Direct delivery of proteins into cells avoids many drawbacks of gene delivery, and thus has emerging applications in biotherapy. However, it remains a challenging task owing to limited charges and relatively large size of proteins. Here, we report an efficient protein delivery system via the co-assembly of fluoroamphiphiles and proteins into nanoparticles. Fluorous substituents on the amphiphiles play essential roles in the formation of uniform nanoparticles, avoiding protein denaturation, efficient endocytosis, and maintaining low cytotoxicity. Structure-activity relationship studies reveal that longer fluorous chain length and higher fluorination degree contribute to more efficient protein delivery, but excess fluorophilicity on the polymer leads to the pre-assembly of fluoroamphiphiles into stable vesicles, and thus failed protein encapsulation and cytosolic delivery. This study highlights the advantage of fluoroamphiphiles over other existing strategies for intracellular protein delivery.

Cytosolic delivery is the major challenge that limits the clinical translation of siRNA-based therapeutics. Although thousands of polymers have been developed for siRNA delivery, the efficiency–toxicity correlation is unsatisfactory. Here, we report a facile strategy to fabricate core–shell-structured nanoparticles with robust siRNA delivery efficiency. The nanoparticle is prepared by entropy-driven complexation of siRNA with a green tea catechin to yield a negatively charged core, followed by coating low-molecular-weight polymers to form the shell. This supramolecular strategy facilitates the polymers condensing siRNA into uniform nanoparticles. The nanoparticle specifically down-regulates target genes in vitro and in vivo, and efficiently attenuates chronic intestinal inflammation in an inflammatory bowel disease model. Notably, the highly efficient nanoparticles are applicable for various polymers with different topologies and chemical compositions, providing a versatile technique to break down the efficiency–toxicity correlation of cationic polymers. The proposed strategy in this study permits the development of a promising platform for polymer-mediated siRNA delivery.

Cytosolic protein delivery is of great importance for basic cell biology and the discovery of novel protein-based biotherapeutics. It remains a challenging task because of the limited binding sites on proteins and their relatively large size. As a result, most current approaches for cytosolic protein delivery need covalent modification on native proteins, which is usually involved with complicated synthesis, reduced protein bioactivity, and unexpected safety concerns. In this study, we proposed a novel strategy to deliver proteins of different molecular sizes and isoelectric points by specific recognitions between natural polyphenols and boronic acid-containing polymers. Protein molecules were decorated with polyphenols via noncovalent hydrogen-bond/hydrophobic interactions or reversible dynamic covalent bonds. The natural polyphenols increase the binding affinity between proteins and boronic acid-containing polymers, allow the release of bound proteins in acidic environments because of pH-sensitive property of catechol–boronate esters, and thus greatly promote the cytosolic delivery efficiency. This strategy showed robust efficiency in the delivery of various proteins such as bovine serum albumin, phycoerythrin, and ribonuclease A and maintained the protein bioactivity after intracellular release. The reported strategy permits the development of a polyphenol-involved polymer platform for cytosolic protein delivery.

Photodynamic therapy (PDT) by insertion of an optical fiber into the bladder cavity has been applied in the clinic for noninvasive treatment of bladder tumors. To avoid systemic phototoxicity, bladder intravesical instillation of a photosensitizer may be an ideal approach for PDT treatment of bladder cancer, in comparison to conventional intravenous injection. However, the instillationbased PDT for bladder cancer treatment remains to be less effective due to the poor urothelial uptake of photosensitizer, as well as the tumor hypoxiaassociated PDT resistance. Herein, it is uncovered that fluorinated polyethylenimine (F-PEI) achieved by mixing with Chorin-e6-conjugated catalase (CAT-Ce6) is able to form self-assembled CAT-Ce6/F-PEI nanoparticles, which show greatly improved cross-membrane, transmucosal, and intratumoral penetration capacities compared with CAT-Ce6 alone or nonfluorinated CAT-Ce6/PEI nanoparticles. Owing to the decomposition of tumor endogenous H 2 O 2 by CAT-Ce6/F-PEI nanoparticles penetrating into bladder tumors, the tumor hypoxia would be effectively relieved to further favor PDT. Therefore, bladder intravesical instillation with CAT-Ce6/F-PEI nanoparticles could offer remarkably improved photodynamic therapeutic effect to destruct orthotopic bladder tumors with reduced systemic toxicity compared to hematoporphyrin, the first-line photosensitizer used for bladder cancer PDT in clinic. This work presents a unique photosensitizer nanomedicine formulation, promising for clinical translation in instillation-based PDT to treat bladder tumors.

There is a continuing quest to rationally fabricate polymeric biomaterials with both high transfection efficiency and minimal toxicity for the emerging opportunities in small interfering RNA (siRNA) delivery. Recently, this goal was promoted highly by developing a robust and efficient strategy to facilitate polymer-mediated RNAi using natural polyphenols with multiple phenol groups that could condense siRNA effectively into negatively charged nanoparticles (NPs). Further coating of these NPs with cationic polymers of low molecular weight enabled their intracellular siRNA delivery. Inspired by the structural and functional features of natural polyphenols, we aimed to further the development of low molecular weight polycatechols as a new class of efficient and biocompatible polymers for siRNA delivery in our current study. The fabricated polycatechols have benefits of requiring only one-step fabrication toward efficient siRNA nanoformulations. Moreover, they could deliver siRNA into cells and silence target genes both in vitro and in vivo. The resulting polycatechol/siRNA formulations were also functionally competent, demonstrating a successful, profound downregulation of a proinflammatory enzyme to attenuate chronic intestinal inflammation in an intestinal injury model. This study provides a new approach in chemistry for the development of efficient synthetic polymers for therapeutic siRNA delivery.