A porphyrin-PEG polymer with rapid renal clearance

Multifunctional and Scalable Nanoparticles for Bimodal Image-Guided Phototherapy in Bladder Cancer Treatment

Rational design of multifunctional nanoplatforms capable of combining therapeutic effects with real-time monitoring of drug distribution and tumor status is emerging as a promising approach in cancer nanomedicine. Here, we introduce pyropheophorbide a-bisaminoquinoline conjugate lipid nanoparticles (PPBC LNPs) as a bimodal system for image-guided phototherapy in bladder cancer treatment. PPBC LNPs not only demonstrate both powerful photodynamic and photothermal effects upon light activation, but also exhibit potent autophagy blockage, effectively inducing bladder cancer cell death. Furthermore, PPBC LNPs possess remarkable photoacoustic (PA) and fluorescence (FL) imaging capabilities, enabling imaging with high-resolution, deep tissue penetration and high sensitivity for tracking drug biodistribution and phototherapy efficacy. Specifically, PA imaging confirms the efficient accumulation of PPBC LNPs within tumor and predicts therapeutic outcomes of photodynamic therapy, while FL imaging confirms their prolonged retention at the tumor site for up to 6 days. PPBC LNPs significantly suppress bladder tumor growth, with several tumors completely ablated following just two doses of the nanoparticles and laser treatment. Additionally, PPBC LNPs were formulated with lipid-based excipients and assembled using microfluidic technology to enhance biocompatibility, stability, and scalability, showing potential for clinical translation. This versatile nanoparticle represents a promising candidate for further development in bladder cancer therapy.

Nanocellulose/activated carbon composite aerogel beads with high adsorption capacity for toxins in blood

Activated carbon is extensively utilized in blood purification applications. However, its performance has been significantly limited by their poor blood compatibility. In this work, 2,2,6,6-tetramethylpiperidinyl-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCN) and activated carbon (AC) were used to form composite beads by the drop curing method to improve hemocompatibility. The TOCN/AC composite beads had porous surface and exhibited extraordinary adsorption properties. The beads had a high adsorption capacity for creatinine with the optimal adsorption capacity of 83.33 mg g-1. And the equilibrium adsorption of bilirubin, uric acid and Cu2+ by TOCN/AC beads was as high as 159.80 mg g-1, 114.61 mg g-1 and 154.0 mg g-1, respectively, with a mass ratio of TOCN to AC of 1:4. It is also observed that the adsorption behavior of TOCN/AC beads on creatinine was consistent with the second-order kinetics and Langmuir isothermal model. The hemolysis rate of TOCN/AC was 1.21 %, indicating that TOCN/AC beads had good blood compatibility. The clearance of creatinine toxin in blood by TOCN/AC beads was as high as 87 % within 90 min. Overall, our produced composite beads had great potential for application in the field of blood purification.

Investigation of polyvinylpyrrolidone-catechol-derived chitosan nanoconjugates allowed for kidney-targeted treatment of cisplatin-induced acute kidney injury and nursing care management

Acute kidney injury (AKI) resulting from cisplatin (Cs) chemotherapy presents a significant challenge in clinical management. The study aimed to fabricate a novel compound Polyvinylpyrrolidone-catechol-derived chitosan nanoconjugates (PCChi-NC) for targeting Cs-induced AKI. Characterization studies utilizing UV-visible spectrophotometry, FT-IR, XRD, and TEM revealed a spherical morphology with diameters ranging from 20 to 60 nm. In vitro assessments utilizing HEK 293 cell lines demonstrated the biocompatibility of PCChi-NC without eliciting toxic effects. Furthermore, PCChi-NC exhibited a notable reduction in Cs-induced cell death in kidney cells, as evidenced by biomarker analysis. Anti-inflammatory analysis of mouse kidney homogenates revealed a decrease in TNF-α and IL-1β levels, indicative of the therapeutic efficacy of PCChi-NC in mitigating Cs-induced kidney inflammation. Moreover, In vivo, experimental analysis was evidenced by stable body weight and histopathological changes in mice. Our findings highlight the potential of PCChi-NC as a promising candidate for targeted therapy in Cs-induced AKI, owing to its unique renal targeting capacity.

Application of Nanomaterial-Mediated Ferroptosis Regulation in Kidney Disease

Kidney diseases are a significant global cause of death and disability, resulting from the destruction of kidney structure and function due to an imbalance between the death of renal parenchymal cells and the proliferation or recruitment of maladaptive cells, caused by various pathogenic factors. Currently, therapies and their efficacy for kidney diseases are limited. Ferroptosis is a newly discovered iron-dependent regulated cell death. The imbalance of iron homeostasis and lipid metabolism affects the occurrence and progression of kidney diseases by triggering ferroptosis, which is considered an important target for the development of kidney disease drugs. However, in clinical practice, targeted ferroptosis therapy for kidney diseases faces obstacles such as poor drug solubility, low drug resistance, and imprecise targeting. With the rapid development of nanomaterials in the medical field, new opportunities have emerged for the precise regulation of ferroptosis in the treatment of kidney diseases. This article provides a detailed introduction to the regulatory mechanisms of ferroptosis, the properties of nanomaterials, and their application in the treatment of kidney diseases, with a focus on discussing the mechanisms of action and therapeutic potential of nanomaterials based on ferroptosis regulation in kidney diseases. The aim of this article is to provide new ideas and directions for future kidney disease treatments.

