High F-Content Perfluoropolyether-Based Nanoparticles for Targeted Detection of Breast Cancer by 19F Magnetic Resonance and Optical Imaging

A polymeric 1H/19F dual-modal MRI contrast agent with a snowman-like Janus nanostructure

Magnetic resonance imaging (MRI) has emerged as a pivotal tool in contemporary medical diagnostics, offering non-invasive and high-resolution visualization of internal structures. Contrast agents are essential for enhancing MRI resolution, accurate lesion detection, and early pathology identification. While gadolinium-based contrast agents are widely used in clinics, safety concerns have prompted exploration of metal-free alternatives, including fluorine and nitroxide radical-based MRI contrast agents. Fluorine-containing compounds exhibit excellent MRI capabilities, with 19F MRI providing enhanced resolution and quantitative assessment. Nitroxide radicals, such as PROXYL and TEMPO, offer paramagnetic properties for MRI contrast. Despite their versatility, nitroxide radicals suffer from lower relaxivity values (r1) compared to gadolinium. Dual-modal imaging, combining 1H and 19F MRI, has gained prominence for its comprehensive insights into biological processes and disease states. However, existing dual-modal agents predominantly utilize gadolinium-organic ligands without incorporating nitroxide radicals. Here, we introduce a novel dual-modal MRI contrast agent (J-CA) featuring a Janus asymmetric nanostructure synthesized via seeded emulsion polymerization and post-modification. J-CA demonstrates excellent in vitro and in vivo performance in both 19F and 1H MRI, with a T2 relaxation time of 5 ms and an r1 value of 0.31 mM-1 s-1, ensuring dual-modal imaging capability. Moreover, J-CA exhibits superior biocompatibility and organ targeting, making it a promising candidate for precise lesion imaging and disease diagnosis. This work introduces a new avenue for metal-free dual-modal MRI, addressing safety concerns associated with traditional contrast agents.

Multifunctional Fluoropolymer-Engineered Magnetic Nanoparticles to Facilitate Blood-Brain Barrier Penetration and Effective Gene Silencing in Medulloblastoma

Patients with brain cancers including medulloblastoma lack treatments that are effective long-term and without side effects. In this study, a multifunctional fluoropolymer-engineered iron oxide nanoparticle gene-therapeutic platform is presented to overcome these challenges. The fluoropolymers are designed and synthesized to incorporate various properties including robust anchoring moieties for efficient surface coating, cationic components to facilitate short interference RNA (siRNA) binding, and a fluorinated tail to ensure stability in serum. The blood-brain barrier (BBB) tailored system demonstrates enhanced BBB penetration, facilitates delivery of functionally active siRNA to medulloblastoma cells, and delivers a significant, almost complete block in protein expression within an in vitro extracellular acidic environment (pH 6.7) - as favored by most cancer cells. In vivo, it effectively crosses an intact BBB, provides contrast for magnetic resonance imaging (MRI), and delivers siRNA capable of slowing tumor growth without causing signs of toxicity - meaning it possesses a safe theranostic function. The pioneering methodology applied shows significant promise in the advancement of brain and tumor microenvironment-focused MRI-siRNA theranostics for the better treatment and diagnosis of medulloblastoma.

Fluorinated Organic Polymers for Cancer Drug Delivery

In the realm of cancer therapy, the spotlight is on nanoscale pharmaceutical delivery systems, especially polymer-based nanoparticles, for their enhanced drug dissolution, extended presence in the bloodstream, and precision targeting achieved via surface engineering. Leveraging the amplified permeation and retention phenomenon, these systems concentrate therapeutic agents within tumor tissues. Nonetheless, the hurdles of systemic toxicity, biological barriers, and compatibility with living systems persist. Fluorinated polymers, distinguished by their chemical idiosyncrasies, are poised for extensive biomedical applications, notably in stabilizing drug metabolism, augmenting lipophilicity, and optimizing bioavailability. Material science heralds the advent of fluorinated polymers that, by integrating fluorine atoms, unveil a suite of drug delivery merits: the hydrophobic traits of fluorinated alkyl chains ward off lipid or protein disruption, the carbon-fluorine bond's stability extends the drug's lifecycle in the system, and a lower alkalinity coupled with a diminished ionic charge bolsters the drug's ability to traverse cellular membranes. This comprehensive review delves into the utilization of fluorinated polymers for oncological pharmacotherapy, elucidating their molecular architecture, synthetic pathways, and functional attributes, alongside an exploration of their empirical strengths and the quandaries they encounter in both experimental and clinical settings.

Polymeric Nanoparticles for Drug Delivery

The recent emergence of nanomedicine has revolutionized the therapeutic landscape and necessitated the creation of more sophisticated drug delivery systems. Polymeric nanoparticles sit at the forefront of numerous promising drug delivery designs, due to their unmatched control over physiochemical properties such as size, shape, architecture, charge, and surface functionality. Furthermore, polymeric nanoparticles have the ability to navigate various biological barriers to precisely target specific sites within the body, encapsulate a diverse range of therapeutic cargo and efficiently release this cargo in response to internal and external stimuli. However, despite these remarkable advantages, the presence of polymeric nanoparticles in wider clinical application is minimal. This review will provide a comprehensive understanding of polymeric nanoparticles as drug delivery vehicles. The biological barriers affecting drug delivery will be outlined first, followed by a comprehensive description of the various nanoparticle designs and preparation methods, beginning with the polymers on which they are based. The review will meticulously explore the current performance of polymeric nanoparticles against a myriad of diseases including cancer, viral and bacterial infections, before finally evaluating the advantages and crucial challenges that will determine their wider clinical potential in the decades to come.

Visualization and Quantification of Drug Release by GSH-Responsive Multimodal Integrated Micelles

Using molecular imaging techniques to monitor biomarkers and drug release profiles simultaneously is highly advantageous for cancer diagnosis and treatment. However, achieving the accurate quantification of both biomarkers and drug release with a single imaging modality is challenging. This study presents the development of a glutathione (GSH)-responsive polymer-based micelle, PEG-SS-FCy7/PEG-SS-GEM (PSFG), which can precisely localize the tumor using bimodal imaging and prevent drug leakage. These PSFG micelles exhibit a small particle size of 106.3 ± 12.7 nm with a uniform size distribution, and the drug loading efficiency can also be easily controlled by changing the PEG-SS-FCy7 (PSF) and PEG-SS-GEM (PSG) feeding ratio. The PSFG micelles display weak fluorescence emission and minimal drug release under physiological conditions but collapse in the presence of GSH to trigger near-infrared fluorescence and the 19F magnetic resonance imaging signal, allowing for real-time monitoring of intracellular GSH levels and drug release. GSH could synergistically promote the disassembly of the micellar structure, resulting in accelerated probe and drug release of up to about 93.1% after 24 h. These prodrug micelles exhibit high in vitro and in vivo antitumor abilities with minimal side effects. The GSH-responsive drug delivery system with dual-modal imaging capability provides a promising imaging-guided chemotherapeutic platform to probe the tumor microenvironment and quantify real-time drug release profiles with minimal side effects.

