Intracellular Hyperbranched Polymerization for Circumventing Cancer Drug Resistance

Biomimetic Parallel Vein-like Two-Dimensional Supramolecular Layers Containing Embedded One-Dimensional Conduits Driven by Cation-π Interaction and Hydrogen Bonding to Promote Photocatalytic Hydrogen Evolution

Two-dimensional supramolecular assemblies (2DSAs) with well-defined nanostructures have emerged as promising candidates for diverse applications, particularly in photocatalysis. However, it still remains a significant challenge to simultaneously achieve effective electron transport and multiple active sites in 2DSA, even though this is crucial for enhancing photocatalytic performance. This reason can be attributed to the lack of a suitable structural paradigm that enables both effective intermolecular orbital overlap and increased substrate contact. Inspired by the parallel venation of monocotyledons that can facilitate substrate transfer, we overcome the limitation, in this study, by integrating parallel-arranged one-dimensional (1D) conduits with edge-on packing motifs to construct biomimetic, parallel vein-like two-dimensional supramolecular layers (PV-2DSLs) through the hierarchical self-assembly of cationically modified, rigid multiarmed monomers. The resulting PV-2DSLs exhibit a long-range aromatic cation-π stacking that can facilitate electron transport. Importantly, the unique structural feature of these PV-2DSLs is the orderly and parallel embedding of 1D conduits within the 2D plane, which is significantly different from the conventional channels formed by the vertical stacking of 2D porous materials. These conduits promote multielectron transfer pathways, leading to enhanced charge separation and carrier transport when coupled with long-range aromatic cation-π stacking. As a consequence, these PV-2DSLs exhibit long excited state lifetime, leading to significantly improved hydrogen production rates up to 3.5 mmol g-1 h-1, which is approximately 17.5 times higher than that of the counterpart without 1D conduits (0.2 mmol g-1 h-1).

Tumor Microenvironment-Responsive Polymer Delivery Platforms for Cancer Therapy

Most chemotherapeutic and bioimaging agents struggle with inadequate bioavailability, primarily due to their limited biocompatibility and lack of specificity in targeting, leading to low or decreased anticancer efficacy and inaccurate imaging. To surmount these obstacles, the development of stimuli-responsive polymer delivery platforms, predominantly leveraging the tumor microenvironment (TME), has emerged as a promising strategy. Therapeutic and diagnostic agents can be released controllably at the tumor site by virtue of the bond cleavage or hydrophobic to hydrophilic transformation of TME-sensitive linkages in TME-responsive systems, thus augmenting cancer treatment and imaging precision, while simultaneously attenuating the damage to healthy tissues and false imaging signals caused by non-specific drug leakage. In this comprehensive review, we scrutinize recent studies of TME-responsive polymer delivery platforms, encompassing pH-, ROS-, GSH-, enzyme-, and hypoxia-responsive vectors, significantly from the perspective of their molecular design and responsive mechanism, and further summarizing their bio-application in drug delivery and diagnostic imaging. Moreover, this review encapsulates the critical challenges and offers an insightful perspective on the future prospects of TME-responsive polymer delivery platforms in terms of molecular and vector design.

Functional Heteroatom Substituted Hyperbranched Polymers: Recent Developments and Perspectives

Heteroatom-substituted hyperbranched polymers (HBPs) have emerged as a versatile class of functional materials, combining the structural merits of hyperbranched architectures with the unique chemical functionalities imparted by heteroatoms such as boron, silicon, phosphorus, sulfur, selenium, and tellurium. These polymers exhibit distinct physicochemical properties, including low viscosity, excellent solubility, high chemical reactivity, and tunable functionality, which position them as promising candidates for diverse applications. This Review highlights the recent advances in heteroatom substituted HBPs, categorizing them from the element group of their heteroatoms (from Group III to Group VI, as well as transition and rare-earth metals). The pivotal role of heteroatoms in modulating polymer properties is explored, with key applications highlighted across four principal domains: fluorescent materials, flame retardants, stimuli-responsive polymers, and polymer modifications. By integrating insights from chemistry, materials science, and interdisciplinary research, this Review underscores the potential of heteroatom-substituted HBPs in addressing current material challenges.

Polymerization in Living Organisms for Biomedical Applications

Intra-tissue polymerization as a kind of polymerization reaction in biological tissues has the advantages of good biocompatibility, accurate localization, and dynamic response. In this review, the progress and applications of intra-tissue polymerization technologies in biomedicine are summarized. The biomedical applications of polymerization in different tissues are discussed, including living neural tissues to improve neural device performance, preparation of electronic devices in plants and animals, polymerization in tumor tissues for therapeutic and monitoring purposes, and polymerization in skin tissues for wound monitoring and therapy. Various polymerization strategies, including electrochemical polymerization, enzymatic polymerization, photopolymerization, and free radical polymerization, are used and described in the different intra-tissue polymerization methods. Moreover, the challenges in this field are discussed, such as the precise control of polymerization reactions and the development of biocompatible materials, and the future development direction of this field is also prospected.

