Gold nanoparticles may offer a novel self-therapeutic treatment for psoriasis

Researchers from the Chinese University of Hong Kong (CUHK) have developed a self-therapeutic gold nanoparticle that can prevent and treat psoriasis by suppressing genes related to the interleukin-17 (IL-17) signalling pathway, without the use of steroids or biologics.

In a study involving an imiquimod (IMQ)-induced mouse model of psoriasis, the gold nanoparticle significantly reduced the Psoriasis Area and Severity Index (PASI) total score (p<0.0001) on day 7 compared with phosphate-buffered saline (negative control group) and betamethasone and calcipotriol ointment (positive control group). [Nano Lett 2021;21:8723-8733]

“Applying this new gold nanoparticle in psoriasis can lead to obvious improvement in skin condition and reduce scales, with an efficacy similar to standard steroid and vitamin D analogue–based therapy, but without inducing common side effects such as hair loss and skin wrinkling,” highlighted the researchers.

Four weeks after application, inductively coupled plasma mass spectrometry (ICP-MS) measurement showed undetectable Au content in the skin and major organs (ie, heart, liver, kidney, brain), indicating no cutaneous or systemic toxicity of the gold nanoparticle.

In the induction period of psoriasis, application of this gold nanoparticle was shown to prevent psoriasis by downregulating genes enriched in downstream IL-17 signalling and genes linked to epidermis hyperproliferation and inflammation.

“The gold nanoparticle offers a simple, safe and effective alternative for treating psoriasis,” concluded Professor Jonathan Choi of the Department of Biomedical Engineering, CUHK.

Nanoparticles have long been studied as carriers to load drugs (ie, steroids or biologics) to epidermis cells. The new class of nanoparticles designed by Choi and his team consists of a 3 nm gold core and an outer coating of polyethylene glycol (PEG) strands modified with octadecyl chains, which enhances entry of the gold core to epidermal keratinocytes.

“The size of this nanoparticle [<15 nm in overall diameter] allows for its retention in epidermal keratinocytes,” explained Choi.

“For the first time, our work reveals the self-therapeutic value of gold nanoparticles in treating psoriasis, contrary to the existing literature that documented the use of gold nanoparticles as drug carriers,” noted the researchers. “There is no need for loading steroids or biologics to the nanoparticles.”

Moving forward, Choi and his team will collaborate with CUHK’s Faculty of Medicine in clinical studies to validate the safety and efficacy of the gold nanoparticles in humans, to provide a safe, effective and new treatment for psoriasis in the future.

“We will explore its therapeutic potential for other skin diseases, such as the more prevalent eczema.” said the researchers.