Design of fluorinated stealth poly(ε-caprolactone) nanocarriers

The covalent functionalization of polymers with fluorinated moieties represents a promising strategy for the development of multimodal systems. Moreover, polymer fluorination often endows the resulting nanocarriers with improved colloidal stability in the biological environment. In this work, we developed fluorinated pegylated (PEG) biodegradable poly(ε-caprolactone) (PCL) drug nanocarriers showing both high colloidal stability and stealth properties, as well as being (19F)-Nuclear Magnetic Resonance (NMR) detectable. The optimized nanocarriers were obtained mixing a PEG-PCL block copolymer with a nonafluoro-functionalized PCL polymer. The role of PEGylation and fluorination on self-assembly and colloidal behavior of the obtained nanoparticles (NPs) was investigated, as well as their respective role on stealth properties and colloidal stability. To prove the feasibility of the developed NPs as potential 19F NMR detectable drug delivery systems, a hydrophobic drug was successfully encapsulated, and the maintenance of the relevant 19F NMR properties evaluated. Drug-loaded fluorinated NPs still retained a sharp and intense 19F NMR signal and good relaxivity parameters (i.e., T1 and T2 relaxation times) in water, which were not impaired by drug encapsulation.

Dual Nanoparticle Conjugates for Highly Sensitive and Versatile Sensing Using 19 F Magnetic Resonance Imaging

Fluorine magnetic resonance imaging (19 F MRI) has emerged as an attractive alternative to conventional 1 H MRI due to enhanced specificity deriving from negligible background signal in this modality. We report a dual nanoparticle conjugate (DNC) platform as an aptamer-based sensor for use in 19 F MRI. DNC consists of core-shell nanoparticles with a liquid perfluorocarbon core and a mesoporous silica shell (19 F-MSNs), which give a robust 19 F MR signal, and superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic quenchers. Due to the strong magnetic quenching effects of SPIONs, this platform is uniquely sensitive and functions with a low concentration of SPIONs (4 equivalents) relative to 19 F-MSNs. The probe functions as a "turn-on" sensor using target-induced dissociation of DNA aptamers. The thrombin binding aptamer was incorporated as a proof-of-concept (DNCThr ), and we demonstrate a significant increase in 19 F MR signal intensity when DNCThr is incubated with human α-thrombin. This proof-of-concept probe is highly versatile and can be adapted to sense ATP and kanamycin as well. Importantly, DNCThr generates a robust 19 F MRI "hot-spot" signal in response to thrombin in live mice, establishing this platform as a practical, versatile, and biologically relevant molecular imaging probe.

Engineered aptamers for molecular imaging

Molecular imaging, including quantification and molecular interaction studies, plays a crucial role in visualizing and analysing molecular events occurring within cells or organisms, thus facilitating the understanding of biological processes. Moreover, molecular imaging offers promising applications for early disease diagnosis and therapeutic evaluation. Aptamers are oligonucleotides that can recognize targets with a high affinity and specificity by folding themselves into various three-dimensional structures, thus serving as ideal molecular recognition elements in molecular imaging. This review summarizes the commonly employed aptamers in molecular imaging and outlines the prevalent design approaches for their applications. Furthermore, it highlights the successful application of aptamers to a wide range of targets and imaging modalities. Finally, the review concludes with a forward-looking perspective on future advancements in aptamer-based molecular imaging.

Fluoropolymer Nanoparticles Synthesized via Reversible-Deactivation Radical Polymerizations and Their Applications

Fluorinated polymeric nanoparticles (FPNPs) combine unique properties of fluorocarbon and polymeric nanoparticles, which has stimulated massive interest for decades. However, fluoropolymers are not readily available from nature, resulting in synthetic developments to obtain FPNPs via free radical polymerizations. Recently, while increasing cutting-edge directions demand tailored FPNPs, such materials have been difficult to access via conventional approaches. Reversible-deactivation radical polymerizations (RDRPs) are powerful methods to afford well-defined polymers. Researchers have applied RDRPs to the fabrication of FPNPs, enabling the construction of particles with improved complexity in terms of structure, composition, morphology, and functionality. Related examples can be classified into three categories. First, well-defined fluoropolymers synthesized via RDRPs have been utilized as precursors to form FPNPs through self-folding and solution self-assembly. Second, thermally and photoinitiated RDRPs have been explored to realize in situ preparations of FPNPs with varied morphologies via polymerization-induced self-assembly and cross-linking copolymerization. Third, grafting from inorganic nanoparticles has been investigated based on RDRPs. Importantly, those advancements have promoted studies toward promising applications, including magnetic resonance imaging, biomedical delivery, energy storage, adsorption of perfluorinated alkyl substances, photosensitizers, and so on. This Review should present useful knowledge to researchers in polymer science and nanomaterials and inspire innovative ideas for the synthesis and applications of FPNPs.

Hyperbranched Polymers: Recent Advances in Photodynamic Therapy against Cancer

Hyperbranched polymers are a class of three-dimensional dendritic polymers with highly branched architectures. Their unique structural features endow them with promising physical and chemical properties, such as abundant surface functional groups, intramolecular cavities, and low viscosity. Therefore, hyperbranched-polymer-constructed cargo delivery carriers have drawn increasing interest and are being utilized in many biomedical applications. When applied for photodynamic therapy, photosensitizers are encapsulated in or covalently incorporated into hyperbranched polymers to improve their solubility, stability, and targeting efficiency and promote the therapeutic efficacy. This review will focus on the state-of-the-art studies concerning recent progress in hyperbranched-polymer-fabricated phototherapeutic nanomaterials with emphases on the building-block structures, synthetic strategies, and their combination with the codelivered diagnostics and synergistic therapeutics. We expect to bring our demonstration to the field to increase the understanding of the structure-property relationships and promote the further development of advanced photodynamic-therapy nanosystems.

