Renal-Clearable PEGylated Porphyrin Nanoparticles for Image-guided Photodynamic Cancer Therapy

Porphyrin-Based Self-Assembled Nanoparticles for PET/MR Imaging of Sentinel Lymph Node Metastasis

Diagnosing of lymph node metastasis is challenging sometimes, and multimodal imaging offers a promising method to improve the accuracy. This work developed porphyrin-based nanoparticles (68Ga-F127-TAPP/TCPP(Mn) NPs) as PET/MR dual-modal probes for lymph node metastasis imaging by a simple self-assembly method. Compared with F127-TCPP(Mn) NPs, F127-TAPP/TCPP(Mn) NPs synthesized by amino-porphyrins (TAPP) doping can not only construct PET/MR bimodal probes but also improve the T1 relaxivity (up to 456%). Moreover, T1 relaxivity can be adjusted by altering the molar ratio of TAPP/TCPP(Mn) and the concentration of F127. However, a similar increase in T1 relaxivity was not observed in the F127-TCPP/TCPP(Mn) NPs, which were synthesized using carboxy-porphyrins (TCPP) doping. In a breast cancer lymph node metastasis mice model, subcutaneous injection of 68Ga-F127-TAPP/TCPP(Mn) NPs through the hind foot pad, the normal lymph nodes and metastatic lymph nodes were successfully distinguished based on the difference of PET standard uptake values and MR signal intensities. Furthermore, the dark brown F127-TAPP/TCPP(Mn) NPs demonstrated the potential for staining and mapping lymph nodes. This study provides valuable insights into developing and applying PET/MR probes for lymph node metastasis imaging.

A metal-organic framework (MOF) built on surface-modified Cu nanoparticles eliminates tumors via multiple cascading synergistic therapeutic effects

Tumors produce a hypoxic environment that greatly influences cancer treatment, and conventional chemotherapeutic drugs cannot selectively accumulate in the tumor region because of the lack of a tumor targeting mechanism, causing increased systemic toxicities and side effects. Hence, designing and developing new nanoplatforms that combine multimodal therapeutic regimens is essential to improve tumor therapeutic efficacy. Herein, we report the synthesis of ultrafine Cu nanoparticles loaded with a drug combination of cisplatin (Pt) and 1-methyl-d-tryptophan (1-MT) and externally coated with 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) photosensitizer, polydopamine (PDA) and CaO2 of MIL-101(Fe) as a new nanoplatform (Cu@MIL-101@PMTPC). The nanoplatform synergistically combined chemodynamic therapy (CDT), photodynamic therapy (PDT), and immunochemotherapy. The Fe3+ in MIL-101(Fe) and the surface Cu nanoparticles exhibited strong ability to consume intracellular glutathione (GSH), thereby generating a Fenton-like response in the tumor microenvironment (TME) with substantial peroxidase (POD)-like and superoxide dismutase (SOD)-like activities. In this design, we used the indoleamine 2,3-dioxygenase (IDO) inhibitor 1-MT to overcome chemotherapy-induced immune escape phenomena including enhanced CD8+ and CD4+ T cell expression, interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) production, and accelerated immunogenic cell death. The targeted release of cisplatin loaded into Cu@MIL-101@PMTPC also reduced toxic side effects of chemotherapy. TCPP generated a large amount of singlet oxygen (1O2) upon specific laser irradiation to effectively kill tumor cells. CaO2 on the outer layer generated oxygen (O2) and hydrogen peroxide (H2O2) to ameliorate hypoxia in the tumor microenvironment, enhance the PDT effect, and provide a continuous supply of H2O2 for the Fenton-like reaction. Thus, this nanocarrier platform exhibited a powerful chemodynamic, photodynamic, and immunochemotherapeutic cascade, providing a new strategy for cancer treatment.

pH-Activatable Pre-Nanozyme Mediated H2S Delivery for Endo-Exogenous Regulation of Oxidative Stress in Acute Kidney Injury

Oxidative stress induced by excess reactive oxygen species (ROS) is a primary pathogenic cause of acute kidney injury (AKI). Development of an effective antioxidation system to mitigate oxidative stress for alleviating AKI remains to be investigated. This study presents the synthesis of an ultra-small Platinum (Pt) sulfur cluster (Pt5.65S), which functions as a pH-activatable prefabricated nanozyme (pre-nanozyme). This pre-nanozyme releases hydrogen sulfide (H2S) and transforms into a nanozyme (Ptzyme) that mimics various antioxidant enzymes, including superoxide dismutase and catalase, within the inflammatory microenvironment. Notably, the Pt5.65S pre-nanozyme exhibits an endo-exogenous synergy-enhanced antioxidant therapeutic mechanism. The Ptzyme reduces oxidative damage and inflammation, while the released H2S gas promotes proneurogenesis by activating Nrf2 and upregulating the expression of antioxidant molecules and enzymes. Consequently, the Pt5.65S pre-nanozyme shows cytoprotective effects against ROS/reactive nitrogen species (RNS)-mediated damage at remarkably low doses, significantly improving treatment efficacy in mouse models of kidney ischemia-reperfusion injury and cisplatin-induced AKI. Based on these findings, the H2S-generating pre-nanozyme may represent a promising therapeutic strategy for mitigating inflammatory diseases such as AKI and others.

Activity-Based Nitric Oxide-Responsive Porphyrin for Site-Selective and Nascent Cancer Ablation

Nitric oxide (NO) generated within the tumor microenvironment is an established driver of cancer progression and metastasis. Recent efforts have focused on leveraging this feature to target cancer through the development of diagnostic imaging agents and activatable chemotherapeutics. In this context, porphyrins represent an extraordinarily promising class of molecules, owing to their demonstrated use within both modalities. However, the remodeling of a standard porphyrin to afford a responsive chemical that can distinguish elevated NO from physiological levels has remained a significant research challenge. In this study, we employed a photoinduced electron transfer strategy to develop a panel of NO-activatable porphyrin photosensitizers (NOxPorfins) augmented with real-time fluorescence monitoring capabilities. The lead compound, NOxPorfin-1, features an o-phenylenediamine trigger that can effectively capture NO (via N2O3) to yield a triazole product that exhibits a 7.5-fold enhancement and a 70-fold turn-on response in the singlet oxygen quantum yield and fluorescence signal, respectively. Beyond demonstrating excellent in vitro responsiveness and selectivity toward NO, we showcase the potent photodynamic therapy (PDT) effect of NOxPorfin-1 in murine breast cancer and human non-small cellular lung cancer cells. Further, to highlight the in vivo efficacy, two key studies were executed. First, we utilized NOxPorfin-1 to ablate murine breast tumors in a site-selective manner without causing substantial collateral damage to healthy tissue. Second, we established a nascent human lung cancer model to demonstrate the unprecedented ability of NOxPorfin-1 to halt tumor growth and progression completely. The results of the latter study have tremendous implications for applying PDT to target metastatic lesions.

A tissue-adhesive F127 hydrogel delivers antioxidative copper-selenide nanoparticles for the treatment of dry eye disease

Dry eye disease (DED) is currently the most prevalent condition seen in ophthalmology outpatient clinics, representing a significant public health issue. The onset and progression of DED are closely associated with oxidative stress-induced inflammation and damage. To address this, an aldehyde-functionalized F127 (AF127) hydrogel eye drop delivering multifunctional antioxidant Cu2-xSe nanoparticles (Cu2-xSe NPs) was designed. The research findings revealed that the Cu2-xSe nanoparticles exhibit unexpected capabilities in acting as superoxide dismutase and glutathione peroxidase. Additionally, Cu2-xSe NPs possess remarkable efficacy in scavenging reactive oxygen species (ROS) and mitigating oxidative damage. Cu2-xSe NPs displayed promising therapeutic effects in a mouse model of dry eye. Detailed investigation revealed that the nanoparticles exert antioxidant, anti-apoptotic, and inflammation-mitigating effects by modulating the NRF2 and p38 MAPK signalling pathways. The AF127 hydrogel eye drops exhibit good adherence to the ocular surface through the formation of Schiff-base bonds. These findings suggest that incorporating antioxidant Cu2-xSe nanoparticles into a tissue-adhesive hydrogel could present a highly effective therapeutic strategy for treating dry eye disease and other disorders associated with reactive oxygen species. STATEMENT OF SIGNIFICANCE: A new formulation for therapeutic eye drops to be used in the treatment of dry eye disease (DED) was developed. The formulation combines copper-selenium nanoparticles (Cu2-xSe NPs) with aldehyde-functionalized Pluronic F127 (AF127). This is the first study to directly examine the effects of Cu2-xSe NPs in ophthalmology. The NPs exhibited antioxidant capabilities and enzyme-like properties. They effectively eliminated reactive oxygen species (ROS) and inhibited apoptosis through the NRF2 and p38 MAPK signalling pathways. Additionally, the AF127 hydrogel enhanced tissue adhesion by forming Schiff-base links. In mouse model of DED, the Cu2-xSe NPs@AF127 eye drops demonstrated remarkable efficacy in alleviating symptoms of DED. These findings indicate the potential of Cu2-xSe NPs as a readily available and user-friendly medication for the management of DED.

