Imaging agents that can be targeted to specific diseases and respond to the microenvironment of the diseased tissue are of considerable interest due to their potential in diagnosing and managing ...diseases. Here we report a new class of branched fluorinated glycopolymers as 19F MRI contrast agents that respond to a reductive environment, for targeted imaging of cancer. The fluorinated glycopolymers can be readily prepared by a one-pot RAFT polymerization of glucose- and fluorine-containing monomers in the presence of a disulfide-containing cross-linking monomer. The incorporation of glucose units along the polymer chain enables these fluorinated glycopolymers to effectively target cancer cells due to interactions with the overexpressed sugar transporters present on the cell surface. In addition, the polymers exhibit an enhanced 19F MRI signal in response to a reductive environment, one of the unique hallmarks of many cancer cells, demonstrating their potential as promising candidates for targeted imaging of cancer.
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IJS, KILJ, NUK, PNG, UL, UM
Polyethylene glycol (PEG) and poly(PEGMA) conjugated nanodiamond (ND) have been synthesized via “grafting to” and “grafting from” methods, respectively. In “grafting to” method, hydroxyl groups on ND ...surface were firstly oxidized to carboxyl groups, and then reacted with thionyl chloride to form acyl chloride groups. The acyl chloride functionalized ND (ND–COCl) was subsequently reacted with poly(ethylene glycol) monomethyl ether (mPEG) in the presence of triethylamine to generate mPEG conjugated ND (ND–mPEG). On the other hand, in “grafting from” method, ND–OH was modified with 2-bromoisobutyryl bromide (ND–Br), and then poly(PEG methyl ether methacrylate) (Poly(PEGMA)) chains were linked on the ND surface through surface-initiated atom transfer radical polymerization (ATRP) using ND–Br as the initiator and Cu(Br)/N,N,N′,N″,N″-pentmethyl diethylenetriamine (PMDETA) as the catalyst and ligand. The polymer conjugated ND particles were characterized using transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, thermal gravimetric analysis (TGA) and X-ray photoelectron spectroscopy (XPS). TGA analyses demonstrated that the polymer weight ratios through “grafting to” and “grafting from” methods were 29.8% and 34.4%, respectively. The mPEG and poly(PEGMA) conjugated ND nanoparticles exhibited enhanced dispersibility in organic media. More importantly, due to the relative high graft ratios and molecular weight, poly(PEGMA) functionalized ND was also dispersed well in water. Given the excellent physicochemical and biological properties of PEG and ND, the methods described in current work might be useful for the preparation of functional ND nanoparticles for potential biomedical applications.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
19F magnetic resonance imaging (19F MRI) agents capable of being activated upon interactions with cancer triggers are attracting increasing attention, although challenges still remain for precise and ...specific detection of cancer tissues. In this study, a novel hybrid 19F MRI agent for pH‐sensitive detection of breast cancer tissues is reported, a composite system designed by conjugating a perfluoropolyether onto the surface of manganese‐incorporated layered double hydroxide (Mn‐LDH@PFPE) nanoparticles. The 19F NMR/MRI signals from aqueous solutions of Mn‐LDH@PFPE nanoparticles are quenched at pH 7.4, but “turned on” following a reduction in pH to below 6.5. This is due to partial dissolution of Mn2+ from the Mn‐LDH nanoparticles and subsequent reduction in the effect of paramagnetic relaxation. Significantly, in vivo experiments reveal that an intense 19F MR signal can be detected only in the breast tumor tissue after intravenous injection of Mn‐LDH@PFPE nanoparticles due to such a specific activation. Thus pH‐activated Mn‐LDH@PFPE nanoparticles are a potential “smart” 19F MRI agent for precise and specific detection of cancer diseases.