Recent Research Progress of 19 F Magnetic Resonance Imaging Probes: Principle, Design, and Their Application

Visualization of biomolecules, cells, and tissues, as well as metabolic processes in vivo is significant for studying the associated biological activities. Fluorine magnetic resonance imaging (19 F MRI) holds potential among various imaging technologies thanks to its negligible background signal and deep tissue penetration in vivo. To achieve detection on the targets with high resolution and accuracy, requirements of high-performance 19 F MRI probes are demanding. An ideal 19 F MRI probe is thought to have, first, fluorine tags with magnetically equivalent 19 F nuclei, second, high fluorine content, third, adequate fluorine nuclei mobility, as well as excellent water solubility or dispersity, but not limited to. This review summarizes the research progresses of 19 F MRI probes and mainly discusses the impacts of structures on in vitro and in vivo imaging performances. Additionally, the applications of 19 F MRI probes in ions sensing, molecular structures analysis, cells tracking, and in vivo diagnosis of disease lesions are also covered in this article. From authors' perspectives, this review is able to provide inspirations for relevant researchers on designing and synthesizing advanced 19 F MRI probes.

Fluorinated hydrogel nanoparticles with regulable fluorine contents and T2 relaxation times as 19F MRI contrast agents

Medical imaging contrast agents that are able to provide detailed biological information have attracted increasing attention. Among the new emerging imaging contrast agents, ¹⁹F magnetic resonance imaging contrast agents (¹⁹F MRI CAs) are extremely promising for their weak background disturbing signal from the body. However, to prepare ¹⁹F MRI CAs with a long T₂ relaxation time and excellent biocompatibility in a simple and highly effective strategy is still a challenge. Herein, we report a new type of ¹⁹F MRI hydrogel nanocontrast agents (¹⁹F MRI HNCAs) synthesized by a surfactant-free emulsion polymerization with commercial fluorinated monomers. The T₂ relaxation time of ¹⁹F MRI HNCA-1 was found to be 25-40 ms, guaranteeing its good imaging ability in vitro. In addition, according to an investigation into the relationship between the fluorine content and ¹⁹F MRI signal intensity, the ¹⁹F MRI signal intensity was not only determined by the fluorine content in ¹⁹F MRI HNCAs but also by the hydration microenvironment around the fluorine atoms. Moreover, ¹⁹F MRI HNCAs demonstrated excellent biocompatibility and imaging capability inside cells. The primary exploration demonstrated that ¹⁹F MRI HNCAs as a new type of ¹⁹F MRI contrast agent hold potential for imaging lesion sites and tracking cells in vivo by ¹⁹F MRI technology.

Biodegradable polyphosphoester micelles act as both background-free 31P magnetic resonance imaging agents and drug nanocarriers

In vivo monitoring of polymers is crucial for drug delivery and tissue regeneration. Magnetic resonance imaging (MRI) is a whole-body imaging technique, and heteronuclear MRI allows quantitative imaging. However, MRI agents can result in environmental pollution and organ accumulation. To address this, we introduce biocompatible and biodegradable polyphosphoesters, as MRI-traceable polymers using the ³¹P centers in the polymer backbone. We overcome challenges in ³¹P MRI, including background interference and low sensitivity, by modifying the molecular environment of ³¹P, assembling polymers into colloids, and tailoring the polymers' microstructure to adjust MRI-relaxation times. Specifically, gradient-type polyphosphonate-copolymers demonstrate improved MRI-relaxation times compared to homo- and block copolymers, making them suitable for imaging. We validate background-free imaging and biodegradation in vivo using Manduca sexta. Furthermore, encapsulating the potent drug PROTAC allows using these amphiphilic copolymers to simultaneously deliver drugs, enabling theranostics. This first report paves the way for polyphosphoesters as background-free MRI-traceable polymers for theranostic applications.

Functional Imaging of Hypoxia: PET and MRI

Molecular and functional imaging have critical roles in cancer care. Existing evidence suggests that noninvasive detection of hypoxia within a particular type of cancer can provide new information regarding the relationship between hypoxia, cancer aggressiveness and altered therapeutic responses. Following the identification of hypoxia inducible factor (HIF), significant progress in understanding the regulation of hypoxia-induced genes has been made. These advances have provided the ability to therapeutically target HIF and tumor-associated hypoxia. Therefore, by utilizing the molecular basis of hypoxia, hypoxia-based theranostic strategies are in the process of being developed which will further personalize care for cancer patients. The aim of this review is to provide an overview of the significance of tumor hypoxia and its relevance in cancer management as well as to lay out the role of imaging in detecting hypoxia within the context of cancer.

Preparation of PFPE-Based Polymeric Nanoparticles via Polymerization-Induced Self-Assembly as Contrast Agents for 19F MRI

Fluorine-19 magnetic resonance imaging (¹⁹F MRI) probes have received considerable research interest as imaging contrast agents (CAs), but they remain neglected and underutilized due to the limited fluorine content or poor performance of fluorinated tracers. Here, we present polymeric nanoparticles (NPs) as ¹⁹F MRI CAs with a simple synthesis method and promising imaging performance. First, hydrophilic random copolymers were synthesized from oligo(ethylene glycol) methyl ether acrylate and perfluoropolyether methacrylate by reversible addition-fragmentation chain transfer (RAFT) polymerization. The optimal fluorine content, polymer concentration, and cytotoxicity as ¹⁹F MRI CAs were investigated in detail. Then, the optimal copolymer was selected as the macromolecular chain transfer agent, and the chain extension was performed with 2-(perfluorooctyl ethyl methacrylate). Subsequently, the NPs with different morphologies, such as ellipsoidal, spherical nanoparticles and vesicles, were prepared in situ by the RAFT-mediated polymerization-induced self-assembly method. In addition, the ¹⁹F MRI signal and cytotoxicity studies further confirmed that these polymeric NPs are nontoxic and have great potential as promising ¹⁹F MRI CAs for biological applications.

Fluoropolymer-MOF Hybrids with Switchable Hydrophilicity for 19F MRI-Monitored Cancer Therapy

Cancer theranostics that combines cancer diagnosis and therapy is a promising approach for personalized cancer treatment. However, current theranostic strategies suffer from low imaging sensitivity for visualization and an inability to target the diseased tissue site with high specificity, thus hindering their translation to the clinic. In this study, we have developed a tumor microenvironment-responsive hybrid theranostic agent by grafting water-soluble, low-fouling fluoropolymers to pH-responsive zeolitic imidazolate framework-8 (ZIF-8) nanoparticles by surface-initiated RAFT polymerization. The conjugation of the fluoropolymers to ZIF-8 nanoparticles not only allows sensitive in vivo visualization of the nanoparticles by ¹⁹F MRI but also significantly prolongs their circulation time in the bloodstream, resulting in improved delivery efficiency to tumor tissue. The ZIF-8-fluoropolymer nanoparticles can respond to the acidic tumor microenvironment, leading to progressive degradation of the nanoparticles and release of zinc ions as well as encapsulated anticancer drugs. The zinc ions released from the ZIF-8 can further coordinate to the fluoropolymers to switch the hydrophilicity and reverse the surface charge of the nanoparticles. This transition in hydrophilicity and surface charge of the polymeric coating can reduce the "stealth-like" nature of the agent and enhance specific uptake by cancer cells. Hence, these hybrid nanoparticles represent intelligent theranostics with highly sensitive imaging capability, significantly prolonged blood circulation time, greatly improved accumulation within the tumor tissue, and enhanced anticancer therapeutic efficiency.

