This invention provides modified IGFBP-derived peptides—collectively termed “immodulator peptides”—and related compositions and methods. Chemical modifications to peptides using small molecules, and sequence extensions to immodulator core sequences exhibit new and surprising biological activities. The invention builds the combinatorial power of the immodulator peptide class further by demonstrating which core sequences bind metal or glycosaminoglycans such as heparin. The invention discloses some surprising biological properties of compositions derived from these modifications, including a host of new therapeutic and diagnostic utilities (e.g. immune modulation of TLR signaling, enhanced collagen synthesis by skin fibroblasts, and synergy with a RIG-I agonist in killing melanoma cells). The invention also teaches methods for enhancing previously disclosed uses of immodulator peptides by showing how the modifications of the invention can boost the efficacy of immodulator peptides in a model of burn trauma.