Encapsulation of NIR-II AIEgens in Virus-like Particles for Bioimaging

Controllable Self-Assembly of V═O Metalloradical Complex with Intramolecular Charge Transfer for Enhanced NIR-II Fluorescence Imaging-Guided Photothermal Therapy

Near-infrared second region (NIR-II) fluorescence imaging provides enhanced tissue penetration, achieving efficient NIR-II fluorescence and photoacoustic imaging (PA)-guided photothermal therapy (PTT) all in one material remains a challenging yet promising approach in cancer treatment. Herein, open-shell V═O metalloradical complex (VONc) is self-assembled into VONc nanospheres (VONc NPs). VONc NPs exhibit light absorption from 300 to 1400 nm, fluorescence spectra ranging from 900 to 1400 nm, and a distinct fluorescence signal even at 1550 nm. Moreover, VONc NPs exhibit outstanding photostability and a higher photothermal conversion efficiency of 46.6% than that of closed-shell zinc naphthalocyanine nanorods (ZnNc NRs). V═O centered metalloradical serves as transient electron-withdrawing groups to facilitate charge transfer (CT), introducing additional nonradiative energy dissipation pathways and enhancing efficient heat generation. In vitro experiments of VONc NPs indicate that a highly effective photothermal action causes harm to both mitochondria and lysosomes, resulting in the death of tumor cells, closed-shell ZnNc NPs exhibit almost no cell killing as contrast. In vivo anti-tumor therapy results of VONc NPs demonstrate excellent NIR-II fluorescence imaging-guided PTT against tumors with a favorable biosafety profile. "Centered metalloradical boosting CT" toward open-shell metal complexes provides significant insight for developing single-material integrated nanosystems for diagnostic and therapeutic applications.

Current Advances in Viral Nanoparticles for Biomedicine

Viral nanoparticles (VNPs) have emerged as crucial tools in the field of biomedicine. Leveraging their biological and physicochemical properties, VNPs exhibit significant advantages in the prevention, diagnosis, and treatment of human diseases. Through techniques such as chemical bioconjugation, infusion, genetic engineering, and encapsulation, these VNPs have been endowed with multifunctional capabilities, including the display of functional peptides or proteins, encapsulation of therapeutic drugs or inorganic particles, integration with imaging agents, and conjugation with bioactive molecules. This review provides an in-depth analysis of VNPs in biomedicine, elucidating their diverse types, distinctive features, production methods, and complex design principles behind multifunctional VNPs. It highlights recent innovative research and various applications, covering their roles in imaging, drug delivery, therapeutics, gene delivery, vaccines, immunotherapy, and tissue regeneration. Additionally, the review provides an assessment of their safety and biocompatibility and discusses challenges and future opportunities in the field, underscoring the vast potential and evolving nature of VNP research.

Benzobisthiadiazole-Based Small Molecular Near-Infrared-II Fluorophores: From Molecular Engineering to Nanophototheranostics

Organic fluorescent molecules with emission in the second near-infrared (NIR-II) biological window have aroused increasing investigation in cancer phototheranostics. Among these studies, Benzobisthiadiazole (BBT), with high electron affinity, is widely utilized as the electron acceptor in constructing donor-acceptor-donor (D-A-D) structured fluorophores with intensive near-infrared (NIR) absorption and NIR-II fluorescence. Until now, numerous BBT-based NIR-II dyes have been employed in tumor phototheranostics due to their exceptional structure tunability, biocompatibility, and photophysical properties. This review systematically overviews the research progress of BBT-based small molecular NIR-II dyes and focuses on molecule design and bioapplications. First, the molecular engineering strategies to fine-tune the photophysical properties in constructing the high-performance BBT-based NIR-II fluorophores are discussed in detail. Then, their biological applications in optical imaging and phototherapy are highlighted. Finally, the current challenges and future prospects of BBT-based NIR-II fluorescent dyes are also summarized. This review is believed to significantly promote the further progress of BBT-derived NIR-II fluorophores for cancer phototheranostics.

