Disclosed are methods and compositions containing functionalized nanoporous silicon particles, useful in a variety of diagnostic and/or therapeutic regimens for delivery of genetic constructs to one or more cells, tissues, and/or organs of interest. Also provided are methods for introducing into selected host cells one or more selected nucleic acid molecules. The present disclosure is also directed to a method of treating a tumor, comprising the step of administering to an individual one or more of the compositions and formulations thereof as described herein.