Biodegradable Hollow Nanoscavengers Restore Liver Functions to Reverse Insulin Resistance in Type 2 Diabetes

Type 2 diabetes (T2D) results from the cells' insulin resistance, and to date, insulin therapy and diabetes medications targeting glycemic management have failed to reverse the increase in T2D prevalence. Restoring liver functions to improve hepatic insulin resistance by reducing oxidative stress is a potential strategy for T2D treatment. Herein, the liver-targeted biodegradable silica nanoshells embedded with platinum nanoparticles (Pt-SiO₂) are designed as reactive oxygen species (ROS) nanoscavengers and functional hollow nanocarriers. Then, 2,4-dinitrophenol-methyl ether (DNPME, mitochondrial uncoupler) is loaded inside Pt-SiO₂, followed by coating a lipid bilayer (D@Pt-SiO₂@L) for long-term effective ROS removal (platinum nanoparticles scavenge overproduced ROS, while DNPME inhibits ROS production) in the liver tissue of T2D models. It is found that D@Pt-SiO₂@L reverses elevated oxidative stress, insulin resistance, and impaired glucose consumption in vitro, and significantly improves hepatic steatosis and antioxidant capacity in diabetic mice models induced by a high-fat diet and streptozotocin. Moreover, intravenous administration of D@Pt-SiO₂@L indicates therapeutic effects on hyperlipidemia, insulin resistance, hyperglycemia, and diabetic nephropathy, which provides a promising approach for T2D treatment by reversing hepatic insulin resistance through long-term ROS scavenging.

A Versatile Theranostic Nanoplatform with Aggregation-Induced Emission Properties: Fluorescence Monitoring, Cellular Organelle Targeting, and Image-Guided Photodynamic Therapy

Photosensitizers (PSs) play a key role in the photodynamic therapy (PDT) of tumors. However, commonly used PSs are prone to intrinsic fluorescence aggregation-caused quenching and photobleaching; this drawback severely limits the clinical application of PDT, necessitating new phototheranostic agents. Herein, a multifunctional theranostic nanoplatform (named TTCBTA NP) is designed and constructed to achieve fluorescence monitoring, lysosome-specific targeting, and image-guided PDT. TTCBTA with a twisted conformation and D-A structure is encapsulated in amphiphilic Pluronic F127 to form nanoparticles (NPs) in ultrapure water. The NPs exhibit biocompatibility, high stability, strong near-infrared emission, and desirable reactive oxygen species (ROSs) production capacity. The TTCBTA NPs also show high-efficiency photo-damage, negligible dark toxicity, excellent fluorescent tracing, and high accumulation in lysosome for tumor cells. Furthermore, TTCBTA NPs are used to obtain fluorescence images with good resolution of MCF-7 tumors in xenografted BALB/c nude mice. Crucially, TTCBTA NPs present a strong tumor ablation ability and image-guided PDT effect by generating abundant ROSs upon laser irradiation. These results demonstrate that the TTCBTA NP theranostic nanoplatform may enable highly efficient near-infrared fluorescence image-guided PDT.

Emerging ultrasmall luminescent nanoprobes for in vivo bioimaging

Photoluminescence (PL) imaging has become a fundamental tool in disease diagnosis, therapeutic evaluation, and surgical navigation applications. However, it remains a big challenge to engineer nanoprobes for high-efficiency in vivo imaging and clinical translation. Recent years have witnessed increasing research efforts devoted into engineering sub-10 nm ultrasmall nanoprobes for in vivo PL imaging, which offer the advantages of efficient body clearance, desired clinical translation potential, and high imaging signal-to-noise ratio. In this review, we present a comprehensive summary and contrastive discussion of emerging ultrasmall luminescent nanoprobes towards in vivo PL bioimaging of diseases. We first summarize size-dependent nano-bio interactions and imaging features, illustrating the unique attributes and advantages/disadvantages of ultrasmall nanoprobes differentiating them from molecular and large-sized probes. We also discuss general design methodologies and PL properties of emerging ultrasmall luminescent nanoprobes, which are established based on quantum dots, metal nanoclusters, lanthanide-doped nanoparticles, and silicon nanoparticles. Then, recent advances of ultrasmall luminescent nanoprobes are highlighted by surveying their latest in vivo PL imaging applications. Finally, we discuss existing challenges in this exciting field and propose some strategies to improve in vivo PL bioimaging and further propel their clinical applications.

NIR-II Self-Luminous Molecular Probe for In Vivo Inflammation Tracking and Cancer PDT Effect Self-Evaluating

Optical imaging in the second near-infrared (NIR-II, 900-1700 nm) window has been extensively investigated for bioimaging. However, a strong autofluorescence background from real-time excitation light significantly reduces the images' quality of NIR-II fluorescence (FL) imaging. To resolve this issue, a NIR-II self-luminous small molecule (CLPD) based on bioluminescence (BL) resonance energy transfer (BRET) mechanism is first developed. The reactive oxygen species (ROS) can trigger NIR-II BL and reduce the NIR-II FL signals of the CLPD simultaneously, enabling ROS-correlated ratiometric BL/FL imaging. CLPD is used for high-contrast NIR-II BL imaging of osteoarthritis as well as guiding the treatment process by ratiometric BL/FL imaging. Moreover, CLPD is applied for NIR-II BL imaging of tumor triggered by the generated ROS during PDT. A correlation between the ratiometric NIR-II BL/FL signal and tumor size is constructed, providing a trustworthy tool for early assessment of PDT effect. Overall, this study presents a novel NIR-II self-luminous small molecular probe for in vivo imaging and provides a strategy for design a self-evaluation system of therapeutic effect.

Light-triggered theranostic hydrogels for real-time imaging and on-demand photodynamic therapy of skin abscesses

The management of wound infection remains the major challenges in real-time diagnosis, effective bacterial elimination and rapid wound healing. Herein, we developed injectable theranostic hydrogels to achieve long-term visual imaging of infected wounds and possible infection recurrence and to launch an on-demand bactericidal effect without using any antibiotics. Antimicrobial peptide ε-polylysine (ePL)-derived hydrogels were prepared through the copolymerization of methacrylated ePL (mPL) and the conjugates with tetrakis(4-carboxyphenyl) porphyrin (mPL-TCPP) and phenol red (mPL-Pr). Light illumination of mPL-TCPP produces reactive oxidative species (ROS) to initiate free radical crosslinking into PL@Pr-TCPP hydrogels without using any additional photoinitiators and concurrently exhibits antibacterial photodynamic therapy (PDT). PL@Pr-TCPP hydrogels experience quick color changes from yellow to orange and finally to red when pH values change from 5.0 to 9.0. The actual pH and related bacterial levels in the wounds could be read from G/B signal ratios of hydrogel colors captured by a smart phone. The conjugation of phenol red and TCPP into hydrogels affords a robust bacterial infection diagnosis and persistent bactericidal effect after cycled light illumination. The bacterial capture by ePL hydrogels strengthens PDT effect through alleviating the short lifetime and action distance of ROS. On a Staphylococcus aureus-infected abscess model, light illumination of the pregel solutions achieves in situ formation of hydrogel dressings. The synergistic bactericidal performance significantly relieves inflammatory status, accelerates collagen deposition, and promotes neovascularization, leading to full recovery of the infected wounds with regeneration of skin accessories. PL@Pr-TCPP hydrogels on the wound bed show color changes upon the recurrence of bacterial infection, which could also be totally eliminated after light illumination. Therefore, this study demonstrates a feasible strategy to develop theranostic hydrogel dressings for life-cycle diagnosis and on-demand treatment of wound infections. STATEMENT OF SIGNIFICANCE: Over 30% of skin and soft tissue infections become chronic even after appropriate antibacterial treatment, and recurrent infections are commonly reported after initial infection. Challenges remain in the development of theranostic wound dressings having the capability of point-of-care diagnosis, life-cycle monitoring and on-demand elimination of bacterial infection. Herein, light-triggered gelation is used to develop theranostic hydrogels for reversible naked-eye diagnosis and on-demand photodynamic therapy of wound infections. Light illumination plays a "one-stone-two-birds" role, i.e., photodynamically produced reactive oxidative species enable bactericidal effect without using any antibiotics, and the generated free radicals initiate crosslinking of hydrogels without using any additional photoinitiators. Bacterial infection-activated color changes of hydrogels could be captured with a smart phone for on-site and persistent monitoring of bacterial infection and wound healing process.

