Recent Advances in Bio‐Compatible Oxygen Singlet Generation and Its Tumor Treatment

Janus-Structured Micro/Nanomotors: Self-Propelled Mechanisms and Biomedical Applications

Self-propelled micro/nanomotors (MNMs), which can convert other energy into mechanical motion, have attracted considerable attention due to their potential applications in diverse fields. Due to the asymmetric structures and 2 or more chemically discrepant composites constructed in the Janus nanoparticles, asymmetrical forces can be created in the physical environment. Thus, MNMs with Janus structures have been widely studied for revealing possible driving mechanisms. This tutorial review covers the most representative examples of Janus-structured MNMs developed so far, which are self-propelled by different mechanisms. We focus on Janus MNMs that exhibit self-propelled motion in liquid environments and their potential applications in biomedicine, including drug delivery, cancer therapy, bioimaging, and biosensing. The driving mechanisms and challenges associated with constructing asymmetric fields are deeply discussed, along with future opportunities for these versatile and promising MNMs. This review provides an overview of the rapidly evolving field of MNMs and their potential applications, serving as a valuable resource for researchers and others interested in this field.

Chemical Design of Magnetic Nanomaterials for Imaging and Ferroptosis-Based Cancer Therapy

Ferroptosis, an iron-dependent form of regulatory cell death, has garnered significant interest as a therapeutic target in cancer treatment due to its distinct characteristics, including lipid peroxide generation and redox imbalance. However, its clinical application in oncology is currently limited by issues such as suboptimal efficacy and potential off-target effects. The advent of nanotechnology has provided a new way for overcoming these challenges through the development of activatable magnetic nanoparticles (MNPs). These innovative MNPs are designed to improve the specificity and efficacy of ferroptosis induction. This Review delves into the chemical and biological principles guiding the design of MNPs for ferroptosis-based cancer therapies and imaging-guided therapies. It discusses the regulatory mechanisms and biological attributes of ferroptosis, the chemical composition of MNPs, their mechanism of action as ferroptosis inducers, and their integration with advanced imaging techniques for therapeutic monitoring. Additionally, we examine the convergence of ferroptosis with other therapeutic strategies, including chemodynamic therapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, and immunotherapy, within the context of nanomedicine strategies utilizing MNPs. This Review highlights the potential of these multifunctional MNPs to surpass the limitations of conventional treatments, envisioning a future of drug-resistance-free, precision diagnostics and ferroptosis-based therapies for treating recalcitrant cancers.

Breaking the deep-red light absorption barrier of iridium(III)-based photosensitizers

Activating photosensitizers with long-wavelength excitation is an important parameter for effective photodynamic therapy due to the minimal toxicity of this light, its superior tissue penetration, and excellent spatial resolution. Unfortunately, most Ir(III) complexes suffer from limited absorption within the phototherapeutic window, rendering them ineffective against deep-seated and/or large tumors, which poses a significant barrier to their clinical application. To address this issue, several efforts have been recently made to shift the absorption of Ir(III) photosensitizers to the deep-red/near-infrared region by using different strategies: functionalization with organic fluorophores, including porphyrinoid compounds, and ligand design via π-extension and donor-acceptor interactions. In this Frontier, we highlight such new developments and the ongoing challenges in this field.

State-of-the-Art Synthesis of Porous Polymer Materials and Their Several Fantastic Biomedical Applications: a Review

Porous polymers, including hydrogels, covalent organic frameworks (COFs), and hyper crosslinked polymers (HCPs), have become essential in biomedical research for their tunable pore architectures, large surface areas, and functional versatility. This review provides a comprehensive overview of their classification and updated synthesis mechanisms, such as 3D printing, electrospinning, and molecular imprinting. Their pivotal roles in drug delivery, tissue engineering, wound healing, and photodynamic/photothermal therapies, focusing on how pore size, distribution, and architecture impact drug release, cellular interactions, and therapeutic outcomes, are explored. Key challenges, including biocompatibility, mechanical strength, controlled degradation, and scalability, are critically assessed alongside emerging strategies to enhance clinical potential. Finally, recent challenges and future perspectives, emphasizing the broader biomedical applications of porous polymers, are addressed. This work provides valuable insights for advancing next-generation biomedical innovations through these materials.

