Near-infrared light triggered photothermal therapy and enhanced photodynamic therapy with a tumor-targeting hydrogen peroxide shuttle

Probing Short-Range Interactions in Isostructural Hydrate and Perhydrate of Dabrafenib by Magic-Angle Spinning Solid-State NMR

Dabrafenib (DBF), an anticancer drug, exhibits isostructural properties in its hydrate (DBF⊃H2O) and perhydrate (DBF⊃H2O2) forms, as revealed by single-crystal X-ray diffraction. Despite the H2O and H2O2 solvent molecules occupying identical locations, the two polymorphs have different thermal behaviors. In general, determination of stoichiometry of H2O in the perhydrate crystals is difficult due to the presence of both H2O and H2O2 in the same crystal voids. This study utilizes magic-angle spinning (MAS) solid-state NMR (SSNMR) combined with gauge-included projector augmented wave calculations to characterize the influence of solvent molecules on the local environment in pseudopolymorphs. SSNMR experiments were employed to assign 1H, 13C, and 15N peaks and identify spectral differences in the isostructural pseudopolymorphs. Proton spectroscopy at fast MAS was used to identify and quantify H2O2/H2O in DBF⊃H2O2 (mixed hydrate/perhydrate). 1H-1H dipolar-coupling-based experiments were recruited to confirm the 3D molecular packing of solvent molecules in DBF⊃H2O and DBF⊃H2O2. Homonuclear (1H-1H) and heteronuclear (1H-14N) distance measurements, in conjunction with diffraction structures and optimized hydrogen atom positions by density functional theory, helped decipher local interactions of H2O2 with DBF and their geometry in DBF⊃H2O2. This integrated X-ray structure, quantum chemical calculations, and NMR study of pseudopolymorphs offer a practical approach to scrutinizing crystallized solvent interactions in the crystal lattice even without high-resolution crystal structures or artificial sample enrichment.

Polymeric functionalization of mesoporous silica nanoparticles: Biomedical insights

Mesoporous silica nanoparticles (MSNs) endowed with polymer coatings present a versatile platform, offering notable advantages such as targeted, pH-controlled, and stimuli-responsive drug delivery. Surface functionalization, particularly through amine and carboxyl modification, enhances their suitability for polymerization, thereby augmenting their versatility and applicability. This review delves into the diverse therapeutic realms benefiting from polymer-coated MSNs, including photodynamic therapy (PDT), photothermal therapy (PTT), chemotherapy, RNA delivery, wound healing, tissue engineering, food packaging, and neurodegenerative disorder treatment. The multifaceted potential of polymer-coated MSNs underscores their significance as a focal point for future research endeavors and clinical applications. A comprehensive analysis of various polymers and biopolymers, such as polydopamine, chitosan, polyethylene glycol, polycaprolactone, alginate, gelatin, albumin, and others, is conducted to elucidate their advantages, benefits, and utilization across biomedical disciplines. Furthermore, this review extends its scope beyond polymerization and biomedical applications to encompass topics such as surface functionalization, chemical modification of MSNs, recent patents in the MSN domain, and the toxicity associated with MSN polymerization. Additionally, a brief discourse on green polymers is also included in review, highlighting their potential for fostering a sustainable future.

Ultrasound-triggered reactive oxygen species effector nanoamplifier for enhanced combination therapy of mutant p53 tumors

Reactive oxygen species (ROS) damage is a crucial method with which to inhibit tumor cell proliferation; however, tumor cells can reduce ROS damage by modulating multiple repair mechanisms, thus, reducing the efficacy of ROS damage in tumor therapy. In this study, we built an ultrasound-triggered ROS damage nanoamplifier using a synergistic strategy consisting of ROS damage and decreased tumor self-protection capability to enhance the treatment efficacy of mutant p53 tumors. A ROS damage nanoamplifier (PT@PTGA) was fabricated using amphiphilic polyglutamic acid (PTGA) to load with a sonosensitizer (protoporphyrin IX, PpIX) and an MTH1 inhibitor (TH287). Under ultrasonic excitation, PpIX catalyzes oxygen to produce singlet oxygen and release TH287 to inhibit MTH1 activity, thereby causing the accumulation of 8-oxo-dGTP, which enhances DNA damage and further induces cell apoptosis. In addition, TH287 allies with ROS to eliminate the mutated p53 protein in tumor cells, thus reducing the self-protective capacity of tumor cells. As a result, the "internal and external" aspects were combined to enhance sensitization for mutant p53 tumor therapy. The construction of a ROS nanoamplifier not only provides an effective strategy for the treatment of mutant p53 tumors but also supplies an integrated platform for tumor diagnosis and therapy.

