Diselenide-triggered hydroxyethyl starch conjugate nanoparticles with cascade drug release properties for potentiating chemo-photodynamic therapy

Dextran-based nanodrugs with mitochondrial targeting/glutathione depleting synergy for enhanced photodynamic therapy

The efficacy of photodynamic therapy (PDT) for malignant tumors is significantly impeded by the short diffusion distance of reactive oxygen species (ROS) and the ROS-consuming glutathione (GSH) overexpressed in tumor cells. Therefore, enhanced PDT can be achieved by the construction of biomacromolecule-based nanodrugs that can specifically target ROS-sensitive mitochondria and deplete intracellular GSH. Herein, we synthesized the dextran-based nano-assemblies by a Graft copolymerization Induced Self-Assembly (GISA) method, in which methyl acrylate and diallyl disulfide (DADS) were copolymerized from a mixed dextran/amino dextran backbone in an aqueous medium. Notably, the disulfide bond-containing DADS served as both GSH-depleting agent and GSH-responsive crosslinker. In order to develop a nanodrug with mitochondrial targeting/GSH depleting synergy, we further conjugated a mitochondria-targeting ligand onto the amino dextran corona, and developed a "loading-post-assembly" strategy to load a hydrophobic photosensitizer protoporphyrin IX or even multi-drugs into the hydrophobic core of the nano-assemblies. Cell and animal studies illustrated that the nanodrug could accumulate in the mitochondria of tumor cells to generate ROS in situ and thus eliminate tumors. Taken together, our work presents the dextran-based nanodrug as an efficient platform to achieve mitochondria-targeting PDT with an enhanced efficiency by simultaneously depleting intracellular GSH.

Recent advances in reactive oxygen species (ROS)-responsive drug delivery systems for photodynamic therapy of cancer

Reactive oxygen species (ROS)-responsive drug delivery systems (DDSs) have garnered significant attention in cancer research because of their potential for precise spatiotemporal drug release tailored to high ROS levels within tumors. Despite the challenges posed by ROS distribution heterogeneity and endogenous supply constraints, this review highlights the strategic alliance of ROS-responsive DDSs with photodynamic therapy (PDT), enabling selective drug delivery and leveraging PDT-induced ROS for enhanced therapeutic efficacy. This review delves into the biological importance of ROS in cancer progression and treatment. We elucidate in detail the operational mechanisms of ROS-responsive linkers, including thioether, thioketal, selenide, diselencide, telluride and aryl boronic acids/esters, as well as the latest developments in ROS-responsive nanomedicines that integrate with PDT strategies. These insights are intended to inspire the design of innovative ROS-responsive nanocarriers for enhanced cancer PDT.

Reactive oxygen species responsive chitooligosaccharides based nanoplatform for sonodynamic therapy in mammary cancer

Sonodynamic therapy (SDT) has been extensively studied as a new type of non-invasive treatment for mammary cancer. However, the poor water solubility and defective biocompatibility of sonosensitizers during SDT hinder the sonodynamic efficacy. Herein, a nanoplatform has been developed to achieve high efficient SDT against mammary cancer through the host-guest interaction of β-cyclodextrin/5-(4-hydroxyphenyl)-10,15,20-triphenylporphyrin (β-CD-TPP) and ferrocenecarboxylic acid/chitooligosaccharides (FC-COS). Moreover, the glucose oxidase (GOx) was loaded through electrostatic adsorption, which efficiently restricts the energy supply in tumor tissues, thus enhancing the therapeutic efficacy of SDT for tumors. Under optimal conditions, the entire system exhibited favorable water solubility, suitable particle size and viable biocompatibility. This facilitated the integration of the characteristics of starvation therapy and sonodynamic therapy, resulting in efficient inhibition of tumor growth with minimal side effects in vivo. This work may provide new insights into the application of natural oligosaccharides for construct multifunctional nanocarrier systems, which could optimize the design and development of sonodynamic therapy strategies and even combination therapy strategies.

Nanomedicines with Versatile GSH-Responsive Linkers for Cancer Theranostics

Glutathione (GSH)-responsive nanomedicines have generated significant interest in biochemistry, oncology, and material sciences due to their diverse applications, including chemical and biological sensors, diagnostics, and drug delivery systems. The effectiveness of these smart GSH-responsive nanomedicines depends critically on the choice of GSH-responsive linkers. Despite their crucial role, comprehensive reviews of GSH-responsive linkers are scarce, revealing a gap in the current literature. This review addresses this gap by systematically summarizing various GSH-responsive linkers and exploring their potential applications in cancer treatment. We provide an overview of the mechanisms of action of these linkers and their bioapplications, evaluating their advantages and limitations. The insights presented aim to guide the development of advanced GSH-responsive agents for cancer diagnosis and therapy.

