Nanozyme-loaded needles spur hair regrowth

A petite patch of microneedles loaded with artificial enzymes works to treat a common form of hair loss and is as effective as an over-the-counter hair loss drug in animal models (ACS Nano 2021, DOI: 10.1021/acsnano.1c05272). The condition, known as androgenic alopecia, is linked to a glut of reactive oxygen species (ROS) in hair follicles and reduced blood vessel formation near them. Fangyuan Li and Jianqing Gao of Zhejiang University and coworkers turned to cerium-based nanozymes, nanoparticles that mimic the activities of catalase and superoxide dismutase, two enzymes that scavenge and digest ROS.

To deliver these nanozymes to hair follicles under the skin, the researchers loaded them into a microneedle patch made of hyaluronic acid. When applied to depilated skin in mice, the patch released its nanozyme cargo within 5 min. The team compared 2 weeks of daily treatments with the drug minoxidil (Rogaine) to five applications of the patch administered over the same time frame. The nanozyme-loaded patches regenerated hair that was comparable in density, coverage, and quality to that regenerated by minoxidil, despite being administered less often. The patch delivers a dual benefit: the needles spur blood flow, and the artificial enzymes clear up ROS. Nanozymes applied without using microneedles had little effect because they didn’t reach hair follicles. And microneedles without nanozymes appeared to trigger growth of thinner hair than that grown using the loaded patch, likely because they only stimulate blood vessel formation, Li says.