The Current State of the Art in PAMAM and PLL Dendrimers, Boron Clusters, and Their Complexes for Biomedical Use

Poly(amidoamine) (PAMAM) and poly-L-lysine (PLL) dendrimers have emerged as highly versatile macromolecular platforms with significant potential in biomedical applications, owing to their well-defined architecture, tunable surface chemistry, and capacity for multivalent functionalization. Their ability to carry substantial molecular payloads and to be engineered for selective interactions with biological systems has positioned them as attractive candidates for targeted drug delivery, including the transport of boron-rich compounds. Recent advances in dendrimer chemistry have enabled the incorporation of boron clusters into PAMAM and PLL structures, creating hybrid systems designed to enhance cellular uptake, improve tumor selectivity, and increase boron accumulation within malignant tissues. Given the growing interest in boron neutron capture therapy (BNCT), the integration of boron clusters into dendrimer structures represents a particularly promising direction for enhancing boron delivery to tumors. This manuscript reviews current knowledge on PAMAM and PLL dendrimers and their boron-functionalized derivatives, summarizing findings from cell culture studies, in vivo models, and clinical or preclinical investigations. Particular attention is given to both the advantageous properties of these dendrimers-such as improved delivery efficiency and biocompatibility-and their potential undesirable biological effects. As such, PAMAM and PLL dendrimers represent an important and evolving class of carriers that may significantly advance the effectiveness of boron neutron capture therapy (BNCT) in cancer treatment.