Living Cell-Mediated Self-Assembly: From Monomer Design and Morphology Regulation to Biomedical Applications

The self-assembly of molecules into highly ordered architectures is a ubiquitous and natural process, wherein molecules spontaneously organize into large structures to perform diverse functions. Drawing inspiration from the formation of natural nanostructures, cell-mediated self-assembly has been developed to create functional assemblies both inside and outside living cells. These techniques have been employed to regulate the cellular world by leveraging the dynamic intracellular and extracellular microenvironment. This review highlights the recent advances and future trends in living cell-mediated self-assembly, ranging from their cytocompatible monomer designs, synthetic strategies, and morphological control to functional applications. The assembly behaviors are also discussed based on the dimensionality of the self-assembled morphologies from zero to three dimensions. Finally, this review explores its promising potential for biomedical applications, clarifying the relationship between initial morphological regulation and the therapeutic effects of subsequent artificial assemblies. Through rationally designing molecular structures and precisely controlling assembly morphologies, living cell mediated self-assembly would provide an innovative platform for executing biological functions.

K+-Responsive Nanoparticles with Charge Reversal and Gating Synergistic Effects for Targeted Intracellular Bacteria Eradication

Intracellular bacteria can evade the attack of the immune system and the bactericidal effects of most antibiotics due to the protective effect of the host cells. Herein, inspired by the stimuli-responsive behaviors of biological ion channels, a kind of synergistic cascade potassium ion (K+)-responsive nanoparticles gated with K+-responsive polymers is ingeniously designed to target intracellular bacteria and then control drug release. Due to the cooperative interaction of host-guest complexation and conformational transition of K+-responsive polymers, the grafted gates based on these polymers could recognize high K+ concentration to reverse the negatively charged nanoparticles into positively charged ones for targeting bacteria and subsequently inducing a switch from the hydrophobic shrinking "off" state to the hydrophilic stretching "on" state for drug release. The K+-responsive nanoparticles can effectively load antibiotics and be endocytosed into the infected cells, and K+-responsive gates can be actuated by a high intracellular K+ concentration. With the efficient synergistic cascade strategy, these K+-responsive nanocarriers can deliver antibiotics to the subcellular region where intracellular bacteria reside and show superior elimination efficiencies in vitro and in vivo than the free drug in delivering vancomycin. The K+-responsive nanocarriers are expected to improve the bioavailability of drugs and enhance their antibacterial efficacy.

Assembly Regulates Gamma Radiation Polymerization of Polytelluoxane

Regulating chemical drug's responsiveness to gamma radiation is crucial for achieving better therapeutic effects in cancer treatment. Most research focused on thermodynamic chemical structure design, while little attention was paid to kinetic regulate strategy, which possesses greater universality and security. In this study, we achieved a kinetic-based regulate strategy of gamma radiation reaction, through the construction of microphase environment during polymerization of polytelluoxane (PTeO). We designed hydrophobic segments forming large compound micelles (LCMs) assembly to create kinetically favorable higher concentration for radiation-induced reaction. It exhibited a > ten times higher responsiveness and, as far as we know, merely required a minimum dosage of 5 Gy for polymerization to occur. What's more, by taking advantages of the assembly change with Te-O hydrophilic segments and gamma radiation, polymerization became milder with lower polydispersity than previous methods. Such kinetic-based regulate strategy could offer a novel perspective on the design of radiation-responsive chemoradiotherapy and other radiation-induced chemical process.

Crosstalk between ROS-inflammatory gene expression axis in the progression of lung disorders

A significant number of deaths and disabilities worldwide are brought on by inflammatory lung diseases. Many inflammatory lung disorders, including chronic respiratory emphysema, resistant asthma, resistance to steroids, and coronavirus-infected lung infections, have severe variants for which there are no viable treatments; as a result, new treatment alternatives are needed. Here, we emphasize how oxidative imbalance contributes to the emergence of provocative lung problems that are challenging to treat. Endogenic antioxidant systems are not enough to avert free radical-mediated damage due to the induced overproduction of ROS. Pro-inflammatory mediators are then produced due to intracellular signaling events, which can harm the tissue and worsen the inflammatory response. Overproduction of ROS causes oxidative stress, which causes lung damage and various disease conditions. Invasive microorganisms or hazardous substances that are inhaled repeatedly can cause an excessive amount of ROS to be produced. By starting signal transduction pathways, increased ROS generation during inflammation may cause recurrent DNA damage and apoptosis and activate proto-oncogenes. This review provides information about new targets for conducting research in related domains or target factors to prevent, control, or treat such inflammatory oxidative stress-induced inflammatory lung disorders.