Renal-clearable probes for disease detection and monitoring

The demand for novel, minimally invasive, cost-effective, and easily readable diagnostic tools, primarily designed for the longitudinal monitoring of diseases and their treatments, has promoted the development of diagnostic systems that selectively target cells, tissues, or organs, at the same time minimizing their nonspecific accumulation, thus reducing the risk of toxicity and side effects. In this review, we explore the development of renal-clearable systems in non-invasive or minimally invasive detection protocols, all with the objective of minimizing nonspecific accumulation and its associated toxicity effects through quick renal excretion. These probes can identify molecules of interest or different healthy states of the patients through the direct analysis of urine (urinalysis). As we discuss, these diagnostics systems hold significant treatment monitoring potential.

Ultrasmall Coinage Metal Nanoclusters as Promising Theranostic Probes for Biomedical Applications

Ultrasmall coinage metal nanoclusters (NCs, <3 nm) have emerged as a novel class of theranostic probes due to their atomically precise size and engineered physicochemical properties. The rapid advances in the design and applications of metal NC-based theranostic probes are made possible by the atomic-level engineering of metal NCs. This Perspective article examines (i) how the functions of metal NCs are engineered for theranostic applications, (ii) how a metal NC-based theranostic probe is designed and how its physicochemical properties affect the theranostic performance, and (iii) how metal NCs are used to diagnose and treat various diseases. We first summarize the tailored properties of metal NCs for theranostic applications in terms of biocompatibility and tumor targeting. We focus our discussion on the theranostic applications of metal NCs in bioimaging-directed disease diagnosis, photoinduced disease therapy, nanomedicine, drug delivery, and optical urinalysis. Lastly, an outlook on the challenges and opportunities in the future development of metal NCs for theranostic applications is provided.

Nanostructured polyvinylpyrrolidone-curcumin conjugates allowed for kidney-targeted treatment of cisplatin induced acute kidney injury

Acute kidney injury (AKI) leads to unacceptably high mortality due to difficulties in timely intervention and less efficient renal delivery of therapeutic drugs. Here, a series of polyvinylpyrrolidone (PVP)-curcumin nanoparticles (PCurNP) are designed to meet the renal excretion threshold (∼45 kDa), presenting a controllable delivery nanosystem for kidney targeting. Renal accumulation of the relatively small nanoparticles, ⁸⁹Zr-PCurNP M10 with the diameter between 5 and 8 nm, is found to be 1.7 times and 1.8 times higher than the accumulation of ⁸⁹Zr-PCurNP M29 (20–50 nm) and M40 (20–50 nm) as revealed by PET imaging. Furthermore, serum creatinine analysis, kidney tissues histology, and tubular injury scores revealed that PCurNP M10 efficiently treated cisplatin-induced AKI. Herein, PCurNP offers a novel and simple strategy for precise PET image-guided drug delivery of renal protective materials.

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PVP-curcumin nanosystems were investigated for treating cisplatin-induced acute kidney injury.

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Inherent oxygens of PCurNP nanoparticles facilitate Zr-89 radiolabeling for PET imaging.

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Modulating the sizes of PCurNP nanoparticles allowed for adjustable kidney targeting and retention as revealed by PET imaging.

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.

Uniform, Length-Tunable Antibacterial 1D Diblock Copolymer Nanofibers

The rapid increase in antibiotic resistant strains of bacteria has led to an urgent need to develop new methods of treating bacterial infections. Antibacterial polymeric nanoparticles are of interest for...

Synthesis and photodynamic efficacy of water-soluble protoporphyrin IX homologue with mPEG550

Protoporphyrin IX (PpIX), which is an efficient photosensitive agent, cannot be used directly in photodynamic therapy due to its aggregation in physiological environment. If PpIX is made water-soluble without losing its photosensitive properties, it can be used in many medical fields, including cancer treatment. Here we report synthesis of PpIX homologue with mPEG550 (Porfipeg) and its photodynamic effects on both in-vitro and in-vivo environment. Porfipeg is synthesized to give PpIX the ability to dissolve in water. Spectrometric (FT-IR, NMR, MS, UV-vis and Fluorescence) measurements were performed. Porfipeg can penetrate into the cells and indicates no cytotoxicity in the dark whereas cell viability significantly reduced with light irradiation. The cells can be visualized by fluorescence microscope. In-vivo experiment revealed that intravenous injection of Porfipeg is more efficient than intraperitoneal injection for the acute photodynamic effects within 30 min. Moreover it is excreted by the kidneys. In conclusion, Porfipeg has remarkable potentials to be used in both fluorescence guidance in surgeries and photodynamic therapy for cancer treatment.