Synthesis of 5-Fluorouracil Polymer Conjugate and 19F NMR Analysis of Drug Release for MRI Monitoring

To monitor the release of fluorinated drugs from polymeric carriers, a novel 19F MRI enzyme-responsive contrast agent was developed and tested. This contrast agent was prepared by conjugation of 5-fluorouracil (5-FU) to hyperbranched poly(N,N-dimethylacrylamide) (HB-PDMA) via an enzyme-degradable peptide linker. Due to the different molecular sizes, the release of 5-FU from the 5-FU polymer conjugate resulted in a sufficiently substantial difference in spin-spin T2 19F NMR/MRI relaxation time that enabled differentiating between attached and released drug states. The 5-FU polymer conjugate exhibited a broad signal and short T2 relaxation time under 19F NMR analysis. Incubation with the enzyme induced the release of 5-FU, accompanied by an extension of T2 relaxation times and an enhancement in the 19F MRI signal. This approach is promising for application in the convenient monitoring of 5-FU drug release and can be used to monitor the release of other fluorinated drugs.

Water-Soluble Chemically Precise Fluorinated Molecular Clusters for Interference-Free Multiplex 19F MRI in Living Mice

Fluorine-19 magnetic resonance imaging (¹⁹F MRI) is gaining widespread interest from the fields of biomolecule detection, cell tracking, and diagnosis, benefiting from its negligible background, deep tissue penetration, and multispectral capacity. However, a wide range of ¹⁹F MRI probes are in great demand for the development of multispectral ¹⁹F MRI due to the limited number of high-performance ¹⁹F MRI probes. Herein, we report a type of water-soluble molecular ¹⁹F MRI nanoprobe by conjugating fluorine-containing moieties with a polyhedral oligomeric silsesquioxane (POSS) cluster for multispectral color-coded ¹⁹F MRI. These chemically precise fluorinated molecular clusters are of excellent aqueous solubility with relatively high ¹⁹F contents and of single ¹⁹F resonance frequency with suitable longitudinal and transverse relaxation times for high-performance ¹⁹F MRI. We construct three POSS-based molecular nanoprobes with distinct ¹⁹F chemical shifts at -71.91, -123.23, and -60.18 ppm and achieve interference-free multispectral color-coded ¹⁹F MRI of labeled cells in vitro and in vivo. Moreover, in vivo ¹⁹F MRI reveals that these molecular nanoprobes could selectively accumulate in tumors and undergo rapid renal clearance afterward, illustrating their favorable in vivo behavior for biomedical applications. This study provides an efficient strategy to expand the ¹⁹F probe libraries for multispectral ¹⁹F MRI in biomedical research.

Nano-Based Theranostic Platforms for Breast Cancer: A Review of Latest Advancements

Breast cancer (BC) is a highly metastatic multifactorial disease with various histological and molecular subtypes. Due to recent advancements, the mortality rate in BC has improved over the past five decades. Detection and treatment of many cancers are now possible due to the application of nanomedicine in clinical practice. Nanomedicine products such as Doxil^® and Abraxane^® have already been extensively used for BC adjuvant therapy with favorable clinical outcomes. However, these products were designed initially for generic anticancer purposes and not specifically for BC treatment. With a better understanding of the molecular biology of BC, several novel and promising nanotherapeutic strategies and devices have been developed in recent years. In this context, multi-functionalized nanostructures are becoming potential carriers for enhanced chemotherapy in BC patients. To design these nanostructures, a wide range of materials, such as proteins, lipids, polymers, and hybrid materials, can be used and tailored for specific purposes against BC. Selective targeting of BC cells results in the activation of programmed cell death in BC cells and can be considered a promising strategy for managing triple-negative BC. Currently, conventional BC screening methods such as mammography, digital breast tomosynthesis (DBT), ultrasonography, and magnetic resonance imaging (MRI) are either costly or expose the user to hazardous radiation that could harm them. Therefore, there is a need for such analytical techniques for detecting BC that are highly selective and sensitive, have a very low detection limit, are durable, biocompatible, and reproducible. In detecting BC biomarkers, nanostructures are used alone or in conjunction with numerous molecules. This review intends to highlight the recent advances in nanomedicine in BC treatment and diagnosis, emphasizing the targeting of BC cells that overexpress receptors of epidermal growth factors. Researchers may gain insight from these strategies to design and develop more tailored nanomedicine for BC to achieve further improvements in cancer specificity, antitumorigenic effects, anti-metastasis effects, and drug resistance reversal effects.

An Activatable 19 F MRI Molecular Probe for Sensing and Imaging of Norepinephrine

Norepinephrine (NE), acting as both a neurotransmitter and hormone, plays a significant role in regulating the action of the brain and body. Many studies have demonstrated a strong correlation between mental disorders and aberrant NE levels. Therefore, it is of urgent demand to develop in vivo analytical methods of NE for diagnostic assessment and mechanistic investigations of mental diseases. Herein, we report a ¹⁹F MRI probe (NRFP) for sensing and imaging NE, which is constructed by conjugating a gadolinium chelate to a fluorine‐containing moiety through a NE‐responsive aromatic thiocarbonate linkage. The capacity and specificity of NRFP for detecting NE is validated with in vitro detecting/imaging experiments. Furthermore, the feasibility of NRFP for visualizing NE in animals is illustrated by ex vivo and in vivo imaging experiments, demonstrating the promising potential of NRFP for selective detection and specific imaging of NE in deep tissues of living subjects.