Fluorinated manganese‐based layered double hydroxide nanoparticles are prepared as pH‐activated 19F MRI agents for specific and sensitive detection of breast cancer cells. The well‐defined nanoparticles can be detected only in breast tumor tissue with negligible 19F MRI signal observed from other organs. The findings have deep implications for the future development of selective “smart” 19F MRI agents.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The development of fluorescent organic nanoparticles (FONs) based on aggregation induced emission (AIE) dyes has attracted significant research interest in recent years. In this work, a novel one-pot ...strategy for the fabrication of AIE-based FONs was developed
via
a combination of RAFT polymerization and enzymatic transesterification for the first time. During this procedure, a hydrophobic tetraphenylethene-functionalized AIE dye (denoted as TPEOH) with a hydroxyl end functional group and a hydrophilic polyethylene glycol monomethyl ether (mPEG-OH,
M
n
= 350) were simultaneously attached onto the methacrylate monomer
via
enzymatic transesterification. The amphiphilic copolymer formed after RAFT polymerization of the functionalized methacrylate monomers tended to self-assemble into FONs with the hydrophobic AIE core covered by a hydrophilic PEG shell. The molar fractions of TPE and PEG in the polymer were about 30.5% and 69.5%, respectively, while
M
n
was 4700 g mol
−1
with a narrow polydispersity index (PDI) (∼1.30). The obtained amphiphilic polymer nanoparticles (denoted as TPE-PEG) demonstrated good fluorescence performance and excellent dispersibility in aqueous solution. More importantly, these FONs possessed a spherical morphology with a uniform size (about 200 nm) and excellent biocompatibility, making them promising for bioimaging applications.
A novel one-pot strategy for the fabrication of AIE-based FONs has been developed
via
a combination of RAFT polymerization and enzymatic transesterification.
A novel, highly efficient methodology to synthesize gradient glycopolymers has been successfully developed involving concurrent enzymatic monomer transformation and reversible addition–fragmentation ...chain transfer (RAFT) polymerization. By synchronizing enzymatic monomer transformation with polymerization, a continuous supply of the second monomer (glycomonomer) is achieved during the polymerization, resulting in a gradient sugar distribution in the final polymer. Detailed studies of the process using GPC and NMR indicate that the gradient glycopolymers synthesized by RAFT were well controlled. Subsequently, 1,2:3,4-di-O-isopropylidene-6-O-methacryloyl-α-d-galactopyranose (DIMAG) moieties were deprotected to regenerate the sugar and achieve amphiphilic bioactive glycopolymers. We demonstrate the synthesis of a set of glycopolymers with different sequential structures, such as statistical, gradient and block glycopolymers. The glycopolymers with block structure show higher affinities toward the RCA120 lectin receptor compared with other structural counterparts. Furthermore, simulation of the self-assembly of three types of copolymers and their binding to lectins provides fundamental insight into this result, revealing the mechanisms underlying the dependence of self-assembling structures and protein adsorption kinetics on the molecular architectures of copolymers.
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IJS, KILJ, NUK, PNG, UL, UM
Purpose
For patients with intractable cancer-related pain, administration of strong opioid analgesics and adjuvant agents by the intrathecal (i.t.) route in close proximity to the target ...receptors/ion channels, may restore pain relief. Hence, the aim of this study was to use bioerodable polymers to encapsulate an opioid analgesic (hydromorphone) and an adjuvant drug (ketamine) to produce prolonged-release formulations for i.t. injection.
Methods
A two-stage microfluidic method was used to fabricate nanoparticles (NPs). The physical properties were characterised using dynamic light scattering and transmission electron microscopy. A pilot
in vivo
study was conducted in a rat model of peripheral neuropathic pain.
Results
The
in vitro
release of encapsulated payload from NPs produced with a polymer mixture (CPP-SA/PLGA 50:50) was sustained for 28 days. In a pilot
in vivo
study, analgesia was maintained over a three day period following i.t. injection of hydromorphone-loaded NPs at 50 μg. Co-administration of ketamine-loaded NPs at 340 μg did not increase the duration of analgesia significantly.