Catalytic Biomaterials-Activated In Situ Chemical Reactions: Strategic Modulation and Enhanced Disease Treatment

Chemical reactions underpin biological processes, and imbalances in critical biochemical pathways within organisms can lead to the onset of severe diseases. Within this context, the emerging field of "Nanocatalytic Medicine" leverages nanomaterials as catalysts to modulate fundamental chemical reactions specific to the microenvironments of diseases. This approach is designed to facilitate the targeted synthesis and localized accumulation of therapeutic agents, thus enhancing treatment efficacy and precision while simultaneously reducing systemic side effects. The effectiveness of these nanocatalytic strategies critically hinges on a profound understanding of chemical kinetics and the intricate interplay of reactions within particular pathological microenvironments to ensure targeted and effective catalytic actions. This review methodically explores in situ catalytic reactions and their associated biomaterials, emphasizing regulatory strategies that control therapeutic responses. Furthermore, the discussion encapsulates the crucial elements-reactants, catalysts, and reaction conditions/environments-necessary for optimizing the thermodynamics and kinetics of these reactions, while rigorously addressing both the biochemical and biophysical dimensions of the disease microenvironments to enhance therapeutic outcomes. It seeks to clarify the mechanisms underpinning catalytic biomaterials and evaluate their potential to revolutionize treatment strategies across various pathological conditions.

Tumor microenvironment-responsive hyperbranched polymers for controlled drug delivery

Hyperbranched polymers (HBPs) have drawn great interest in the biomedical field on account of their special morphology, low viscosity, self-regulation, and facile preparation methods. Moreover, their large intramolecular cavities, high biocompatibility, biodegradability, and targeting properties render them very suitable for anti-tumor drug delivery. Recently, exploiting the specific characteristics of the tumor microenvironment, a range of multifunctional HBPs responsive to the tumor microenvironment have emerged. By further introducing various types of drugs through physical embedding or chemical coupling, the resulting HBPs based delivery systems have played a crucial part in improving drug stability, increasing effective drug concentration, decreasing drug toxicity and side effects, and enhancing anti-tumor effect. Here, based on different types of tumor microenvironment stimulation signals such as pH, redox, temperature, etc., we systematically review the preparation and response mechanism of HBPs, summarize the latest advances in drug delivery applications, and analyze the challenges and future research directions for such nanomaterials in biomedical clinical applications.

Precise Regulations at the Subcellular Level through Intracellular Polymerization, Assembly, and Transformation

A living cell is an intricate machine that creates subregions to operate cell functions effectively. Subcellular dysfunction has been identified as a potential druggable target for successful drug design and therapy. The treatments based on intracellular polymerization, self-assembly, or transformation offer various advantages, including enhanced blood circulation of monomers, long-term drug delivery pharmacokinetics, low drug resistance, and the ability to target deep tissues and organelles. In this review, we discuss the latest developments of intracellular synthesis applied to precisely control cellular functions. First, we discuss the design and applications of endogenous and exogenous stimuli-triggered intracellular polymerization, self-assembly, and dynamic morphology transformation of biomolecules at the subcellular level. Second, we highlight the benefits of these strategies applied in cancer diagnosis and treatment and modulating cellular states or cell metabolism of living systems. Finally, we conclude the recent progress in this field, discuss future perspectives, analyze the challenges of the intracellular functional reactions for regulation, and find future opportunities.

Artificial Polymerizations in Living Organisms for Biomedical Applications

Within living organisms, numerous nanomachines are constantly involved in complex polymerization processes, generating a diverse array of biomacromolecules for maintaining biological activities. Transporting artificial polymerizations from lab settings into biological contexts has expanded opportunities for understanding and managing biological events, creating novel cellular compartments, and introducing new functionalities. This review summarizes the recent advancements in artificial polymerizations, including those responding to external stimuli, internal environmental factors, and those that polymerize spontaneously. More importantly, the cutting-edge biomedical application scenarios of artificial polymerization, notably in safeguarding cells, modulating biological events, improving diagnostic performance, and facilitating therapeutic efficacy are highlighted. Finally, this review outlines the key challenges and technological obstacles that remain for polymerizations in biological organisms, as well as offers insights into potential directions for advancing their practical applications and clinical trials.