Switching from Molecules to Functional Materials: Breakthroughs in Photochromism With MOFs

Photochromic materials with properties that can be dynamically tailored as a function of external stimuli are a rapidly expanding field driven by applications in areas ranging from molecular computing, nanotechnology, or photopharmacology to programable heterogeneous catalysis. Challenges arise, however, when translating the rapid, solution-like response of stimuli-responsive moieties to solid-state materials due to the intermolecular interactions imposed through close molecular packing in bulk solids. As a result, the integration of photochromic compounds into synthetically programable porous matrices, such as metal-organic frameworks (MOFs), has come to the forefront as an emerging strategy for photochromic material development. This review highlights how the core principles of reticular chemistry (on the example of MOFs) play a critical role in the photochromic material performance, surpassing the limitations previously observed in solution or solid state. The symbiotic relationship between photoresponsive compounds and porous frameworks with a focus on how reticular synthesis creates avenues toward tailorable photoisomerization kinetics, directional energy and charge transfer, switchable gas sorption, and synergistic chromophore communication is discussed. This review not only focuses on the recent cutting-edge advancements in photochromic material development, but also highlights novel, vital-to-pursue pathways for multifaceted functional materials in the realms of energy, technology, and biomedicine.

Heavy Atom Effect on the Intersystem Crossing of a Boron Difluoride Formazanate Complex-Based Photosensitizer: Experimental and Theoretical Studies

Photodynamic therapy (PDT) is a photochemical-based treatment approach that involves using light to activate photosensitizers (PSs). Attractively, PDT is one of the alternative cancer treatments due to its noninvasive technique. By utilizing the heavy atom effect, this work modified a class of formazan dyes to improve intersystem crossing (ISC) to improve reactive oxygen species (ROS) generation for PDT treatment. Two methods were used to observe the ROS generation enhanced by ISC of the synthesized complexes including, (1) recording DPBF decomposition caused by the ROS, and (2) calculating the potential energy curves for photophysical mechanisms of BF2 -formazanate dyes using the DFT and nudged elastic band (NEB) methods. The photophysical properties of the dyes were studied using spectroscopic techniques and X-ray crystallography, as well as DFT calculations. The experimental and theoretical results and in vitro cellular assays confirmed the potential use of the newly synthesized iodinated BF2 -formazanate dyes in PDT.

RGD peptide modified platinum nanozyme Co-loaded glutathione-responsive prodrug nanoparticles for enhanced chemo-photodynamic bladder cancer therapy

Bladder cancer is one of the most common malignant tumors in the urinary system worldwide. The poor permeability and uncontrollable release of drug and hypoxia of tumor tissues were the main reasons leading to poor therapeutic effect of chemo-photodynamic therapy for bladder cancer. To solve the above problems, a tumor-targeting peptide Arg-Gly-Asp (RGD) modified platinum nanozyme (PtNP) co-loaded glutathione (GSH)-responsive prodrug nanoparticles (PTX-SS-HPPH/Pt@RGD-NP) was constructed. Firstly, a GSH-responsive prodrug (PTX-SS-HPPH) was prepared by introducing a disulfide bond between paclitaxel (PTX) and photosensitizer 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH), which could realize the GSH-responsive release of the drug at the tumor sites. Also, the distearoylphosphoethanolamine-poly (ethylene glycol)-RGD peptide (DSPE-PEG-RGD) modified the prodrug to enhance the targeting and permeability ability to bladder cancer cells. Besides, to alleviate the hypoxia of tumor tissues, PtNP was introduced to produce oxygen (O₂) and improve photodynamic therapy efficiency. The results showed that the PTX-SS-HPPH/Pt@RGD-NP could achieve GSH-responsive drug release in tumor microenvironment, enhance the drug accumulation time and permeability at tumor sites in T24 subcutaneous tumor model and T24 orthotopic bladder tumor model, and alleviate hypoxia in tumor tissues, thus realizing enhanced chemo-photodynamic therapy for bladder cancer, and providing new strategies and methods for clinical treatment of bladder cancer.

