Coordination Polymer Nanoparticles Research Articles

Manganese coordination polymer nanoparticles with excellent oxidase-like activity for the rapidly and selectively colorimetric detection of glutathione

Novel kinds of manganese coordination polymer nanoparticles (Mn-IMZs CPNs) were fabricated through self-assemble of imidazole with Mn2+ ions in aqueous solution. The prepared Mn-IMZs CPNs, with remarkable stability, exhibit excellent oxidase-like activity that can effectively catalyze the conversion of the dissolved O2 to O2•−, turning the colorless 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidized TMB (ox-TMB). Based on the inhibitory effect of glutathione (GSH) on the TMB oxidation, a rapid and highly sensitive colorimetric method for the detection of GSH was developed, and the linear ranges are 1.25–50 μM and 50–112.5 μM. Besides, the discriminative detection of GSH from cysteine was achieved by using the time lag between N-ethylmaleimide on the destruction of thiol compounds. Finally, the developed method was successfully applied in the quantification of GSH in tablets and rabbit plasma with high accuracy and good recovery.

Portable visual assay for anthrax biomarker based on lanthanide coordination polymer nanoparticles and smartphone-integrated mini-device

A novel portable sensor based on LML-Tb3+-AMP NPs and a custom-built device was fabricated for real-time and visual detection of anthracis biomarker.

Cobalt-based coordination polymer imitating nanozymatic Peroxido-Reductase activity for specific and sensitive detection of Fe(II) ions

Nanozyme based sensors have evolved as an equable and productive approach for detecting obnoxious metal ions in water samples. A coherent and methodical outlook for nanozymatic sensors is provided in this work. A Co(II) based coordination polymer [Co(L)1.5(ac)3]n named Co-CP, (L = N, N-(benzo-3,8-phenanthroline-2,7-diyl)diisonicotinamide and ac = CH3COO–) has been synthesized in this paper. Co(II) based coordination polymer nanoparticles (Co-CP NPs) constructed by using hand grinding process stimulates the nanozymatic action due to increased surface area and exposure of catalytically active sites. The fabricated Co-CP NPs were characterized using various sophisticated analytical techniques such as SCXRD, HRTEM, FESEM, PXRD etc. The NPs thus formed were about 27 nm in size and pertain porous sites. The Co-CP NPs exhibited peroxido-reductase mimicking activity for TMB(3,3′,5,5′-tetramethylbenzidine) oxidation. The catalytic action of the Co-CP NPs was utilized to detect Fe(II) ion selectively with a detection limit of 0.66 µM. The kinetics for the study were described using Michaelis-Menten curve. The Km and Vmax values for H2O2 and Co-CP NPs were analyzed further to access the catalytic action of Co-CP NPs. XPS and zeta potential analysis were evidenced to elucidate the detection mechanism. The compatibility and practicality of the present method was also assured by actual water samples from different sources that showed good recovery percentage. Therefore, an economical, manageable and equable approach for using CPs as a sensing tool is provided hereby.

Ultrasmall Bi/Cu Coordination Polymer Combined with Glucose Oxidase for Tumor Enhanced Chemodynamic Therapy by Starvation and Photothermal Treatment.

Multi-modal combination therapy for tumor is expected to have superior therapeutic effect compared with monotherapy. In this study, a super-small bismuth/copper-gallic acid coordination polymer nanoparticle (BCN) protected by polyvinylpyrrolidone is designed, which is co-encapsulated with glucose oxidase (GOX) by phospholipid to obtain nanoprobe BCGN@L. It shows that BCN has an average size of 1.8 ± 0.7nm, and photothermal conversion of BCGN@L is 31.35% for photothermal imaging and photothermal therapy (PTT). During the treatment process of 4T1 tumor-bearing nude mice, GOX catalyzes glucose in the tumor to generate gluconic acid and hydrogen peroxide (H2 O2 ), which reacts with copper ions (Cu2+ ) to produce toxic hydroxyl radicals (•OH) for chemodynamic therapy (CDT) and new fresh oxygen (O2 ) to supply to GOX for further catalysis, preventing tumor hypoxia. These reactions increase glucose depletion for starvation therapy , decrease heat shock protein expression, and enhance tumor sensitivity to low-temperature PTT. The in vitro and in vivo results demonstrate that the combination of CDT with other treatments produces excellent tumor growth inhibition. Blood biochemistry and histology analysis suggests that the nanoprobe has negligible toxicity. All the positive results reveal that the nanoprobe can be a promising approach for incorporation into multi-modal anticancer therapy.

