Green Layer-by-Layer Assembly of Porphyrin/G-Quadruplex-Based Near-Infrared Nanocomposite Photosensitizer with High Biocompatibility and Bioavailability

Diagnosis and Vulnerability Risk Assessment of Atherosclerotic Plaques Using an Amino Acid-Assembled Near-Infrared Ratiometric Nanoprobe

To reduce the risk of atherosclerotic disease, it is necessary to not only diagnose the presence of atherosclerotic plaques but also assess the vulnerability risk of plaques. Accurate detection of the reactive oxygen species (ROS) level at plaque sites represents a reliable way to assess the plaque vulnerability. Herein, through a simple one-pot reaction, two near-infrared (NIR) fluorescent dyes, one is ROS responsive and the other is inert to ROS, are coassembled in an amphiphilic amino acid-assembled nanoparticle. In the prepared NIR fluorescent amino acid nanoparticle (named FANP), the fluorescent properties and ROS-responsive behaviors of the two fluorescent dyes are well maintained. Surface camouflage through red blood cell membrane (RBCM) encapsulation endows the finally obtained FANP@RBCM nanoprobe with not only further reduced cytotoxicity and improved biocompatibility but also increased immune escape capability, prolonged blood circulation time, and thus enhanced accumulation at atherosclerotic plaque sites. In vitro and in vivo experiments demonstrate that FANP@RBCM not only works well in probing the occurrence of atherosclerotic plaques but also enables plaque vulnerability assessment through the accurate detection of the ROS level at plaque sites in a reliable ratiometric mode, thereby holding great promise as a versatile tool for the diagnosis and risk assessment of atherosclerotic disease.

Type-I Photodynamic Therapy Induced by Pt-Coordination of Type-II Photosensitizers into Supramolecular Complexes

Platinum supramolecular complexes based on photosensitizers have garnered great interest in photodynamic therapy (PDT) due to Pt (II) centers as chemotherapeutic agents to eliminate tumor cells completely, which greatly improve the antitumor efficacy of PDT. However, in comparison to precursor photosensitizer ligand, the formed platinum supramolecular complexes typically exhibit inferior outcomes in terms of reactive oxygen species (ROS) generation. How to boost ROS generation in the formed platinum supramolecular complexes for enhanced PDT is an enticing yet highly challenging task. Here we report a Pt-coordination-based dimeric photosensitizer complex (Cz-BTZ-Py)2Pt(OTf)2. It is found that comparing with photosensitizer ligand Cz-BTZ-Py, the formed supramolecular complex exhibit redshifts of absorption wavelength as well as enhanced ROS generation efficiency. Moreover, type-I ROS generation (O2⋅-) is produced in the formed platinum supramolecular complexes mainly due to a reduced energy gap ΔEST resulting from exciton coupling between two photosensitizer ligands. And type-I ROS (O2⋅-) generation significantly amplifies the photodynamic therapy (PDT) outcomes. In vitro evaluation shows excellent photochemotherapy performance of (Cz-BTZ-Py)2Pt(OTf)2 nanoparticles. We anticipate this work would provide a novel approach to design type-I photosensitizers for efficient PDT.

Optimized strategies of ROS-based nanodynamic therapies for tumor theranostics

Reactive oxygen species (ROS) play a crucial role in regulating the metabolism of tumor growth, metastasis, death and other biological processes. ROS-based nanodynamic therapies (NDTs) are becoming attractive due to non-invasive, low side effects and tumor-specific advantages. NDTs have rapidly developed into numerous branches, such as photodynamic therapy, chemodynamic therapy, sonodynamic therapy and so on. However, the complexity of the tumor microenvironment and the limitations of existing sensitizers have greatly restricted the therapeutic effects of NDTs, which heavily rely on ROS levels. To address the limitations of NDTs, various strategies have been developed to increase ROS yield, which is an urgent aspect for the positive development of NDTs. In this review, the nanodynamic potentiation strategies in terms of unique properties and universalities of NDTs are comprehensively outlined. We mainly summarize the current dilemmas faced by each NDT and the respective solutions. Meanwhile, the NDTs universalities-based potentiation strategies and NDTs-based combined treatments are elaborated. Finally, we conclude with a discussion of the key issues and challenges faced in the development and clinical transformation of NDTs.

