Hypocrellin-Based Multifunctional Phototheranostic Agent for NIR-Triggered Targeted Chemo/Photodynamic/Photothermal Synergistic Therapy against Glioblastoma

A glutathione responsive photosensitizer based on hypocrellin B for photodynamic therapy

As a typical natural photosensitizer, hypocrellin B (HB) offers the advantages of high molar extinction coefficient, high phototoxicity, low dark toxicity, and fast metabolism in vivo. However, the lack of tumor specificity hinders its clinical applications. Herein, we designed and synthesized a glutathione (GSH) responsive photosensitizer based on HB. The 7 - nitro - 2,1,3 - benzoxadiazole (NBD) covalently connected to HB not only served as a fluorescence quenching group but also as a GSH activating group. The photosensitizer HB-NBD showed almost no fluorescence and singlet oxygen generation as a result of the photoinduced electron transfer between HB and NBD. The designed photosensitizer HB-NBD can be activated by GSH in solutions and cancer cells, and then obtain recuperative fluorescence and photosensitive activity.

Ultrasound-Controlled Prodrug Activation: Emerging Strategies in Polymer Mechanochemistry and Sonodynamic Therapy

Ultrasound has gained prominence in biomedical applications due to its noninvasive nature and ability to penetrate deep tissue with spatial and temporal resolution. The burgeoning field of ultrasound-responsive prodrug systems exploits the mechanical and chemical effects of ultrasonication for the controlled activation of prodrugs. In polymer mechanochemistry, materials scientists exploit the sonomechanical effect of acoustic cavitation to mechanochemically activate force-sensitive prodrugs. On the other hand, researchers in the field of sonodynamic therapy adopt fundamentally distinct methodologies, utilizing the sonochemical effect (e.g., generation of reactive oxygen species) of ultrasound in the presence of sonosensitizers to induce chemical transformations that activate prodrugs. This cross-disciplinary review comprehensively examines these two divergent yet interrelated approaches, both of which originated from acoustic cavitation. It highlights molecular and materials design strategies and potential applications in diverse therapeutic contexts, from chemotherapy to immunotherapy and gene therapy methods, and discusses future directions in this rapidly advancing domain.

Advancing Photodynamic Therapy with Nano-Conjugated Hypocrellin: Mechanisms and Clinical Applications

Hypocrellin-based photodynamic therapy (PDT) is developing as a viable cancer therapeutic option, especially when enhanced by nanoconjugation. This review investigates the methods by which nano-conjugated hypocrellin enhances therapeutic efficacy and precision when targeting cancer cells. These nanoconjugates encapsulate or covalently bind hypocrellin photosensitizers (PSs), allowing them to accumulate preferentially in malignancies. When activated by light, the nanoconjugates produce singlet oxygen and other reactive oxygen species (ROS), resulting in oxidative stress that selectively destroys cancer cells while protecting healthy tissues. We look at how they can be used to treat a variety of cancers. Clinical and preclinical studies show that they have advantages such as increased water solubility, improved tumor penetration, longer circulation times, and tailored delivery, all of which contribute to fewer off-target effects and overall toxicity. Ongoing research focuses on improving these nanoconjugates for better tumor targeting, drug release kinetics, and overcoming biological obstacles. Furthermore, the incorporation of developing technologies such as stimuli-responsive nanocarriers and combination therapies opens exciting opportunities for enhancing hypocrellin-based PDT. In conclusion, the combination of hypocrellin and nanotechnology constitutes a significant approach to cancer treatment, increasing the efficacy and safety of PDT. Future research will seek to create conjugates including hypocrellin, herceptin, and gold nanoparticles to induce apoptosis in human breast cancer cells in vitro, opening possibilities for therapeutic applications.