An intelligent “chemical tongue” for high-order monitoring ATP-related physiological phosphates and ATP hydrolysis through diverse transduction principles

For discriminating diverse analytes and monitoring a specific chemical reaction, the emerging multi-channel “chemical nose/tongue” is challenging multi-material “chemical nose/tongue”. The former contributes greatly to integrating different transduction principles from a single sensing material, avoiding the need for complex design, high cost, and tedious operation involved with the latter. Therefore, this high-order sensing puts a particular emphasis on the effects of encapsulation. Herein, the plasmonic gold nanoparticles (Au NPs) are encapsulated as a core into the fluorescent guanine monophosphate-Tb3+ infinite coordination polymer nanoparticles (GMP-Tb ICPs) to obtain a core-shell nanocomposite named Au NPs@GMP-Tb ICPs. Hence, a dual-channel “chemical tongue” based on Au NPs@GMP-Tb ICPs is present to realize high-order sensing of adenosine triphosphate (ATP)-related physiological phosphates and the monitoring of ATP hydrolysis. Considering the affinity of Tb3+ towards P–O bonds, four inorganic phosphates and three nucleotide phosphates with different phosphate group numbers and steric hindrance effect directly regulate two stimulus responses (fluorescence intensity and UV–vis absorbance) of Au NPs@GMP-Tb ICPs. Robust statistical methods, such as linear discriminant analysis and hierarchical cluster analysis, are used to recognize each phosphate by the developed sensor array either in the aqueous solution or in complex media such as serum, together with efficiently monitored ATP hydrolysis at different intervals. These findings and blind test clarify that the designed “chemical tongue” guarantees interference resistance and strengthens analytical capacity, together with offering valuable insight into “lab-on-a-nanoparticle” development for monitoring specific chemical reactions.

High-efficiency fluorescent coordination polymer nanoparticles co-doped with Ce3+/Tb3+ ions for curcumin detection.

Curcumin (Cur) possesses diverse biological and pharmacologic effects. It is widely used as a food additive and therapeutic medicine. A study to determine a sensitive detection method for Cur is necessary and meaningful. In this work, double rare earth ions co-doped fluorescent coordination polymer nanoparticles (CPNPs) were developed for the Cur detection. The CPNPs were synthesized by using adenosine monophosphate (AMP) as bridge ligands via coordination self-assembly with Ce3+ and Tb3+. The AMP-Ce/Tb CPNPs exhibited the characteristic green fluorescence of Tb3+ and had high luminescence efficiency. Under the optimal conditions, the fluorescence intensity of AMP-Ce/Tb CPNPs could be significantly quenched by Cur. The fluorescence quenching extent at λex/λem of 300 nm/544 nm showed a good linear relationship with the Cur concentration in the range of 10 to 1000 nM. The detection limit was as low as 8.0 nM (S/N = 3). This method was successfully applied to the determination of Cur in real samples with satisfactory results. The luminescence mechanism of AMP-Ce/Tb CPNPs and the fluorescence quenching mechanism of the CPNPs by Cur were both examined.