Unique Random-Block Polymer Architecture for Site-Specific Mitochondrial Sequestration-Aided Effective Chemotherapeutic Delivery and Enhanced Fluorocarbon Segmental Mobility-Facilitated 19F Magnetic Resonance Imaging

The elevation of the chemotherapeutic efficacy and attenuation of its side effects on healthy cells and tissues become one of the prime targets for the treatment of cancer. Toward this direction, a sequential receptor and mitochondria dual-targeting strategy was implemented in the DX TP PG BN ¹⁹F theranostic polymer that was anchored with the chemotherapeutic agent doxorubicin, receptor-targeting biotin, and mitochondria-targeting triphenylphosphonium cations. The polymer was flourished with a unique ¹⁹F magnetic resonance imaging (MRI) tracer that exhibited high segmental mobility and eventually led to prolonged T₂ relaxation time. Furthermore, for the sake of amphiphilicity, the DX TP PG BN ¹⁹F polymer spontaneously aggregated into nano-sphere with positive zeta potential, where the MRI tracer and biotin embedded at the exterior and displayed site-specific targeting and remarkable ¹⁹F MRI capability simultaneously. The mitochondria-targeting competency of the DX TP PG BN ¹⁹F theranostic polymer was investigated by comparing the non-mitochondrial-targeting DX PG BN ¹⁹F polymer using fluorescence microscopic cell imaging in human cervical, HeLa, and breast MCF-7 carcinoma cell lines. Moreover, cytotoxicity experiments of the aforementioned theranostic polymers clarified the enhancement of the chemotherapeutic efficacy of DX TP PG BN ¹⁹F theranostic polymers through effective and precise mitochondrial doxorubicin delivery that forced to follow the apoptotic path.

Multiplexed Analysis of the Cellular Uptake of Polymeric Nanocarriers

Polymeric nanocarriers (PNCs) are versatile drug delivery vehicles capable of delivering a variety of therapeutics. Quantitatively monitoring their uptake in biological systems is essential for realizing their potential as next-generation delivery systems; however, existing quantification strategies are limited due to the challenges of detecting polymeric materials in complex biological samples. Here, we describe a metal-coded mass tagging approach that enables the multiplexed quantification of the PNC uptake in cells using mass spectrometry (MS). In this approach, PNCs are conjugated with ligands that bind strongly to lanthanide ions, allowing the PNCs to be sensitively quantitated by inductively coupled plasma-MS. The metal-coded tags have little effect on the properties or toxicity of the PNCs, making them biocompatible. We demonstrate that the conjugation of different metals to the PNCs enables the multiplexed analysis of cellular uptake of multiple distinct PNCs at the same time. This multiplexing capability should improve the design and optimization of PNCs by minimizing biological variability and reducing analysis time, effort, and cost.

A Multifunctional Contrast Agent for 19F-Based Magnetic Resonance Imaging

Magnetic resonance imaging, MRI, relying on ¹⁹F nuclei has attracted much attention, because the isotopes exhibit a high gyromagnetic ratio (comparable to that of protons) and have 100% natural abundance. Furthermore, due to the very low traces of intrinsic fluorine in biological tissues, fluorine labeling allows easy visualization in vivo using ¹⁹F-based MRI. However, one of the drawbacks of the available fluorine tracers is their very limited solubility in water. Here, we detail the design and preparation of a set of water-compatible fluorine-rich polymers as contrast agents that can enhance the effectiveness of ¹⁹F-based MRI. The agents are synthesized using the nucleophilic addition reaction between poly(isobutylene-alt-maleic anhydride) copolymer and a mixture of amine-appended fluorine groups and polyethylene glycol (PEG) blocks. This allows control over the polymer architecture and stoichiometry, resulting in good affinity to water solutions. We further investigate the effects of introducing additional segmental mobility to the fluorine moieties in the polymer, by inserting a PEG linker between the moieties and the polymer backbone. We find that controlling the polymer stoichiometry and introducing additional segmental mobility enhance the NMR signals and narrow the peak profile. In particular, we assess the impact of the PEG linker on T₂* and T₁ relaxation times, using a series of gradient-recalled echo images with varying echo times, TE, or recovery time, TR, respectively. We find that for equivalent concentrations, the PEG linker greatly increases T₂*, while maintaining high T₁ values, as compared to polymers without this linker. Phantom images collected from these compounds show bright signals over a background with high intensities.

Non-metallic T2-MRI agents based on conjugated polymers

Developing non-metallic contrast agents of clinically applied magnetic resonance imaging (MRI) is an alternative strategy to reduce the toxicity of heavy metal elements in current MRI agents. These non-metallic MRI agents usually generate contrasts by unpaired electrons, which are prone to be deactivated by in vivo radical scavenging pathways. Since the unpaired electrons in conjugated polymers exhibit satisfying stability for in vivo imaging, developing conjugated polymers based MRI agents may solve the in vivo stability problem of current non-metallic agents. However, MRI-active properties have not been reported in existing conjugated polymers yet. Herein we report on MRI-active conjugated polymer nanoparticles based on polypyrrole (PPy), which can be used for in vivo imaging. Our method not only introduce a kind of non-metallic MRI agents but extends the applications of conjugated polymers from optical imagings to MRI.

The toxicity of heavy metals for MRI contrast agents is an issue. Here, the authors report on the development of conjugated polymers nanoparticles based on paramagnetic polypyrrole to generate T2 MRI contrast effects by changing the interactions between polarons and water protons.

Acid-Triggered H2O2 Self-Supplying Nanoplatform for 19F-MRI with Enhanced Chemo-Chemodynamic Therapy

The real-time tracking and efficacy evaluation of therapeutic nanoplatforms especially in deep-tissues is of great importance but faces challenges. Meanwhile, chemodynamic therapy (CDT), relying on Fenton reaction by converting H₂O₂ into toxic hydroxyl radicals (•OH), has drawn wide interests in the fabrication of nanozymes for tumor therapy, while endogenous H₂O₂ is usually insufficient for effective CDT. Here, we report the pH-responsive multifunctional nanoplatforms consisting of copper peroxide (CP) nanoparticles, paclitaxel (PTX) and perfluoro-15-crown-5-ether (PFCE), for ¹⁹F magnetic resonance imaging guided and enhanced chemo-chemodynamic synergetic therapy with self-supplied H₂O₂ stemmed from the decomposition of CP nanoparticles under acid conditions in tumor. The decomposition of CP nanoparticles further promotes the release of PTX for enhanced chemotherapy. Both in vitro and in vivo results indicate that the efficient generation of •OH and drug release effectively inhibits tumor growth. Furthermore, ¹⁹F MRI signal can clearly track the fate of nanoplatforms in tumor and guide tumor treatment. This work provides a promising strategy for the rational design and construction of multifunctional nanoplatforms for imaging-guided synergistic therapy of deep seated tumor.