Smart Nanomaterials in Cancer Theranostics: Challenges and Opportunities

Cancer is ranked as the second leading cause of death globally. Traditional cancer therapies including chemotherapy are flawed, with off-target and on-target toxicities on the normal cells, requiring newer strategies to improve cell selective targeting. The application of nanomaterial has been extensively studied and explored as chemical biology tools in cancer theranostics. It shows greater applications toward stability, biocompatibility, and increased cell permeability, resulting in precise targeting, and mitigating the shortcomings of traditional cancer therapies. The nanoplatform offers an exciting opportunity to gain targeting strategies and multifunctionality. The advent of nanotechnology, in particular the development of smart nanomaterials, has transformed cancer diagnosis and treatment. The large surface area of nanoparticles is enough to encapsulate many molecules and the ability to functionalize with various biosubstrates such as DNA, RNA, aptamers, and antibodies, which helps in theranostic action. Comparatively, biologically derived nanomaterials perceive advantages over the nanomaterials produced by conventional methods in terms of economy, ease of production, and reduced toxicity. The present review summarizes various techniques in cancer theranostics and emphasizes the applications of smart nanomaterials (such as organic nanoparticles (NPs), inorganic NPs, and carbon-based NPs). We also critically discussed the advantages and challenges impeding their translation in cancer treatment and diagnostic applications. This review concludes that the use of smart nanomaterials could significantly improve cancer theranostics and will facilitate new dimensions for tumor detection and therapy.

Dual size/charge-switchable and multi-responsive gelatin-based nanocluster for targeted anti-tumor therapy

Biopolymers with excellent biocompatibility and biodegradability show great potential for designing drug nanocarriers, while it's difficult to fabricate smart vehicles with multiple switching (size, surface, shape) based on biopolymers alone. Here, we report a dual size/charge-switchable and multi-responsive doxorubicin-loaded gelatin-based nanocluster (DOX-icluster) for improved tumor penetration and targeted anti-tumor therapy. The DOX-icluster was electrostatically assembled from folic acid and dimethylmaleic anhydride modified gelatin (FA-GelDMA) and small-sized DOX-loaded NH₂ modified hollow mesoporous organosilicon nanoparticles (DOX-HMON-NH₂). DOX-icluster had an initial size of about 199 nm at neutral pH. After accumulation in tumor tissue, the DMA bond of FA-GelDMA was cleaved and gelatin was degraded by matrix metalloproteinase (MMP-2), thus 48 nm and positively charged DOX-HMON-NH₂ was released to facilitate penetration and cell internalization. DOX-HMON-NH₂ was further degraded by intracellular glutathione (GSH) with releasing 48.1 % of DOX. The cellular uptake results indicated that the fabricated icluster promoted the uptake of DOX by 4T1 cells. With enhanced penetration efficacy, the tumor spheroids volume treated with DOX-icluster was reduced to 15.1 % on day 7. This cytocompatible multi-responsive gelatin-based icluster with size-shrinking and charge-reversible characteristics may be used as a significant drug carrier for tumor therapy.