Stabilized, ROS-sensitive β-cyclodextrin-grafted hyaluronic supramolecular nanocontainers for CD44-targeted anticancer drug delivery

Hyaluronic acid (HA)-based tumor microenvironment-responsive nanocontainers are attractive candidates for anticancer drug delivery due to HA's excellent biocompatibility, biodegradability, and CD44-targeting properties. Nevertheless, the consecutive synthesis of stabilized, stealthy, responsive HA-based multicomponent nanomedicines generally requires multi-step preparation and purification procedures, leading to batch-to-batch variation and scale-up difficulties. To develop a facile yet robust strategy for promoted translations, a silica monomer containing a cross-linkable diethoxysilyl unit was prepared to enable in situ crosslinking without any additives. Further combined with the host-guest inclusion complexation between β-cyclodextrin-grafted HA (HA-CD) and ferrocene-functionalized polymers, ferrocene-terminated poly(oligo(ethylene glycol) methyl ether methacrylate (Fc-POEGMA) and Fc-terminated poly(ε-caprolactone)-b-poly(3-(diethoxymethylsilyl)propyl(2-(methacryloyloxy)ethyl) carbamate) (Fc-PCL-b-PDESPMA), a reactive oxygen species (ROS)-sensitive supramolecular polymer construct, Fc-POEGMA/Fc-PCL-b-PDESPMA@HA-CD was readily fabricated to integrate stealthy POEGMA, tumor active targeting HA, and an in situ cross-linkable PDESPMA sequence. Supramolecular amphiphilic copolymers with two different POEGMA contents of 25 wt% (P1) and 20 wt% (P2) were prepared via a simple physical mixing process, affording two core-crosslinked (CCL) micelles via an in situ sol-gel process of ethoxysilyl groups. The P1-based CCL micelles show not only desired colloidal stability against high dilution, but also an intracellular ROS-mimicking environment-induced particulate aggregation that is beneficial for promoted intracellular release of the loaded cargoes. Most importantly, P1-based nanomedicines exhibited greater cytotoxicity in CD44 receptor-positive HeLa cells than that in CD44 receptor-negative MCF-7 cells. Overall, this work developed HA-based nanomedicines with sufficient extracellular colloidal stability and efficient intracellular destabilization properties for enhanced anticancer drug delivery via smart integration of in situ crosslinking and supramolecular complexation.

Design of pH/Redox Co-Triggered Degradable Diselenide-Containing Polyprodrug via a Facile One-Pot Two-Step Approach for Tumor-Specific Chemotherapy

The diselenide bond has attracted intense interest for drug delivery systems (DDSs) for tumor chemotherapy, owing to it possessing higher redox sensitivity than the disulfide one. Various redox-responsive diselenide-containing carriers have been developed for chemotherapeutics delivery. However, the premature drug leakage from these DDSs was significant enough to cause toxic side effects on normal cells. Here, a pH/redox co-triggered degradable polyprodrug was designed as a drug self-delivery system (DSDS) by incorporating drug molecules as structural units in the polymer main chains, using a facile one-pot two-step approach. The proposed PDOX could only degrade and release drugs by breaking both the neighboring acid-labile acylhydrazone and the redox-cleavable diselenide conjugations in the drug's structural units, triggered by the higher acidity and glutathione (GSH) or reactive oxygen species (ROS) levels in the tumor cells. Therefore, a slow solubility-controlled drug release was achieved for tumor-specific chemotherapy, indicating promising potential as a safe and efficient long-acting DSDS for future tumor treatment.

ROS-responsive and triple-synergistic mitochondria-targeted polymer micelles for efficient induction of ICD in tumor therapeutics

Immunogenic cell death (ICD) represents a modality of apoptosis distinguished by the emanation of an array of damage-related molecular signals. This mechanism introduces a novel concept in the field of contemporary tumor immunotherapy. The inception of reactive oxygen species (ROS) within tumor cells stands as the essential prerequisite and foundation for ICD induction. The formulation of highly efficacious photodynamic therapy (PDT) nanomedicines for the successful induction of ICD is an area of significant scientific inquiry. In this work, we devised a ROS-responsive and triple-synergistic mitochondria-targeted polymer micelle (CAT/CPT-TPP/PEG-Ce6, CTC) that operates with multistage amplification of ROS to achieve the potent induction of ICD. Utilizing an "all-in-one" strategy, we direct both the PDT and chemotherapeutic units to the mitochondria. Concurrently, a multistage cyclical amplification that caused by triple synergy strategy stimulates continuous, stable, and adequate ROS generation (domino effect) within the mitochondria of cells. Conclusively, influenced by ROS, tumor cell-induced ICD is effectively activated, remodeling immunogenicity, and enhancing the therapeutic impact of PDT when synergized with chemotherapy. Empirical evidence from in vitro study substantiates that CTC micelles can efficiently provoke ICD, catalyzing CRT translocation, the liberation of HMGB1 and ATP. Furthermore, animal trials corroborate that polymer micelles, following tail vein injection, can induce ICD, accumulate effectively within tumor tissues, and markedly inhibit tumor growth subsequent to laser irradiation. Finally, transcriptome analysis was carried out to evaluate the changes in tumor genome induced by CTC micelles. This work demonstrates a novel strategy to improve combination immunotherapy using nanotechnology.