Viral protein-based nanoparticles (part 2): Pharmaceutical applications

Viral protein nanoparticles (ViP NPs) such as virus-like particles and virosomes are structures halfway between viruses and synthetic nanoparticles. The biological nature of ViP NPs endows them with the biocompatibility, biodegradability, and functional properties that many synthetic nanoparticles lack. At the same time, the absence of a viral genome avoids the safety concerns of viruses. Such characteristics of ViP NPs offer a myriad of opportunities for theirapplication at several points across disease development: from prophylaxis to diagnosis and treatment. ViP NPs present remarkable immunostimulant properties, and thus the vaccination field has benefited the most from these platforms capable of overcoming the limitations of both traditional and subunit vaccines. This was reflected in the marketing authorization of several VLP- and virosome-based vaccines. Besides, ViP NPs inherit the ability of viruses to deliver their cargo to target cells. Because of that, ViP NPs are promising candidates as vectors for drug and gene delivery, and for diagnostic applications. In this review, we analyze the pharmaceutical applications of ViP NPs, describing the products that are commercially available or under clinical evaluation, but also the advances that scientists are making toward the implementation of ViP NPs in other areas of major pharmaceutical interest.

Facile and green fabrication of tumor- and mitochondria-targeted AIEgen-protein nanoparticles for imaging-guided photodynamic cancer therapy

In recent years, aggregation-induced emission (AIE)-active materials have been emerging as a promising means for bioimaging and phototherapy. However, the majority of AIE luminogens (AIEgens) need to be encapsulated into versatile nanocomposites to improve their biocompatibility and tumor targeting. Herein, we prepared a tumor- and mitochondria-targeted protein nanocage by the fusion of human H-chain ferritin (HFtn) with a tumor homing and penetrating peptide LinTT1 using genetic engineering technology. The LinTT1-HFtn could serve as a nanocarrier to encapsulate AIEgens via a simple pH-driven disassembly/reassembly process, thereby fabricating the dual-targeting AIEgen-protein nanoparticles (NPs). The as designed NPs exhibited an improved hepatoblastoma-homing property and tumor penetrating ability, which is favorable for tumor-targeted fluorescence imaging. The NPs also presented a mitochondria-targeting ability, and efficiently generated reactive oxygen species (ROS) upon visible light irradiation, making them valuable for inducing efficient mitochondrial dysfunction and intrinsic apoptosis in cancer cells. In vivo experiments demonstrated that the NPs could provide the accurate tumor imaging and dramatic tumor growth inhibition with minimal side effects. Taken together, this study presents a facile and green approach for fabrication of tumor- and mitochondria-targeted AIEgen-protein NPs, which can serve as a promising strategy for imaging-guided photodynamic cancer therapy. STATEMENT OF SIGNIFICANCE: AIE luminogens (AIEgens) show strong fluorescence and enhanced ROS generation in the aggregate state, which would facilitate the image-guided photodynamic therapy [12-14]. However, the major obstacles that hinder biological applications are their lack of hydrophilicity and selective targeting [15]. To address this issue, this study presents a facile and green approach for the fabrication of tumor‑ and mitochondria‑targeted AIEgen-protein nanoparticles via a simple disassembly/reassembly of the LinTT1 peptide-functionalized ferritin nanocage without any harmful chemicals or chemical modification. The targeting peptide-functionalized nanocage not only restricts the intramolecular motion of AIEgens leading to enhanced fluorescence and ROS production, but also confers good targeting to AIEgens.

Next-generation viral nanoparticles for targeted delivery of therapeutics: Fundamentals, methods, biomedical applications, and challenges

INTRODUCTION

Viral nanoparticles (VNPs) are virus-based nanocarriers that have been studied extensively and intensively for biomedical applications. However, their clinical translation is relatively low compared to the predominating lipid-based nanoparticles. Therefore, this article describes the fundamentals, challenges, and solutions of the VNP-based platform, which will leverage the development of next-generation VNPs.

AREAS COVERED

Different types of VNPs and their biomedical applications are reviewed comprehensively. Strategies and approaches for cargo loading and targeted delivery of VNPs are examined thoroughly. The latest developments in controlled release of cargoes from VNPs and their mechanisms are highlighted too. The challenges faced by VNPs in biomedical applications are identified, and solutions are provided to overcome them.

EXPERT OPINION

In the development of next-generation VNPs for gene therapy, bioimaging and therapeutic deliveries, focus must be given to reduce their immunogenicity, and increase their stability in the circulatory system. Modular virus-like particles (VLPs) which are produced separately from their cargoes or ligands before all the components are coupled can speed up clinical trials and commercialization. In addition, removal of contaminants from VNPs, cargo delivery across the blood brain barrier (BBB), and targeting of VNPs to organelles intracellularly are challenges that will preoccupy researchers in this decade.