Chlorin e6-loaded goat milk-derived extracellular vesicles for Cerenkov luminescence-induced photodynamic therapy

PURPOSE

Photodynamic therapy (PDT) is a promising cancer treatment strategy with rapid progress in preclinical and clinical settings. However, the limitations in penetration of external light and precise delivery of photosensitizers hamper its clinical translation. As such, the internal light source such as Cerenkov luminescence (CL) from decaying radioisotopes offers new opportunities. Herein, we show that goat milk-derived extracellular vesicles (GEV) can act as a carrier to deliver photosensitizer Chlorin e6 (Ce6) and tumor-avid 18F-FDG can activate CL-induced PDT for precision cancer theranostics.

METHODS

GEV was isolated via differential ultracentrifugation of commercial goat milk and photosensitizer Ce6 was loaded by co-incubation to obtain Ce6@GEV. Tumor uptake of Ce6@GEV was examined using confocal microscopy and flow cytometry. To demonstrate the ability of 18F-FDG to activate photodynamic effects against cancer cells, apoptosis rates were measured using flow cytometry, and the production of 1O2 was measured by reactive oxygen species (ROS) monitoring kit. Moreover, we used the IVIS device to detect Cherenkov radiation and Cerenkov radiation energy transfer (CRET). For animal experiments, a small-animal IVIS imaging system was used to visualize the accumulation of the GEV drug delivery system in tumors. PET/CT and CL images of the tumor site were performed at 0.5, 1, and 2 h. For in vivo antitumor therapy, changes of tumor volume, survival time, and body weight in six groups of tumor-bearing mice were monitored. Furthermore, the blood sample and organs of interest (heart, liver, spleen, lungs, kidneys, and tumor) were collected for hematological analysis, immunohistochemistry, and H&E staining.

RESULTS

Confocal microscopy of 4T1 cells incubated with Ce6@GEV for 4 h revealed strong red fluorescence signals in the cytoplasm, which demonstrated that Ce6 loaded in GEV could be efficiently delivered into tumor cells. When Ce6@GEV and 18F-FDG co-existed incubated with 4T1 cells, the cell viability plummeted from more than 88.02 ± 1.30% to 23.79 ± 1.59%, indicating excellent CL-induced PDT effects. In vivo fluorescence images showed a peak tumor/liver ratio of 1.36 ± 0.09 at 24 h after Ce6@GEV injection. For in vivo antitumor therapy, Ce6@GEV + 18F-FDG group had the best tumor inhibition rate (58.02%) compared with the other groups, with the longest survival rate (35 days, 40%). During the whole treatment process, neither blood biochemical analysis nor histological observation revealed vital organ damage, suggesting the biosafety of this treatment strategy.

CONCLUSIONS

The simultaneous accumulation of 18F-FDG and Ce6 in tumor tissues is expected to overcome the deficiency of traditional PDT. This strategy has the potential to extend PDT to a variety of tumors, including metastases, using targeted radiotracers to provide internal excitation of light-responsive therapeutics. We expect that our method will play a critical role in precision treatment of deep solid tumors.

Pegylation – in search of balance and enhanced bioavailability

In the process of finding better therapeutics, thousands of new molecules are synthesised every day. Many of these can be poorly soluble in water, leading to a potentially promising drug being rejected during testing due to its poor solubility. Polyethylene glycol (PEG) has become known as an excellent modification to remedy this and was initially used to increase circulation time and reduce the immunogenicity of therapeutic proteins. Thus significantly increasing their safety and range of use. Another group of compounds in which significant benefits of pegylation have been seen are photosensitisers. Used in photodynamic therapy, they are often characterised by very high hydrophobicity. Pegylation of their structure significantly increases their affinity for cancer cells and facilitates their penetration through cell membranes. Classical small-molecule drugs can benefit from temporary combinations hydrolysed in the body or very short PEG chains. This approach allows a significant increase in the bioavailability of the drug while avoiding the disadvantages of small molecule pegylation. However, the most common motive for pegylation recently is the creation of drug carriers. Liposomes and nanoparticles make it possible to exploit the advantages of PEG to stabilise their structure and increase circulation time while not modifying the structure of the active compound. Unfortunately, PEGs also have their drawbacks. The first is their high molecular weight range, especially for longer chains, which poses difficulties in purification. Another is the emergence of antibodies directed against PEG. Nevertheless, pegylation is still an up-and-coming method for modifying pharmaceutically active molecules.

Low dimensional nanomaterials for treating acute kidney injury

Acute kidney injury (AKI) is one of the most common severe complications among hospitalized patients. In the absence of specific drugs to treat AKI, hemodialysis remains the primary clinical treatment for AKI patients. AKI treatment has received significant attention recently due to the excellent drug delivery capabilities of low-dimensional nanomaterials (LDNs) and their unique therapeutic effects. Diverse LDNs have been proposed to treat AKI, with promising results and the potential for future clinical application. This article aims to provide an overview of the pathogenesis of AKI and the recent advances in the treatment of AKI using different types of LDNs. In addition, it is intended to provide theoretical support for the design of LDNs and implications for AKI treatment.

Shape-directed drug release and transport of erythrocyte-like nanodisks augment chemotherapy

Nanoparticle shape has been recognized as a crucial parameter to affect the transport across various biological barriers, but its impact on drug release and the resulting therapeutic efficacy is less understood. Inspired by erythrocytes with shape-facilitated oxygen-carrying and penetrating abilities, we constructed artificial erythrocyte-like nanoparticles (RNDs) by wrapping discoidal mesoporous silica nanoparticles with red blood cell membrane. We observed that, compared with their spherical and rod-shaped counterparts with monotonic drug release profiles, RNDs displayed an on-demand drug release pattern mimicking natural erythrocytes, that is, they could rapidly release loaded oxygen and doxorubicin (DOX) in hypoxic condition but were relatively stable in high oxygen areas. Besides, the discoidal shape also endowed RNDs with facilitated transport capability in tumor extracellular matrix, contributing to increased tumor permeability. In tumor models, systemically administrated RNDs efficiently infiltrate throughout tumor tissue, successfully relieve tumor hypoxia, and further altered the cancer cell cycle status from G1 to G2 phase, enhancing cancer cell sensitivity to DOX correlated with improved chemotherapy efficacy. In contrast, nanospheres show hampered permeability, and nanorods suffer from insufficient intratumoral drug accumulation. These findings can offer guidelines for the use of particle shape as a design criterion to control drug release, transportation, and therapeutics delivery.

A mitochondria-targeting lipid-small molecule hybrid nanoparticle for imaging and therapy in an orthotopic glioma model

Hybrid lipid‒nanoparticle complexes have shown attractive characteristics as drug carriers due to their integrated advantages from liposomes and nanoparticles. Here we developed a kind of lipid-small molecule hybrid nanoparticles (LPHNPs) for imaging and treatment in an orthotopic glioma model. LPHNPs were prepared by engineering the co-assembly of lipids and an amphiphilic pheophorbide a‒quinolinium conjugate (PQC), a mitochondria-targeting small molecule. Compared with the pure nanofiber self-assembled by PQC, LPHNPs not only preserve the comparable antiproliferative potency, but also possess a spherical nanostructure that allows the PQC molecules to be administrated through intravenous injection. Also, this co-assembly remarkably improved the drug-loading capacity and formulation stability against the physical encapsulation using conventional liposomes. By integrating the advantages from liposome and PQC molecule, LPHNPs have minimal system toxicity, enhanced potency of photodynamic therapy (PDT) and visualization capacities of drug biodistribution and tumor imaging. The hybrid nanoparticle demonstrates excellent curative effects to significantly prolong the survival of mice with the orthotopic glioma. The unique co-assembly of lipid and small molecule provides new potential for constructing new liposome-derived nanoformulations and improving cancer treatment.

Porphyrins as Chelating Agents for Molecular Imaging in Nuclear Medicine

Porphyrin ligands, showing a significant affinity for cancer cells, also have the ability to chelate metallic radioisotopes to form potential diagnostic radiopharmaceuticals. They can be applied in single-photon emission computed tomography (SPECT) and positron emission tomography (PET) to evaluate metabolic changes in the human body for tumor diagnostics. The aim of this paper is to present a short overview of the main metallic radionuclides complexed by porphyrin ligands and used in these techniques. These chelation reactions are discussed in terms of the complexation conditions and kinetics and the complex stability.