Intracellular infection-responsive macrophage-targeted nanoparticles for synergistic antibiotic immunotherapy of bacterial infection

Intracellular bacteria are considered to play a key role in the failure of bacterial infection therapy and increase of antibiotic resistance. Nanotechnology-based drug delivery carriers have been receiving increasing attention for improving the intracellular antibacterial activity of antibiotics, but are accompanied by disadvantages such as complex preparation procedures, lack of active targeting, and monotherapy, necessitating further design improvements. Herein, nanoparticles targeting bacteria-infected macrophages are fabricated to eliminate intracellular bacterial infections via antibiotic release and upregulation of intracellular reactive oxygen species (ROS) levels and proinflammatory responses. These nanoparticles were formed through the reaction of the amino group on selenocystamine dihydrochloride and the aldehyde group on oxidized dextran (ox-Dex), which encapsulates vancomycin (Van) through hydrophobic interactions. These nanoparticles could undergo targeted uptake by macrophages via endocytosis and respond to the bacteria-infected intracellular microenvironment (ROS and glutathione (GSH)) for controlled release of antibiotics. Furthermore, these nanoparticles could consume intracellular GSH and promote a significant increase in the level of ROS in macrophages, subsequently up-regulating the proinflammatory response to reinforce antibacterial activity. These nanoparticles can accelerate bacteria-infected wound healing. In this work, nanoparticles were fabricated for bacteria-infected macrophage-targeted and microenvironment-responsive antibiotic delivery, cellular ROS generation, and proinflammatory up-regulation activity to eliminate intracellular bacteria, which opens up a new possibility for multifunctional drug delivery against intracellular infection.

A comprehensive review on singlet oxygen generation in nanomaterials and conjugated polymers for photodynamic therapy in the treatment of cancer

A key role in lessening humanity's continuous fight against cancer could be played by photodynamic therapy (PDT), a minimally invasive treatment employed in the medical care of a range of benign disorders and malignancies. Cancerous tissue can be effectively removed by using a light source-excited photosensitizer. Singlet oxygen and reactive oxygen species are produced via the photosensitizer as a result of this excitation. In the recent past, researchers have put in tremendous efforts towards developing photosensitizer molecules for photodynamic treatment (PDT) to treat cancer. Conjugated polymers, characterized by their efficient fluorescence, exceptional photostability, and strong light absorption, are currently under scrutiny for their potential applications in cancer detection and treatment through photodynamic and photothermal therapy. Researchers are exploring the versatility of these polymers, utilizing sophisticated chemical synthesis and adaptable polymer structures to create new variants with enhanced capabilities for generating singlet oxygen in photodynamic treatment (PDT). The incorporation of photosensitizers into conjugated polymer nanoparticles has proved to be beneficial, as it improves singlet oxygen formation through effective energy transfer. The evolution of nanotechnology has emerged as an alternative avenue for enhancing the performance of current photosensitizers and overcoming significant challenges in cancer PDT. Various materials, including biocompatible metals, polymers, carbon, silicon, and semiconductor-based nanomaterials, have undergone thorough investigation as potential photosensitizers for cancer PDT. This paper outlines the recent advances in singlet oxygen generation by investigators using an array of materials, including graphene quantum dots (GQDs), gold nanoparticles (Au NPs), silver nanoparticles (Ag NPs), titanium dioxide (TiO2), ytterbium (Yb) and thulium (Tm) co-doped upconversion nanoparticle cores (Yb/Tm-co-doped UCNP cores), bismuth oxychloride nanoplates and nanosheets (BiOCl nanoplates and nanosheets), and others. It also stresses the synthesis and application of systems such as amphiphilic block copolymer functionalized with folic acid (FA), polyethylene glycol (PEG), poly(β-benzyl-L-aspartate) (PBLA10) (FA-PEG-PBLA10) functionalized with folic acid, tetra(4-hydroxyphenyl)porphyrin (THPP-(PNIPAM-b-PMAGA)4), pyrazoline-fused axial silicon phthalocyanine (HY-SiPc), phthalocyanines (HY-ZnPcp, HY-ZnPcnp, and HY-SiPc), silver nanoparticles coated with polyaniline (Ag@PANI), doxorubicin (DOX) and infrared (IR)-responsive poly(2-ethyl-2-oxazoline) (PEtOx) (DOX/PEtOx-IR NPs), particularly in NIR imaging-guided photodynamic therapy (fluorescent and photoacoustic). The study puts forward a comprehensive summary and a convincing justification for the usage of the above-mentioned materials in cancer PDT.