In Vivo Fluorescence Imaging-Guided Development of Near-Infrared AIEgens

In vivo fluorescence imaging has received extensive attention due to its distinguished advantages of excellent biosafety, high sensitivity, dual temporal-spatial resolution, real-time monitoring ability, and non-invasiveness. Aggregation-induced emission luminogens (AIEgens) with near-infrared (NIR) absorption and emission wavelengths are ideal candidate for in vivo fluorescence imaging for their large Stokes shift, high brightness and superior photostability. NIR emissive AIEgens provide deep tissue penetration depth as well as low interference from tissue autofluorescence. Here in this review, we summarize the molecular engineering strategies for constructing NIR AIEgens with high performances, including extending π-conjugation system and strengthen donor (D)-acceptor (A) interactions. Then the encapsulation strategies for increasing water solubility and biocompatibility of these NIR AIEgens are highlighted. Finally, the challenges and prospect of fabricating NIR AIEgens for in vivo fluorescence imaging are also discussed. We hope this review would provide some guidelines for further exploration of new NIR AIEgens.

Pt(II) metallacycles encapsulated by ferritin enable precise cancer combination chemo-photodynamic therapy

Different from common anti-tumor drugs, organoplatinum(II) metallacycles can integrate imaging and other therapeutic capabilities by incorporating corresponding functional donor ligands to enable potential applications in biomedicine. However, most of the emerging therapeutic agents not only show poor solubility and selectivity but also have serious side effects and unsatisfactory efficacy and encounter the tendency to develop drug resistance due to their single treatment model. Herein, an organoplatinum(II) metallacycle (PtM) was designed and synthesized using coordination-driven self-assembly via the combination of a metallic chemotherapy precursor and a reactive oxygen species generating organic precursor. The hydrophobic PtM molecules were encapsulated in the cavity of human heavy chain ferritin (HFn) during the reassembly of HFn to prepare the active targeting nanoagent HFn-PtM for use in chemo-photodynamic combination therapy. The HFn-PtM nanoagents exhibited excellent stability in buffer (pH from 5 to 7.2), alleviating the concern of drug leakage during circulation. A cellular uptake assay indicated that HFn-PtM could efficiently enter specific cells that overexpress the transferrin receptor 1. In vitro and in vivo anti-tumor investigations revealed that HFn-PtM exhibited excellent anti-tumor efficiency with negligible systemic toxicity. This work provides a strategy for the easy construction of multifunctional organoplatinum-based tumor-targeted drugs.

Virus-like nanoparticles as a theranostic platform for cancer

Virus-like nanoparticles (VLPs) are natural polymer-based nanomaterials that mimic viral structures through the hierarchical assembly of viral coat proteins, while lacking viral genomes. VLPs have received enormous attention in a wide range of nanotechnology-based medical diagnostics and therapies, including cancer therapy, imaging, and theranostics. VLPs are biocompatible and biodegradable and have a uniform structure and controllable assembly. They can encapsulate a wide range of therapeutic and diagnostic agents, and can be genetically or chemically modified. These properties have led to sophisticated multifunctional theranostic platforms. This article reviews the current progress in developing and applying engineered VLPs for molecular imaging, drug delivery, and multifunctional theranostics in cancer research.

Aggregation-induced emission (AIE)-Based nanocomposites for intracellular biological process monitoring and photodynamic therapy

As a non-invasive visualization technique, photoluminescence imaging (PLI) has found its huge value in many biological applications associated with intracellular process monitoring and early and accurate diagnosis of diseases. PLI can also be combined with therapeutics to build imaging-guided theragnostic platforms for achieving early and precise treatment of diseases. Photodynamic therapy (PDT) as a quintessential phototheranostics technology has gained great benefits from the combination with PLI. Recently, aggregation-induced emission (AIE)-active materials have emerged as one of the most promising bioimaging and phototheranostic agents. Most of AIEgens, however, need to be chemically engineered to form versatile nanocomposites with improved their photophysical property, photochemical activity, biocompatibility, etc. In this review, we focus on three categories of AIE-active nanocomposites and highlight their application progresses in the intracellular biological process monitoring and PLI-guided PDT. We hope this review can guide further development of AIE-active nanocomposites and promote their practical applications for monitoring intracellular biological processes and imaging-guided PDT.

Recent Progress in Second Near-Infrared (NIR-II) Fluorescence Imaging in Cancer

Cancer continues to be one of the leading causes of death worldwide, and its incidence is on the rise. Although cancer diagnosis and therapy have advanced significantly in recent decades, it is still a challenge to achieve the accurate identification and localization of cancer and to complete tumor elimination with a maximum preservation of normal tissue. Recently, second near-infrared region (NIR-II, 1000-1700 nm) fluorescence has shown great application potential in cancer theranostics due to its inherent advantages, such as great penetration capacity, minimal tissue absorption and scattering, and low autofluorescence. With the development of fluorescence imaging systems and fluorescent probes, tumor detection, margin definition, and individualized therapy can be achieved quickly, enabling an increasingly accurate diagnosis and treatment of cancer. Herein, this review introduces the role of NIR-II fluorescence imaging in cancer diagnosis and summarizes the representative applications of NIR-II image-guided treatment in cancer therapy. Ultimately, we discuss the present challenges and future perspectives on fluorescence imaging in the field of cancer theranostics and put forward our opinions on how to improve the accuracy and efficiency of cancer diagnosis and therapeutics.