New porphyrin photosensitizers-Synthesis, singlet oxygen yield, photophysical properties and application in PDT

This research on porphyrin-based photosensitizer system has a very important theoretical and practical significance in the photodynamic therapy (PDT) treatment of cancer. Based on this, in this article, a series of porphyrin derivatives were first designed and synthesized, and a "push-pull" porphyrin photosensitizer with two symmetrical ethanethioate groups was finally constructed. Based on the characterization of their chemical structures (¹H and¹³C NMR, MS, IR, and UV-Vis spectroscopy) and the use of the density functional theory (DFT) and time-dependent DFT (TDDFT) to address the nature of the excited states as well as the dark/phototoxicity, the results have indicated the relationship between the porphyrin structure and properties. The experimental and theoretical UV-Vis absorption properties of porphyrins were discussed. The four porphyrin compounds synthesized all demonstrated a high capacity to generate singlet oxygen under long-wavelength (590 nm) light and low dark toxicity. Compared with the conventional porphyrin photosensitizers, P4 with a CT band (from 580 to 750 nm) is beneficial to the penetration of the light, presenting the potential for applications in PDT.

Molecularly Self-Engineered Nanoamplifier for Boosting Photodynamic Therapy via Cascade Oxygen Elevation and Lipid ROS Accumulation

Photodynamic therapy (PDT) has been extensively explored as a noninvasive cancer treatment modality. However, the dilemma of tumor hypoxia and short half-life of singlet oxygen (¹O₂) severely restrict the therapeutic efficacy of PDT. Herein, we develop a facile three-in-one PDT nanoamplifier (AA@PPa/Hemin NPs) assembled by pyropheophorbide a (PPa), hemin, and arachidonic acid (AA). Interestingly, AA not only acts as an enabler to facilitate the assembly of PPa and hemin in the construction of ternary hybrid nanoassemblies but also acts as a lipid reactive oxygen species (ROS) amplifier for robust PDT. In tumor cells, hemin plays the role of a catalase-like catalyst that accelerates the production of oxygen (O₂) from hydrogen peroxide (H₂O₂), significantly alleviating tumor hypoxia. Under laser irradiation, vast amounts of ¹O₂ generated by PPa trigger the peroxidation of AA to produce large amounts of cytotoxic lipid ROS, immensely amplifying the efficiency of PDT by promptly eliciting cellular oxidative stress. As expected, AA@PPa/Hemin NPs exert potent antitumor activity in a 4T1 breast-tumor-bearing BALB/c mice xenograft model. Such a cascade nanohybrid amplifier provides a novel codelivery platform for accurate and effective PDT of cancer.

NIR-Active Porphyrin-Decorated Lipid Microbubbles for Enhanced Therapeutic Activity Enabled by Photodynamic Effect and Ultrasound in 3D Tumor Models of Breast Cancer Cell Line and Zebrafish Larvae

Porphyrin is known to enable the photodynamic effect during cancer drug delivery and molecular imaging. However, its hydrophobicity and tendency to aggregate in an aqueous medium create a significant hurdle for its use as an anticancer drug. Loading porphyrin onto biocompatible delivery vehicles can enhance its efficacy. This can be achieved by using gas-filled microbubbles that can be administered intravenously. This study aimed at developing near-infrared (NIR)-active porphyrin-loaded lipid microbubbles with anticancer activity enhanced by sonodynamic and photodynamic effects. The porphyrin-loaded microbubbles were studied for their cell toxicity, cellular uptake of porphyrin, and effect on cellular three-dimensional (3D) invasion of breast cancer cells (MDA-MB-231) in cellulo. Toxicity studies in zebrafish larvae (Danio rerio) in the presence and absence of photodynamic and sonodynamic therapy were also conducted. The results suggest that with a higher concentration of porphyrin loaded on microbubbles, the porphyrin-loaded microbubbles display a higher therapeutic effect facilitated by photodynamic and sonodynamic therapy, which results in enhanced cellular uptake and cellular toxicity. A lower concentration of loaded porphyrin microbubbles exhibits high cellular viability and good fluorescence intensity in the NIR region, which can be exploited for bioimaging applications.

Self-assembly of amphiphilic amino acid derivatives for biomedical applications

Amino acids are one of the simplest biomolecules and they play an essential role in many biological processes. They have been extensively used as building blocks for the synthesis of functional nanomaterials, thanks to their self-assembly capacity. In particular, amphiphilic amino acid derivatives can be designed to enrich the diversity of amino acid-based building blocks, endowing them with specific properties and/or promoting self-assembly through hydrophobic interactions, hydrogen bonding, and/or π-stacking. In this review, we focus on the design of various amphiphilic amino acid derivatives able to self-assemble into different types of nanostructures that were exploited for biomedical applications, thanks to their excellent biocompatibility and biodegradability.

