Clinically Approved MRI Contrast Agents as Imaging Labels for a Porous Iron‐Based MOF Nanocarrier: A Systematic Investigation in a Clinical MRI Setting

Mn(II)-MOF nanoparticles conjugated with EOB-PEG as high-performance hepatobiliary-specific MRI contrast agents

Hepatobiliary magnetic resonance imaging (MRI) is a crucial diagnostic tool for early detection and staging of liver tumors. However, the currently available hepatobiliary-specific contrast agents (CAs), acyclic Gd chelates, suffer from limited kinetic stability and may pose serious toxicity risks to patients with specific functional impairments. In light of these concerns, Mn-based MRI CAs have gained increasing attention as potential alternatives to Gd-based agents, despite challenges in their stability and relaxivity. Herein, we present a novel hepatobiliary-specific CA in the form of Mn(II)-based metal-organic framework (MOF) nanoparticles conjugated with ethoxybenzyl-poly(ethylene glycol) (EOB-PEG) ligands. These nanoparticles exhibit significantly higher relaxivity (r1 = 66.4 mM-1 s-1 in 4.5% HSA) compared to a commercial hepatobiliary-specific CA, Gd-EOB-DTPA (r1 = 11.2 mM-1 s-1 in 4.5% HSA), along with excellent biocompatibility. This enables them to achieve equivalent imaging contrast with a substantially lower metal concentration (0.025 mmol Mn2+ per kg BW vs. 0.1 mmol Gd3+ per kg BW for the commercial Gd-EOB-DTPA). Furthermore, our MOF-based nanoparticles demonstrate precise diagnostic capabilities in vivo, as evidenced by their performance in orthotopic HCC mouse models. This progress holds great promise for the development of advanced hepatobiliary-specific CAs, which could significantly enhance early liver cancer diagnosis by providing clearer and safer imaging options.

Biomedical Metal-Organic Framework Materials: Perspectives and Challenges

Metal-organic framework (MOF) materials are gaining significant interest in biomedical research, owing to their high porosity, crystallinity, and structural and compositional diversity. Their versatile hybrid organic/inorganic chemistry endows MOFs with the capacity to retain organic (drug) molecules, metals, and gases, to effectively channel electrons and photons, to survive harsh physiological conditions such as low pH, and even to protect sensitive biomolecules. Extensive preclinical research has been carried out with MOFs to treat several pathologies and, recently, their integration with other biomedical materials such as stents and implants has demonstrated promising performance in regenerative medicine. However, there remains a significant gap between MOF preclinical research and translation into clinically and societally relevant medicinal products. Here, we outline the intrinsic features of MOFs and discuss how these are suited to specific biomedical applications like detoxification, drug and gas delivery, or as (combination) therapy platforms. We furthermore describe relevant examples of how MOFs have been engineered and evaluated in different medical indications, including cancer, microbial, and inflammatory diseases. Finally, we critically examine the challenges facing their translation into the clinic, with the goal of establishing promising research directions and more realistic approaches that can bridge the translational gap of MOFs and MOF-containing (nano)materials.

Advancements in materials, manufacturing, propulsion and localization: propelling soft robotics for medical applications

Soft robotics is an emerging field showing immense potential for biomedical applications. This review summarizes recent advancements in soft robotics for in vitro and in vivo medical contexts. Their inherent flexibility, adaptability, and biocompatibility enable diverse capabilities from surgical assistance to minimally invasive diagnosis and therapy. Intelligent stimuli-responsive materials and bioinspired designs are enhancing functionality while improving biocompatibility. Additive manufacturing techniques facilitate rapid prototyping and customization. Untethered chemical, biological, and wireless propulsion methods are overcoming previous constraints to access new sites. Meanwhile, advances in tracking modalities like computed tomography, fluorescence and ultrasound imaging enable precision localization and control enable in vivo applications. While still maturing, soft robotics promises more intelligent, less invasive technologies to improve patient care. Continuing research into biocompatibility, power supplies, biomimetics, and seamless localization will help translate soft robots into widespread clinical practice.