Traditional herbal medicine and nanomedicine: Converging disciplines to improve therapeutic efficacy and human health

Traditional herbal medicine (THM), an ancient science, is a gift from nature. For thousands of years, it has helped humans fight diseases and protect life, health, and reproduction. Nanomedicine, a newer discipline has evolved from exploitation of the unique nanoscale morphology and is widely used in diagnosis, imaging, drug delivery, and other biomedical fields. Although THM and nanomedicine differ greatly in time span and discipline dimensions, they are closely related and are even evolving toward integration and convergence. This review begins with the history and latest research progress of THM and nanomedicine, expounding their respective developmental trajectory. It then discusses the overlapping connectivity and relevance of the two fields, including nanoaggregates generated in herbal medicine decoctions, the application of nanotechnology in the delivery and treatment of natural active ingredients, and the influence of physiological regulatory capability of THM on the in vivo fate of nanoparticles. Finally, future development trends, challenges, and research directions are discussed.

Recent Advances in Photosensitizers as Multifunctional Theranostic Agents for Imaging-Guided Photodynamic Therapy of Cancer

In recent years tremendous effort has been invested in the field of cancer diagnosis and treatment with an overall goal of improving cancer management, therapeutic outcome, patient survival, and quality of life. Photodynamic Therapy (PDT), which works on the principle of light-induced activation of photosensitizers (PS) leading to Reactive Oxygen Species (ROS) mediated cancer cell killing has received increased attention as a promising alternative to overcome several limitations of conventional cancer therapies. Compared to conventional therapies, PDT offers the advantages of selectivity, minimal invasiveness, localized treatment, and spatio-temporal control which minimizes the overall therapeutic side effects and can be repeated as needed without interfering with other treatments and inducing treatment resistance. Overall PDT efficacy requires proper planning of various parameters like localization and concentration of PS at the tumor site, light dose, oxygen concentration and heterogeneity of the tumor microenvironment, which can be achieved with advanced imaging techniques. Consequently, there has been tremendous interest in the rationale design of PS formulations to exploit their theranostic potential to unleash the imperative contribution of medical imaging in the context of successful PDT outcomes. Further, recent advances in PS formulations as activatable phototheranostic agents have shown promising potential for finely controlled imaging-guided PDT due to their propensity to specifically turning on diagnostic signals simultaneously with photodynamic effects in response to the tumor-specific stimuli. In this review, we have summarized the recent progress in the development of PS-based multifunctional theranostic agents for biomedical applications in multimodal imaging combined with PDT. We also present the role of different imaging modalities; magnetic resonance, optical, nuclear, acoustic, and photoacoustic in improving the pre-and post-PDT effects. We anticipate that the information presented in this review will encourage future development and design of PSs for improved image-guided PDT for cancer treatment.

Hemicyanine-Based Near-Infrared Activatable Probes for Imaging and Diagnosis of Diseases

Molecular activatable probes with near-infrared (NIR) fluorescence play a critical role in in vivo imaging of biomarkers for drug screening and disease diagnosis. With structural diversity and high fluorescence quantum yields, hemicyanine dyes have emerged as a versatile scaffold for the construction of activatable optical probes. This Review presents a survey of hemicyanine-based NIR activatable probes (HNAPs) for in vivo imaging and early diagnosis of diseases. The molecular design principles of HNAPs towards activatable optical signaling against various biomarkers are discussed with a focus on their broad applications in the detection of diseases including inflammation, acute organ failure, skin diseases, intestinal diseases, and cancer. This progress not only proves the unique value of HNAPs in preclinical research but also highlights their high translational potential in clinical diagnosis.

Ultra-small natural product based coordination polymer nanodots for acute kidney injury relief

Acute kidney injury (AKI) is frequently associated with reactive oxygen species (ROS) and causes high mortality in clinics annually, and nanotechnology-mediated antioxidative therapy is emerging as a novel strategy for AKI treatment. Herein, four kinds of natural antioxidants are able to coordinate with iron (Fe) ions to form ultra-small coordination polymer nanodots (CPNs) with good water dispersibility and strong ROS scavenging ability. In particular, Fe-curcumin CPNs (Fe-Cur CPNs) are applied for cellular ROS scavenging and rhabdomyolysis-induced AKI relief.

Hydrophilic Biocompatible Poly(Acrylic Acid-co-Maleic Acid) Polymer as a Surface-Coating Ligand of Ultrasmall Gd2O3 Nanoparticles to Obtain a High r1 Value and T1 MR Images

The water proton spin relaxivity, colloidal stability, and biocompatibility of nanoparticle-based magnetic resonance imaging (MRI) contrast agents depend on the surface-coating ligands. Here, poly(acrylic acid-co-maleic acid) (PAAMA) (Mw = ~3000 amu) is explored as a surface-coating ligand of ultrasmall gadolinium oxide (Gd2O3) nanoparticles. Owing to the numerous carboxylic groups in PAAMA, which allow its strong conjugation with the nanoparticle surfaces and the attraction of abundant water molecules to the nanoparticles, the synthesized PAAMA-coated ultrasmall Gd2O3 nanoparticles (davg = 1.8 nm and aavg = 9.0 nm) exhibit excellent colloidal stability, extremely low cellular toxicity, and a high longitudinal water proton spin relaxivity (r1) of 40.6 s-1mM-1 (r2/r1 = 1.56, where r2 = transverse water proton spin relaxivity), which is approximately 10 times higher than those of commercial molecular contrast agents. The effectiveness of PAAMA-coated ultrasmall Gd2O3 nanoparticles as a T1 MRI contrast agent is confirmed by the high positive contrast enhancements of the in vivo T1 MR images at the 3.0 T MR field.