PLGA-graphene quantum dot nanocomposites targeted against αvβ3 integrin receptor for sorafenib delivery in angiogenesis

Angiogenesis is a vital step in many severe diseases such as cancer, diabetic retinopathy, and rheumatoid arthritis. Sorafenib (SFB), a multi-tyrosine kinase inhibitor, has recently been shown to inhibit tumor progression and suppress angiogenesis. Its narrow therapeutic window, however, has limited its clinical application and therapeutic efficacy. Accordingly, in this study, a nanocomposite formulation comprising of graphene quantum dots (GQDs) and poly (D, l-lactide-co-glycolide) (PLGA) nanoparticles was functionalized with an integrin-targeting ligand (RGD peptide) to improve SFB delivery for the treatment of angiogenesis. Physicochemical and biological properties of the targeted nanocomposite were evaluated in terms of chemical structure, morphology, particle size, zeta potential, photoluminescence, and cell toxicity. The loading capacity of the nanocomposite was optimized at different drug-to-PLGA ratios. Drug release behavior was also investigated at 37 °C in pH = 7.4. The SFB-to-PLGA ratio of 1:3 was selected as the optimum condition which resulted in the encapsulation efficiency and encapsulation capacity of 68.93 ± 1.39 and 18.77 ± 0.46, respectively. Photoluminescence properties of GQD in nanocomposite were used to track the delivery system. The results indicated that conjugating targeting ligand could enhance cellular uptake of nanocomposite in cells overexpressing integrin receptors. In vivo anti-angiogenesis activity of targeted nanocomposite was investigated in chick chorioallantoic membrane (CAM). The findings showed that SFB loaded in the targeted nanocomposite reduced VEGF secretion in vitro and its anti-angiogenic effect surpass free SFB. Thanks to its unique therapeutic and bioimaging properties, the developed nanocomposite could be an effective drug delivery system for poorly water-soluble therapeutic agents.

Recent advances in in situ oxygen-generating and oxygen-replenishing strategies for hypoxic-enhanced photodynamic therapy

Cancer is a leading cause of death worldwide, accounting for an estimated 10 million deaths by 2020. Over the decades, various strategies for tumor therapy have been developed and evaluated. Photodynamic therapy (PDT) has attracted increasing attention due to its unique characteristics, including low systemic toxicity and minimally invasive nature. Despite the excellent clinical promise of PDT, hypoxia is still the Achilles' heel associated with its oxygen-dependent nature related to increased tumor proliferation, angiogenesis, and distant metastases. Moreover, PDT-mediated oxygen consumption further exacerbates the hypoxia condition, which will eventually lead to the poor effect of drug treatment and resistance and irreversible tumor metastasis, even limiting its effective application in the treatment of hypoxic tumors. Hypoxia, with increased oxygen consumption, may occur in acute and chronic hypoxia conditions in developing tumors. Tumor cells farther away from the capillaries have much lower oxygen levels than cells in adjacent areas. However, it is difficult to change the tumor's deep hypoxia state through different ways to reduce the tumor tissue's oxygen consumption. Therefore, it will become more difficult to cure malignant tumors completely. In recent years, numerous investigations have focused on improving PDT therapy's efficacy by providing molecular oxygen directly or indirectly to tumor tissues. In this review, different molecular oxygen supplementation methods are summarized to alleviate tumor hypoxia from the innovative perspective of using supplemental oxygen. Besides, the existing problems, future prospects and potential challenges of this strategy are also discussed.