19 F MRI Nanotheranostics for Cancer Management: Progress and Prospects

Fluorine magnetic resonance imaging (¹⁹ F MRI) is a promising imaging technique for cancer diagnosis because of its excellent soft tissue resolution and deep tissue penetration, as well as the inherent high natural abundance, almost no endogenous interference, quantitative analysis, and wide chemical shift range of the ¹⁹ F nucleus. In recent years, scientists have synthesized various ¹⁹ F MRI contrast agents. By further integrating a wide variety of nanomaterials and cutting-edge construction strategies, magnetically equivalent ¹⁹ F atoms are super-loaded and maintain satisfactory relaxation efficiency to obtain high-intensity ¹⁹ F MRI signals. In this review, the nuclear magnetic resonance principle underlying ¹⁹ F MRI is first described. Then, the construction and performance of various fluorinated contrast agents are summarized. Finally, challenges and future prospects regarding the clinical translation of ¹⁹ F MRI nanoprobes are considered. This review will provide strategic guidance and panoramic expectations for designing new cancer theranostic regimens and realizing their clinical translation.

Nanotechnology as a Versatile Tool for 19F-MRI Agent’s Formulation: A Glimpse into the Use of Perfluorinated and Fluorinated Compounds in Nanoparticles

Simultaneously being a non-radiative and non-invasive technique makes magnetic resonance imaging (MRI) one of the highly sought imaging techniques for the early diagnosis and treatment of diseases. Despite more than four decades of research on finding a suitable imaging agent from fluorine for clinical applications, it still lingers as a challenge to get the regulatory approval compared to its hydrogen counterpart. The pertinent hurdle is the simultaneous intrinsic hydrophobicity and lipophobicity of fluorine and its derivatives that make them insoluble in any liquids, strongly limiting their application in areas such as targeted delivery. A blossoming technique to circumvent the unfavorable physicochemical characteristics of perfluorocarbon compounds (PFCs) and guarantee a high local concentration of fluorine in the desired body part is to encapsulate them in nanosystems. In this review, we will be emphasizing different types of nanocarrier systems studied to encapsulate various PFCs and fluorinated compounds, headway to be applied as a contrast agent (CA) in fluorine-19 MRI (¹⁹F MRI). We would also scrutinize, especially from studies over the last decade, the different types of PFCs and their specific applications and limitations concerning the nanoparticle (NP) system used to encapsulate them. A critical evaluation for future opportunities would be speculated.

Biological Utility of Fluorinated Compounds: from Materials Design to Molecular Imaging, Therapeutics and Environmental Remediation

The applications of fluorinated molecules in bioengineering and nanotechnology are expanding rapidly with the controlled introduction of fluorine being broadly studied due to the unique properties of C-F bonds. This review will focus on the design and utility of C-F containing materials in imaging, therapeutics, and environmental applications with a central theme being the importance of controlling fluorine-fluorine interactions and understanding how such interactions impact biological behavior. Low natural abundance of fluorine is shown to provide sensitivity and background advantages for imaging and detection of a variety of diseases with ¹⁹F magnetic resonance imaging, ¹⁸F positron emission tomography and ultrasound discussed as illustrative examples. The presence of C-F bonds can also be used to tailor membrane permeability and pharmacokinetic properties of drugs and delivery agents for enhanced cell uptake and therapeutics. A key message of this review is that while the promise of C-F containing materials is significant, a subset of highly fluorinated compounds such as per- and polyfluoroalkyl substances (PFAS), have been identified as posing a potential risk to human health. The unique properties of the C-F bond and the significant potential for fluorine-fluorine interactions in PFAS structures necessitate the development of new strategies for facile and efficient environmental removal and remediation. Recent progress in the development of fluorine-containing compounds as molecular imaging and therapeutic agents will be reviewed and their design features contrasted with environmental and health risks for PFAS systems. Finally, present challenges and future directions in the exploitation of the biological aspects of fluorinated systems will be described.

Synthesis and solution properties of telechelic poly(2-isopropyl-2-oxazoline) bearing perfluoro end groups

Telechelic FPIPOZ and its precursor N3PIPOZ films reassembled into discs and short fibers, respectively, when exposed to THF vapor.

Activatable Multiplexed 19F Magnetic Resonance Imaging Visualizes Reactive Oxygen and Nitrogen Species in Drug-Induced Acute Kidney Injury

In vivo levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are critical to many physiological and pathological processes. Because of the distinct differences in their biological generation and effects, simultaneously visualizing both of them could help deepen our insights into the mechanistic details of these processes. However, real-time and deep-tissue imaging and differentiation of ROS- and RNS-related molecular events in living subjects still remain a challenge. Here, we report the development of two activatable ¹⁹F magnetic resonance imaging (MRI) molecular probes with different ¹⁹F chemical shifts and specific responsive behaviors for simultaneous in vivo detection and deep-tissue imaging of O₂^•- and ONOO^-. These probes are capable of real-time visualization and differentiation of O₂^•- and ONOO^- in living mice with drug-induced acute kidney injury by interference-free multiplexed hot-spot ¹⁹F MRI, illustrating the potential of this technique for background-free real-time imaging of diverse biological processes, accurate diagnosis of various diseases in deep tissues, and rapid toxicity evaluation of assorted drugs.

Synthesis of Fluorinated Polyhydroxyalkanoates from Marine Bioresources as a Promising Biomaterial Coating

By successive enzymatic and chemical modifications, novel fluorinated polyhydroxyalkanoates were synthesized and characterized. Unsaturated polyhydroxyalkanoate, PHAU, was first produced by fermentation using marine bacteria Pseudomonas raguenesii, and a graft copolymer PHAU-g-C₈F₁₇ was further prepared by controlled thiol-ene reaction in the presence of perfluorodecanethiol (PFDT). The PFDT grafting is realized by two different processes. In the first method, PHAU was previously solubilized in toluene. The grafting in solution is more efficient than the direct heterogeneous grafting onto a PHAU film. The degrees of grafting were determined by ¹H NMR. The characterization of the microstructure by SEM-EDX and modulated and conventional DSC showed the formation of microdomains due to the organization of the hydrophobic segments of graft PFDT. Biomaterials prepared by 3D printing and coated by PHAU-g-C₈F₁₇ have the potential to be used as novel contrast agents as shown by Hahn echo experiments.

19 F MRI Probes for Multimodal Imaging*

Magnetic resonance imaging (MRI) is one of the most powerful imaging tools today, capable of displaying superior soft-tissue contrast. This review discusses developments in the field of ¹⁹ F MRI multimodal probes in combination with optical fluorescence imaging (OFI), ¹ H MRI, chemical exchange saturation transfer (CEST) MRI, ultrasonography (USG), X-ray computed tomography (CT), single photon emission tomography (SPECT), positron emission tomography (PET), and photoacoustic imaging (PAI). In each case, multimodal ¹⁹ F MRI probes compensate for the deficiency of individual techniques and offer improved sensitivity or accuracy of detection over unimodal counterparts. Strategies for designing ¹⁹ F MRI multimodal probes are described with respect to their structure, physicochemical properties, biocompatibility, and the quality of images.