Metalloporphyrins in Medicine: From History to Recent Trends

The history of metalloporphyrins dates back more than 200 years ago. Metalloporphyrins are excellent catalysts, capable of forming supramolecular systems, participate in oxygen photosynthesis, transport, and used as contrast agents or superoxide dismutase mimetics. Today, metalloporphyrins represent complexes of conjugated π-electron system and metals from the entire periodic system. However, the effect of these compounds on living systems has not been fully understood, and researchers are exploring the properties of metalloporphyrins thereby extending their further application. This review provides an overview of the variety of metalloporphyrins that are currently used in different medicine fields and how metalloporphyrins became the subject of scientists' interest. Currently, metalloporphyrins utilization has expanded significantly, which gave us an opprotunuty to summarize recent progress in metalloporphyrins derivatives and prospects of their application in the treatment and diagnosis of different diseases.

Thinking outside the macrocycle: Potential biomedical roles for nanostructured porphyrins and phthalocyanines — a SPP/JPP Young Investigator Award paper

Porphyrins and phthalocyanines feature strong light absorption, capacity for metal chelation, and a track record of use in human therapeutic applications. Various conjugates and formulations of these macrocycles have shown potential to forge new applications in the biomedical sciences. Our lab has explored several such approaches including porphyrin polymer hydrogels, porphyrin-lipid nanovesicles, and surfactant-stripped micelles. These all feature in common a high density of tetrapyrroles, as well as unique functional properties. Porphyrin polymer hydrogels with high porphyrin density and bright fluorescence emission were demonstrated for use as a new class of implantable biosensors. Porphyrin-lipid nanovesicles hold potential for phototherapy, imaging, and also drug and vaccine delivery. Surfactant-stripped micelles have been developed for high-contrast photoacoustic imaging. In this ICPP Young Investigator Award brief perspective, we discuss our own efforts on these fronts. Taken together, the results show that tetrapyrroles enable new approaches for tackling biomedical problems and also confirm what was already well-known to members of the Society of Porphyrins and Phthalocyanines: that these molecules are remarkably versatile and enable research to flow in unexpected directions.

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.

Selenium-Doped Carbon Quantum Dots Act as Broad-Spectrum Antioxidants for Acute Kidney Injury Management

The manifestation of acute kidney injury (AKI) is associated with poor patient outcomes, with treatment options limited to hydration or renal replacement therapies. The onset of AKI is often associated with a surfeit of reactive oxygen species. Here, it is shown that selenium-doped carbon quantum dots (SeCQDs) have broad-spectrum antioxidant properties and prominent renal accumulation in both healthy and AKI mice. Due to these properties, SeCQDs treat or prevent two clinically relevant cases of AKI induced in murine models by either rhabdomyolysis or cisplatin using only 1 or 50 µg per mouse, respectively. The attenuation of AKI in both models is confirmed by blood serum measurements, kidney tissue staining, and relevant biomarkers. The therapeutic efficacy of SeCQDs exceeds amifostine, a drug approved by the Food and Drug Administration that also acts by scavenging free radicals. The findings indicate that SeCQDs show great potential as a treatment option for AKI and possibly other ROS-related diseases.

Fluoro-Photoacoustic Polymeric Renal Reporter for Real-Time Dual Imaging of Acute Kidney Injury

Photoacoustic (PA) imaging agents detect disease tissues and biomarkers with increased penetration depth and enhanced spatial resolution relative to traditional optical imaging, and thus hold great promise for clinical applications. However, existing PA imaging agents often encounter the issues of slow body excretion and low-signal specificity, which compromise their capability for in vivo detection. Herein, a fluoro-photoacoustic polymeric renal reporter (FPRR) is synthesized for real-time imaging of drug-induced acute kidney injury (AKI). FPRR simultaneously turns on both near-infrared fluorescence (NIRF) and PA signals in response to an AKI biomarker (γ-glutamyl transferase) with high sensitivity and specificity. In association with its high renal clearance efficiency (78% at 24 h post-injection), FPRR can detect cisplatin-induced AKI at 24 h post-drug treatment through both real-time imaging and optical urinalysis, which is 48 h earlier than serum biomarker elevation and histological changes. More importantly, the deep-tissue penetration capability of PA imaging results in a signal-to-background ratio that is 2.3-fold higher than NIRF imaging. Thus, the study not only demonstrates the first activatable PA probe for real-time sensitive imaging of kidney function at molecular level, but also highlights the polymeric probe structure with high renal clearance.