Synthesis, Renal Clearance, and Photothermal Therapy Based on the Self-Assembly of a Nanomedicine Consisting of Quaterrylene Bisimide and Glycocluster Conjugates

Renal-clearable nanomedicines are considered the next generation of nanomedicines, and show potential application for future clinical translations. However, it is important to determine whether self-assembly can form large aggregates that accrue in tumors and then tailor the size of these assemblies to be excreted renally. In this paper, a renal-clearable nanomedicine based on quanterrylene bisimide-mannose conjugates (QDI-Man) was developed. QDI-Man showed a high renal clearance efficiency of 80.31 ± 2.85% in mice. We confirmed that the self-assembly of QDI-Man exhibited a dynamic adjustment process through the renal filtration thresholds, that is, "aggregation → self-regulating the aggregate size through the renal filtration thresholds → reaggregating into aggregates". Benefiting from the modification of mannose-based glycoclusters, QDI-Man showed selective photothermal therapy because of the mannose receptors overexpressed in breast cancer cells, and showed good photothermal therapy in mice. This paper developed a dynamic adjustment theory for effective renal clearance based on organic self-assembly.

Design of Smart Nanomedicines for Effective Cancer Treatment

Nanomedicine is a novel field of study that involves the use of nanomaterials to address challenges and issues that are associated with conventional therapeutics for cancer treatment including, but not limited to, low bioavailability, low water-solubility, narrow therapeutic window, nonspecific distribution, and multiple side effects of the drugs. Multiple strategies have been exploited to reduce the nonspecific distribution, and thus the side effect of the active pharmaceutical ingredients (API), including active and passive targeting strategies and externally controllable release of the therapeutic cargo. Site-specific release of the drug prevents it from impacting healthy cells, thereby significantly reducing side effects. API release triggers can be either externally applied, as in ultrasound-mediated activation, or induced by the tumor. To rationally design such nanomedicines, a thorough understanding of the differences between the tumor microenvironment versus that of healthy tissues must be pared with extensive knowledge of stimuli-responsive biomaterials. Herein, we describe the characteristics that differentiate tumor tissues from normal tissues. Then, we introduce smart materials that are commonly used for the development of smart nanomedicines to be triggered by stimuli such as changes in pH, temperature, and enzymatic activity. The most recent advances and their impact on the field of cancer therapy are further discussed.

H2O2 generation enhancement by ultrasonic nebulisation with a zinc layer for spray disinfection

With the outbreak of COVID-19, microbial pollution has gained increasing attention as a threat to human health. Consequently, many research efforts are being devoted to the development of efficient disinfection methods. In this context, hydrogen peroxide (H₂O₂) stands out as a green and broad-spectrum disinfectant, which can be produced and sprayed in the air directly by cavitation in ultrasonic nebulisation. However, the yield of H₂O₂ obtained by ultrasonic nebulisation is too low to satisfy the requirements for disinfection by spraying and needs to be improved to achieve efficient disinfection of the air and objects. Herein, we report the introduction of a zinc layer into an ultrasonic nebuliser to improve the production of H₂O₂ and generate additional Zn²⁺ by self-corrosion, achieving good disinfecting performance. Specifically, a zinc layer was assembled on the oscillator plate of a commercial ultrasonic nebuliser, resulting in a 21-fold increase in the yield of H₂O₂ and the production of 4.75 μg/mL Zn²⁺ in the spraying droplets. When the generated water mist was used to treat a bottle polluted with Escherichia coli for 30 min, the sterilisation rate reached 93.53%. This ultrasonic nebulisation using a functional zinc layer successfully enhanced the production of H₂O₂ while generating Zn²⁺, providing a platform for the development of new methodologies of spray disinfection.

pH and Temperature Double-Switch Hybrid Micelles for Controllable Drug Release

pH/temperature dual-responsive hybrid micelles were prepared for constructing a double-locked drug delivery system. The temperature-sensitive polyethylene glycol-poly(tetrahydropyranylmethacrylate)-polyethylene glycol (PEG-PTHPMA-PEG) triblock copolymers were synthesized by reversible addition-fragmentation chain transfer polymerization and amide coupling reaction. pH-sensitive poly(2-(diisopropylamino ethylmethacrylate)-polyethylene glycol (PDPA-PEG) diblock polymers were introduced, which could self-assemble with PEG-PTHPMA-PEG in aqueous solutions to form hybrid micelles. The anticancer drug doxorubicin, which was encapsulated in the core of the hybrid micelles, could be released only under simultaneous stimulations of pH and temperature. It was proved that the micelles could maintain their structural stability under a unilateral stimulus, while the structure collapsed and recombined under a double stimulus, which triggered a large amount of drug release. Furthermore, the excellent biocompatibility and dual sensitivity of the vector were also proved by cytotoxicity experiments. The dual-responsive hybrid micelles designed here showed the advantages of a double insurance lock of drug leakage and precise controllability of drug release, which could act as accurate drug delivery systems.

A review of advances in the last decade on targeted cancer therapy using 177Lu: focusing on 177Lu produced by the direct neutron activation route

Lutetium-177 [T½ = 6.76 d; Eβ (max) = 0.497 MeV; maximum tissue range ~2.5 mm; 208 keV γ-ray] is one of the most important theranostic radioisotope used for the management of various oncological and non-oncological disorders. The present review chronicles the advancement in the last decade in 177Lu-radiopharmacy with a focus on 177Lu produced via direct 176Lu (n, γ) 177Lu nuclear reaction in medium flux research reactors. The specific nuances of 177Lu production by various routes are described and their pros and cons are discussed. Lutetium, is the last element in the lanthanide series. Its chemistry plays a vital role in the preparation of a wide variety of radiopharmaceuticals which demonstrate appreciable in vivo stability. Traditional bifunctional chelators (BFCs) that are used for 177Lu-labeling are discussed and the upcoming ones are highlighted. Research efforts that resulted in the growth of various 177Lu-based radiopharmaceuticals in preclinical and clinical settings are provided. This review also summarizes the results of clinical studies with potent 177Lu-based radiopharmaceuticals that have been prepared using medium specific activity 177Lu produced by direct neutron activation route in research reactors. Overall, the review amply demonstrates the practicality of the medium specific activity 177Lu towards formulation of various clinically useful radiopharmaceuticals, especially for the benefit of millions of cancer patients in developing countries with limited reactor facilities.

A Bright, Renal-Clearable NIR-II Brush Macromolecular Probe with Long Blood Circulation Time for Kidney Disease Bioimaging

Early detection of kidney disease is of vital importance due to its current prevalence worldwide. Fluorescence imaging, especially in the second near-infrared window (NIR-II) has been regarded as a promising technique for the early diagnosis of kidney disease due to the superior resolution and sensitivity. However, the reported NIR-II organic renal-clearable probes are hampered by their low brightness (ϵ_max Φ_f>1000 nm <10 M^-1  cm^-1 ) and limited blood circulation time (t_1/2 <2 h), which impede the targeted imaging performance. Herein, we develop the aza-boron-dipyrromethene (aza-BODIPY) brush macromolecular probes (Fudan BDIPY Probes (FBP 912)) with high brightness (ϵ_max Φ_f>1000 nm ≈60 M^-1  cm^-1 ), which is about 10-fold higher than that of previously reported NIR-II renal-clearable organic probes. FBP 912 exhibits an average diameter of ≈4 nm and high renal clearance efficiency (≈65 % excretion through the kidney within 12 h), showing superior performance for non-invasively diagnosis of renal ischemia-reperfusion injury (RIR) earlier than clinical serum-based protocols. Additionally, the high molecular weight polymer brush enables FBP 912 with prolonged circulation time (t_1/2 ≈6.1 h) and higher brightness than traditional PEGylated renal-clearable control fluorophores (t_1/2 <2 h), facilitating for 4T1 tumor passive targeted imaging and renal cell carcinoma active targeted imaging with higher signal-to-noise ratio and extended retention time.

Photo-Driven Delivery of 125I-Labeled Nanomicelles for Nucleus-Targeted Internal Conversion Electron-Based Cancer Therapy

As a kind of high linear energy transfer (LET) radiation, internal conversion electrons are emitted from some radionuclides, such as ¹²⁵I, triggering severe DNA damage to tumor cells when transported into the nucleus. Herein, we develop a curcumin-loaded nanomicelle composed of a photosensitizer chlorin e6 (Ce6) and amphiphilic poly(ethylene glycol) (poly(maleic anhydride-alt-1-octadecene)-poly(ethylene glycol) (C₁₈-PMH-PEG)) to deliver ¹²⁵I into the nucleus under 660 nm laser irradiation, leading to the optimized imaging-guided internal conversion electron therapy of cancer. Ce6-containing nanomicelles (Ce6-C₁₈-PEG) self-assemble with nucleus-targeted curcumin (Cur), obtaining Ce6-C₁₈-PEG/Cur nanoparticles. After labeling Cur with ¹²⁵I, Ce6-C₁₈-PEG/Cur enables single-photon emission computed tomography and fluorescence imaging of the tumor, serving as a guide for follow-up laser irradiation. Notably, the 660 nm laser-triggered photodynamic reaction of Ce6 optimizes the delivery of Ce6-C₁₈-PEG/¹²⁵I-Cur at various stages, including tumor accumulation, cellular uptake, and lysosome escape, causing plenty of ¹²⁵I-Cur to enter the nucleus. By this strategy, Ce6-C₁₈-PEG/¹²⁵I-Cur showed optimal antitumor efficacy and high biosafety in mice treated with local 660 nm laser irradiation using efficient energy deposition of internally converted electrons over short distances. Therefore, our work provides a novel strategy to optimize ¹²⁵I delivery for tumor treatment.

