Artificial metalloenzyme assembly in cellular compartments for enhanced catalysis.

Artificial metalloenzymes (ArMs) integrated within whole cells have emerged as promising catalysts; however, their sensitivity to metal centers remains a systematic challenge, resulting in diminished activity and turnover. Here we address this issue by inducing in cellulo liquid-liquid phase separation through a self-labeling fusion protein, HaloTag-SNAPTag. This strategy creates membraneless, isolated liquid condensates within Escherichia coli as protective compartments for the assembly of ArMs using the same fusion protein.

Ligand-Receptor Interaction-Induced Intracellular Phase Separation: A Global Disruption Strategy for Resistance-Free Lethality of Pathogenic Bacteria.

Addressing the global challenge of bacterial resistance demands innovative approaches, among which multitargeting is a widely used strategy. Current strategies of multitargeting, typically achieved through drug combinations or single agents inherently aiming at multiple targets, face challenges such as stringent pharmacokinetic and pharmacodynamic requirements and cytotoxicity concerns. In this report, we propose a bacterial-specific global disruption approach as a vastly expanded multitargeting strategy that effectively disrupts bacterial subcellular organization.

Multi-targeting oligopyridiniums: Rational design for biofilm dispersion and bacterial persister eradication.

The development of effective antibacterial drugs to combat bacterial infections, particularly the biofilm-related infections, remains a challenge. There are two important features of bacterial biofilms, which are well-known critical factors causing biofilms hard-to-treat in clinical, including the dense and impermeable extracellular polymeric substances (EPS) and the metabolically repressed dormant and persistent bacterial population embedded. These characteristics largely increase the difficulty for regular antibiotic treatment due to insufficient penetration into EPS.

Combination of Backbone Rigidity and Richness in Aryl Structures Enables Direct Membrane Translocation of Polymer Scaffolds for Efficient Gene Delivery.

The development of cell-penetrating polymers with endocytosis-independent cell uptake pathways has emerged as a prominent strategy to enhance the transfection efficiency. Inspired by the rigid α-helical structure that endows polypeptides with cell-penetrating ability, we propose that a rigid backbone can facilitate the corresponding polymer vector's performance in gene delivery by bypassing the difficult endosomal escape process. Meanwhile, the installation of aromatic domains, as a way to promote gene transfection efficiency, is employed through the construction of a poly(benzyl ether) (PBE)-based scaffold in this work.

Chemical Biology Approach to Reveal the Importance of Precise Subcellular Targeting for Intracellular Eradication.

Intracellular bacterial pathogens, such as , that may hide in intracellular vacuoles represent the most significant manifestation of bacterial persistence. They are critically associated with chronic infections and antibiotic resistance, as conventional antibiotics are ineffective against such intracellular persisters due to permeability issues and mechanistic reasons. Direct subcellular targeting of vacuoles suggests an explicit opportunity for the eradication of these persisters, but a comprehensive understanding of the chemical biology nature and significance of precise vacuole targeting remains limited.

A nanoscale MOF-based heterogeneous catalytic system for the polymerization of N-carboxyanhydrides enables direct routes toward both polypeptides and related hybrid materials.

Synthetic polypeptides have emerged as versatile tools in both materials science and biomedical engineering due to their tunable properties and biodegradability. While the advancements of N-carboxyanhydride (NCA) ring-opening polymerization (ROP) techniques have aimed to expedite polymerization and reduce environment sensitivity, the broader implications of such methods remain underexplored, and the integration of ROP products with other materials remains a challenge. Here, we show an approach inspired by the success of many heterogeneous catalysts, using nanoscale metal-organic frameworks (MOFs) as co-catalysts for NCA-ROP accelerated also by peptide helices in proximity.

Orientation-controlled membrane anchoring of bioorthogonal catalysts on live cells via liposome fusion-based transport.

An obstacle to conducting diverse bioorthogonal reactions in living systems is the sensitivity of artificial metal catalysts. It has been reported that artificial metallocatalysts can be assembled in "cleaner" environments in cells for stabilized performance, which is powerful but is limited by the prerequisite of using specific cells. We report here a strategy to establish membrane-anchored catalysts with precise spatial control via liposome fusion-based transport (MAC-LiFT), loading bioorthogonal catalytic complexes onto either or both sides of the membrane leaflets.

Amphiphilic Nano-Swords for Direct Penetration and Eradication of Pathogenic Bacterial Biofilms.

Bacterial biofilms are major causes of persistent and recurrent infections and implant failures. Biofilms are formable by most clinically important pathogens worldwide, such as , , and , causing recalcitrance to standard antibiotic therapy or anti-biofilm strategies due to amphiphilic impermeable extracellular polymeric substances (EPS) and the presence of resistant and persistent bacteria within the biofilm matrix. Herein, we report our design of an oligoamidine-based amphiphilic "nano-sword" with high structural compacity and rigidity.

