The Potential of Cytokinins as Innovative Components of Multifunctional Biomaterials: Mechanisms of Biological Activity and Potential in Tissue Regeneration—In Vitro Studies—Review

Phytohormones, specifically from the cytokinin family, represent a promising class of sustainable, non-immunogenic alternatives to animal-derived growth factors in skin tissue engineering. This review explores the innovative integration of selected cytokinins—namely kinetin (K), benzyladenine (BA), and traumatic acid (TA)—into biocompatible biomaterials, focusing on their distinct molecular mechanisms and regenerative capacities in human cell models. At the cellular level, these compounds comprehensively modulate cell fate, proliferation, and survival. Benzyladenine and its derivatives regulate cell cycle transitions, enhance D-type cyclin expression, and selectively inhibit phosphodiesterase-4 (PDE4), thereby suppressing tumor necrosis factor-alpha synthesis to deliver crucial intrinsic anti-inflammatory benefits. Concurrently, kinetin functions as an advanced molecular shield and potent free radical scavenger, delaying the morphological features of fibroblast senescence and protecting nuclear DNA against oxidative damage by preventing 8-oxo-dG formation. Furthermore, the plant wound hormone traumatic acid exhibits a dual biological activity; it selectively serves as a significant antioxidant that accelerates extracellular matrix remodeling by driving protein and collagen biosynthesis in normal skin fibroblasts, while shifting to a pro-oxidant, cytotoxic mechanism in cancerous cells. By merging these specialized anti-inflammatory, anti-aging, and matrix-stimulating pathways into biocompatible scaffolds or hydrogels, cytokinin-functionalized biomaterials eliminate the safety and contamination risks associated with mammalian cell products. Ultimately, this approach establishes a highly cost-effective, scalable, and multi-functional platform capable of driving advanced tissue repair, enhancing wound healing dynamics, and ensuring significant biocompatibility.