Gadolinium-porphyrin based polymer nanotheranostics for fluorescence/magnetic resonance imaging guided photodynamic therapy

Nanotheranostics for fluorescence/magnetic resonance (FL/MR) dual-modal imaging guided photodynamic therapy (PDT) are highly desirable in precision and personalized medicine. In this study, a facile non-covalent electrostatic interaction induced self-assembly strategy is developed to effectively encapsulate gadolinium porphyrin (Gd-TCPP) into homogeneous supramolecular nanoparticles (referred to as Gd-PNPs). Gd-PNPs exhibit the following advantages: (1) excellent FL imaging property, high longitudinal relaxivity (16.157 mM^-1 s^-1), and good singlet oxygen (¹O₂) production property; (2) excellent long-term colloidal stability, dispersity and biocompatibility; and (3) enhanced in vivo FL/MR imaging guided tumor growth inhibition efficiency for CT 26 tumor-bearing mice. This study provides a new strategy to design and synthesize metalloporphyrin-based nanotheranostics for imaging-guided cancer therapy with enhanced theranostic properties.

Safety Evaluation of Nanotechnology Products

Nanomaterials are now being used in a wide variety of biomedical applications. Medical and health-related issues, however, have raised major concerns, in view of the potential risks of these materials against tissue, cells, and/or organs and these are still poorly understood. These particles are able to interact with the body in countless ways, and they can cause unexpected and hazardous toxicities, especially at cellular levels. Therefore, undertaking in vitro and in vivo experiments is vital to establish their toxicity with natural tissues. In this review, we discuss the underlying mechanisms of nanotoxicity and provide an overview on in vitro characterizations and cytotoxicity assays, as well as in vivo studies that emphasize blood circulation and the in vivo fate of nanomaterials. Our focus is on understanding the role that the physicochemical properties of nanomaterials play in determining their toxicity.

Water-Soluble Non-Ionic PEGylated Porphyrins: A Versatile Category of Dyes for Basic Science and Applications

This review arises from the need to rationalize the huge amount of information on the structural and spectroscopic properties of a peculiar class of porphyrin derivatives-the non-ionic PEGylated porphyrins-collected during almost two decades of research. The lack of charged groups in the molecular architecture of these porphyrin derivatives is the leitmotif of the work and plays an outstanding role in highlighting those interactions between porphyrins, or between porphyrins and target molecules (e.g., hydrophobic-, hydrogen bond related-, and coordination-interactions, to name just a few) that are often masked by stronger electrostatic contributions. In addition, it is exactly these weaker interactions between porphyrins that make the aggregated forms more prone to couple efficiently with external perturbative fields like weak hydrodynamic vortexes or temperature gradients. In the absence of charge, solubility in water is very often achieved by covalent functionalization of the porphyrin ring with polyethylene glycol chains. Various modifications, including of chain length or the number of chains, the presence of a metal atom in the porphyrin core, or having two or more porphyrin rings in the molecular architecture, result in a wide range of properties. These encompass self-assembly with different aggregate morphology, molecular recognition of biomolecules, and different photophysical responses, which can be translated into numerous promising applications in the sensing and biomedical field, based on turn-on/turn-off fluorescence and on photogeneration of radical species.

Cu,Zn Dopants Boost Electron Transfer of Carbon Dots for Antioxidation

Enzyme-mimicking nanomaterials for antioxidative therapy is a promising star to treat more than 200 diseases or control their progressions through scavenging excessive reactive oxygen species (ROS), such as O₂^•- and H₂ O₂ . However, they can inversely produce stronger ROS (e.g., •OH) under many disease conditions (e.g., low pH for myocardial ischemia). Herein, a biocompatible -Cu-O-Zn- bimetallic covalent doped carbon dots (CuZn-CDs) processing both catalase (CAT) and superoxide dismutase activities are reported, mainly because of their abundant electrons and the excellent electron transfer abilities. In addition, Cu dopant helps to balance the positive charge at Zn dopant resulting from low pH, enabling CuZn-CDs to still process CAT ability rather than peroxidase ability. Benefiting from it, CuZn-CDs exhibit sufficient in vitro ROS scavenging ability and cardiomyocyte protective effect against ROS-induced damage. In vivo results further demonstrate that CuZn-CDs can protect the heart from ischemia-reperfusion injury. In addition to antioxidative therapy, the rapid renal clearance and low toxicity properties of CuZn-CDs in animal model reveal high biocompatibility which will facilitate clinical use.

Nanoformulations of Ursolic Acid: A Modern Natural Anticancer Molecule

Background: Ursolic acid (UA) is a natural pentacyclic triterpene derived from fruit, herb, and other plants. UA can act on molecular targets of various signaling pathways, inhibit the growth of cancer cells, promote cycle stagnation, and induce apoptosis, thereby exerting anticancer activity. However, its poor water-solubility, low intestinal mucosal absorption, and low bioavailability restrict its clinical application. In order to overcome these deficiencies, nanotechnology, has been applied to the pharmacological study of UA.

Objective: In this review, we focused on the absorption, distribution, and elimination pharmacokinetics of UA in vivo, as well as on the research progress in various UA nanoformulations, in the hope of providing reference information for the research on the anticancer activity of UA.

Methods: Relevant research articles on Pubmed and Web of Science in recent years were searched selectively by using the keywords and subheadings, and were summarized systematically.

Key finding: The improvement of the antitumor ability of the UA nanoformulations is mainly due to the improvement of the bioavailability and the enhancement of the targeting ability of the UA molecules. UA nanoformulations can even be combined with computational imaging technology for monitoring or diagnosis.

Conclusion: Currently, a variety of UA nanoformulations, such as micelles, liposomes, and nanoparticles, which can increase the solubility and bioactivity of UA, while promoting the accumulation of UA in tumor tissues, have been prepared. Although the research of UA in the nanofield has made great progress, there is still a long way to go before the clinical application of UA nanoformulations.

Artificially engineered antiferromagnetic nanoprobes for ultra-sensitive histopathological level magnetic resonance imaging

Histopathological level imaging in a non-invasive manner is important for clinical diagnosis, which has been a tremendous challenge for current imaging modalities. Recent development of ultra-high-field (UHF) magnetic resonance imaging (MRI) represents a large step toward this goal. Nevertheless, there is a lack of proper contrast agents that can provide superior imaging sensitivity at UHF for disease detection, because conventional contrast agents generally induce T2 decaying effects that are too strong and thus limit the imaging performance. Herein, by rationally engineering the size, spin alignment, and magnetic moment of the nanoparticles, we develop an UHF MRI-tailored ultra-sensitive antiferromagnetic nanoparticle probe (AFNP), which possesses exceptionally small magnetisation to minimize T2 decaying effect. Under the applied magnetic field of 9 T with mice dedicated hardware, the nanoprobe exhibits the ultralow r2/r1 value (~1.93), enabling the sensitive detection of microscopic primary tumours (<0.60 mm) and micrometastases (down to 0.20 mm) in mice. The sensitivity and accuracy of AFNP-enhanced UHF MRI are comparable to those of the histopathological examination, enabling the development of non-invasive visualization of previously undetectable biological entities critical to medical diagnosis and therapy.

Facile Synthesis of a Croconaine-Based Nanoformulation for Optoacoustic Imaging and Photothermal Therapy

Near-infrared (NIR) light absorbing theranostic agents can integrate optoacoustic imaging and photothermal therapy for effective personalized precision medicine. However, most of these agents face the challenges of unstable optical properties, material-associated toxicity, and nonbiodegradability, all of which limit their biomedical application. Several croconaine-based organic agents able to overcome some of these limitations have been recently reported, but these suffer from complicated multistep synthesis protocols. Herein, the use of CR760, a croconaine dye with excellent optical properties, is reported for nanoparticle formulation and subsequent optoacoustic imaging and photothermal therapy. Importantly, CR760 can be conveniently prepared in a single step from commercially available materials. Furthermore, CR760 can be covalently attached, via a polyethylene glycol linker, to the α_v β₃ integrin ligand c(RGDyC), resulting in self-assembled nanoparticles (NPs) with cancer-targeting capability. Such CR760RGD-NPs exhibit strong NIR absorption, high photostability, high optoacoustic generation efficiency, and active tumor-targeting, making them ideal candidates for optoacoustic imaging. Due to favorable electron transfer, CR760RGD-NPs display a 45.37% photothermal conversion efficiency thereby rendering them additionally useful for photothermal therapy. Targeted tumor elimination, biosafety, and biocompatibility are demonstrated in a 4T1 murine breast tumor model. This work points to the use of CR760RGD-NPs as a promising nanoagent for NIR-based cancer phototheranostics.

