[China Tech] Researchers Develop Targeted Nano-Therapy to Treat Arthritis at the Cellular Level

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Researchers at Xinhua Hospital in Shanghai and in Singapore have developed a nano-delivery system that targets arthritis-affected cells, giving hope to 500 million arthritis patients worldwide.

Progressive arthritis degrades joint cartilage, causing pain, swelling, and mobility issues. Current treatments mostly alleviate symptoms but do not stop disease progression.

Treatment is challenging because cartilage tissue is a dense, net-like labyrinth with holes around 60 nanometers wide – one-thousandth the width of a human hair. Drug molecules larger than this cannot enter tissue. Synovial fluid removes small-molecule medicines from the joint cavity within hours.

Existing technologies struggle to distinguish between healthy and afflicted cells due to the irregular distribution of sick cartilage cells inside joints.

"Drug delivery to knee cartilage cells is like asking a courier to deliver a cargo to one room in a big building," said Dr Su Jiacan, the study's chief investigator from Xinhua Hospital. Su noted that the courier gets lost inside the building, and the medicine is quickly cleansed from the joint before reaching its target.

To overcome this challenge, the scientists used viruses, which can recognize and penetrate certain cells.

"In viruses such as HIV and influenza, surface glycoproteins act like keys: they identify and bind to target cells, unlocking them under specific signals," Su said.

The researchers then created a viral glycoprotein-like peptide that can infiltrate sick cells.

A 16-nanometer delivery system was created by connecting this peptide to drug carriers small enough to transit the cartilage network but large enough to resist rapid clearance.

Experiments on animals indicated that the drug delivery mechanism works.

The research team is evaluating preclinical safety and hopes to start clinical trials in three to five years. Once developed, this nano-based therapy could heal arthritis and restore pain-free mobility.

Nature Nanotechnology's publication of the study sparked widespread interest in the medical community.