Synthesis and Discovery of Schiff Base Bearing Furopyrimidinone for Selective Recognition of Zn2+ and its Applications in Cell Imaging and Detection of Cu2

A simplefuro [2,3-d]pyrimidinone-based Schiff base FPS was synthesized via aza-Wittig reaction and structure elucidation was carried out by spectroscopic studies FT-IR, 1H NMR, and 13C NMR and mass spectrometry. FPS showed weak fluorescence emission in methanol and the selectivity of FPS to different metal ions (Mn²⁺, Ca²⁺, Fe²⁺, Fe³⁺, Mg²⁺, Al³⁺, Ba²⁺, Ag⁺, Co²⁺, Na⁺, K⁺, Cu²⁺, Zn²⁺, Pb²⁺, Bi³⁺) were studied by absorption and fluorescence titration. The results show that FPS has selective fluorescence sensing behavior for Zn²⁺ ions and the limit of detection (LOD) was calculated to be 1.19 × 10^–8 mol/L. Moreover, FPS-Zn²⁺ acts as a metal based highly selective and sensitive new chemosensor for Cu²⁺ ions and the LOD was calculated to be 2.25 × 10^–7 mol/L. In accordance with the results and theoretical calculations, we suspected that the binding mechanisms of FPS to Zn²⁺ and Cu²⁺ were assigned to be the cooperative interaction of Zn²⁺(Cu²⁺)-N.

PEG-Polymer Encapsulated Aggregation-Induced Emission Nanoparticles for Tumor Theranostics

In the field of tumor imaging and therapy, the aggregation-caused quenching (ACQ) effect of fluorescent dyes at high concentration is a great challenge. In this regard, the aggregation-induced emission luminogens (AIEgens) show great potential, since AIEgens effectively overcome the ACQ effect and have better fluorescence quantum yield, photobleaching resistance, and photosensitivity. Polyethylene glycol (PEG)-polymer is the most commonly used carrier to prepare nanoparticles (NPs). The advantage of PEGylation is that it can greatly prolong the metabolic half-life and reduce immunogenicity and toxicity. Considering that the hydrophobicity of most AIEgens hinders their application in organisms, the use of PEG-polymer encapsulation is an effective strategy to overcome this obstacle. Importantly, bioactive functional groups can be modified on PEG-polymers to enhance the biological effect of NPs. The combination of powerful AIEgens and PEG-polymers provides a new strategy for tumor imaging and therapy, which is promising for clinical application.

Rapidly liver-clearable rare-earth core-shell nanoprobe for dual-modal breast cancer imaging in the second near-infrared window

BACKGROUND

Fluorescence imaging as the beacon for optical navigation has wildly developed in preclinical studies due to its prominent advantages, including noninvasiveness and superior temporal resolution. However, the traditional optical methods based on ultraviolet (UV, 200-400 nm) and visible light (Vis, 400-650 nm) limited by their low penetration, signal-to-noise ratio, and high background auto-fluorescence interference. Therefore, the development of near-infrared-II (NIR-II 1000-1700 nm) nanoprobe attracted significant attentions toward in vivo imaging. Regrettably, most of the NIR-II fluorescence probes, especially for inorganic NPs, were hardly excreted from the reticuloendothelial system (RES), yielding the anonymous long-term circulatory safety issue.

RESULTS

Here, we develop a facile strategy for the fabrication of Nd3+-doped rare-earth core-shell nanoparticles (Nd-RENPs), NaGdF4:5%Nd@NaLuF4, with strong emission in the NIR-II window. What's more, the Nd-RENPs could be quickly eliminated from the hepatobiliary pathway, reducing the potential risk with the long-term retention in the RES. Further, the Nd-RENPs are successfully utilized for NIR-II in vivo imaging and magnetic resonance imaging (MRI) contrast agents, enabling the precise detection of breast cancer.

CONCLUSIONS

The rationally designed Nd-RENPs nanoprobes manifest rapid-clearance property revealing the potential application toward the noninvasive preoperative imaging of tumor lesions and real-time intra-operative supervision.