Enzyme-instructed intramitochondrial polymerization for enhanced anticancer treatment without the development of drug-resistance

Intracellular polymerization in living cells motivated chemists to generate polymeric structures with a multitude of possibilities to interact with biomacromolecules. However, out-of-control of the intracellular chemical reactions would be an obstacle restricting its application, providing the toxicity of non-targeted cells. Here, we reported intracellular thioesterase-mediated polymerization for selectively occurring polymerization using disulfide bonds in cancer cells. The acetylated monomers did not form disulfide bonds even under an oxidative environment, but they could polymerize into the polymeric structure after cleavage of acetyl groups only when encountered activity of thioesterase enzyme. Furthermore, acetylated monomers could be self-assembled with doxorubicin, providing doxorubicin loaded micelles for efficient intracellular delivery of drug and monomers. Since thioesterase enzymes were overexpressed in cancer cells specifically, the micelles were disrupted under activity of the enzyme and the polymerization could occur selectively in the cancer mitochondria. The resulting polymeric structures disrupted the mitochondrial membrane, thus activating the cellular death of cancer cells with high selectivity. This strategy selectively targets diverse cancer cells involving drug-resistant cells over normal cells. Moreover, the mitochondria targeting strategy overcomes the development of drug resistance even with repeated treatment. This approach provides a way for selective intracellular polymerization with desirable anticancer treatment.

Light-mediated intracellular polymerization

The synthesis of synthetic intracellular polymers offers groundbreaking possibilities in cellular biology and medical research, allowing for novel experiments in drug delivery, bioimaging and targeted cancer therapies. These macromolecules, composed of biocompatible monomers, are pivotal in manipulating cellular functions and pathways due to their bioavailability, cytocompatibility and distinct chemical properties. This protocol details two innovative methods for intracellular polymerization. The first one uses 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone (Irgacure 2959) as a photoinitiator for free radical polymerization under UV light (365 nm, 5 mW/cm2). The second method employs photoinduced electron transfer-reversible addition-fragmentation chain-transfer polymerization with visible light (470 nm, 100 mW/cm2). We further elaborate on isolating these intracellular polymers by streptavidin/biotin interaction or immobilized metal ion affinity chromatography for polymers tagged with biotin or histidine. The entire process, from polymerization to isolation, takes ~48 h. Moreover, the intracellular polymers thus generated demonstrate significant potential in enhancing actin polymerization, in bioimaging applications and as a novel avenue in cancer treatment strategies. The protocol extends to animal models, providing a comprehensive approach from cellular to systemic applications. Users are advised to have a basic understanding of organic synthesis and cell biology techniques.

Visualizing Chain Growth of Polytelluoxane via Polymerization Induced Emission

Visualizing polymer chain growth is always a hot topic for tailoring structure-function properties in polymer chemistry. However, current characterization methods are limited in their ability to differentiate the degree of polymerization in real-time without isolating the samples from the reaction vessel, let alone to detect insoluble polymers. Herein, a reliable relationship is established between polymer chain growth and fluorescence properties through polymerization induced emission. (TPE-C2)2 -Te is used to realize in situ oxidative polymerization, leading to the aggregation of fluorophores. The relationship between polymerization degree of growing polytelluoxane (PTeO) and fluorescence intensity is constructed, enabling real-time monitoring of the polymerization reaction. More importantly, this novel method can be further applied to the observation of the polymerization process for growing insoluble polymer via surface polymerization. Therefore, the development of visualization technology will open a new avenue for visualizing polymer chain growth in real-time, regardless of polymer solubility.

Hyaluronic acid coated nano-particles for H2O2-elevation augmented photo-/chemodynamic therapy

In recent years, the association of chemodynamic therapy (CDT) with photodynamic therapy (PDT) has attracted much attention due to their mutually reinforced property. Nevertheless, how to further strengthen their performance is still a big challenge. Given the PDT/CDT therapeutic mechanism, the H2O2 amount might affect their final performance. Thus, in this paper, our synthesized pH-responsive Fenton agents (ferrocene-cinnamaldehyde conjugates, Fc-CA) were encapsulated in hyaluronic acid (HA) coated porphyrin-based MOF to obtain supramolecular nano-particles (Fc-CA-PCN-HA). After the CD44-receptor mediated internalization, the released Fc-CA could further dissociate in the acidic pH micro-environment. The released CA can activate the NADPH oxidase to elevate the H2O2 amount which could be preferable to produce more ·OH through Fenton reaction for cancer cells apoptosis. Additionally, O2 was also generated in the CDT which could alleviate tumor hypoxia condition and be provided as the reactant for PDT to produce more 1O2. Thus, given the excellent cascade reactions induced therapeutic performance of Fc-CA-PCN-HA in vitro and in vivo, the H2O2-elevation strategy might further enhance the PDT/CDT outcomes.