Nanoparticles containing retinoic acid have reduced irritancy of retinoic acid and are suitable for subcutaneous or intravenous administration, as well as for use in sustained-release preparation. The sum of the weight percent of the titanium dioxide and the weight percent of the optional contrast enhancing material is at least 3 weight percent based on total weight of the microporous material. The laser source generates a laser beam that the beam steering device receives and redirects along either a surgical pathway or an alignment pathway.