Co-delivery of three synergistic chemotherapeutics in a core-shell nanoscale coordination polymer for the treatment of pancreatic cancer

The combination chemotherapy regimen FOLFIRINOX comprising folinic acid, 5-fluorouracil, irinotecan, and oxaliplatin is the first-line treatment for patients with advanced pancreatic cancer, but its use remains prohibitive for the majority of patients due to severe side effects. Here, we report a core-shell nanoscale coordination polymer (NCP) nanoparticle co-delivering a potent and synergistic combination of oxaliplatin, gemcitabine, and SN38 (OGS), for the treatment of pancreatic cancer in mouse models. OGS contains key synergistic components of FOLFIRINOX in a controllable drug ratio., It exhibited particle stability in blood circulation and enhanced deposition of the drugs in acidic tumor environments. In vitro, OGS showed superior cytotoxicity over free drug combinations and robust cytotoxic synergism among its three components. In vivo, OGS improved drug circulation, increased tumor deposition, and exhibited superior antitumor efficacy over the free drug combination in both subcutaneous and orthotopic pancreatic tumor models. OGS treatment achieved 75–91% tumor growth inhibition and prolonged mouse survival by 1.6- to 2.8-folds while minimizing systemic toxicities such as neutropenia, hepatotoxicity, and renal toxicity. This work uncovers a novel and clinically relevant nanomedicine strategy to co-deliver synergistic combination chemotherapies for difficult-to-treat cancers.

Integrated ratiometric luminescence sensing strategy based on encapsulation of guests in heterobinuclear lanthanide coordination polymer nanoparticles for glucose detection in human serum

Lanthanide coordination polymers (LnCPs) can be used as a host platform to encapsulate functional guest molecules for the construction of integrated sensing platforms. In this work, two guest molecules, rhodamine B (RhB) and glucose oxidase (GOx), were successfully encapsulated in a heterobinuclear lanthanide coordination polymer synthesized by self-assembly of Ce3+, Tb3+ and adenosine monophosphate (AMP) to form RhB&GOx@AMP-Tb/Ce. Both guest molecules show good storage stability and minimal leakage. The higher catalytic activity and stability of RhB&GOx@AMP-Tb/Ce is obtained due to the confinement effect compared to free GOx. RhB&GOx@AMP-Tb/Ce exhibits superior luminescence based on the internal tandem energy transfer process of the nanoparticles (Ce3+→Tb3+→RhB). Glucose can be oxidized in the presence of GOx to form gluconic acid and H2O2. Subsequently, Ce3+ in the AMP-Tb/Ce host structure can be oxidized by H2O2 to Ce4+, thereby interrupt the internal energy transfer process and cause ratiometric luminescence response. Benefiting from the synergistic effect, the smart integrated luminescent glucose probe exhibits a wide linear range (0.4–80 μM) and a low detection limit (74.3 nM) with high sensitivity, selectivity and simplicity, enabling the quantitative detection of glucose in human serum. This work describes a good strategy to construct an integrated luminescence sensor based on lanthanide coordination polymers.

Aggregation‐induced emission artificial enzyme (AIEzyme) with DNase‐like activity: Imaging and matrix cleavage for combating bacterial biofilm

AbstractDNase‐catalyzed hydrolysis of extracellular DNA (eDNA) has been widely employed to eradicate intractable biofilms. Although aggregation‐induced emission (AIE) has become the ideal tool for killing planktonic bacteria, AIE luminogens (AIEgens) often lack DNase‐mimetic activity, so as to suffer from poor anti‐biofilm capacity. Here, an “AIEzyme”, a kind of AIE nanomaterial with enzyme‐like activity, is designed and synthesized, where the AIEgens are used as the ligands of Zr‐based coordination polymer nanoparticles. Not only does AIEzyme have enduring DNase‐mimetic activity with low activation energy, but also structural rigidity‐stabilized fluorescence. Due to the long‐acting hydrolysis for eDNA in biofilm, AIEzyme can efficiently disorganize the established biofilms with good penetrability and realize the healing of superbug‐infected wounds under only one dose of AIEzyme. This work provides a strategy to endow ordinary AIEgens with DNase‐like and anti‐biofilm activities. Moreover, AIEzymes can be observed by virtue of their own AIE character, facilitating the study on self‐positioning and residual amount of AIEzymes in wounds. The concept “AIEzyme” would hopefully stimulate the tremendous expansion for the tool kits and the application of AIEgens and artificial enzymes.