Construction of Kevlar nanofiber/graphene oxide composite beads as safe, self-anticoagulant, and highly efficient hemoperfusion adsorbents

Recently emerged hemoperfusion absorbents, e.g. ion-exchange resin, activated carbon, and other porous materials, provide numerous novel possibilities to cure chronic liver failure (CLF) and renal failure (CRF). However, the limited adsorption performance and unsatisfactory blood compatibility significantly impede the development of the absorbents. Hence, designing safe and self-anticoagulant hemoperfusion absorbents with robust toxin clearance remains a considerable challenge. Here, brand new Kevlar-based composite gel beads for hemoperfusion are prepared by interface assembly based on π-π interaction. First, Kevlar nanofiber-graphene oxide (K-GO) beads are produced by liquid-liquid phase separation. Then, sodium p-styrenesulfonate (SS) is adsorbed onto the K-GO interface by π-π interaction and initiated to achieve the composite gel (K-GO/PSS) beads with an interfacial crosslinked structure. Such composite gel beads possess superior mechanical strength and self-anticoagulation capability, owing to the dual-network structure and heparin-mimicking gel structure, respectively. Furthermore, the K-GO/PSS beads show robust adsorption capacities for different kinds of toxins due to their strong charge and π-π interactions. A simulated hemoperfusion experiment in vitro demonstrates that the concentrations of the toxins in the blood can be restored to normal values within 30 minutes. In general, we envision that such composite gel beads will provide new strategies for future clinical CLF and CRF treatments.

Self-Amplified Photodynamic Therapy through the 1 O2 -Mediated Internalization of Photosensitizers from a Ppa-Bearing Block Copolymer

Nanocarriers are employed to deliver photosensitizers for photodynamic therapy (PDT) through the enhanced penetration and retention effect, but disadvantages including the premature leakage and non-selective release of photosensitizers still exist. Herein, we report a 1 O2 -responsive block copolymer (POEGMA-b-P(MAA-co-VSPpaMA) to enhance PDT via the controllable release of photosensitizers. Once nanoparticles formed by the block copolymer have accumulated in a tumor and have been taken up by cancer cells, pyropheophorbide a (Ppa) could be controllably released by singlet oxygen (1 O2 ) generated by light irradiation, enhancing the photosensitization. This was demonstrated by confocal laser scanning microscopy and in vivo fluorescence imaging. The 1 O2 -responsiveness of POEGMA-b-P(MAA-co-VSPpaMA) block copolymer enabled the realization of self-amplified photodynamic therapy by the regulation of Ppa release using NIR illumination. This may provide a new insight into the design of precise PDT.

Treating Acute Kidney Injury with Antioxidative Black Phosphorus Nanosheets

Black phosphorus nanosheets (BPNSs) have been actively employed as nanomedicine agents for photothermal and photodynamic therapy by virtue of their unique optical properties. However, their chemical reactivity as a competent biomaterial has not been fully explored yet. Here, we report on the use of BPNSs as reactive oxygen species (ROS) scavengers to cure acute kidney injury (AKI) in mice. Importantly, in vivo analysis in mice revealed that BPNSs were preferably accumulated in kidney. We found that BPNSs alleviated oxidative-pressure-induced cellular apoptosis. In a ROS-triggered acute kidney injury (AKI) model, BPNSs effectively consumed ROS in kidney, demonstrating high efficacy for curing AKI. BPNSs also exhibited excellent biocompatibility and biodegradability, making them promising candidates for therapeutic treatment of AKI and other renal diseases.

A Renal-Clearable Macromolecular Reporter for Near-Infrared Fluorescence Imaging of Bladder Cancer

Bladder cancer (BC) is a prevalent disease with high morbidity and mortality; however, in vivo optical imaging of BC remains challenging because of the lack of cancer-specific optical agents with high renal clearance. Herein, a macromolecular reporter (CyP1) was synthesized for real-time near-infrared fluorescence (NIRF) imaging and urinalysis of BC in living mice. Because of the high renal clearance (ca. 94 % of the injection dosage at 24 h post-injection) and its cancer biomarker (APN=aminopeptidase N) specificity, CyP1 can be efficiently transported to the bladder and specially turn on its NIRF signal to report the detection of BC in living mice. Moreover, CyP1 can be used for optical urinalysis, permitting the ex vivo tracking of tumor progression for therapeutic evaluation and easy translation of CyP2 as an in vitro diagnostic assay. This study not only provides new opportunities for non-invasive diagnosis of BC, but also reveals useful guidelines for the development of molecular reporters for the detection of bladder diseases.

Renal-clearable Molecular Semiconductor for Second Near-Infrared Fluorescence Imaging of Kidney Dysfunction

Real-time imaging of kidney function is important to assess the nephrotoxicity of drugs and monitor the progression of renal diseases; however, it remains challenging because of the lack of optical agents with high renal clearance and high signal-to-background ratio (SBR). Herein, a second near-infrared (NIR-II) fluorescent molecular semiconductor (CDIR2) is synthesized for real-time imaging of kidney dysfunction in living mice. CDIR2 not only has a high renal clearance efficiency (≈90 % injection dosage at 24 h post-injection), but also solely undergoes glomerular filtration into urine without being reabsorbed and secreted in renal tubules. Such a unidirectional renal clearance pathway of CDIR2 permits real-time monitoring of kidney dysfunction in living mice upon nephrotoxic exposure. Thus, this study not only introduces a molecular renal probe but also provides useful molecular guidelines to increase the renal clearance efficiency of NIR-II fluorescent agents.