Lipid Nanoparticles for Brain Tumor Theranostics: Challenges and Status

Lipid nanoparticles have been recognized as a powerful weapon for delivering various imaging and therapeutic agents to the localized solid tumors, especially brain tumors individually or in combination. Promisingly, lipid-based nanosystems have been considered as safe delivery systems which are even approved by the Food and Drug Administration (FDA) and the European Medicines Agency (EMA). One recent spotlight of lipid nanoparticles as COVID-19 mRNA vaccines where lipid nanoparticles play an important role in effectively protecting and delivering mRNA to the desired cells. As of now, successive progress in lipid-based nanocarriers, viz., nanoliposomes, solid lipid nanoparticles, ionizable lipid nanostructures, etc., with better biochemical and biophysical stabilities, has been noticed and reported. Moreover, lipid nanostructures have been considered as versatile therapeutics platforms for a variety of diseases due to their biocompatibility, ability to protect and deliver therapeutics to the localized site, and better reproducibility and reliability. However, lipid nanoparticles still face morphological and biochemical changes upon their in vivo administration. These changes alter the specific biological and pathological response of lipid nanoparticles during their personalized brain tumor theranostics. Second, lipid nanomedicine still faces major challenges of zero premature leakage of loaded cargo, long-term colloidal stability, and off targeting. Herein, various lipid-based nanomedicines for brain tumor imaging and therapeutics "theranostics" have been reviewed and summarized considering major aspects of preclinical and clinical studies. On the other hand, engineering and biological challenges of lipid theranostics systems with relevant advantages and guidelines for clinical practice for different brain tumors have also been discussed. This review provides in-depth knowledge of lipid nanoparticle-based theranostics agents for brain tumor imaging and therapeutics.

A Review of the Efficacy of Nanomaterial-Based Natural Photosensitizers to Overcome Multidrug Resistance in Cancer

Natural photosensitizers (PS) are compounds derived from nature, with photodynamic properties. Natural PSs have a similar action to that of commercial PSs, where cancer cell death occurs by necrosis, apoptosis, and autophagy through ROS generation. Natural PSs have garnered great interest over the last few decades because of their high biocompatibility and good photoactivity. Specific wavelengths could cause phytochemicals to produce harmful ROS for photodynamic therapy (PDT). However, natural PSs have some shortcomings, such as reduced solubility and lower uptake, making them less appropriate for PDT. Nanotechnology offers an opportunity to develop suitable carriers for various natural PSs for PDT applications. Various nanoparticles have been developed to improve the outcome with enhanced solubility, optical adsorption, and tumor targeting. Multidrug resistance (MDR) is a phenomenon in which tumor cells develop resistance to a wide range of structurally and functionally unrelated drugs. Over the last decade, several researchers have extensively studied the effect of natural PS-based photodynamic treatment (PDT) on MDR cells. Though the outcomes of clinical trials for natural PSs were inconclusive, significant advancement is still required before PSs can be used as a PDT agent for treating MDR tumors. This review addresses the increasing literature on MDR tumor progression and the efficacy of PDT, emphasizing the importance of developing new nano-based natural PSs in the fight against MDR that have the required features for an MDR tumor photosensitizing regimen.

Terpenes-Modified Lipid Nanosystems for Temozolomide, Improving Cytotoxicity against Glioblastoma Human Cancer Cells In Vitro

Currently, increasing the efficiency of glioblastoma treatment is still an unsolved problem. In this study, a combination of promising approaches was proposed: (i) an application of nanotechnology approach to create a new terpene-modified lipid system (7% w/w), using soybean L-α-phosphatidylcholine, N-carbonyl-methoxypolyethylene glycol-2000)-1,2-distearoyl-sn-glycero-3-phosphoethanolamine for delivery of the chemotherapy drug, temozolomide (TMZ, 1 mg/mL); (ii) use of TMZ associated with natural compounds-terpenes (1% w/w) abietic acid and Abies sibirica Ledeb. resin (A. sibirica). Different concentrations and combinations of terpene-lipid systems were employed to treat human cancer cell lines T 98G (glioblastoma), M-Hela (carcinoma of the cervix) and human liver cell lines (Chang liver). The terpene-lipid systems appeared to be unilamellar and of spherical shape under transmission electron microscopy (TEM). The creation of a TMZ-loaded terpene-lipid nanosystem was about 100 nm in diameter with a negative surface charge found by dynamic light scattering. The 74% encapsulation efficiency allowed the release time of TMZ to be prolonged. The modification by terpenes of TMZ-loaded lipid nanoparticles improved by four times the cytotoxicity against human cancer T 98G cells and decreased the cytotoxicity against human normal liver cells. Terpene-modified delivery lipid systems are of potential interest as a combination therapy.