Thioflavin-T-Incorporated Cerium-ATP Coordination Polymer Nanoparticles: A Promising System for Detection of Uranyl Ion (UO22+) in Aqueous Medium.

Lanthanide-based coordination polymer nanoparticles (Ln-CPNs) are studied for analytical and biomedical sensing, mainly utilizing the luminescent properties of lanthanides. However, the inclusion of fluorescent guest molecules within the nanoparticles can lead to a stimuli-responsive system with modulated photo-physical properties that can be useful for detecting analytes. In this work, we have synthesized cerium(III) coordination polymer nanoparticles using adenosine triphosphate (ATP) molecules as the ligands. The porous polymeric structure enables CPNs for reversible inclusion and release of thioflavin-T (ThT), which is a weakly emissive dye in the free state but becomes highly emissive when incorporated into the Ce-ATP CPNs. Modulation of the photo-physical properties of ThT-incorporated CPNs in response to the radiotoxic and environmentally alarming uranyl ion (UO22+) has been used for its detection in aqueous medium in the range of 0-20 μM by fluorimetry with an LOD of 80 ng mL-1 (0.34 μM) in deionized water without interference from the most commonly occurring metal ions. Furthermore, the sensing platform has been successfully utilized for UO22+ determination in seawater sample without any pre-treatment and adjustment of pH.

Visualizing stimulus-responsive dual-ligand fluorescent probes for hypochlorite: A novel strategy for real application in tap water.

As an effective ingredient of disinfectants, ClO- inevitably remains in water, which induces potential health hazards such as lung damage and kidney disease. In this study, we synthesized stimulus-responsive dual-ligand luminol-Tb-GMP coordination polymer nanoparticles (luminol-Tb-GMP CPNPs) as highly selective fluorescent probes for the real-time and visual detection of ClO- . CPNPs consist of Tb3+ , a nuclear metal, that coordinates with GMP and luminol, an auxiliary ligand. GMP can be oxidized by ClO- and damage its structure, resulting in fluorescence quenching of CPNPs. The two-ligand CPNPssensor has a rapid fluorescent response, significant fluorescent color change, and high sensitivity, with a linear range of 2-18 μM and a detection limit of 0.14 μM. It has been successfully used to detect ClO- in tap water, fountain water, and drinking water. Simultaneously, the portable filter paper strip was prepared to expand the range of applications outside the laboratory, which will provide a promising application for the real-time and semiquantitative analysis of ClO- .

Engineered procyanidin-Fe nanoparticle alleviates intestinal inflammation through scavenging ROS and altering gut microbiome in colitis mice.

Inflammatory bowel disease (IBD) is an idiopathic chronic inflammatory bowel disease characterized by inflammation, intestinal barrier injury, and imbalance of gut microbiota. Excess accumulation of reactive oxygen species (ROS) is closely correlated with the development and reoccurrence of IBD. Previous researches demonstrate that procyanidin, as a natural antioxidant, exhibits strong ability of eliminating ROS, thus showing good therapeutic effects in the inflammation-related diseases. Non-etheless, its poor stability and solubility always limits the therapeutic outcomes. Here, we typically designed an antioxidant coordination polymer nanoparticle using the engineering of procyanidin (Pc) and free iron (Fe), named Pc-Fe nanozyme, for effectively scavenging ROS and further inhibiting inflammation while altering the gut microbiome for the treatment of colitis. Furthermore, in vitro experiments uncover that Pc-Fe nanoparticles exert strong multi biomimic activities, including peroxidase, and glutathione peroxidase, for the scavenging of ROS and protecting cells from oxidative injury. In addition, the colon accumulation of Pc-Fe nanozyme effectively protects the intestinal mucosa from oxidative damage while significantly downregulates pro-inflammatory factors, repairs the intestinal barriers and alternates gut microbiome after orally administrated in sodium dextran sulfate (DSS) induced colitis mice. The results collectively illustrate that the multienzyme mimicking Pc-Fe nanozyme owns high potential for treating IBD through scavenging ROS, inhibiting inflammation, repairing gut barriers and alternating gut microbiome, which further promising its clinical translation on IBD treatment and other ROS induced intestinal diseases.