Renal-clearable ultrasmall covalent organic framework nanodots as photodynamic agents for effective cancer therapy

Covalent organic frameworks (COFs) and their derivatives represent an emerging class of crystalline porous materials with broad potential applications. However, the biomedical applications of them were limited by the large size, low dispersivity, poor bioavailability within cells and metabolic problems. Herein, renal-clearable ultrasmall COF nanodots have been synthesized and utilized as efficient cancer therapy agents. A simple liquid exfoliation strategy was used to prepare COF nanodots. After polyethylene glycol (PEG) conjugation, the PEG coated COF nanodots (COF nanodots-PEG) showed improved physiological stability and biocompatibility. In addition, the well isolated porphyrin molecules endowed COF nanodots-PEG good light-triggered reactive oxygen species production ability, which showed excellent photodynamic therapy efficiency with good tumor accumulation ability. In particular, due to the ultrasmall size, COF nanodots-PEG could be cleared from the body through the renal filtration with no appreciable in vivo toxicity. Our study highlights the potential of COFs-based nanoparticles for biomedical applications.

PEGylated rhenium nanoclusters: a degradable metal photothermal nanoagent for cancer therapy

A common issue of functional nanoagents for potential clinical translation is whether they are biodegradable or renal clearable. Previous studies have widely explored noble metal nanoparticles (Au and Pd) as the first generation of photothermal nanoagents for cancer therapy, but all of the reported noble metal nanoparticles are non-degradable. On the other hand, rhenium (Re), one of the noble and precious metals with a high atomic number (Z = 75), has been mainly utilized as a jet superalloy or chemical catalyst, but the biological characteristics and activity of Re nanoparticles have never been evaluated until now. To address these issues, here we report a simple and scalable liquid-reduction strategy to synthesize PEGylated Re nanoclusters, which exhibit intrinsically high photothermal conversion efficacy (33.0%) and high X-ray attenuation (21.2 HU mL mg-1), resulting in excellent photothermal ablation (100% tumor elimination) and higher CT enhancement (15.9 HU mL mg-1 for commercial iopromide in clinics). Impressively, biocompatible Re nanoclusters can degrade into renal clearable ReO4 - ions after exposure to H2O2, and thus achieve much higher renal clearance efficiency than conventional gold nanoparticles. This work reveals the potential of theranostic application of metallic Re nanoclusters with both biodegradation and renal clearance properties and provides insights into the design of degradable metallic platforms with high clinical prospects.

Metalloporphyrin Nanoparticles: Coordinating Diverse Theranostic Functions

Metalloporphyrins serve key roles in natural biological processes and also have demonstrated utility for biomedical applications. They can be encapsulated or grafted in conventional nanoparticles or can self-assemble themselves at the nanoscale. A wide range of metals can be stably chelated either before or after porphyrin nanoparticle formation, without the necessity of any additional chelator chemistry. The addition of metals can substantially alter a range of behaviors such as modulating phototherapeutic efficacy; conferring responsiveness to biological stimuli; or providing contrast for magnetic resonance, positron emission or surface enhanced Raman imaging. Chelated metals can also provide a convenient handle for bioconjugation with other molecules via axial coordination. This review provides an overview of some recent biomedical, nanoparticulate approaches involving gain-of-function metalloporphyrins and related molecules.

Molybdenum-based nanoclusters act as antioxidants and ameliorate acute kidney injury in mice

Acute kidney injury (AKI) is a common reactive oxygen species (ROS)-related renal disease that causes numerous deaths annually, yet only supportive treatment is currently available in the clinics. Development of antioxidants with high accumulation rates in kidneys is highly desired to help prevent AKI. Here we report molybdenum-based polyoxometalate (POM) nanoclusters with preferential renal uptake as novel nano-antioxidants for kidney protection. These POM nanoclusters, with a readily variable valence state of molybdenum ions, possess the capability to scavenge detrimental ROS. Our results demonstrate that POM nanoclusters can efficiently alleviate clinical symptoms in mice subjected to AKI, as verified by dynamic PET imaging with ⁶⁸Ga-EDTA, serum tests, kidney tissue staining, and biomarkers detection in the kidneys. The protective effect of POM nanoclusters against AKI in living animals suggests exploring their use for the treatment of AKI patients, as well as patients with other ROS-related diseases.

There are currently no effective therapies available for acute kidney injury (AKI). Here the authors generate molybdenum-based polyoxometalate nanoclusters and show that these have preferential renal uptake and can ameliorate AKI pathology in mice by scavenging reactive oxygen species.

DNA origami nanostructures can exhibit preferential renal uptake and alleviate acute kidney injury

Patients with acute kidney injury (AKI) frequently require kidney transplantation and supportive therapies, such as rehydration and dialysis. Here, we show that radiolabelled DNA origami nanostructures (DONs) with rectangular, triangular and tubular shapes accumulate preferentially in the kidneys of healthy mice and mice with rhabdomyolysis-induced AKI, and that rectangular DONs have renal-protective properties, with efficacy similar to the antioxidant N-acetylcysteine-a clinically used drug that ameliorates contrast-induced AKI and protects kidney function from nephrotoxic agents. We evaluated the biodistribution of DONs non-invasively via positron emission tomography, and the efficacy of rectangular DONs in the treatment of AKI via dynamic positron emission tomography imaging with 68Ga-EDTA, blood tests and kidney tissue staining. DNA-based nanostructures could become a source of therapeutic agents for the treatment of AKI and other renal diseases.