Combined delivery of salinomycin and docetaxel by dual-targeting gelatinase nanoparticles effectively inhibits cervical cancer cells and cancer stem cells

Intra-tumor heterogeneity is widely accepted as one of the key factors, which hinders cancer patients from achieving full recovery. Especially, cancer stem cells (CSCs) may exhibit self-renewal capacity, which makes it harder for complete elimination of tumor. Therefore, simultaneously inhibiting CSCs and non-CSCs in tumors becomes a promising strategy to obtain sustainable anticancer efficacy. Salinomycin (Sal) was reported to be critical to inhibit CSCs. However, the poor bioavailability and catastrophic side effects brought about limitations to clinical practice. To solve this problem, we previously constructed gelatinase-stimuli nanoparticles composed of nontoxic, biocompatible polyethylene glycol-polycaprolactone (PEG-PCL) copolymer with a gelatinase-cleavable peptide Pro-Val-Gly-Leu-Iso-Gly (PVGLIG) inserted between the two blocks of the copolymer. By applying our “smart” gelatinase-responsive nanoparticles for Sal delivery, we have demonstrated specific accumulation in tumor, anti-CSCs ability and reduced toxicity of Sal-NPs in our previous study. In the present study, we synthesized Sal-Docetaxel-loaded gelatinase-stimuli nanoparticles (Sal-Doc NP) and confirmed single emulsion as the optimal method of producing Sal-Doc NPs (Sal-Doc SE-NP) in comparison with nanoprecipitation. Sal-Doc SE-NPs inhibited both CSCs and non-CSCs in mice transplanted with cervical cancer, and might be associated with enhanced restriction of epithelial-mesenchymal transition (EMT) pathway. Besides, the tumorigenic capacity and growing speed were obviously suppressed in Sal-Doc-SE-NPs-treated group in rechallenge experiment. Our results suggest that Sal-Doc-loaded gelatinase-stimuli nanoparticles could be a promising strategy to enhance antitumor efficacy and reduce side effects by simultaneously suppressing CSCs and non-CSCs.

A porous material excited by near-infrared light for photo/chemodynamic and photothermal dual-mode combination therapy

Photodynamic therapy (PDT) and photothermal therapy (PTT) are well-developed light therapy methods for cancer; however, both have a few areas that need improvement. A sustained PDT effect depends on the sustained generation of reactive oxygen species (ROS); therefore, adjusting the type of photosensitizer or the reaction mechanism to prolong the duration of the oxidation-reduction reaction is a possible solution for the continuation of the PDT effect. Further, if PTT could be combined with other treatments, it would bring about a more satisfactory therapeutic effect. To increase the treatment effect of the above two therapeutic methods, a collaborative treatment model of photo/chemodynamic therapy (PCDT) and PTT is needed and is the focus of this study. On the one hand, PCDT is a therapy that integrates PDT with Fenton-like reactions, and Fenton-like reactions can help PDT to produce more ROS by making better use of H₂O₂ in the tumor microenvironment. On the other hand, the PTT effect can also promote PCDT effects to some extent because rising temperature can elevate the redox reaction rate. Therefore, a copper oxide semiconductor photosensitizer was selected in this research to realize the abovementioned therapeutic purposes and experimental concepts. A porous silica carrier can facilitate the uniform attachment of the copper oxide photosensitizer to the SiO₂ surface to form a relatively uniform nanostructure, and the nanoporous structure can increase the performance of the whole material to a certain extent. Based on these perspectives, SiO₂@CuO nanotube (NT), an agent of both Fenton-like photosensitization and photothermal reagent, is synthesized by the hydrothermal co-precipitation template approach to shrink the tumor through the combined effect of PCDT and PTT. In this system, copper ions can participate in the Fenton-like reactions and make better use of H₂O₂ to generate more ROS. Herein, 808 nm light was chosen for irradiation because of its suitable excitation ability, applicable penetration and low intrinsic damage. The experimental results show that SiO₂@CuO NT is a promising agent that combines PCDT and PTT for cancer treatment. This work provides guidance for the synthesis of Fenton-like photosensitizers for the PCDT effect.

Highly Red Light-Emitting Erbium- and Lutetium-Doped Core-Shell Upconverting Nanoparticles Surface-Modified with PEG-Folic Acid/TCPP for Suppressing Cervical Cancer HeLa Cells

Photodynamic therapy (PDT) combined with upconverting nanoparticles (UCNPs) are viewed together as an effective method of ablating tumors. After absorbing highly tissue-penetrating near-infrared (NIR) light, UCNPs emit a shorter wavelength light (~660 nm) suitable for PDT. In this study, we designed and prepared highly red fluorescence-emitting silica-coated core-shell upconverting nanoparticles modified with polyethylene glycol (PEG5k)-folic acid and tetrakis(4-carboxyphenyl)porphyrin (TCPP) (UCNPs@SiO2-NH2@FA/PEG/TCPP) as an efficient photodynamic agent for killing tumor cells. The UCNPs consisted of two simple lanthanides, erbium and lutetium, as the core and shell, respectively. The unique core-shell combination enabled the UCNPs to emit red light without green light. TCPP, folic acid, and PEG were conjugated to the outer silica layer of UCNPs as a photosensitizing agent, a ligand for tumor attachment, and a dispersing stabilizer, respectively. The prepared UCNPs of ~50 nm diameter and -34.5 mV surface potential absorbed 808 nm light and emitted ~660 nm red light. Most notably, these UCNPs were physically well dispersed and stable in the aqueous phase due to PEG attachment and were able to generate singlet oxygen (1O2) with a high efficacy. The HeLa cells were treated with each UCNP sample (0, 1, 5, 10, 20, 30 μg/mL as a free TCPP). The results showed that the combination of UCNPs@SiO2-NH2@FA/PEG/TCPP and the 808 nm laser was significantly cytotoxic to HeLa cells, almost to the same degree as naïve TCPP plus the 660 nm laser based on MTT and Live/Dead assays. Furthermore, the UCNPs@SiO2-NH2@FA/PEG/TCPP was well internalized into HeLa cells and three-dimensional HeLa spheroids, presumably due to the surface folic acid and small size in conjunction with endocytosis and the nonspecific uptake. We believe that our UCNPs@SiO2-NH2@FA/PEG/TCPP will serve as a new platform for highly efficient and deep-penetrating photodynamic agents suitable for various tumor treatments.

A Multistage Cooperative Nanoplatform Enables Intracellular Co-Delivery of Proteins and Chemotherapeutics for Cancer Therapy

Combining intracellularly active proteins with chemotherapeutics represents a promising strategy for synergistic cancer therapy. However, the lack of nanocarrier systems for delivery into cancer cells and controlled intracellular release of both physicochemically very distinct cargos significantly impedes the biomedical translation of this combination strategy in cancer therapy. Here, a well-designed triblock copolymer, mPEG-b-PGCA-b-PGTA, is reported for application in a multistage cooperative drug delivery nanoplatform that accomplishes effective intracellular co-delivery of hydrophilic ribonuclease A (RNase A) and hydrophobic doxorubicin (DOX). RNase A bioreversibly modified with phenylboronic acid groups via a ROS-cleavable carbamate linker is incorporated into the triblock copolymer nanoparticles with high efficiency through a pH-reversible phenylboronic acid-catechol linkage. The reversible covalent conjugations between RNase A and the triblock copolymer endow the nanoparticles with high stability under normal physiological conditions. Upon cellular internalization, the cooperative release of DOX and RNase A from the triblock copolymer nanoparticles is triggered at multiple stages by endosomal acidic environment and subsequent DOX-enhanced intracellular ROS environment. This leads to enhanced synergistic anticancer effects as demonstrated both in vitro and in vivo. Given the versatility of dynamic covalent conjugations, this work provides a universal and stable platform for intracellular co-delivery of various combinations of proteins and chemotherapeutics.