Construction of fluorescence and colorimetric tandem dual-mode sensor by modulating fluorescence and oxidase-like activity via valence switching of cerium-based coordination polymer nanoparticles for sarcosine detection.

A fluorescence and colorimetric tandem dual-mode sensor was established by modulating fluorescence and oxidase-like activity via valence switching of cerium-based coordination polymer nanoparticles (Ce-CPNs) for the detection of sarcosine (Sar) which is considered as a potential biomarker for the diagnosis of prostate cancer (PCa). In the present research, sarcosine oxidase (SOX) specifically catalyzes the oxidation of Sar to yield H2O2 which can rapidly oxidize Ce(III)-CPNs to generate Ce(IV)-CPNs in appropriate alkaline solution. The generated Ce(IV)-CPNs create a markedly weakened fluorescent signal at 350nm, while they can induce oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to generate blue TMBox through emerging good oxidase-like activity. The sensing platform can realize accurate, stable, and high-throughput detection of Sar because of the tandem dual signal output mechanism. More attractively, the chromogenic hydrogel sensing device using smartphone photographing has achieved perfect results for the on-site sensing of Sar in urine specimens without large experimental equipments, demonstrating its considerable clinical application potential in the early diagnosis of PCa.

Detecting phosphate using lysine-sensitized terbium coordination polymer nanoparticles as ratiometric luminescence probes.

Probes for detecting phosphate ions (Pi) are required for environmental monitoring and to protect human health. Here, novel ratiometric luminescent lanthanide coordination polymer nanoparticles (CPNs) were successfully prepared and used to selectively and sensitively detect Pi. The nanoparticles were prepared from adenosine monophosphate (AMP) and Tb3+, and lysine (Lys) was used as a sensitizer (through the antenna effect) to switch on Tb3+ luminescence at 488 and 544nm while Lys luminescence at 375nm was quenched because of energy transfer from Lys to Tb3+. The complex involved is here labeled AMP-Tb/Lys. Pi destroyed the AMP-Tb/Lys CPNs and therefore decreased the AMP-Tb/Lys luminescence intensity at 544nm and increased the luminescence intensity at 375nm at an excitation wavelength of 290nm, meaning ratiometric luminescence detection was possible. The ratio between the luminescence intensities at 544 and 375nm (I544/I375) was strongly associated with the Pi concentration between 0.1 and 6.0μM, and the detection limit was 0.08μM. The dual-emission reverse-change ratio luminescence sensing method can exclude environmental effects, so the proposed assay was found to be very selective. The method was successfully used to detect Pi in real water samples, and acceptable recoveries were found, suggesting that the method could be used in practice to detect Pi in water samples.

Photothermal enhanced fluorescence quenching of Tb-norfloxacin for ultrasensitive human epididymal 4 detection.