Porphyrins as ligands for 64copper: background and trends

Porphyrins and 64Cu have emerged as a novel synergic option for applications in PET molecular imaging. Both the characteristics and photophysical properties of macrocyclic porphyrins and the relatively long half-life of the copper isotope, in addition to the increased tumor-specific uptake of porphyrins compared to normal cells, make this complex an attractive option not only for diagnosis but also for therapeutic applications. Herein, we present an overview of the latest results on the development of PET agents based on porphyrins and 64Cu, including methods used to improve the selectivity of these macrocycles when conjugated with biological units such as monoclonal antibodies, peptides or proteins.

Highly Effective Radioisotope Cancer Therapy with a Non-Therapeutic Isotope Delivered and Sensitized by Nanoscale Coordination Polymers

Nuclear medicine with radioisotopes is extremely useful for clinical cancer diagnosis, prognosis, and treatment. Herein, polyethylene glycol (PEG)-modified nanoscale coordination polymers (NCPs) composed of hafnium (Hf⁴⁺) and tetrakis (4-carboxyphenyl) porphyrin (TCPP) are prepared via a one-pot reaction. By chelation with the porphyrin structure of TCPP, such Hf-TCPP-PEG NCPs could be easily labeled with ^99mTc⁴⁺, an imaging radioisotope widely used for single-photon emission computed tomography (SPECT) in a clinical environment. Interestingly, Hf, as a high- Z element in such ^99mTc-Hf-TCPP-PEG NCPs, could endow nontherapeutic ^99mTc with the therapeutic function of killing cancer cells, likely owing to the interaction of Hf with γ rays emitted from ^99mTc to produce charged particles for radiosensitization. With efficient tumor retention, as revealed by SPECT imaging, our ^99mTc-Hf-TCPP-PEG NCPs offer exceptional therapeutic results in eliminating tumors with moderate doses of ^99mTc after either local or systemic administration. Importantly, those biodegradable NCPs could be rapidly excreted without much long-term body retention. Our work, showing the success of applying NCPs for radioisotope therapy (RIT), presents a potential concept for the realization of highly effective cancer treatment with ^99mTc, a short-half-life (6.0 h) diagnostic radioisotope, which is promising for cancer RIT with enhanced efficacy and reduced side effects.

Strategies for the enhanced intracellular delivery of nanomaterials

The intracellular delivery of nanomaterials and drugs has been attracting increasing research interest, mainly because of their important effects and functions in several organelles. Targeting specific organelles can help treat or decrease the symptoms of diabetes, cancer, infectious, and autoimmune diseases. Tuning biological and chemical properties enables the creation of functionalized nanomaterials with enhanced intracellular uptake, ability to escape premature lysosome degradation, and to reach a specific target. Here, we provide an update of recent advances in the intracellular delivery mechanisms that could help drugs reach their target more efficiently.

Assessing Photosensitizer Targeting Using Meso-Tetra(Carboxyphenyl) Porphyrin

Mesotetra(4-carboxyphenyl)porphyrin (mTCPP) is a commercially available small molecule fluorophore and photosensitizer with four free carboxylic acid groups. mTCPP can readily be conjugated with amines for facile attachment of functional groups. In this work, we synthesized and assessed tetravalent, lysine-conjugated mTCPP, for its potential applications in targeted imaging and photodynamic therapy. Fmoc-protected d-lysine or l-lysine was conjugated to mTCPP via amide coupling with the epsilon amine group of lysine, followed by Fmoc deprotection. The resulting compounds did not dissolve well in aqueous solvent, but could be solubilized with the assistance of surfactants, including cholic acid. The l-amino acid transporter (LAT1) can uptake diverse neutral l-amino acids. In vitro studies with U87 cells revealed a non-specific uptake of the hydrophobic Fmoc-protected lysine-conjugated mTCPP precursors, but not d- or l-lysine mTCPP. Likewise, only the Fmoc-protected compounds induced substantial phototoxicty in cells following incubation and irradiation with blue light. These experimental results do not provide evidence to suggest that lysine-mTCPP is able to specifically target cancer cells. However, they do highlight mTCPP as a convenient and accessible framework for assessing molecular targeting of photosensitizers.