Nanoarchitectonics with porphyrins and related molecules

An emerging concept, nanoarchitectonics, is supposed to work on the preparation of functional materials systems from nanoscale components. Because porphyrin derivatives show their importance in many research targets, discussions on nanoarchitectonics with porphyrins and related molecules would provide meaningful opportunities to consider effective usages of the nanoarchitectonics. This review article explains various examples of nanoarchitectonics approaches with porphyrin derivatives. The examples are especially focused on two topics: (i) materials nanoarchitectonics for nanofibers, metal-organic frameworks, covalent organic frameworks, and hydrogen-bonded organic frameworks; (ii) interfacial nanoarchitectonics for surface monolayers (self-assembled monolayers), Langmuir-Blodgett films, and layer-by-layer assemblies. Functions and properties can be enhanced upon their organization in specific dimensions and arrangements in nanostructured frameworks. In many cases, interface-specific organization would lead to advanced performances with high efficiency and specificity. Even though only limited examples are described here, various possibilities are actually suggested. Not limited to porphyrin families, nanoarchitectonics for functional materials has to be considered with a wide range of materials.

Metal-Organic Framework-Based Nanoagents for Effective Tumor Therapy by Dual Dynamics-Amplified Oxidative Stress

Overproduction of reactive oxygen species (ROS) within tumors can cause oxidative stress on tumor cells to induce death, which has motivated us to develop ROS-mediated tumor therapies, such as typical photodynamic therapy (PDT) and Fenton reaction-mediated chemodynamic therapy (CDT). However, these therapeutic modalities suffer from compromised treatment efficacy owing to their limited generation of highly reactive ROS in a tumor microenvironment (TME). In this work, a nanoscale iron-based metal-organic framework, MIL-101(Fe), is synthesized as a Fenton nanocatalyst to perform the catalytic conversion of hydroxyl radicals (·OH) from hydrogen peroxide (H₂O₂) under the acidic environment and as a biocompatible and biodegradable nanocarrier to deliver a 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP) photosensitizer for light-activated singlet oxygen (¹O₂) generation. By coupling such chemodynamic/photodynamic effects, the photosensitizer-integrated nanoagents (MIL-101(Fe)@TCPP) could enable more ROS production within tumors to induce amplified oxidative damage for tumor-specific synergistic therapy. In vitro results show that MIL-101(Fe)@TCPP nanoagents achieve the acid-responsive CDT and effective PDT, and synergistic CDT/PDT provides an enhanced therapeutic effect. Ultimately, based on such synergistic therapy, MIL-101(Fe)@TCPP nanoagents cause a significant tumor growth inhibition in vivo without severe side effects, showing great potential for anti-tumor application.

Applications of Aptamer-Bound Nanomaterials in Cancer Therapy

Cancer is still a major disease that threatens human life. Although traditional cancer treatment methods are widely used, they still have many disadvantages. Aptamers, owing to their small size, low toxicity, good specificity, and excellent biocompatibility, have been widely applied in biomedical areas. Therefore, the combination of nanomaterials with aptamers offers a new method for cancer treatment. First, we briefly introduce the situation of cancer treatment and aptamers. Then, we discuss the application of aptamers in breast cancer treatment, lung cancer treatment, and other cancer treatment methods. Finally, perspectives on challenges and future applications of aptamers in cancer therapy are discussed.

