Feasibility of Photodynamic Therapy for Glioblastoma with the Mitochondria-Targeted Photosensitizer Tetramethylrhodamine Methyl Ester (TMRM)

Mitochondria-targeted BODIPY dyes for small molecule recognition, bio-imaging and photodynamic therapy

Mitochondria are essential for a diverse array of biological functions. There is increasing research focus on developing efficient tools for mitochondria-targeted detection and treatment. BODIPY dyes, known for their structural versatility and excellent spectroscopic properties, are being actively explored in this context. Numerous studies have focused on developing innovative BODIPYs that utilize optical signals for imaging mitochondria. This review presents a comprehensive overview of the progress made in this field, aiming to investigate mitochondria-related biological events. It covers key factors such as design strategies, spectroscopic properties, and cytotoxicity, as well as mechanism to facilitate their future application in organelle imaging and targeted therapy. This work is anticipated to provide valuable insights for guiding future development and facilitating further investigation into mitochondria-related biological sensing and phototherapy.

Phototherapy for age-related brain diseases: Challenges, successes and future

Brain diseases present a significant obstacle to both global health and economic progress, owing to their elusive pathogenesis and the limited effectiveness of pharmaceutical interventions. Phototherapy has emerged as a promising non-invasive therapeutic modality for addressing age-related brain disorders, including stroke, Alzheimer's disease (AD), and Parkinson's disease (PD), among others. This review examines the recent progressions in phototherapeutic interventions. Firstly, the article elucidates the various wavelengths of visible light that possess the capability to penetrate the skin and skull, as well as the pathways of light stimulation, encompassing the eyes, skin, veins, and skull. Secondly, it deliberates on the molecular mechanisms of visible light on photosensitive proteins, within the context of brain disorders and other molecular pathways of light modulation. Lastly, the practical application of phototherapy in diverse clinical neurological disorders is indicated. Additionally, this review presents novel approaches that combine phototherapy and pharmacological interventions. Moreover, it outlines the limitations of phototherapeutics and proposes innovative strategies to improve the treatment of cerebral disorders.

Mitochondrial NIR imaging probe mitigating oxidative damage by targeting HDAC6

Despite the apparent copious fluorescent probes targeting mitochondria, the development of low cytotoxic probes is still needed for improving validation of mitochondrial function assessment. Herein, we report a novel cyanine-based NIR fluorescent probe, T2, which selectively targets mitochondria with significantly low toxicity by modulating the intracellular redox status. Additionally, T2 inhibits oxidative stress-induced cell death in cortical neurons. This study provides new insight into developing low-toxic mitochondrial imaging agents by regulating redox homeostasis.

Recent Development of Advanced Fluorescent Molecular Probes for Organelle-Targeted Cell Imaging

Fluorescent molecular probes are very powerful tools that have been generally applied in cell imaging in the research fields of biology, pathology, pharmacology, biochemistry, and medical science. In the last couple of decades, numerous molecular probes endowed with high specificity to particular organelles have been designed to illustrate intracellular images in more detail at the subcellular level. Nowadays, the development of cell biology has enabled the investigation process to go deeply into cells, even at the molecular level. Therefore, probes that can sketch a particular organelle's location while responding to certain parameters to evaluate intracellular bioprocesses are under urgent demand. It is significant to understand the basic ideas of organelle properties, as well as the vital substances related to each unique organelle, for the design of probes with high specificity and efficiency. In this review, we summarize representative multifunctional fluorescent molecular probes developed in the last decade. We focus on probes that can specially target nuclei, mitochondria, endoplasmic reticulums, and lysosomes. In each section, we first briefly introduce the significance and properties of different organelles. We then discuss how probes are designed to make them highly organelle-specific. Finally, we also consider how probes are constructed to endow them with additional functions to recognize particular physical/chemical signals of targeted organelles. Moreover, a perspective on the challenges in future applications of highly specific molecular probes in cell imaging is also proposed. We hope that this review can provide researchers with additional conceptual information about developing probes for cell imaging, assisting scientists interested in molecular biology, cell biology, and biochemistry to accelerate their scientific studies.

Targeted photodynamic therapy of glioblastoma mediated by platelets with photo-controlled release property

Photodynamic therapy (PDT) has recently emerged as a promising, targeted treatment modality for glioblastoma (GBM) which is the most vicious type of brain tumor. Successful GBM-PDT hinges upon light activation of a photosensitizer accumulated in the tumor. However, inadequate tumor accumulation of photosensitizer severely limits the success of PDT of GBM. To tackle this difficulty, we herein propose a drug delivery strategy of "platelets with photo-controlled release property". This strategy exploits platelets as carriers to deliver a photosensitizer which, in the current study, is a nano-composite (BNPD-Ce6) comprised of chlorine e6 (Ce6) loaded to boron nitride nanoparticles with a surface coating of polyglycerol and doxorubicin. To demonstrate the working mechanism and therapeutic advantage of this strategy, we loaded mouse platelets with BNPD-Ce6 to yield the nano-device BNPD-Ce6@Plt. In vitro experiments showed BNPD-Ce6@Plt to have a high loading capacity and efficiency. Laser irradiation (LI) at a wavelength of 808 nm induced ROS generation in BNPD-Ce6@Plt which displayed rapid activation, aggregation, and speedy discharge of BNPD-Ce6 into co-cultured GL261 mouse GBM cells which in turn, after LI, exhibited marked ROS generation, DNA damage, reduced viability, and cell death. In vivo animal experiments, mice that were intravenously injected with BNPD-Ce6@Plt exhibited rapid and extensive BNPD-Ce6 accumulation in both subcutaneous and intra-brain GL261 tumors shortly after LI of the tumors and the tumors displayed massive tissue necrosis after LI for a second time. Finally, a PDT regimen of two intravenous BNPD-Ce6@Plt injections each followed by multiple times of extracranial LI at the tumor site significantly inhibited the growth of intra-brain GL261 tumors and markedly increased the survival of the host animals. No apparent tissue damage was found in vital organs. Our findings make a compelling case for the notion that platelets are efficient carriers that can photo-controllably deliver nano-photosensitizers to achieve highly targeted and efficacious PDT of GBM. This work presents a novel approach to GBM-PDT with great translational potential.

Photodynamic Therapy

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Progress and Viewpoints of Multifunctional Composite Nanomaterials for Glioblastoma Theranostics

The most common malignant tumor of the brain is glioblastoma multiforme (GBM) in adults. Many patients die shortly after diagnosis, and only 6% of patients survive more than 5 years. Moreover, the current average survival of malignant brain tumors is only about 15 months, and the recurrence rate within 2 years is almost 100%. Brain diseases are complicated to treat. The reason for this is that drugs are challenging to deliver to the brain because there is a blood–brain barrier (BBB) protection mechanism in the brain, which only allows water, oxygen, and blood sugar to enter the brain through blood vessels. Other chemicals cannot enter the brain due to their large size or are considered harmful substances. As a result, the efficacy of drugs for treating brain diseases is only about 30%, which cannot satisfy treatment expectations. Therefore, researchers have designed many types of nanoparticles and nanocomposites to fight against the most common malignant tumors in the brain, and they have been successful in animal experiments. This review will discuss the application of various nanocomposites in diagnosing and treating GBM. The topics include (1) the efficient and long-term tracking of brain images (magnetic resonance imaging, MRI, and near-infrared light (NIR)); (2) breaking through BBB for drug delivery; and (3) natural and chemical drugs equipped with nanomaterials. These multifunctional nanoparticles can overcome current difficulties and achieve progressive GBM treatment and diagnosis results.