Renal-Clearable Ultrasmall Coordination Polymer Nanodots for Chelator-Free 64Cu-Labeling and Imaging-Guided Enhanced Radiotherapy of Cancer

Developing tumor-homing nanoparticles with integrated diagnostic and therapeutic functions, and meanwhile could be rapidly excreted from the body, would be of great interest to realize imaging-guided precision treatment of cancer. In this study, an ultrasmall coordination polymer nanodot (CPN) based on the coordination between tungsten ions (WVI) and gallic acid (W-GA) was developed via a simple method. After polyethylene glycol (PEG) modification, PEGylated W-GA (W-GA-PEG) CPNs with an ultrasmall hydrodynamic diameter of 5 nm were rather stable in various physiological solutions. Without the need of chelator molecules, W-GA-PEG CPNs could be efficiently labeled with radioisotope 64Cu2+, enabling positron emission tomography (PET) imaging, which reveals efficient tumor accumulation and rapid renal clearance of W-GA-PEG CPNs upon intravenous injection. Utilizing the radio-sensitizing function of tungsten with strong X-ray absorption, such W-GA-PEG CPNs were able to greatly enhance the efficacy of cancer radiotherapy in inhibiting the tumor growth. With fast clearance and little long-term body retention, those W-GA-PEG CPNs exhibited no appreciable in vivo toxicity. This study presents a type of CPNs with excellent imaging and therapeutic abilities as well as rapid renal clearance behavior, promising for further clinic translation.

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

Noninvasive dynamic positron emission tomography (PET) imaging was used to investigate the balance between renal clearance and tumor uptake behaviors of polyethylene glycol (PEG)-modified porphyrin nanoparticles (TCPP-PEG) with various molecular weights. TCPP-PEG10K nanoparticles with clearance behavior would be a good candidate for PET image-guided photodynamic therapy.

Enhanced Fluorescence Emission and Singlet Oxygen Generation of Photosensitizers Embedded in Injectable Hydrogels for Imaging-Guided Photodynamic Cancer Therapy

Benefiting from their inherent localized and controlled release properties, hydrogels are ideal delivery systems for therapeutic drugs or nanoparticles. In particular, applications of hydrogels for the delivery and release of photoresponsive drugs or nanoparticles are receiving increasing attention. However, the effect of the hydrogel matrix on the fluorescence emission and singlet oxygen generation efficiency of the embedded photosensitizers (PSs) has not been clarified. Herein, meso-tetrakis(1-methylpyridinium-4-yl)porphyrin (TMPyP) as a water-soluble PS was encapsulated into an injectable hydrogel formed by glycol chitosan and dibenzaldehyde-terminated telechelic poly(ethylene glycol). Compared to free TMPyP solution, the TMPyP encapsulated in the hydrogel exhibits three distinct advantages: (1) more singlet oxygen was generated under the same laser irradiation condition; (2) much longer tumor retention was observed due to the low fluidity of the hydrogel; and (3) the fluorescence intensity of TMPyP was significantly enhanced in the hydrogel due to its decreased self-quenching effect. These excellent characteristics lead to remarkable anticancer efficacy and superior fluorescence emission property of the TMPyP-hydrogel system, promoting the development of imaging-guided photodynamic therapy.

Positron emission tomography and nanotechnology: A dynamic duo for cancer theranostics

Development of novel imaging probes for cancer diagnosis is critical for early disease detection and management. The past two decades have witnessed a surge in the development and evolution of radiolabeled nanoparticles as a new frontier in personalized cancer nanomedicine. The dynamic synergism of positron emission tomography (PET) and nanotechnology combines the sensitivity and quantitative nature of PET with the multifunctionality and tunability of nanomaterials, which can help overcome certain key challenges in the field. In this review, we discuss the recent advances in radionanomedicine, exemplifying the ability to tailor the physicochemical properties of nanomaterials to achieve optimal in vivo pharmacokinetics and targeted molecular imaging in living subjects. Innovations in development of facile and robust radiolabeling strategies and biomedical applications of such radionanoprobes in cancer theranostics are highlighted. Imminent issues in clinical translation of radiolabeled nanomaterials are also discussed, with emphasis on multidisciplinary efforts needed to quickly move these promising agents from bench to bedside.

Thermosensitive porphyrin-incorporated hydrogel with four-arm PEG-PCL copolymer (II): doxorubicin loaded hydrogel as a dual fluorescent drug delivery system for simultaneous imaging tracking in vivo

Visualization of a drug delivery system could reveal the pharmacokinetic properties, which is essential for the design of a novel drug delivery system. In vivo optical imaging offers an advanced tool to monitor the drug release process and the therapeutic effect by the combination of fluorescence imaging and bioluminescence imaging. Multispectral fluorescence imaging can separate the drug and the carrier without interference. Herein, a dual fluorescent anti-tumor drug delivery system was monitored with the doxorubicin-loaded hydrogel to further explore the application of the porphyrin-incorporated hydrogel with four-arm PEG-PCL copolymer as a drug carrier, based on the beneficial fluorescence and good biocompatibility of the porphyrin incorporated hydrogel. Using nude mice bearing luciferase expressed hepatic tumor as models, the whole process from the drug delivery to the tumor therapeutic effects were real time visualized simultaneously after administration at interval from 0 to 18 d. The imaging results suggest that the fluorescence signals of the drug and the carrier can be separated and unmixed from the drug-loaded hydrogel successfully, avoiding the interference of the fluorescence signals. The tumor growth or inhibition can be real time tracked and analyzed quantitatively by bioluminescence imaging. Noninvasive continuous tracking the in vivo drug delivery process simultaneously is a potential trend for the precise drug delivery and treatment.