NIR-II xanthene dyes with structure-inherent bacterial targeting for efficient photothermal and broad-spectrum antibacterial therapy

Development of novel broad-spectrum sterilization is an efficient strategy that can overcome drug resistance and avoid antibiotics abuse toward bacterial-infected diseases. Photothermal therapy (PTT) in the second near-infrared (NIR-II) therapeutic window with an increased tissue penetration and elevated maximal permissible exposure has attracted considerable attention in antibacterial applications. However, the lack of bacterial-targeted photothermal agents limits their further development. Herein, we developed three xanthene derivatives (CNs) with intense light harvesting ability around 1180 nm. Their bulky planar conformations facilitated the formation of H-aggregates with outstanding photothermal conversion ability and good photostability in the NIR-II therapeutic bio window. By manipulating side chains of CNs, their liposomes exhibited different surface charges, ranging from negative to positive. Remarkably, the intermolecular hydrogen bonding of CN3 dimer drived the positively charged xanthene skeleton exposed to the periphery, which endowed it natural bacterial targeting potency. Therefore, CN3 possessed a good NIR-II photothermal and broad-spectrum sterilization against Gram-positive and Gram-negative bacteria. The photothermal antibacterial activities for S. aureus and E. coli were 99.4% and 99.2%, respectively, promoting significant wound healing in bacteria-infected mice with superior biocompatibility. This structure-inherent bacterial targeting strategy as a proof-of-concept shows an efficient broad-spectrum bacterial inactivation, indicating more encouraging NIR-II photothermal antibacterial therapy. STATEMENT OF SIGNIFICANCE: Photothermal therapy (PTT) in the second near-infrared region (NIR-II, 1000-1700 nm) enables the treatment of deep inflammation more satisfactory due to higher tissue penetration depth. In this work, three new NIR-II xanthene derivatives (CNs) with intense light harvesting ability around 1180 nm were developed. CNs showed typical H-aggregated performance with bulky planar conformations and outstanding photothermal conversion ability. Density functional theory calculations revealed that the intermolecular hydrogen bonding of CN3 dimer drived the exposure of positively charged xanthene skeleton to periphery of dimer. Therefore, CN3 NPs possessed natural bacterial targeting potency and excellent NIR-II photothermal and broad-spectrum sterilization, and so as to significantly promote the wound healing of Gram-positive / negative bacteria infected mice.

Nanotechnological advancements in the brain tumor therapy: a novel approach

Nanotechnological advancements over the past few years have led to the development of newer treatment strategies in brain cancer therapy which leads to the establishment of nano oncology. Nanostructures with high specificity, are best suitable to penetrate the blood-brain barrier (BBB). Their desired physicochemical properties, such as small sizes, shape, higher surface area to volume ratio, distinctive structural features, and the possibility to attach various substances on their surface transform them into potential transport carriers able to cross various cellular and tissue barriers, including the BBB. The review emphasizes nanotechnology-based treatment strategies for the exploration of brain tumors and highlights the current progress of different nanomaterials for the effective delivery of drugs for brain tumor therapy.

Multifunctional nanotheranostics for near infrared optical imaging-guided treatment of brain tumors

Malignant brain tumors, a heterogeneous group of primary and metastatic neoplasms in the central nervous system (CNS), are notorious for their highly invasive and devastating characteristics, dismal prognosis and low survival rate. Recently, near-infrared (NIR) optical imaging modalities including fluorescence imaging (FLI) and photoacoustic imaging (PAI) have displayed bright prospect in innovation of brain tumor diagnoses, due to their merits, like noninvasiveness, high spatiotemporal resolution, good sensitivity and large penetration depth. Importantly, these imaging techniques have been widely used to vividly guide diverse brain tumor therapies in a real-time manner with high accuracy and efficiency. Herein, we provide a systematic summary of the state-of-the-art NIR contrast agents (CAs) for brain tumors single-modal imaging (e.g., FLI and PAI), dual-modal imaging (e.g., FLI/PAI, FLI/magnetic resonance imaging (MRI) and PAI/MRI) and triple-modal imaging (e.g., MRI/FLI/PAI and MRI/PAI/computed tomography (CT) imaging). In addition, we update the most recent progress on the NIR optical imaging-guided therapies, like single-modal (e.g., photothermal therapy (PTT), chemotherapy, surgery, photodynamic therapy (PDT), gene therapy and gas therapy), dual-modal (e.g., PTT/chemotherapy, PTT/surgery, PTT/PDT, PDT/chemotherapy, PTT/chemodynamic therapy (CDT) and PTT/gene therapy) and triple-modal (e.g., PTT/PDT/chemotherapy, PTT/PDT/surgery, PTT/PDT/gene therapy and PTT/gene/chemotherapy). Finally, we discuss the opportunities and challenges of the CAs and nanotheranostics for future clinic translation.