Novel Organic Superbase Dopants for Ultraefficient N-Doping of Organic Semiconductors.

Doping is a powerful technique for engineering the electrical properties of organic semiconductors (OSCs), yet efficient n-doping of OSCs remains a central challenge. Herein, the discovery of two organic superbase dopants, namely P2-t-Bu and P4-t-Bu as ultra-efficient n-dopants for OSCs is reported. Typical n-type semiconductors such as N2200 and PC BM are shown to experience a significant increase of conductivity upon doping by the two dopants.

A Membrane-Embedded Macromolecular Catalyst with Substrate Selectivity in Live Cells.

Substrate selectivity is one of the most attractive features of natural enzymes from their "bind-to-catalyze" working flow and is thus a goal for the development of synthetic enzyme mimics that mediate abiotic transformations. However, despite the recent success in the preparation of substrate-selective enzyme mimics based on single-chain nanoparticles, examples extending such selectivity into living systems have been absent. In this article, we report the substrate selectivity of an enzyme-mimicking macromolecular catalyst based on a cationic dense-shell nanoparticle (DSNP) scaffold.

Revealing the Electrophilic-Attack Doping Mechanism for Efficient and Universal p-Doping of Organic Semiconductors.

Doping is of great importance to tailor the electrical properties of semiconductors. However, the present doping methodologies for organic semiconductors (OSCs) are either inefficient or can only apply to some OSCs conditionally, seriously limiting their general applications. Herein, a novel p-doping mechanism is revealed by investigating the interactions between the dopant trityl tetrakis(pentafluorophenyl) borate (TrTPFB) and poly(3-hexylthiophene) (P3HT).

Improving the Hemocompatibility of Antimicrobial Peptidomimetics through Amphiphilicity Masking Using a Secondary Amphiphilic Polymer.

Antimicrobial peptidomimetics (AMPMs) have received widespread attention as potentially powerful weapons against antibiotic resistance. However, AMPMs' membrane disruption mechanism not only brings resistance-resistant nature, but also nonspecific binding and disruption toward eukaryotic cell membranes, and consequently, their hemolytic activity is the primary concern on clinical applications. Here, the preparation and screening of an AMPM library is reported, through which a best-performing hit, PT-b1, can be obtained.

Molecularly pure miktoarm spherical nucleic acids: preparation and usage as a scaffold for abiotic intracellular catalysis.

We present a fullerene-based strategy that allows the synthesis of molecularly pure miktoarm spherical nucleic acids (SNAs) with diverse structures, which, with post-functionalization, could serve as efficient scaffolds for intracellular catalysis. The SNA structure promotes cell permeability, nucleic acid stability, and catalytic efficiency, making the platform ideal for reactions. Consequently, the tris(triazole)-bearing miktoarm SNA was able to effectively mediate intracellular copper-catalyzed alkyne-azide cycloaddition at nanomolar level of copper, and facilitate the same reaction in live zebrafish.

Dendronized Arm Snowflake Polymer as a Highly Branched Scaffold for Cellular Imaging and Delivery.

Incorporation of branched structures is a major pathway to build macromolecules with desired three-dimensional (3D) structures, which are of high importance in the rational design of functional polymeric scaffolds. Dendrimers and hyperbranched polymers have been extensively studied for this purpose, but proper gain-of-function for these structures usually requires large enough molecular weights and a highly branched interior so that a spherical 3D core-shell architecture can be obtained, yet it is generally challenging to achieve precise control over the structure, high molecular weight, and high degree of branching (DoB) simultaneously. In this article, we present a set of snowflake-shaped star polymers with functional cores and dendronized arms, which ensure a high DoB and an overall globular conformation, thus facilitating the introduction of functional moieties onto the easily achieved scaffold without the need for high-generation dendrons.

An alternatingly amphiphilic, resistance-resistant antimicrobial oligoguanidine with dual mechanisms of action.

The increasing number of infections caused by multi-drug resistance (MDR) bacteria is an omen of a new global challenge. As one of the countermeasures under development, antimicrobial peptides (AMPs) and AMP mimics have emerged as a new family of antimicrobial agents with high potential, due to their low resistance generation rate and effectiveness against MDR bacterial strains resulted from their membrane-disrupting mechanism of action. However, most reported AMPs and AMP mimics have facially amphiphilic structures, which may lead to undesired self-aggregation and non-specific binding, as well as increased cytotoxicity toward mammalian cells, all of which put significant limits on their applications.

Design and Engineering of Metal Catalysts for Bio-orthogonal Catalysis in Living Systems.

