SkinJect said it raised nearly $3 million for the patch it’s developing to treat skin cancers.

The $2.5 million equity round, revealed yesterday in a regulatory filing, involved 13 unnamed investors, Pittsburgh-based SkinJect said.

The company is working on a thumb-sized device that features a dissolvable microneedle array to deliver drugs directly to top layers of the skin. It is designed to treat basal and non-melanoma skin cancer by causing an immune system reaction to fight the cancer cells, according to SkinJect’s website. The University of Pittsburgh licensed the patch in August 2016.

SkinJect’s dissolvable microneedles penetrate the skin and dissolve to deliver the cancer-killing drug. The microneedles are made from an FDA-approved cellulose-like material that carries the drug that is capable of killing cells and stimulating an immunological response from the lesions.

One topical application per week for three weeks in 10-minute office visits is needed, according to the company. SkinJect says that lesion reoccurrence at the treatment site can be prevented because of the stimulation of the immune system caused by the patch.