Interaction effects between macromolecules and photosensitizer on the ability of AlPc and InPc-loaded PHB magnetic nanoparticles in photooxidatizing simple biomolecules

The parameters used in the preparation of polymeric nanoparticles can influence its ability to photooxidate biomolecules. This work evaluated the effects of four parameter to prepare Poly(3-hydroxybutyrate) (PHB) nanoparticle loaded with aluminum and indium phthalocyanine (AlPc and InPc), together with iron oxide nanoparticles, assessing their influence on the size, the entrapment efficiency, and the nanoparticles recovery efficacy. The capability of free, and encapsulated, AlPc and InPc in photooxidating the bovine serum albumin (BSA) and tryptophan (Trp) was monitored by fluorescence. The AlPc-loaded nanoparticles had a larger size and a greater entrapment efficiency than that obtained by InPc-loaded nanoparticles. The free InPc was more efficient than the free AlPc to photooxidize the BSA and Trp; whereas the encapsulated AlPc was more efficient than encapsulated InPc to photooxidize the biomolecules. The higher hydrophobicity of the AlPc, combined with the greater aggregation state and the major interaction with the BSA, quenching the capacity of the free AlPc to photooxidate the biomolecules; whereas the greater interaction of the AlPc with PHB reduce the aggregation effect on the free molecules in the aqueous phase and increase the entrapment efficiency, resulting in an improving of the photodynamic efficiency and an increase of the photooxidation rate constant.

Multifunctional Nanosystems Powered Photodynamic Immunotherapy

Photodynamic Therapy (PDT) with the intrinsic advantages including non-invasiveness, spatiotemporal selectivity, low side-effects, and immune activation ability has been clinically approved for the treatment of head and neck cancer, esophageal cancer, pancreatic cancer, prostate cancer, and esophageal squamous cell carcinoma. Nevertheless, the PDT is only a strategy for local control of primary tumor, that it is hard to remove the residual tumor cells and inhibit the tumor metastasis. Recently, various smart nanomedicine-based strategies are developed to overcome the barriers of traditional PDT including the drawbacks of traditional photosensitizers, limited tissue penetrability of light, inefficient induction of tumor cell death and tumor resistance to the therapy. More notably, a growing number of studies have focused on improving the therapeutic efficiency by eliciting host immune system with versatile nanoplatforms, which heralds a broader clinical application prospect of PDT in the future. Herein, the pathways of PDT induced-tumor destruction, especially the host immune response is summarized, and focusing on the recent progress of nanosystems-enhanced PDT through eliciting innate immunity and adaptive immunity. We expect it will provide some insights for conquering the drawbacks current PDT and expand the range of clinical application through this review.

Recent advances in ZnO-based photosensitizers: Synthesis, modification, and applications in photodynamic cancer therapy

Zinc oxide nanoparticles (ZnO NPs) are important semiconductor materials with interesting photo-responsive properties. During the past, ZnO-based NPs have received considerable attention for photodynamic therapy (PDT) due to their biocompatibility and excellent potential of generating tumor-killing reactive oxygen species (ROS) through gentle photodynamic activation. This article provides a comprehensive review of the recent developments and improvements in optical properties of ZnO NPs as photosensitizers for PDT. The optical properties of ZnO-based photosensitizers are significantly dependent on their charge separation, absorption potential, band gap engineering, and surface area, which can be adjusted/tuned by doping, compositing, and morphology control. Here, we first summarize the recent progress in the charge separation capability, absorption potential, band gap engineering, and surface area of nanosized ZnO-based photosensitizers. Then, morphology control that is closely related to their synthesis method is discussed. Following on, the state-of-art for the ZnO-based NPs in the treatment of hypoxic tumors is comprehensively reviewed. Finally, we provide some outlooks on common targeted therapy methods for more effective tumor killing, including the attachment of small molecules, antibodies, ligands molecules, and receptors to NPs which further improve their selective distribution and targeting, hence improving the therapeutic effectiveness. The current review may provide useful guidance for the researchers who are interested in this promising dynamic cancer treatment technology.