Lattice distortion of CaF2 nanocrystals for shortening their 19F longitude relaxation time

As a promising ¹⁹F MRI tracer, the relatively slow lattice-spin relaxation of CaF₂ nanocrystals leads to an unacceptable scanning time in MR imaging, hampering their application. We herein controlled the size and lattice distortion of CaF₂ nanocrystals and showed that the shortened interplanar spacing pronouncedly sped up the longitude relaxation.

Imaging cancer cells with nanostructures: Prospects of nanotechnology driven non-invasive cancer diagnosis

The application of nanostructured materials in medicine is a rapidly evolving area of research that includes both the diagnosis and treatment of various diseases. Metals, metal oxides and carbon-based nanomaterials have shown much promise in medical technological advancements due to their tunable physical, chemical and biological properties. The nanoscale properties, especially the size, shape, surface chemistry and stability makes them highly desirable for diagnosing and treating various diseases, including cancers. Major applications of nanomaterials in cancer diagnosis include in vivo bioimaging and molecular marker detection, mainly as image contrast agents using modalities such as radio, magnetic resonance, and ultrasound imaging. When a suitable targeting ligand is attached on the nanomaterial surface, it can help pinpoint the disease site during imaging. The application of nanostructured materials in cancer diagnosis can help in the early detection, treatment and patient follow-up . This review aims to gather and present the information regarding the application of nanotechnology in cancer diagnosis. We also discuss the challenges and prospects regarding the application of nanomaterials as cancer diagnostic tools.

Therapeutic oxygen delivery by perfluorocarbon-based colloids

After the protocol-related indecisive clinical trial of Oxygent, a perfluorooctylbromide/phospholipid nanoemulsion, in cardiac surgery, that often unduly assigned the observed untoward effects to the product, the development of perfluorocarbon (PFC)-based O₂ nanoemulsions ("blood substitutes") has come to a low. Yet, significant further demonstrations of PFC O₂-delivery efficacy have continuously been reported, such as relief of hypoxia after myocardial infarction or stroke; protection of vital organs during surgery; potentiation of O₂-dependent cancer therapies, including radio-, photodynamic-, chemo- and immunotherapies; regeneration of damaged nerve, bone or cartilage; preservation of organ grafts destined for transplantation; and control of gas supply in tissue engineering and biotechnological productions. PFC colloids capable of augmenting O₂ delivery include primarily injectable PFC nanoemulsions, microbubbles and phase-shift nanoemulsions. Careful selection of PFC and other colloid components is critical. The basics of O₂ delivery by PFC nanoemulsions will be briefly reminded. Improved knowledge of O₂ delivery mechanisms has been acquired. Advanced, size-adjustable O₂-delivering nanoemulsions have been designed that have extended room-temperature shelf-stability. Alternate O₂ delivery options are being investigated that rely on injectable PFC-stabilized microbubbles or phase-shift PFC nanoemulsions. The latter combine prolonged circulation in the vasculature, capacity for penetrating tumor tissues, and acute responsiveness to ultrasound and other external stimuli. Progress in microbubble and phase-shift emulsion engineering, control of phase-shift activation (vaporization), understanding and control of bubble/ultrasound/tissue interactions is discussed. Control of the phase-shift event and of microbubble size require utmost attention. Further PFC-based colloidal systems, including polymeric micelles, PFC-loaded organic or inorganic nanoparticles and scaffolds, have been devised that also carry substantial amounts of O₂. Local, on-demand O₂ delivery can be triggered by external stimuli, including focused ultrasound irradiation or tumor microenvironment. PFC colloid functionalization and targeting can help adjust their properties for specific indications, augment their efficacy, improve safety profiles, and expand the range of their indications. Many new medical and biotechnological applications involving fluorinated colloids are being assessed, including in the clinic. Further uses of PFC-based colloidal nanotherapeutics will be briefly mentioned that concern contrast diagnostic imaging, including molecular imaging and immune cell tracking; controlled delivery of therapeutic energy, as for noninvasive surgical ablation and sonothrombolysis; and delivery of drugs and genes, including across the blood-brain barrier. Even when the fluorinated colloids investigated are designed for other purposes than O₂ supply, they will inevitably also carry and deliver a certain amount of O₂, and may thus be considered for O₂ delivery or co-delivery applications. Conversely, O₂-carrying PFC nanoemulsions possess by nature a unique aptitude for ¹⁹F MR imaging, and hence, cell tracking, while PFC-stabilized microbubbles are ideal resonators for ultrasound contrast imaging and can undergo precise manipulation and on-demand destruction by ultrasound waves, thereby opening multiple theranostic opportunities.

Nanotechnology for Cancer Imaging: Advances, Challenges, and Clinical Opportunities

Nanoparticle (NP) imaging applications have the potential to improve cancer diagnostics, therapeutics, and treatment management. In biomedical research and clinical practice, NPs can serve as labels or labeled carriers for monitoring drug delivery or serve as imaging agents for enhanced imaging contrast, as well as providing improved signal sensitivity and specificity for in vivo imaging of molecular and cellular processes. These qualities offer exciting opportunities for NP-based imaging agents to address current limitations in oncologic imaging. Despite substantial advancements in NP design and development, very few NP-based imaging agents have translated into clinics within the past 5 years. This review highlights some promising NP-enabled imaging techniques and their potential to address current clinical cancer imaging limitations. Although most examples provided herein are from the preclinical space, discussed imaging solutions could offer unique in vivo tools to solve biologic questions, improve cancer treatment effectiveness, and inspire clinical translation innovation to improve patient care. Keywords: Molecular Imaging-Cancer, Molecular Imaging-Nanoparticles, Molecular Imaging-Optical Imaging, Metastases, Oncology, Surgery, Treatment Effects.

