The current invention provides methods, as well as compositions useful in such methods, involving application of energy to a tissue of interest to generate a liquefied sample comprising tissue constituents so as to provide for rapid tissue sampling, as well as qualitative and/or quantitative detection of analytes that may be part of tissue constituents (e.g., several types of biomolecules, drugs, and microbes). Determination of tissue composition can be used in a variety of applications, including diagnosis or prognosis of local as well as systemic diseases, evaluating bioavailability of therapeutics in different tissues following drug administration, forensic detection of drugs-of-abuse, evaluating changes in the tissue microenvironment following exposure to a harmful agent, and various other applications.