A non-irritating skin cleanser that contains water, a non-ionic surfactant, and a glyceryl monoester of a fatty acid. The method includes focusing at least one light pulse into a predetermined area inside an object using at least one excitation wavelength, wherein a fluorescence signal is based on at least a local excitation optical fluence and properties of fluorophores in the predetermined area. The graphoepitaxy DSA directing confinement well is filled with a block copolymer. A system can include, for example, an elongated shaft and a neuromodulation and sampling assembly having a neuromodulation and a sampling element. The light and sound generating units are coupled to one another to form a unitary assembly.