Bioinspired Conjugated Tri-Porphyrin-Based Intracellular pH-Sensitive Metallo-Supramolecular Nanoparticles for Near-Infrared Photoacoustic Imaging-Guided Chemo- and Photothermal Combined Therapy

Porphyrins have been extensively used in clinical phototherapy. However, most of them exhibited absorption below 700 nm. We report conjugated tri-porphyrins showing absorption within a biological phototherapy window (700-850 nm). On this basis, bioinspired intracellular pH-sensitive metallo-supramolecular nanoparticles (NPs) are designed. They provide the simultaneous photothermal therapy and chemotherapy. After treatment by tail vein injection, the tumor was completely relieved without recurrence in a course of 27 days. These bioinspired intracellular pH-sensitive metallo-supramolecular NPs show excellent potential application in near-infrared photoacoustic imaging-guided chemo-photothermal combined therapy.

Aptamer-Targeted Photodynamic Platforms for Tumor Therapy

Achieving controlled and accurate delivery of photosensitizers (PSs) into tumor sites is a major challenge in conventional photodynamic therapy (PDT). Aptamer is a short oligonucleotide sequence (DNA or RNA) with a folded three-dimensional structure, which can selectively bind to specific small molecules, proteins, or the whole cells. Aptamers could act as ligands and be modified onto PSs or nanocarriers, enabling specific recognition and binding to tumor cells or their membrane proteins. The resultant aptamer-modified PSs or PSs-containing nanocarriers generate amounts of reactive oxygen species with light irradiation and obtain superior photodynamic therapeutic efficiency in tumors. Herein, we overview the recent progress in the designs and applications of aptamer-targeted photodynamic platforms for tumor therapy. First, we focus on the progress on the rational selection of aptamers and summarize the applications of aptamers which have been applied for targeted tumor diagnosis and therapy. Then, aptamer-targeted photodynamic therapies including various aptamer-PSs, aptamer-nanocarriers containing PSs, and aptamer-nano-photosensitizers are highlighted. The aptamer-targeted synergistically therapeutic platforms including PDT, photothermal therapy, and chemotherapy, as well as the imaging-guided theranostics, are also discussed. Finally, we offer an insight into the development trends and future perspectives of aptamer-targeted photodynamic platforms for tumor therapy.

DNA nanostructure-based nucleic acid probes: construction and biological applications

In recent years, DNA has been widely noted as a kind of material that can be used to construct building blocks for biosensing, in vivo imaging, drug development, and disease therapy because of its advantages of good biocompatibility and programmable properties. However, traditional DNA-based sensing processes are mostly achieved by random diffusion of free DNA probes, which were restricted by limited dynamics and relatively low efficiency. Moreover, in the application of biosystems, single-stranded DNA probes face challenges such as being difficult to internalize into cells and being easily decomposed in the cellular microenvironment. To overcome the above limitations, DNA nanostructure-based probes have attracted intense attention. This kind of probe showed a series of advantages compared to the conventional ones, including increased biostability, enhanced cell internalization efficiency, accelerated reaction rate, and amplified signal output, and thus improved in vitro and in vivo applications. Therefore, reviewing and summarizing the important roles of DNA nanostructures in improving biosensor design is very necessary for the development of DNA nanotechnology and its applications in biology and pharmacology. In this perspective, DNA nanostructure-based probes are reviewed and summarized from several aspects: probe classification according to the dimensions of DNA nanostructures (one, two, and three-dimensional nanostructures), the common connection modes between nucleic acid probes and DNA nanostructures, and the most important advantages of DNA self-assembled nanostructures in the applications of biosensing, imaging analysis, cell assembly, cell capture, and theranostics. Finally, the challenges and prospects for the future development of DNA nanostructure-based nucleic acid probes are also discussed.