Supramolecular micelles as multifunctional theranostic agents for synergistic photodynamic therapy and hypoxia-activated chemotherapy

Photodynamic therapy (PDT), where a photosensitizer (under light irradiation) converts molecular oxygen to singlet oxygen to elicit programmed cell death, is a promising cancer treatment modality with a high temporal and spatial resolution. However, only limited cancer treatment efficacy has been achieved in clinical PDT due to the hypoxic conditions of solid tumor microenvironment that limits the generation of singlet oxygen, and PDT process often leads to even more hypoxic microenvironment due to the consumption of oxygens during therapy. Herein, we designed novel supramolecular micelles to co-deliver photosensitizer and hypoxia-responsive prodrug to improve the overall therapeutic efficacy. The supramolecular micelles (CPC) were derived from a polyethylene glycol (PEG) system dually tagged with hydrophilic cucurbit[7]uril (CB[7]) and hydrophobic Chlorin e6 (Ce6), respectively on each end, for synergistic antitumor therapy via PDT of Ce6 and chemotherapy of a hypoxia-responsive prodrug, banoxantrone (AQ4N), loaded into the cavity of CB[7]. In addition, CPC was further modularly functionalized by folate (FA) via strong host-guest interaction between folate-amantadine (FA-ADA) and CB[7] to produce a novel nanoplatform, AQ4N@CPC-FA, for targeted delivery. AQ4N@CPC-FA exhibited enhanced cellular uptake, negligible cytotoxicity and good biocompatibility, and improved intracellular reactive oxygen species (ROS) generation efficiency. More importantly, in vivo evaluation of AQ4N@CPC-FA revealed a synergistic antitumor efficacy between PDT of Ce6 and hypoxia-activated chemotherapy of AQ4N (that can be converted to chemotherapeutic AQ4 for tumor chemotherapy in response to the strengthened hypoxic tumor microenvironment during PDT treatment). This study not only provides a new nanoplatform for synergistic photodynamic-chemotherapeutic treatment, but also offers important new insights to design and development of multifunctional supramolecular drug delivery system. STATEMENT OF SIGNIFICANCE: Photodynamic therapy (PDT) has exhibited a variety of advantages for cancer phototherapy as compared to traditional chemotherapy. However, the unsatisfactory therapeutic efficacy by PDT alone as a result of the enhanced tumor hypoxia during PDT has limited its clinical application. Herein, we designed multifunctional supramolecular micelles to co-deliver photosensitizer and hypoxia-responsive prodrug to improve the overall therapeutic efficacy. The supramolecular micelles are biocompatible and possess strong red absorption, controlled drug release profile, and ultimately enhanced therapeutic outcome via PDT-chemotherapy. This study not only provides a new nanoplatform for synergistic photodynamic-chemotherapeutic treatment of cancer, but also offers important new insights to design and development of multifunctional supramolecular drug delivery tool for multi-modality cancer therapy.

Application of Nano-Drug Delivery System Based on Cascade Technology in Cancer Treatment

In the current cancer treatment, various combination therapies have been widely used, such as photodynamic therapy (PDT) combined with chemokinetic therapy (CDT). However, due to the complexity of the tumor microenvironment (TME) and the limitations of treatment, the efficacy of current treatment options for some cancers is unsatisfactory. Nowadays, cascade technology has been used in cancer treatment and achieved good therapeutic effect. Cascade technology based on nanotechnology can trigger cascade reactions under specific tumor conditions to achieve precise positioning and controlled release, or amplify the efficacy of each drug to improve anticancer efficacy and reduce side effects. Compared with the traditional treatment, the application of cascade technology has achieved the controllability, specificity, and effectiveness of cancer treatment. This paper reviews the application of cascade technology in drug delivery, targeting, and release via nano-drug delivery systems in recent years, and introduces their application in reactive oxygen species (ROS)-induced cancer treatment. Finally, we briefly describe the current challenges and prospects of cascade technology in cancer treatment in the future.

IR780-based nanomaterials for cancer imaging and therapy

IR780, a small molecule with a strong optical property and excellent photoconversion efficiency following near infrared (NIR) irradiation, has attracted increasing attention in the field of cancer treatment and imaging. This review is focused on different IR780-based nanoplatforms and the application of IR780-based nanomaterials for cancer bioimaging and therapy. Thus, this review summarizes the overall aspects of IR780-based nanomaterials that positively impact cancer biomedical applications.