Structural modification of NIR-II fluorophores for angiography beyond 1300 nm: Expanding the xanthene universe

Fluorescence bioimaging via the second near-infrared (NIR-II) window can provide precise images with a low background signal due to attenuated absorption and scattering in biological tissues. However, it is challenging to realize organic fluorophores' absorption/emission wavelength beyond 1300 nm depending on their intrinsic emission of monomers. Reducing parasitic aggregation caused quenching (ACQ) effect is expected as an efficient strategy to achieve fluorescence bioimaging in an ideal region. Herein, two NIR-II xanthene fluorophores (CM1 and CM2) with different side chains on identical skeletons were synthesized. Besides, their corresponding assemblies (CM1 NPs and CM2 NPs) were subsequently prepared, which exhibited distinct spectroscopic properties. Notably, CM2 NPs exhibited a significantly reduced ACQ effect with maximal absorption/emission extended to 1235/1250 nm. Molecular dynamics simulations revealed that intermolecular hydrogen bond, π-π interaction, and CH-π interaction of CM2 were essential for the reduced ACQ effect. In vivo hindlimb angiography showed that CM2 NPs could distinguish the neighboring artery and vein in high resolution. Besides, CM2 NPs could achieve angiography beyond 1300 nm and even resolve capillaries as small as 0.23 mm. This study provides a new strategy for reducing the ACQ effect by controlling different side chains of NIR-II xanthene dyes for angiography beyond 1300 nm.

Nanotechnology-Based Combinatorial Anti-Glioblastoma Therapies: Moving from Terminal to Treatable

Aggressive glioblastoma (GBM) has no known treatment as a primary brain tumor. Since the cancer is so heterogeneous, an immunosuppressive tumor microenvironment (TME) exists, and the blood–brain barrier (BBB) prevents chemotherapeutic chemicals from reaching the central nervous system (CNS), therapeutic success for GBM has been restricted. Drug delivery based on nanocarriers and nanotechnology has the potential to be a handy tool in the continuing effort to combat the challenges of treating GBM. There are various new therapies being tested to extend survival time. Maximizing therapeutic effectiveness necessitates using many treatment modalities at once. In the fight against GBM, combination treatments outperform individual ones. Combination therapies may be enhanced by using nanotechnology-based delivery techniques. Nano-chemotherapy, nano-chemotherapy–radiation, nano-chemotherapy–phototherapy, and nano-chemotherapy–immunotherapy for GBM are the focus of the current review to shed light on the current status of innovative designs.

New Xanthene Dyes with NIR-II Emission Beyond 1200 nm for Efficient Tumor Angiography and Photothermal Therapy

Fluorescence (FL) bioimaging in the second near-infrared window (NIR-II, 1000-1700 nm) provides improved imaging quality and high resolution for diagnosis of deep-seated tumors. However, integrating FL bioimaging and photothermal therapy (PTT) in a single photoactive molecule exhibits a great challenge because a dramatic increase of PTT in the NIR-II window benefitting from the nonradiative decay will sacrifice the fluorescence brightness that is unfavorable for FL bioimaging. Therefore, balancing the radiative decay and nonradiative decay is an effective and rational design strategy. Herein, four NIR-II xanthene dyes (CL1-CL4) are synthesized with maximal emission beyond 1200 nm under 1064 nm excitation. CL4 exhibits the largest fluorescence quantum yield and a significant fluorescence enhancement after complexation with fetal bovine serum (FBS). As-prepared CL4/FBS has a maximal emission of 1235 nm and a high photothermal conversion efficiency of 36% under 1064 nm excitation. Bright and refined tumor vessels with a fine resolution of 0.23 mm can be clearly distinguished by CL4/FBS. In vivo studies show that a balanced utilization of fluorescence and photothermy in the NIR-II window is successfully achieved with superior biocompatibility. This efficient strategy provides promising avenue for precise theranostics of deep tumors.

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.