Nanomedicines for Renal Management: From Imaging to Treatment

Nanomedicine has benefited from recent advances in chemistry and biomedical engineering to produce nanoscale materials as theranostic agents. Well-designed nanomaterials may present optimal biological properties, influencing circulation, retention, and excretion for imaging and treatment of various diseases. As the understanding of nanomedicine pharmacokinetics expands continuously, efficient renal clearance of nanomedicines can significantly increase the signal-to-background ratio for precision diagnosis and lower potential toxicity for improved treatment. Studies on nanomaterial-kidney interactions have led to many novel findings on the underlying principles of nanomaterial renal clearance, targeting, and accumulation. In return, the optimized nanomedicines confer significant benefits to the detection and treatment of kidney dysfunction.In this Account, we present an overview of recent progress in the development of nanomaterials for kidney theranostics, aiming to speed up translation and expand possible applications. We start by introducing biological structures of the kidney and their influence on renal targeting, retention, and clearance. Several key factors regarding renal accumulation and excretion, including nanomaterial types, sizes, and shapes, surface charges, and chemical modifications, are identified and discussed. Next, we highlight our recent efforts investigating kidney-interacting nanomaterials and introduce representative nanomedicines for imaging and treatment of kidney diseases. Multiple renal-clearable and renal-accumulating nanomedicines were devised for kidney function imaging. By employing renal-clearable nanomedicines, including gold nanoparticles, porphyrin polymers, DNA frameworks, and polyoxometalate clusters, we were able to noninvasively evaluate split renal function in healthy and diseased mice. Further engineering of renal-accumulating nanosystems has shifted attention from renal diagnosis to precision kidney protection. Many biocompatible nanomedicines, such as DNA origami, selenium-doped carbon quantum dots, melanin nanoparticles, and black phosphorus have all played essential roles in diminishing excessive reactive oxygen species for kidney treatment and protection. Finally, we discuss the challenges and perspectives of nanomaterials for renal care, their future clinical translation, and how they may affect the current landscape of clinical practices. We believe that this Account updates our current understanding of nanomaterial-kidney interactions for further design and control of nanomedicines for specific kidney diagnosis and treatment. This timely Account will generate broad interest in integrating nanotechnology and nanomaterial-biological interaction for state-of-the-art theranostics of renal diseases.

A pH-Responsive System Based on Fluorescence Enhanced Gold Nanoparticles for Renal Targeting Drug Delivery and Fibrosis Therapy

Background

Stimuli-responsive gold nano-assemblies have attracted attention as drug delivery systems in the biomedical field. However, there are challenges achieving targeted delivery and controllable drug release for specific diseases.

Materials and Methods

In this study, a glutathione (GSH)-modified fluorescent gold nanoparticle termed AuLA-GSH was prepared and a Co²⁺-induced self-assembly drug delivery platform termed AuLA-GSH-Co was constructed. Both the pH-responsive character and drug loading behavior of AuLA-GSH-Co were studied in vitro. Kidney-targeting capability was investigated in vitro and in vivo. Finally, the anti-fibrosis efficiency of AuLA-GSH-Co in a mouse model of unilateral ureteral obstruction (UUO) was explored.

Results

AuLA-GSH-Co was sensitive to pH changes and released Co²⁺ in acidic conditions, allowing it to have controllable drug release abilities. AuLA-GSH-Co was found to improve cellular uptake of Co²⁺ ions compared to CoCl₂ in vitro. AuLA-GSH exhibited specific renal targeting and prolonged renal retention time with low non-specific accumulation in vivo. Moreover, the anti-fibrosis efficiency of AuLA-GSH-Co was higher compared to CoCl₂ in a mouse model of unilateral ureteral obstruction (UUO).

Conclusion

AuLA-GSH-Co could greatly enhance drug delivery efficiency with renal targeting capability and obviously relieve renal fibrosis, providing a promising strategy for renal fibrosis therapy.

Phenol-like group functionalized graphene quantum dots structurally mimicking natural antioxidants for highly efficient acute kidney injury treatment

Acute kidney injury (AKI) is a syndrome characterized by rapid loss of renal excretory function with high in-hospital mortality. The excess generation of reactive oxygen species (ROS) in the kidneys during AKI has been considered a major cause of renal failure. Currently available antioxidants for AKI treatment often lack the required antioxidative efficacy or renal accumulation rate. Herein, inspired by the structure of natural phenolic antioxidants, phenol-like group functionalized graphene quantum dots (h-GQDs) with both high ROS scavenging efficacy and renal specificity are constructed for AKI antioxidative therapy. Similar to natural polyphenols, the abundant phenol-like groups on h-GQDs are demonstrated to be the active components exerting antioxidative effects. Further exhaustive mechanistic investigations indicate that the ultrahigh antioxidative activity of h-GQDs originates not solely from the phenol-like groups, but also from the synergy between adjacent phenol-like groups, as well as the removal of unfavorable carbonyl groups on h-GQDs. In AKI mice, h-GQDs can effectively protect the kidneys from oxidative injury with only a one-sixteenth dose of the clinical antioxidant N-acetylcysteine (NAC) and show no evidence of toxicity. The findings of this study will facilitate development of high-performance carbon-based antioxidative platforms via structure–activity relationships for treating AKI and other ROS-related diseases.

Phenol-like group functionalized graphene quantum dots that structurally mimic natural antioxidants are constructed as high-efficacy reactive oxygen species scavengers for acute kidney injury antioxidative therapy.

An Ultrasmall RuO2 Nanozyme Exhibiting Multienzyme-like Activity for the Prevention of Acute Kidney Injury

Oxidative stress induced by reactive oxygen species (ROS) is one of the major pathological mechanisms of acute kidney injury (AKI). Inorganic nanomaterial-mediated antioxidant therapy is considered a promising method for the prevention of AKI; however, currently available antioxidants for AKI exhibit limited clinical efficacy due to the glomerular filtration threshold (∼6 nm). To address this issue, we developed ultrasmall RuO₂ nanoparticles (RuO₂NPs) (average size ≈ 2 nm). The NPs show excellent antioxidant activity and low biological toxicity. In addition, they can pass through the glomerulus to be excreted. These properties in combination make the ultrasmall RuO₂NPs promising as a nanozyme for the prevention of AKI. The NP catalytic properties mimic the activity of catalase, peroxidase, superoxide dismutase, and glutathione peroxidase. The nanozyme can be efficiently and rapidly absorbed by human embryonic kidney cells while significantly reducing ROS-induced apoptosis by eliminating excess ROS. After intravenous injection, the ultrasmall RuO₂NPs significantly inhibit the development of AKI in mice. In vivo toxicity experiments demonstrate the biosafety of the NPs after long-term preventing. The multienzyme-like activity and biocompatibility of the ultrasmall RuO₂NPs makes them of great interest for applications in the fields of biomedicine and biocatalysis.

Renal clearable nanocarriers: Overcoming the physiological barriers for precise drug delivery and clearance

Physiological barriers encountered in the clinical translation of cancer nanomedicines inspire the community to more deeply understand nano-bio interactions in not only tumor microenvironment but also entire body and develop new nanocarriers to tackle these barriers. Renal clearable nanocarriers are one kind of these newly emerged drug delivery systems (DDSs), which enable drugs to rapidly penetrate into the tumor cores with no need of long blood retention and escape macrophage uptake in the meantime they can also enhance body elimination of non-targeted anticancer drugs. As a result, they can improve therapeutic efficacies and reduce side effects of anticancer drugs. Not limited to anticancer drugs, diagnostic agents can also be achieved with these renal clearable DDSs, which might also be applied to improve the precision in the gene editing and immunotherapy in the future.

SiO2@Cu7S4 nanotubes for photo/chemodynamic and photo-thermal dual-mode synergistic therapy under 808 nm laser irradiation

Photodynamic therapy (PDT) is a light-based modality for tumor treatment that involves the generation of reactive oxygen species (ROS) by the combination of light, a photosensitizer, and molecular oxygen. Nevertheless, the therapeutic effects of PDT are limited by hypoxic conditions that worsen with oxygen consumption during the PDT process. Photo/chemodynamic therapy (PCDT) based on the Fenton reaction is one strategy to improve ROS generation, provided a highly effective Fenton reagent is developed. In this research, SiO₂@Cu₇S₄ nanotubes (NTs) were synthesized as a PCDT agent. This double-valence metal-sulfide composite material can react with H₂O₂ at the tumor site. SiO₂@Cu₇S₄ NTs can produce more ROS than the traditional PDT agents, and besides, they can also be used as a photothermal therapy (PTT) agent. SiO₂@Cu₇S₄ NTs will trigger the PTT effect under 808 nm irradiation and generate a large amount of heat to eradicate cancer cells. This heat will also promote the PCDT effect by increasing the reaction rate. Thus, the SiO₂@Cu₇S₄ NT is a suitable material for PCDT and PTT synergistic oncotherapy. The 808 nm laser is selected as the appropriate excitation source, providing adequate penetration and minimal harm to normal cells. The experimental data presented herein demonstrate the promising photosensitive, Fenton-like, and photothermal performance of SiO₂@Cu₇S₄ NTs. Furthermore, the findings could promote the development of PCDT and PTT synergistic therapy. Thus, this research provides a feasible method to design a single, multifunctional material for cancer treatment.