Tumor Microenvironment Targeting Nano-Bio Emulsion for Synergistic Combinational X-Ray PDT with Oncolytic Bacteria Therapy

Various cancer therapies have been developed, but tumor recurrence with incomplete tumor killing and remaining tumor cells/tissues is frequent in monotherapies. Herein, a nano-bio therapeutic emulsion formulated with multifunctional nanoscintillators and anaerobic Clostridium novyi-NT spores for synergistic image-guided combinational cancer therapy is reported. MRI visible nanoscintillators (NSs) are synthesized with a NaGdF4 :Tb,Ce@NaGdF4 core/shell structure for an image-guided X-ray photodynamic therapy (PDT) of the normoxic peripheral tumor. An anaerobic oncolytic bacterium (C. novyi-NT) therapy is combined to treat the hypoxic central tumor tissues. Photosensitizer-coated NSs (PS-NSs) and C. novyi-NT spores are emulsified with clinically available ethiodized oil (Lipiodol) to be the nano-bio therapeutic emulsion and injected into the tumor with computed tomography image guidance. The distribution of nano-bio therapeutic emulsion, including PS-NSs and anaerobic C. novyi-NT spores in the tumor site, is confirmed by both X-ray and T1 -weighted magnetic resonance imaging. Following the image-guided X-ray PDT and anaerobic C. novyi- NT combination treatment, apoptotic cell death in cancer tissues, including both peripheral and central tumor regions, is significantly higher than in the control groups. This combination therapy approach using a nano-bio therapeutic emulsion is expected to overcome the limitations of conventional cancer therapy, resulting in increased cancer-therapeutic efficacy.

Versatile Nanoplatforms with enhanced Photodynamic Therapy: Designs and Applications

As an emerging antitumor strategy, photodynamic therapy (PDT) has attracted intensive attention for the treatment of various malignant tumors owing to its noninvasive nature and high spatial selectivity in recent years. However, the therapeutic effect is unsatisfactory on some occasions due to the presence of some unfavorable factors including nonspecific accumulation of PS towards malignant tissues, the lack of endogenous oxygen in tumors, as well as the limited light penetration depth, further hampering practical application. To circumvent these limitations and improve real utilization efficiency, various enhanced strategies have been developed and explored during the past years. In this review, we give an overview of the state-of-the-art advances progress on versatile nanoplatforms for enhanced PDT considering the enhancement from targeting or responsive, chemical and physical effect. Specifically, these effects mainly include organelle-targeting function, tumor microenvironment responsive release photosensitizers (PS), self-sufficient O2 (affinity oxygen and generating oxygen), photocatalytic water splitting, X-rays light stimulate, surface plasmon resonance enhancement, and the improvement by resonance energy transfer. When utilizing these strategies to improve the therapeutic effect, the advantages and limitations are addressed. Finally, the challenges and prospective will be discussed and demonstrated for the future development of advanced PDT with enhanced efficacy.

Bioactive silver phosphate/polyindole nanocomposites

Materials capable of releasing reactive oxygen species (ROS) can display antibacterial and anticancer activity, and may also have anti-oxidant capacity if they suppress intracellular ROS (e.g. nitric oxide, NO) resulting in anti-inflammatory activity. Herein we report silver phosphate (Ag₃PO₄)/polyindole (Pln) nanocomposites which display antibacterial, anticancer and anti-inflammatory activity, and have therefore potential for a variety of biomedical applications.

Materials capable of releasing reactive oxygen species (ROS) can display antibacterial and anticancer activity, and may also have antioxidant capacity if they suppress intracellular ROS (e.g. nitric oxide, NO) resulting in anti-inflammatory activity.

Nanoparticle-based drug delivery systems for controllable photodynamic cancer therapy

Compared with the traditional treatment, photodynamic therapy (PDT) in the treatment of malignant tumors has the advantages of less damage to normal tissues, quick therapeutic effect, and ability to repeat treatments to the same site. However, most of the traditional photosensitizers (PSs) have severe skin photosensitization, poor tumor targeting, and low therapeutic effect in hypoxic tumor environment, which limit the application of PDT. Nanoparticle-based drug delivery systems can improve the targeting of PSs and release drugs with controllable photoactivity at predetermined locations, so as to achieve desired therapeutic effects with minimal side-effects. The present review summarizes the current nanoparticle platforms for PDT, and offers the description of different strategies including tumor-targeted delivery, controlled-release of PSs and the triggered photoactivity to achieve controllable PDT by nanoparticle-based drug delivery systems. The challenges and prospects for further development of intelligent PSs for PDT are also discussed.