A novel hypocrellin-based assembly for sonodynamic therapy against glioblastoma

The non-invasive treatment of glioblastoma (GBM) is of great significance and can greatly reduce the complications of craniotomy. Sonodynamic therapy (SDT) is an emerging tumor therapeutic strategy that overcomes some fatal flaws of photodynamic therapy (PDT). Different from PDT, SDT has deep tissue penetration and can be applied in the non-invasive treatment of deep-seated tumors. However, effective sonosensitizers that can be used for SDT of GBM are still very rare. Herein, we have prepared a suitable assembly based on a hypocrellin derivative (CTHB) with good biocompatibility. Excitedly, the hypocrellin-based assembly (CTHB NPs) can effectively produce reactive oxygen species under ultrasound stimulation. The inherent fluorescence and photoacoustic imaging characteristics of the CTHB NPs are conducive to the precise positioning of the tumors. It has been proved both in subcutaneous and in intracranial tumor models that CTHB NPs can be used as an effective sonosensitizer to inhibit tumor growth under ultrasound irradiation. This hypocrellin-based assembly has a good clinical prospect in the non-invasive treatment of GBM.

Multifunctional AIE iridium (III) photosensitizer nanoparticles for two-photon-activated imaging and mitochondria targeting photodynamic therapy

Developing novel photosensitizers for deep tissue imaging and efficient photodynamic therapy (PDT) remains a challenge because of the poor water solubility, low reactive oxygen species (ROS) generation efficiency, serve dark cytotoxicity, and weak absorption in the NIR region of conventional photosensitizers. Herein, cyclometalated iridium (III) complexes (Ir) with aggregation-induced emission (AIE) feature, high photoinduced ROS generation efficiency, two-photon excitation, and mitochondria-targeting capability were designed and further encapsulated into biocompatible nanoparticles (NPs). The Ir-NPs can be used to disturb redox homeostasis in vitro, result in mitochondrial dysfunction and cell apoptosis. Importantly, in vivo experiments demonstrated that the Ir-NPs presented obviously tumor-targeting ability, excellent antitumor effect, and low systematic dark-toxicity. Moreover, the Ir-NPs could serve as a two-photon imaging agent for deep tissue bioimaging with a penetration depth of up to 300 μm. This work presents a promising strategy for designing a clinical application of multifunctional Ir-NPs toward bioimaging and PDT.

Phylogenetic Position of Shiraia-Like Endophytes on Bamboos and the Diverse Biosynthesis of Hypocrellin and Hypocrellin Derivatives

The main active ingredients of the fruiting bodies of Shiraia bambusicola and Rubroshiraia bambusae are Hypocrellins, belonging perylenequinones with potential photodynamic activity against cancer and microbial diseases. However, the strains of S. bambusicola and R. bambusae do not produce hypocrellins in culture, so resource exploitation of natural products was seriously restricted. In this study, a series of novel Shiraia-like fungal endophyte strains, with varying sporulation ability and synthesizing diverse secondary metabolites, was isolated from different bamboos. Based on phylogenetic analyses and morphological characteristics of the endophytes, Pseudoshiraia conidialis gen. et sp. nov. is proposed. The secondary metabolites of different fruiting bodies and strains have been comprehensively analyzed for the first time, finding that the endophytic strains are shown not only to produce hypocrellins, but also other perylenequinonoid compounds. It was noteworthy that the highest yield of total perylenequinone production and hypocrellin A appeared in P. conidialis CNUCC 1353PR (1410.13 mg/L), which was significantly higher than any other wild type P. conidialis strains in published reports. In view of these results, the identification of Shiraia-like endophytes not only confirm the phylogenetic status of similar strains, but will further assist in developing the production of valuable natural products.

Recent advances in theranostic agents based on natural products for photodynamic and sonodynamic therapy

The integration of diagnosis and therapy based on natural products has been receiving considerable attention in recent years because nature can contribute many fantastic functional molecules with good biocompatibility and low toxicity. Diagnostic and therapeutic agents combined with the technique of photodynamic therapy (PDT) and sonodynamic therapy (SDT) have been extensively developed thanks to the advantages of PDT and SDT, such as good selectivity, low toxicity, and noninvasive treatment for cancers and other diseases compared with traditional treatments. In this review, we summarize the recent advances in theranostic agents for natural products categorized as porphyrins, perylenequinone, curcumin, and others. Some representative examples of disease diagnosis in fluorescence/photoacoustic imaging and disease treatment in PDT/SDT were introduced. Potential limitations and future perspectives of these natural products for theranostic agents were also discussed.