase release and mitochondrial activity, respectively. Interactions of AuNPs with protein components of a frequently used in vitro cell culture medium supplement, foetal calf serum, were investigated using mass spectrometry.ResultsAlthough cells internalised all AuNPs, uptake rates and specific routes of intracellular trafficking were dependent upon chitosan-functionalisation. Accordingly, an enhanced immune response was found to be chitosan-functionalisation-dependent, in the form of CCL2, IL-1β, TNF-α and IL-6 secretion, and expression of IL-1β and NLRP3 mRNA. A corresponding increase in cytotoxicity was found in response to chitosan-coated AuNPs. Furthermore, chitosan-functionalisation was shown to induce an increase in unique proteins associating with these highly charged AuNPs.ConclusionsIt can be concluded that functionalisation of AuNPs with the perceived non-toxic biocompatible molecule chitosan at a high density can elicit functionalisation-dependent intracellular trafficking mechanisms and provoke strong pro-inflammatory conditions, and that a high affinity of these NP-conjugates for biomolecules may be implicit in these cellular responses.Electronic supplementary materialThe online version of this article (doi:10.1186/s12951-015-0146-9) contains supplementary material, which is available to authorized users.

Chitosan gold nanoparticles induce cell death in HeLa and MCF-7 cells through reactive oxygen species production

“…Nanoparticles have been shown to be interesting options in cancer diagnostics and therapeutics, [1][2][3] as an alternative to nonviral delivery systems. 4 Among the different types of nanoparticles, gold nanoparticles (AuNPs) have been demonstrated to inhibit proliferation and induce cell death on different types of cancer cell lines; [1][2][3][5][6][7] moreover, they have been shown to be safe in several biological models, and interesting agents for drug delivery and photothermal therapy against cancer. 8 Cervical cancer and breast cancer are among the leading causes of mortality in women around the world.…”

“…20 For this reason, it is essential to study the particular characteristics of the nanoparticles and to evaluate them in different types of cells. Few reports have described the biological effects of CH-AuNPs in cancer cells, 5,17 and there is no description of their effect in primary healthy cells. Additionally, their mechanism of action in cancer cells is poorly understood.…”

Chitosan biopolymer functionalized gold nanoparticles with controlled cytotoxicity and improved antifilarial efficacy

“…In this circumstance, surface functionalization of GNPs may be planned and executed in a more effective way for betterment of bioactivity. One such functionalization can be with chitosan, which enables its efficient interaction and permeation of cellular membranes, providing an effective adjuvant [15][16][17][18][19][20]. As both GNPs and chitosan have been shown to have low toxicity and high biocompatibility, their composite material should also be less cytotoxic and biocompatible.…”

Cytotoxic Effect of Chitosan-Gold Nanoparticles on Two Cell Lines in Culture

“…AuNPs have been reported as being nontoxic and biocomapatible with mouse macrophages (RAW264.7 cell line) (Shukla et al, 2005). In contrast, 10 nm AuNPs coated with chitosan were found to be cytotoxic to human acute monocytic leukemia line THP-1 (Boyles et al, 2015). Chitosan coated AuNPs have been shown to promote bone formation (Choi et al, 2015) and proposed as carriers for insulin delivery (Bhumkar et al, 2007).…”