Researchers have developed a non-invasive eye drop delivery system that could offer a safer and more effective treatment for retinoblastoma (RB), a form of eye cancer most commonly affecting children. The study was published in Science Advances.

Treating retinoblastoma requires penetrating the protective barrier surrounding the eye. Current methods, including injections, chemotherapy, and radiotherapy, are often painful and can cause vision loss and other serious side effects. The new approach uses tiny vesicles called exosomes derived from pig semen (SEVs), which have naturally evolved proteins that enable them to cross biological barriers.

The research team engineered eye drops combining SEVs with folic acid and a nanozyme system (CMG) composed of carbon dots, manganese dioxide, and glucose oxidase. The CMG system triggers oxidative stress in tumour cells, leading to their destruction whilst sparing healthy tissue. Folic acid helps target tumours, whilst SEVs temporarily and reversibly open tight junctions in the eye’s protective layers, enabling drug entry through both corneal and conjunctival pathways.

In mouse models with eye tumours, mice treated with the eye drop system showed significant tumour reduction over 30 days compared to untreated animals and those receiving alternative treatments. The treated group retained only approximately 2.35% of residual tumour mass after 30 days and maintained near-normal eye clarity, whilst untreated mice developed severe abnormal blood vessel growth and opacity.

The researchers noted the method avoids potential structural damage and systemic toxicity associated with existing delivery approaches. The platform may also prove useful for other ocular conditions, including age-related macular degeneration and diabetic retinopathy. Further development is required before human trials, including addressing manufacturing standardisation and safety considerations.

Source: Medical Xpress / Science Advances (2026)