The invention relates to methods and systems that can be used for treatment and/or diagnosis. In one aspect, the present invention involves systems and methods for activating a biological cascade in a subject, and administering, to the subject, a composition or a component comprising an agent able to bind a product of a biological cascade or otherwise interact with the biological cascade. The biological cascade may be, for example, a coagulation cascade, a complement cascade, an inflammation cascade, or the like. In some cases, the concentration of a protein, the metabolic demand for a substrate, or the like may be increased as a result of activation of the biological cascade. As a specific non-limiting example, in one set of embodiments, the biological cascade may be a coagulation cascade and the composition administered to the subject may include a fibrin-binding peptide and an antitumor species. By activating the biological cascade, e.g., with an activation composition or by applying energy, coagulation may be induced in a tumor, which the antitumor species may associate with due to an increase in fibrin caused by the coagulation cascade. In addition, in certain aspects, the present invention involves systems and methods for changing tissue from a first state to a second state, for instance, with a first composition comprising nanoparticles. The second composition may be more responsive to the tissue in the second state than in the first state in some cases. In still other aspects, the present invention is generally directed to systems and methods for making such compositions, systems and methods for promoting such compositions, kits involving such compositions, or the like.