In the past two decades, bio-orthogonal transformations mediated by biocompatible metal catalysts in living systems have shown enormous potential in both synthetic biology and medicinal chemistry. These metal-mediated bio-orthogonal reactions, many of which could not be accomplished by natural enzymes, have created more possibilities in organic chemistry and biological sciences. Despite all of the challenges for making those abiotic catalysts work in complicated biological environments, many catalytic systems working in living systems have been reported, mediating different transformations such as uncaging of fluorescent probes, pro-drug activation, glycan or protein activation, labeling of proteins or cell surfaces, and drug synthesis.

Independent control over size, valence, and elemental composition in the synthesis of DNA-nanoparticle conjugates.

DNA-nanoparticle conjugates have found widespread use in sensing, imaging, and as components of devices. However, their synthesis remains relatively complicated and empirically based, often requiring specialized protocols for conjugates of different size, valence, and elemental composition. Here we report a novel, bottom-up approach for the synthesis of DNA-nanoparticle conjugates, based on ring-opening metathesis polymerization (ROMP), intramolecular crosslinking, and template synthesis.

Water-Soluble, Zwitterionic Poly-photosensitizers as Carrier-Free, Photosensitizer-Self-Delivery System for in Vivo Photodynamic Therapy.

Polymeric nanoparticles (NPs) have been widely established to deliver most of the hydrophobic chemo-drugs or photosensitizers (PSs) for cancer therapy. However, this strategy is usually hindered by the relatively low drug loading capacity and the undesired toxicity as well as the immunogenicity caused by the nontherapeutic, polymeric carriers. The carrier-free, drug self-delivery systems, in which the chemo-drugs or their prodrugs themselves formed the NPs without the addition of nontherapeutic carriers, have been extensively developed to achieve a high drug loading capacity and low systemic toxicity.

Poly(photosensitizer) Nanoparticles for Enhanced in Vivo Photodynamic Therapy by Interrupting the π-π Stacking and Extending Circulation Time.

The natural planar and rigid structures of most of the hydrophobic photosensitizers (PSs) [such as tetraphenyl porphyrin (TPP)] significantly reduce their loading efficiencies in polymeric nanoparticles (NPs) because of the strong π-π interaction-induced aggregation. This aggregation-caused quenching will further reduce the quantum yield of singlet oxygen (O) generation and weaken the efficiency of photodynamic therapy (PDT). In addition, the small molecular PSs exhibit short tumor retention time and tend to be easily cleared once released.

Functionalizable, Side Chain-Immolative Poly(benzyl ether)s.

Herein, we report a poly(benzyl ether)-based self-immolative polymer (SIP) with pendant pyridine disulfide groups. Cleavage of the side-chain disulfides leads to the formation of phenolates, which initiate depolymerization from the side chain. Due to the higher density of the disulfide groups compared to that of the chain-end-capping group, which normally is responsible for initiating depolymerization of SIPs, the side chain-immolative polymer (ScIP) can be readily degraded in the solid state where the mobility of polymer chains is substantially limited.

Intrinsically cell-penetrating multivalent and multitargeting ligands for myotonic dystrophy type 1.

Developing highly active, multivalent ligands as therapeutic agents is challenging because of delivery issues, limited cell permeability, and toxicity. Here, we report intrinsically cell-penetrating multivalent ligands that target the trinucleotide repeat DNA and RNA in myotonic dystrophy type 1 (DM1), interrupting the disease progression in two ways. The oligomeric ligands are designed based on the repetitive structure of the target with recognition moieties alternating with bisamidinium groove binders to provide an amphiphilic and polycationic structure, mimicking cell-penetrating peptides.

Enzyme-like Click Catalysis by a Copper-Containing Single-Chain Nanoparticle.

A major challenge in performing reactions in biological systems is the requirement for low substrate concentrations, often in the micromolar range. We report that copper cross-linked single-chain nanoparticles (SCNPs) are able to significantly increase the efficiency of copper(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reactions at low substrate concentration in aqueous buffer by promoting substrate binding. Using a fluorogenic click reaction and dye uptake experiments, a structure-activity study is performed with SCNPs of different size and copper content and substrates of varying charge and hydrophobicity.

Designed transition metal catalysts for intracellular organic synthesis.

The development of synthetic, metal-based catalysts to perform intracellular bioorthogonal reactions represents a relatively new and important area of research that combines transition metal catalysis and chemical biology. The ability to perform reactions in cellulo, especially those transformations without a natural counterpart, offers a versatile tool for medicinal chemists and chemical biologists. With proper modification of the metal catalysts, it is even possible to direct a reaction to certain intracellular sites.

Bottom-Up Strategy To Prepare Nanoparticles with a Single DNA Strand.

We describe the preparation of cross-linked, polymeric organic nanoparticles (ONPs) with a single, covalently linked DNA strand. The structure and functionalities of the ONPs are controlled by the synthesis of their parent linear block copolymers that provide monovalency, fluorescence and narrow size distribution. The ONP can also guide the deposition of chloroaurate ions allowing gold nanoparticles (AuNPs) to be prepared using the ONPs as templates.