Glyconanofluorides as Immunotracers with a Tunable Core Composition for Sensitive Hotspot Magnetic Resonance Imaging of Inflammatory Activity

Nature-inspired nanosized formulations based on an imageable, small-sized inorganic core scaffold, on which biomolecules are assembled to form nanobiomimetics, hold great promise for both early diagnostics and developed therapeutics. Nevertheless, the fabrication of nanobiomimetics that allow noninvasive background-free mapping of pathological events with improved sensitivity, enhanced specificity, and multiplexed capabilities remains a major challenge. Here, we introduce paramagnetic glyconanofluorides as small-sized (<10 nm) glycomimetics for immunotargeting and sensitive noninvasive in vivo19F magnetic resonance imaging (MRI) mapping of inflammation. A very short T1 relaxation time (70 ms) of the fluorides was achieved by doping the nanofluorides' solid crystal core with paramagnetic Sm3+, resulting in a significant 8-fold enhancement in their 19F MRI sensitivity, allowing faster acquisition and improved detectability levels. The fabricated nanosized glycomimetics exhibit significantly enhanced uptake within activated immune cells, providing background-free in vivo mapping of inflammatory activity, demonstrated in both locally induced inflammation and clinically related neuropathology animal models. Fabricating two types of nanofluorides, each with a distinct chemical shift, allowed us to exploit the color-like features of 19F MRI to map, in real time, immune specificity and preferred targetability of the paramagnetic glyconanofluorides, demonstrating the approach's potential extension to noninvasive multitarget imaging scenarios that are not yet applicable for nanobiomimetics based on other nanocrystal cores.

Fluorinated porphyrin-based theranostics for dual imaging and chemo-photodynamic therapy

Convenient strategies to transform regular liposomes or nano-micelles into multifunctional theranostics would be highly valuable in cancer therapy. Herein, we developed an amphiphilic fluorinated porphyrin dendrimer as a multifunctional "add-on" module which would self-assemble onto liposomal drug delivery systems and conveniently transform the liposomes into novel theranostics. Through cancer cells and murine xenograft tumor model assays, the theranostics showed valuable fluorescence/19F magnetic resonance dual modal imaging and highly efficient chemo-photodynamic therapy. The modular strategy facilitates the convenient and standardized preparation of multifunctional theranostics.

Fluorine Labeling of Nanoparticles and In Vivo 19F Magnetic Resonance Imaging

Fluorinated nanoparticles have increasing applications, but they are still challenging to prepare, especially in the case of water-soluble fluorinated nanoparticles. Herein, a fluorine labeling strategy is presented that is based on the conjugation of custom-made small fluorinated building blocks, obtained by simple synthetic transformations, with carboxylated gold nanoparticles through a convenient phase-transfer process. The synthesis of four fluorinated building blocks with different chemical shifts in ¹⁹F nuclear magnetic resonance and varied functionalities is reported, along with their conjugation onto nanoparticles. Fluorinated nanoparticles of small core size obtained by this conjugation methodology and by direct synthesis presented high transverse relaxation times (T₂) ranging from 518 to 1030 ms, and a large number of equivalent fluorine atoms per nanoparticle (340-1260 fluorine atoms), which made them potential candidates for ¹⁹F magnetic resonance related applications. Finally, nontargeted fluorinated nanoparticles were probed by performing in vivo ¹⁹F magnetic resonance spectroscopy (¹⁹F MRS) in mice. Nanoparticles were detected at both 1 and 2 h after being injected. ¹⁹F MRI images were also acquired after either intravenous or subcutaneous injection. Their fate was studied by analyzing the gold content in tissues by ICP-MS. Thus, the present work provides a general fluorination strategy for nanoparticles and shows the potential use of small fluorinated nanoparticles in magnetic-resonance-related applications.

Oxygen-Delivering Polyfluorocarbon Nanovehicles Improve Tumor Oxygenation and Potentiate Photodynamic-Mediated Antitumor Immunity

Hypoxia is a critical cause of tumor immunosuppression, and it significantly limits the efficacy of many anticancer modalities. Herein, we report an amphiphilic F₁₁-derivative-based oxygen-delivering polyfluorocarbon nanovehicle loading photodynamic DiIC₁₈(5) and reactive oxygen species (ROS)-sensitive prodrug of chemo-immunomodulatory gemcitabine (PF₁₁DG), aimed at relieving tumor hypoxia and boosting antitumor immunity for cancer therapy. We optimized F₁₁-based polyfluorocarbon nanovehicles with a 10-fold enhancement of tumor oxygenation. PF₁₁DG exhibited intriguing capabilities, such as oxygen-dissolving, ROS production, and responsive drug release. In tumors, PF₁₁DG exhibited flexible intratumoral permeation and boosted robust antitumor immune responses upon laser irradiation. Notably, the treatment of PF₁₁DG plus laser irradiation (PF₁₁DG+L) significantly retarded the tumor growth with an 82.96% inhibition in the 4T1 breast cancer model and a 93.6% inhibition in the PANC02 pancreatic cancer model with better therapeutic benefits than non-oxygen-delivering nanovehicles. Therefore, this study presents an encouraging polyfluorocarbon nanovehicle with deep tumor-penetrating and hypoxia-relieving capacity to boost antitumor immunity for cancer treatment.

Tuning the thermoresponsive properties of PEG-based fluorinated polymers and stimuli responsive drug release for switchable 19F magnetic resonance imaging

Switching on of the 19F MRI signal via stimuli-responsive release of hydrophobic drug from PEG-based partly-fluorinated polymers due to change in thermoresponsive properties.

Fluoropolymers in biomedical applications: state-of-the-art and future perspectives

Biomedical applications of fluoropolymers in gene delivery, protein delivery, drug delivery, ¹⁹F MRI, PDT, anti-fouling, anti-bacterial, cell culture, and tissue engineering.

Delicately Designed Cancer Cell Membrane-Camouflaged Nanoparticles for Targeted 19F MR/PA/FL Imaging-Guided Photothermal Therapy

Our exploration of multimodal nanoprobes aims to combine photoacoustic (PA) imaging, ¹⁹F magnetic resonance (MR), and fluorescence (FL) imaging, which offers complementary advantages such as high spatial resolution, unlimited penetration, and high sensitivity to enable more refined images for accurate tumor diagnoses. In this research, perfluorocarbons (PFCs) and indocyanine green (ICG) are encapsulated by poly(lactic-co-glycolic acid) (PLGA) for intravital ¹⁹F MR/FL/PA tri-modal imaging-guided photothermal therapy. Then, it is coated with an A549 cancer cell membrane (AM) to fabricate versatile theranostic nanoprobes (AM-PP@ICGNPs). After systemic administration, FLI reveals time-dependent tumor homing of NPs with high sensitivity, ¹⁹F MRI provides tumor localization of NPs without background signal interference, and PAI illustrates the detailed distribution of NPs inside the tumor with high spatial resolution. What is more, AM-PP@ICGNPs accumulated in the tumor area exhibit a prominent photothermal effect (48.4 °C) under near infrared (NIR) laser irradiation and realize an enhanced antitumor response in vivo. These benefits, in combination with the excellent biocompatibility, make AM-PP@ICGNPs a potential theranostic nanoagent for accurate tumor localization and ultimately achieve superior cancer therapy.