Attenuated Salmonella typhimurium-mediated tumour targeting imaging based on peptides

Attenuated bacteria-mediated tumor targeting diagnosis will provide a novel strategy for further cancer treatments owing to the intrinsic facultative anaerobic characteristic of bacteria and rapid proliferation in the tumor sites. In this work, we firstly investigate the in vivo behaviour of the attenuated Salmonella typhimurium (S. typhimuriumΔppGpp/lux) after intravenous injection. S. typhimurium exhibits rapid proliferation in tumor sites after three days of injection through bioluminescence imaging, the Luria-Bertani plate and the Gram-staining assay. In contrast, S. typhimurium does not proliferate in the normal tissues and could be excreted from the body of mice. Afterwards, a targeting peptide ubiquicidin (UBI) labeled with fluorescent dye Cy5.5 or radionuclide ¹²⁵I was intravenously injected into the mice with or without S. typhimurium treatments for in vivo fluorescence imaging and single-photon emission computed tomography (SPECT/CT) imaging, respectively. The results show that the peptide UBI could specifically target the two independent bacteria-infected tumor models, the 4T1 murine breast cancer model and the CT26 mouse colon cancer model, realizing the sensitive multimodal imaging of tumors. Such a strategy (bacteria-mediated tumor targeting) may further improve the sensitivity to early diagnosis of tumors. We hope that our developed strategy could further be extended to cancer theranostics in the future, bringing good news for cancer patients.

Ultrasmall copper-based nanoparticles for reactive oxygen species scavenging and alleviation of inflammation related diseases

Oxidative stress is associated with many acute and chronic inflammatory diseases, yet limited treatment is currently available clinically. The development of enzyme-mimicking nanomaterials (nanozymes) with good reactive oxygen species (ROS) scavenging ability and biocompatibility is a promising way for the treatment of ROS-related inflammation. Herein we report a simple and efficient one-step development of ultrasmall Cu_5.4O nanoparticles (Cu_5.4O USNPs) with multiple enzyme-mimicking and broad-spectrum ROS scavenging ability for the treatment of ROS-related diseases. Cu_5.4O USNPs simultaneously possessing catalase-, superoxide dismutase-, and glutathione peroxidase-mimicking enzyme properties exhibit cytoprotective effects against ROS-mediated damage at extremely low dosage and significantly improve treatment outcomes in acute kidney injury, acute liver injury and wound healing. Meanwhile, the ultrasmall size of Cu_5.4O USNPs enables rapid renal clearance of the nanomaterial, guaranteeing the biocompatibility. The protective effect and good biocompatibility of Cu_5.4O USNPs will facilitate clinical treatment of ROS-related diseases and enable the development of next-generation nanozymes.

Double security drug delivery system DDS constructed by multi-responsive (pH/redox/US) microgel

In this paper, the multi-responsive core-shell microgels were prepared for constructing a double-locked drug delivery system. The pH- sensitive poly(2-(diisopropylamino ethylmethacry-late)-block-poly(ethyleneimine) diblock copolymers (PDPA-b-PEI) were synthesized and used to prepare micelles through their self-assembly in neutral solution. Redox-responsive gel shells were formed by Michael addition of primary amine group of branched PEI using disulfide as a cross-linker, which was specifically cleaved by glutathione (GSH). Anticancer drug doxorubicin DOX and perfluorohexane (PFH) could be encapsulated in the core of microgel. The DOX was released sustainably only under the condition of pH and GSH were both right. For example, under neutral condition with GSH, DOX could not release swimmingly due to the core of microgels was in hydrophobic state and wrapped the DOX firmly, although the gel shells were collapsed by GSH. When exposed to ultrasound, the drug released abruptly and achieved a complete release instantly. Moreover, it was found that the structure of the microgels was not destroyed after the ultrasound stimulus but had undergone an expansion-recovery process. Finally, it was demonstrated that the microgel had a "double security" effect, ensuring the low drug leakage during the normal blood circulation and efficient drug release under the pH/redox/ultrasound stimulus. The multi-responsive microgels designed here, which combines the usage of both endogenous and exogenous stimuli, has the advantages of low side-effect, high spatiotemporal controllability and complete release.

RBC Membrane Camouflaged Semiconducting Polymer Nanoparticles for Near-Infrared Photoacoustic Imaging and Photothermal Therapy

Semiconducting conjugated polymer nanoparticles (SPNs) represent an emerging class of phototheranostic materials with great promise for cancer treatment. In this report, low-bandgap electron donor-acceptor (D-A)-conjugated SPNs with surface cloaked by red blood cell membrane (RBCM) are developed for highly effective photoacoustic imaging and photothermal therapy. The resulting RBCM-coated SPN (SPN@RBCM) displays remarkable near-infrared light absorption and good photostability, as well as high photothermal conversion efficiency for photoacoustic imaging and photothermal therapy. Particularly, due to the small size (< 5 nm), SPN@RBCM has the advantages of deep tumor penetration and rapid clearance from the body with no appreciable toxicity. The RBCM endows the SPNs with prolonged systematic circulation time, less reticuloendothelial system uptake and reduced immune-recognition, hence improving tumor accumulation after intravenous injection, which provides strong photoacoustic signals and exerts excellent photothermal therapeutic effects. Thus, this work provides a valuable paradigm for safe and highly efficient tumor photoacoustic imaging and photothermal therapy for further clinical translation.

Tumor microenvironment-responsive multifunctional peptide coated ultrasmall gold nanoparticles and their application in cancer radiotherapy

Two important features are required for promising radiosensitizers: one is selective tumor cell targeting to enhance the therapeutic outcome via lethal DNA damage and the other is rapid clearance to enable excellent biocompatibility for potential clinical application. Herein, ultrasmall gold nanoparticles (Au NPs) with diameter smaller than 5 nm were prepared and covered with a multifunctional peptide to endow them with selective tumor cell uptake capability. Combined with X-ray irradiation, the responsive Au NPs demonstrated superior radio-sensitizing toxicity and rapid renal clearance in vivo. Methods: A responsive peptide (Tat-R-EK) consists of three build blocks were used: a cell and even nuclear penetrating block derived from human immunodeficiency virus-1 transactivator of transcription protein (Tat), an cathepsin B cleavable linker, and a zwitterionic antifouling block. Ultrasmall Au NPs were prepared and then covered by the peptide via the Au-S bonds between gold and thiol groups from cysteine. The morphology, colloidal stability and the responsiveness of obtained Au@Tat-R-EK NPs were studied using transmittance electron microscopy and dynamic laser scattering. The selective cancer cell uptake and accumulation of Au@Tat-R-EK NPs in cancer tissue were studied via ICP-MS in vitro and in vivo, respectively. The cytotoxicity of Au@Tat-R-EK NPs on HepG2 cancer cells was evaluated in terms of cell viability, DNA damage, intracellular reactive oxygen species generation, and apoptosis analysis. Finally, the biocompatibility and tumor destruction ability against orthotopic LM3 liver cancers were verified in vivo. Results: Multifunctional peptide modified ultrasmall Au NPs were successfully prepared. The Au NPs exhibited enough colloidal stability and cathepsin B-responsive surface change, leading to selectively uptake by cancer cells in vitro and accumulation to tumor sites in vivo. Combined with X-ray irradiation, the responsive Au NPs demonstrated superior radio-sensitizing cytotoxicity in vitro and therapeutic outcome on mouse liver cancer in vivo. The ultrasmall size enables rapid clearance of the Au NPs, guarantees the biocompatibility in vivo for potential clinical applications. Conclusion: Some obstacles faced by the Au NPs-based radiotherapy, such as short circulation half-life, non-specific distribution, slow clearance and low radio-sensitizing effect, were effective solved through rational design of the smart nanomedicine. This work provides new insight in designing tumor microenvironment-responsive nanomedicine in cancer radiotherapy.

Degradable Carbon-Silica Nanocomposite with Immunoadjuvant Property for Dual-Modality Photothermal/Photodynamic Therapy

Carbon nanomaterials have flourished for cancer therapy for decades. However, their practical applications on clinical bases still pose a challenge to address the dilemma of metabolism in vivo. In this study, an attempt is made to design a degradable carbon-silica nanocomposite (CSN) with immunoadjuvant property, which could undergo an enzyme-free degradation process into small particles (∼5 nm) and facilitate its clinical application. CSN harbors photothermal and photodynamic properties and as an immunoadjuvant would help to generate tumor-associated antigens and mature dendritic cells (DCs). Potent antitumor effects have been achieved in both 4T1 and patient-derived xenograft tumor models with tumor inhibition efficiencies of 93.2% and 92.5%, respectively. We believe that this strategy will benefit the possible clinical translation and carbon-silica-nanomaterial-based cancer therapy.