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Supramolecular polymers (SPs) are an emerging class of drug transporters employed to improve drug therapy. Through the rational design of self-assembling monomers, one can optimize the properties of the resulting supramolecular nanostructures, such as size, shape, surface chemistry, release, and, therefore, biological fates. This study highlights the design of isomeric SN38 prodrugs through the conjugation of hydrophilic oligo(ethylene glycol) (OEG) with hydroxyls at positions 10 and 20 on hydrophobic SN-38. Self-assembling prodrug (SAPD) isomers 10-OEG-SN38 and 20-OEG-SN38 can self-assemble into giant nanotubes and filamentous assemblies, respectively, via aromatic associations that dominate self-assembly. Our study reveales the influence of modification sites on the assembly behavior and ability of the SN38 SAPDs, as well as drug release and subsequent in vitro and in vivo antitumor effects. The SAPD modified at position 20 exhibits stronger π–π interactions among SN38 units, leading to more compact packing and enhanced assembly capability, whereas OEG at position 10 poses steric hindrance for aromatic associations. Importantly, owing to its higher chemical and supramolecular stability, 20-OEG-SN38 outperforms 10-OEG-SN38 and irinotecan, a clinically used prodrug of SN38, in a CT26 tumor model, demonstrating enhanced tumor growth inhibition and prolonged animal survival. This study presents a new strategy of using interactions among drug molecules as dominating features to create supramolecular assemblies. It also brings some insights into creating effective supramolecular drug assemblies via the engineering of self-assembling building blocks, which could contribute to the optimization of design principles for supramolecular drug delivery systems. [ABSTRACT FROM AUTHOR]

Owing to their excellent tissue-penetration ability, near-infrared (NIR) photothermal-responsive intelligent materials show remarkable advantages in biomedical applications. However, the majority the previously reported NIR-absorbing agents are metal- and carbon-based nanoparticles, both of which possess low photothermal conversion efficiency and poor biocompatibility. Herein, polydopamine modified black phosphorus (pBP) nanosheet-containing poly(vinyl alcohol) (PVA) composite hydrogels are facilely fabricated via a freezing/thawing approach. Taking advantage of the high photothermal conversion efficiency of pBP, the prepared composite hydrogels exhibit a fascinating on-demand NIR-responsive drug release behavior. An in vitro cell culture study demonstrates that these composite hydrogels present good biocompatibility and cellular interaction. Moreover, since the incorporated pBP nanosheets can form a strong hydrogen bonding interaction within the PVA matrix, the composite hydrogels also show enhanced mechanical properties. We believe that the robust mechanical properties and excellent biocompatibility accompanied by the highly controllable NIR-responsive drug release performance of the obtained composite hydrogel augur well for its diverse future applications in the biomedical field. [ABSTRACT FROM AUTHOR]