In situ injectable thermoresponsive nanocomposite hydrogel based on hydroxypropyl chitosan for precise synergistic calcium-overload, photodynamic and photothermal tumor therapy

Traditional therapies have poor accuracy and significant toxic side effects in the process of tumor treatment. The non-traditional treatment methods with high accuracy and efficacy are worth exploring and investigating. Herein, a strategy that enables precise and synergistic therapies of calcium-overload, photodynamic, and photothermal through facile near infrared (NIR) irradiation was carried out base on the injectable and self-healable hydrogel encapsulating indocyanine green (ICG)-loaded and bovine serum albumin (BSA)-modified calcium peroxide (CaO2) nanoparticles (ICG@CaO2-BSA NPs) and bismuth sulfide (Bi2S3) nanorods. The hydrogel fabricated through the dynamic Schiff-base bonds between hydroxypropyl chitosan (HPCS) and aldehyde-modified Pluronic F127 (F127-CHO) as the delivery substrate for functional substances could adhere and grip tumor tissues due to the adhesion of hydroxyl groups in HPCS and the hydrophobic aggregation caused by thermoresponsiveness of F127-CHO. CaO2 in ICG@CaO2-BSA NPs decomposed in the tumor micro-acidic environment to produce calcium ions (Ca2+) and hydrogen peroxide (H2O2), while ICG generated reactive oxygen species (ROS) under NIR irradiation, the photothermal effect of Bi2S3 nanorods and ICG under NIR irradiation could increase the temperature of tumor tissues and ultimately achieve precise tumor cell destruction. Therefore, this strategy will provide promising prospects for precise and efficient treatment of tumors.

Preparation and evaluation of oxidized-dextran based on antibacterial hydrogel for synergistic photodynamic therapy

Skin trauma is a widespread, extremely susceptible health issue that affects people all over the world. In this study, an innovative antibacterial hydrogel (ODAA hydrogel) with photosensitizer and antibiotics was developed. Oxidized dextran (ODEX) was used as a carrier to prepare a pH-responsive hydrogel by loading the antibiotic amikacin (AMK) and the photosensitizer hexyl 5-aminolevulinate (HAL) via imine bonds. The ODAA hydrogel has a uniformly distributed cavity structure. The cumulative release rates of HAL and AMK in a simulated inflammatory environment at pH 5.0 were approximately 62.3 % and 71.9 % during 15 days. These results demonstrate the ODAA hydrogel's ability to deliver antibiotics on demand, where the antibiotic content is reduced within the effective range. Regarding the in vitro antibacterial behavior, the combination of HAL and AMK synergistically destroyed the majority of Gram-positive and Gram-negative bacteria through several pathways with broad-spectrum antibacterial effects. ODAA hydrogel has been shown to be biocompatible, nearly non-cytotoxic, and capable of promoting wound healing. It is anticipated that the simultaneous targeted delivery of multiple drugs to lesions in the same carrier at ideal dose ratios for particular therapeutic combinations will produce the most synergistic effects.

Nanomaterial surface modification toolkit: Principles, components, recipes, and applications

Surface-functionalized nanostructures are at the forefront of biotechnology, providing new opportunities for biosensors, drug delivery, therapy, and bioimaging applications. The modification of nanostructures significantly impacts the performance and success of various applications by enabling selective and precise targeting. This review elucidates widely practiced surface modification strategies, including click chemistry, cross-coupling, silanization, aldehyde linkers, active ester chemistry, maleimide chemistry, epoxy linkers, and other protein and DNA-based methodologies. We also delve into the application-focused landscape of the nano-bio interface, emphasizing four key domains: therapeutics, biosensing, environmental monitoring, and point-of-care technologies, by highlighting prominent studies. The insights presented herein pave the way for further innovations at the intersection of nanotechnology and biotechnology, providing a useful handbook for beginners and professionals. The review draws on various sources, including the latest research articles (2018-2023), to provide a comprehensive overview of the field.