Cucurbit[10]uril-Encapsulated Cationic Porphyrins with Enhanced Fluorescence Emission and Photostability for Cell Imaging

Porphyrins are widely applied for imaging, diagnosis, and treatment of diseases because of their excellent photophysical properties. However, porphyrins easily tend to aggregate driven by hydrophobic interaction and π-π stacking in an aqueous medium, which causes fluorescence quenching of the porphyrins as well as limitation of cell uptake and intracellular accumulation. Herein, cucurbit[10]uril (CB[10]) was used to fully encapsulate cationic porphyrin (CPor) in the large cavity with strong binding affinity in aqueous solutions, and the CPor aggregates were efficient disassembled, companying remarkable enhancing its fluorescence intensity. The CB[10]-based host-guest complex provided excellent protection to CPor, resulting in less susceptibility to oxidation and imparting higher photostability to CPor for cell imaging. In addition, by complexation with CB[10], it was found that the fluorescence signals and photostability of CPor were also effectively improved in cells with different reactive oxygen species levels. It is highly anticipated that the large macrocyclic host cavity-triggered large-guest encapsulation strategy in this work will provide a convenient and efficient method for designing supramolecular porphyrin dyes, thus broadening the diagnosis and imaging application in cells and microorganisms.

Self-Assembled Platinum Supramolecular Metallacycles Based on a Novel TADF Photosensitizer for Efficient Cancer Photochemotherapy

Recently, supramolecular coordination complexes (SCCs) based on photosensitizers as bridging ligands have attracted great attention in cancer therapy owing to their synergistic effect between photodynamic therapy (PDT) and chemotherapy. Herein, a highly emissive supramolecular platinum triangle BTZPy-Pt based on a novel type of photosensitizer BTZPy with thermally activated delayed fluorescence (TADF) was fabricated. The BTZPy and BTZPy-Pt exhibited strong luminescence emission in the visible range with high quantum yields (quantum yields (QYs) for BTZPy and BTZPy-Pt were about 78 and 62% in ethanol solutions, respectively). Additionally, BTZPy had been proved to be an excellent photosensitizer with superior ¹O₂ generation capability (the ¹O₂ generation quantum yield reached up to ca. 95%) for PDT. By the combination of the excellent phototoxicity of BTZPy and the antitumor activity of the Pt center, the platinum triangle BTZPy-Pt demonstrated a highly efficient anticancer performance toward HeLa cells (IC₅₀: 0.5 μg mL^-1). This study not only provides a blueprint to fabricate new types of photosensitizers but also paves a way to design novel SCCs for efficient PDT.

A novel pH-responsive Fe-MOF system for enhanced cancer treatment mediated by the Fenton reaction

A novel pH-responsive Fe-MOF system for enhancing cancer treatment mediated by a Fenton reaction.

Recent development of amorphous metal coordination polymers for cancer therapy

Nanoscale metal coordination polymers (NCPs), built from metal ions and organic ligands, have attracted tremendous interest in biomedical applications. This is mainly due to their mesoporous structure, tunable size and morphology and versatile functionality. NCPs can be further divided into nanoscale metal-organic frameworks (NMOFs) and amorphous coordination polymer particles (ACPPs) depending on their structural crystallinity. NMOFs as nanocarriers have been extensively reviewed. However, the highlights of ACPPs as theranostic nanoplatforms are still limited. In this review, the recent progress of ACPPs as theranostic nanoplatforms is summarized based on what types of organic linkers used. The ACPPs are divided into three main parts: photosensitizers-based ACPPs, chemical drugs-based ACPPs, and biomolecules-based ACPPs. Finally, the prospects and challenges of the ACPPs for enhanced biomedical applications are also discussed. STATEMENT OF SIGNIFICANCE: Over the last decades, amorphous metal coordination polymers (ACPPs), constructed by metal ions and organic linkers, have attracted enormous interest in cancer treatment owing to their high drug loading capability, facile synthetic procedures, low long-term toxicity, and mild preparation conditions. In this review, we highlight the recent progress of ACPPs for biomedical application based on different types of organic building blocks including photosensitizers, chemical drugs, and biomolecules. Moreover, the prospects and challenges of ACPPs for clinical application are also discussed. We hope this review entitled "Recent development of amorphous metal coordination polymers for cancer therapy" would arise the researchers' interest in this field to accelerate their clinical application in cancer therapy.