The present disclosure provides methods for detecting biological print(s) or biological fluid(s) or target low molecular weight analyte(s) therein comprising contacting the suspected print(s) or fluid(s) with porous semiconductor substrates or microparticles (MPs) under conditions to allow said semiconductor substrates or microparticles to adhere to the print(s) or fluid(s) or analyte(s) therein, and analysing the adhered porous semiconductor substrates or MPs to detect the print(s), fluid(s) or analytes when present. The disclosure also includes method for making porous semiconductor substrates.