Application and Development Prospect of Nanoscale Iron Based Metal-Organic Frameworks in Biomedicine

Metal-organic frameworks (MOFs) are coordination polymers that comprise metal ions/clusters and organic ligands. MOFs have been extensively employed in different fields (eg, gas adsorption, energy storage, chemical separation, catalysis, and sensing) for their versatility, high porosity, and adjustable geometry. To be specific, Fe2+/Fe3+ exhibits unique redox chemistry, photochemical and electrical properties, as well as catalytic activity. Fe-based MOFs have been widely investigated in numerous biomedical fields over the past few years. In this study, the key index requirements of Fe-MOF materials in the biomedical field are summarized, and a conclusion is drawn in terms of the latest application progress, development prospects, and future challenges of Fe-based MOFs as drug delivery systems, antibacterial therapeutics, biocatalysts, imaging agents, and biosensors in the biomedical field.

PDA-coated CPT@MIL-53 (Fe) based Theranostic Nanoplatform for pH-Responsive and MRI-Guided Chemotherapy

Theranostic nanoplatform for multimodal diagnosis and treatment of tumors is a currently research hotspot in the field of nanomedicine. MOF-based theranostic nanoplatforms of integrating drug delivery with magnetic resonance imaging...

The in vivo fate of tobacco mosaic virus nanoparticle theranostic agents modified by the addition of a polydopamine coat

Plant virus nanoparticles (VNPs) have multiple advantages over their synthetic counterparts including the cost-effective large-scale manufacturing of uniform particles that are easy to functionalize. Tobacco mosaic virus (TMV) is one of the most promising VNP scaffolds, reflecting its high aspect ratio and ability to carry and/or display multivalent therapeutic ligands and contrast agents. Here we investigated the circulation, protein corona, immunogenicity, and organ distribution/clearance of TMV particles internally co-labeled with cyanine 5 (Cy5) and chelated gadolinium (Gd) for dual tracking by fluorescence imaging and optical emission spectrometry, with or without an external coating of polydopamine (PDA) to confer photothermal and photoacoustic capabilities. The PDA-coated particles (Gd-Cy5-TMV-PDA) showed a shorter plasma circulation time and broader distribution to organs of the reticuloendothelial system (liver, lungs, and spleen) than uncoated Gd-Cy5-TMV particles (liver and spleen only). The Gd-Cy5-TMV-PDA particles were surrounded by 2-10-fold greater protein corona (containing mainly immunoglobulins) compared to Gd-Cy5-TMV particles. However, the enzyme-linked immunosorbent assay (ELISA) revealed that PDA-coated particles bind 2-fold lesser to anti-TMV antibodies elicited by particle injection than uncoated particles, suggesting that the PDA coat enables evasion from systemic antibody surveillance. Gd-Cy5-TMV-PDA particles were cleared from organs after 8 days compared to 5 days for the uncoated particles. The slower tissue clearance of the coated particles makes them ideal for theranostic applications by facilitating sustained local delivery in addition to multimodal imaging and photothermal capabilities. We have demonstrated the potential of PDA-coated proteinaceous nanoparticles for multiple biomedical applications.

Artificial Bioaugmentation of Biomacromolecules and Living Organisms for Biomedical Applications

The synergistic union of nanomaterials with biomaterials has revolutionized synthetic chemistry, enabling the creation of nanomaterial-based biohybrids with distinct properties for biomedical applications. This class of materials has drawn significant scientific interest from the perspective of functional extension via controllable coupling of synthetic and biomaterial components, resulting in enhancement of the chemical, physical, and biological properties of the obtained biohybrids. In this review, we highlight the forefront materials for the combination with biomacromolecules and living organisms and their advantageous properties as well as recent advances in the rational design and synthesis of artificial biohybrids. We further illustrate the incredible diversity of biomedical applications stemming from artificially bioaugmented characteristics of the nanomaterial-based biohybrids. Eventually, we aim to inspire scientists with the application horizons of the exciting field of synthetic augmented biohybrids.

Iron-Based Metal-Organic Frameworks in Drug Delivery and Biomedicine

Metal-organic frameworks (MOFs) are crystalline materials comprising metal centers and organic linkers that feature structural rigidity and functional flexibility. These attractive materials offer large surface areas, high porosity, and good chemical stability; they have shown promise in chemistry (H₂ separation and catalysis), magnetism, and optics. They have also shown potential for drug delivery following the demonstration in 2006 that chromium-based MOFs can be loaded with ibuprofen. Since then, iron-based MOFs (Fe-MOFs) have been shown to offer high drug loading and excellent biocompatibility. The present review focuses on the synthesis and surface modifications of Fe-MOFs as well as their applications in drug delivery and biomedicine.