Nanomedicine-Enabled Modulation of Tumor Hypoxic Microenvironment for Enhanced Cancer Therapy

Hypoxia is a common condition of solid tumors that is mainly caused by enhanced tumor proliferative activity and dysfunctional vasculature. In the treatment of hypoxic human solid tumors, many conventional therapeutic approaches (e.g., oxygen-dependent photodynamic therapy, anticancer drug-based chemotherapy or X-ray induced radiotherapy) become considerably less effective or ineffective. In recent years, various strategies have been explored to deliver or generate oxygen inside solid tumors to overcome tumorous hypoxia and show promising evidence to improve the antitumor efficiency. In this review, the extrinsic regulation of tumor hypoxia via nanomaterial delivery is discussed followed by a summary of the mechanisms through which the modulated tumor hypoxic microenvironment improves therapeutic efficacy. The review concludes with future perspectives, to specifically address the translation of nanomaterial-based therapeutic strategies for clinical applications.

Fighting Hypoxia to Improve PDT

Photodynamic therapy (PDT) has drawn great interest in recent years mainly due to its low side effects and few drug resistances. Nevertheless, one of the issues of PDT is the need for oxygen to induce a photodynamic effect. Tumours often have low oxygen concentrations, related to the abnormal structure of the microvessels leading to an ineffective blood distribution. Moreover, PDT consumes O2. In order to improve the oxygenation of tumour or decrease hypoxia, different strategies are developed and are described in this review: 1) The use of O2 vehicle; 2) the modification of the tumour microenvironment (TME); 3) combining other therapies with PDT; 4) hypoxia-independent PDT; 5) hypoxia-dependent PDT and 6) fractional PDT.

Combinatorial photochemotherapy on liver cancer stem cells with organoplatinum(ii) metallacage-based nanoparticles

Liver cancer is a kind of lethal and aggressive malignant neoplasm with a high rate of relapse and metastasis after therapy. An important cause for the relapse and metastasis is the existence of liver cancer stem cells (CSCs), which have high resistance to chemotherapy and high tumorigenic potential. Therefore, it is crucial to develop new methods to eradicate CSCs in tumors. Herein, we develop a photodynamic therapy (PDT) that features bimodal metallacage-loaded nanoparticles (MNPs) for integrated chemotherapy. This platform achieves chemo-photodynamic combinational therapy. Organoplatinum(ii) metallacage-loaded nanoparticles show excellent ability to kill liver CSCs, decreasing their mobility and sphenoid formation ability under near-infrared laser irradiation. Importantly, MNPs can successfully penetrate into 3D tumor spheroids, which display higher drug resistance compared to traditional 2D cultured cells. This destroys CSCs and prevents subsequent tumor formation in vivo. With the excellent combinational therapeutic results in hand, the working mechanisms of MNPs were then studied. MNPs under NIR light irradiation can generate reactive oxygen species (ROS), resulting in damage of mitochondrial membrane and subsequent cell apoptosis with chemotherapeutic platinum. This study proves the great potential of MNPs for combinational cancer therapy, providing a new insight for the next generation of nanomedicines.