Conclusions
The two-stage microfluidic method allowed efficient production of analgesic/adjuvant drug-loaded NPs. Our proof-of-principle
in vivo
study shows prolonged hydromorphone analgesic for 78 h after single i.t. injection. At the i.t. dose administered, ketamine released from NPs was insufficient to augment hydromorphone analgesia.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Quantum dots (QDs) of formamidinium lead triiodide (FAPbI3) perovskite hold great potential, outperforming their inorganic counterparts in terms of phase stability and carrier lifetime, for ...high‐performance solar cells. However, the highly dynamic nature of FAPbI3 QDs, which mainly originates from the proton exchange between oleic acid and oleylamine (OAm) surface ligands, is a key hurdle that impedes the fabrication of high‐efficiency solar cells. To tackle such an issue, here, protonated‐OAm in situ to strengthen the ligand binding at the surface of FAPbI3 QDs, which can effectively suppress the defect formation during QD synthesis and purification processes is selectively introduced. In addition, by forming a halide‐rich surface environment, the ligand density in a broader range for FAPbI3 QDs without compromising their structural integrity, which significantly improves their optoelectronic properties can be modulated. As a result, the power conversion efficiency of FAPbI3 QD solar cells (QDSCs) is enhanced from 7.4% to 13.8%, a record for FAPbI3 QDSCs. Furthermore, the suppressed proton exchange and reduced surface defects in FAPbI3 QDs also enhance the stability of QDSCs, which retain 80% of the initial efficiency upon exposure to ambient air for 3000 hours.
An in situ surface ligand regulation strategy for deliberately controlling protonated‐oleylamine (OAm) dominated surface binding of formamidinium lead triiodide quantum dots (FAPbI3 QDs) is demonstrated. The QDs present reduced long‐chain insulating ligand density without compromising their structural integrity, leading to the corresponding QD solar cell a record power conversion efficiency of 13.8% for FAPbI3 QDSCs.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The synthesis of polymers with various functional groups has always been the core of polymer chemistry. Traditionally, there are two approaches to prepare such polymers: i) preparing functional ...monomers first and then conducting polymerization to get target functional polymers; and ii) post‐modification of a precursor polymer. Both methods unavoidably involve separation and purification of intermediate products, which is laborious and time‐consuming. A one‐pot synthesis strategy, which combines monomer preparation and controlled polymerization in just one reactor to generate well‐defined polymers efficiently, is thus proposed. Recent advances in the one‐pot synthesis of multifunctional polymers through a multicomponent system are provided in this article.
One‐pot strategies, which combine in situ monomer synthesis and controlled radical polymerization together, are applied into innovative functional polymer preparation. This methodology is simple, efficient, and versatile. In this talent article, most advances in one‐pot synthesis strategies are summarized and their further applications are discussed.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Minimizing the interaction of nanomedicines with the mononuclear phagocytic system (MPS) is a critical challenge for their clinical translation. Conjugating polyethylene glycol (PEG) to nanomedicines ...is regarded as an effective approach to reducing the sequestration of nanomedicines by the MPS. However, recent concerns about the immunogenicity of PEG highlight the demand of alternative low‐fouling polymers as innovative coating materials for nanoparticles. Herein, a highly hydrophilic sulfoxide‐containing polymer—poly(2‐(methylsulfinyl)ethyl acrylate) (PMSEA)—is used for the surface coating of iron oxide nanoparticles (IONPs). It is found that the PMSEA polymer coated IONPs have a more hydrophilic surface than their PEGylated counterparts, and demonstrate remarkably reduced macrophage cellular uptake and much less association with human plasma proteins. In vivo study of biodistribution and pharmacokinetics further reveals a much‐extended blood circulation (≈2.5 times longer in terms of elimination half‐life t1/2) and reduced accumulation (approximately two times less) in the organs such as the liver and spleen for IONPs coated by PMSEA than those by PEG. It is envisaged that the highly hydrophilic sulfoxide‐containing polymers have huge potential to be employed as an advantageous alternative to PEG for the surface functionalization of a variety of nanoparticles for long circulation and improved delivery.
An innovative class of sulfoxide‐containing polymer is used as an exceptional surface functionalization material for nanoparticles. The highly hydrophilic nature of the polymer endows nanoparticles with remarkable low‐fouling property as demonstrated by weak interaction with plasma proteins, prolonged blood circulation, and improved biodistribution profile of conjugated nanoparticles.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
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