Molecular Containers Derived from [60]Fullerene through Peroxide Chemistry

Molecular containers can keep guest molecules in a confined space that is completely separated from the solution. They have wide potential applications, including selective trapping of reactive intermediates, catalysis within the cavity, and molecular delivery. Numerous molecular containers have been prepared through covalent bonds, metal-ligand interactions and H-bonding or hydrophobic interactions. Fullerenes are all-carbon molecules with a spherical structure. Partial opening of the cage structure results in open-cage fullerenes, which can serve as molecular containers for various small molecules and atoms. Compared with classical molecular containers, open-cage fullerenes exhibit some unusual phenomena because of the unique structure of the fullerene cage. The synthesis of an open-cage fullerene with a large enough orifice as a molecular container requires consecutive cleavage of multiple fullerene skeleton bonds within a local area on the cage surface. In spite of the difficulty, remarkable progress has been achieved. Several reactions have been reported to cleave fullerene C-C bonds selectively to form open-cage fullerenes, some of which have been successfully used as molecular containers for molecules such as H₂O. The size and shape of the orifice play a key role in the encapsulation of the guest molecule. To date the focus in this area has been the preparation of open-cage fullerenes and encapsulation of small molecules. Little information has been reported about the functional properties of these host-guest systems. Potential applications of these systems need to be explored. This Account mainly presents our results on the encapsulation of small molecules in open-cage fullerenes prepared in my group. The preparation of our open-cage fullerenes is based on fullerene-mixed peroxides, which are briefly mentioned herein. The encapsulation and release of a single molecule of water is discussed in detail. Quantitative water encapsulation was achieved by heating the open-cage fullerene in a homogeneous CDCl₃/H₂O/EtOH mixture at 80 °C for 18 h. The kinetics of the water release process was studied by blackbody IR radiation-induced dissociation (BIRD) and theoretical calculations. The trapped water could also be released by H-bonding with HF. To control the encapsulation and release processes, we prepared open-cage fullerenes with a switchable stopper on the rim of the orifice. Besides H₂O, encapsulations of H₂, HF, CO, O₂, and H₂O₂ were also achieved by using different open-cage fullerenes. The encapsulation of CO is quite unusual in that the trapped CO is derived from a fullerene skeleton carbon that was pushed into the cavity by oxidation under ambient conditions at room temperature. The trapped O₂/H₂O₂ could be released slowly under mild conditions, and these systems are now being studied as a new type of oxygen-releasing materials for biomedical research. The present results demonstrate that open-cage fullerenes are suitable molecular containers for small molecules. Our future work will focus on optimizing the conditions for the preparation of open-cage fullerenes and applications of open-cage fullerenes in areas such as oxygen delivery for photodynamic therapy.

Hybrids of Polymeric Capsules, Lipids, and Nanoparticles: Thermodynamics and Temperature Rise at the Nanoscale and Emerging Applications

The importance of thermodynamics does not need to be emphasized. Indeed, elevated temperature processes govern not only industrial scale production but also self-assembly, chemical reaction, interaction between molecules, etc. Not surprisingly, biological processes typically take place at a specific temperature. Here, we look at possibilities to raise the localized temperature by a laser around noble-metal nanoparticles incorporated into shells of layer-by-layer polyelectrolyte microcapsules-freely suspended delivery vehicles in an aqueous solution, developed in the Department of Interfaces, Max Planck Institute of Colloids and Interfaces, headed by Helmuth Möhwald. Understanding the mechanisms of localized temperature rise is essential, that is why we analyze the influence of incident intensity, nanoparticle size, their distribution and aggregation state, as well as thermodynamics at the nanoscale. This leads us to scrutinize "global" (used for thermal encapsulation) versus "local" (used for release of encapsulated materials) temperature rise. Similar analysis is extended to planar polymeric coatings, the lipid membrane system of vesicles and cells, on which nanoparticles are adsorbed. Insights are provided into the mechanisms of physicochemical and biological effects, the nature of which has always been profoundly, interactively, and engagingly discussed in the Department of Interfaces. This analysis is combined with recent developments providing outlook and highlighting a broad range of emerging applications.

Persistent generation of hydroxyl radicals in Tris-Co(ii) complex-H2O2 systems for long-lasting multicolored chemical lights

Luminol tablet-Tris-Co(ii) complex-PVP-H2O2 systems exhibit 13 hours of intensive and stable chemiluminescence (CL) due to the continuous generation of ˙OH and sustained-release. Multicolored chemical lights were prepared through CL resonance energy transfer. This work presents a new method for the fabrication of bright chemical lights in aqueous solution for emergencies.

Intracellular transglutaminase-catalyzed polymerization and assembly for bioimaging of hypoxic neuroblastoma cells

An intracellular polymerization and assembly strategy was proposed for selectively bioimaging of hypoxic neuroblastoma cells, which was prospected for further tracing and locating brain tumors in vivo.