A fluorescence quenching enhanced immunoassay has been developed to achieve ultrasensitive recognition of human epididymal 4 (HE4) modifying the fluorescence quencher. The carboxymethyl cellulose sodium-functionalized Nb2C MXene nanocomposite (CMC@MXene) was firstly introduced to quench the fluorescence signal of the luminophore Tb-Norfloxacin coordination polymer nanoparticles (Tb-NFX CPNPs). The Nb2C MXene nanocomposite as fluorescent nanoquencher inhibits the electron transfer between Tb and NFX to quench the fluorescent signal by coordinating the strongly electronegative carboxyl group on CMC with Tb (III) of Tb-NFX complex. Simultaneously, due to the superior photothermal conversion capability of CMC@MXene, the fluorescence signal has been further weakened by the photothermal effect driven non-radiative decay of the excited state under near-infrared laser irradiation. The constructed fluorescent biosensor based on CMC@MXene probe finally realized the enhanced fluorescence quenching effect, and achieved ultra-high sensitivity and selective detection of HE4, exhibiting a wide linear relationship with HE4 concentration on the logarithmic axis in the range of 10-5 to 10ng/mL and a low detection limit of 3.3fg/mL (S/N = 3). This work not only provides an enhanced fluorescent signal quenching method for the detection of HE4, but also provides novel insights for the design of fluorescent sensor toward different biomolecules.

Ultrarapid Microwave-Assisted Synthesis of Fluorescent Silver Coordination Polymer Nanoparticles and Its Application in Detecting Alkaline Phosphatase Activity

Fluorescent silver coordination polymer nanoparticles (Ag-TPA CPNs) were synthesized using a combination of terephthalic acid (TPA) and silver nitrate via an ultrarapid microwave-assisted strategy within 15 min. The Ag-TPA CPNs displayed a high fluorescent quantum yield (QY = 20.19%) and large Stokes shift (~200 nm), with two emission peaks at 490 nm and 520 nm under an excitation wavelength of 320 nm. A fluorescent "turn-off" method using fluorescent Ag-TPA CPNs was applied to detect the alkaline phosphatase (ALP) activity on the basis of the ALP-catalyzed hydrolysis of ascorbic acid 2-phosphate (AA2P) to ascorbic acid (AA), and the AA product triggered the reduction of Ag+ ions into silver nanoparticles. The fluorescent lifetime of Ag-TPA CPNs decreased from 3.93 ms to 3.80 ms after the addition of ALP, which suggests that this fluorescent "turn-off" detection of ALP activity is a dynamic quenching process. The fluorescent intensity had a linear relationship with the concentration of ALP in the range of 0.2-12 mU/mL (r = 0.991) and with a limit of detection (LOD) of 0.07 mU/mL. It showed high selectivity in ALP detection towards metal ions and amino acids, as well as other enzymes such as horseradish peroxidase, glucose oxidase, tyrosinase, trypsin, lysozyme, and superoxides. When it was applied for the fluorescent "turn-off" detection of ALP activity in serum samples, mean recovery levels ranging from 99.5% to 101.2% were obtained, with relative standard deviations (RSDs) lower than 4% accuracy. Therefore, it is an efficient and accurate tool for analyzing ALP levels in biosamples.

Self-Assembled Core-Shell Nanoscale Coordination Polymer Nanoparticles Carrying a Sialyltransferase Inhibitor for Cancer Metastasis Inhibition.

Despite hypersialylation of cancer cells together with a significant upregulation of sialyltransferase (ST) activity contributes to the metastatic cascade at multiple levels, there are few dedicated tools to interfere with their expression. Although transition state-based ST inhibitors are well-established, they are not membrane permeable. To tackle this problem, herein, we design and construct long-circulating, self-assembled core-shell nanoscale coordination polymer (NCP) nanoparticles carrying a transition state-based ST inhibitor, which make the inhibitor transmembrane and potently strip diverse sialoglycans from various cancer cells. In the experimental lung metastasis and metastasis prevention models, the nanoparticle device (NCP/STI) significantly inhibits metastases formation without systemic toxicity. This strategy enables ST inhibitors to be applied to cells and animals by providing them with a well-designed nanodelivery system. Our work opens a new avenue to the development of transition state-based ST inhibitors and demonstrates that NCP/STI holds great promise in achieving metastases inhibition for multiple cancers.

Water-Stable Upconverting Coordination Polymer Nanoparticles for Transparent Films and Anticounterfeiting Patterns with Air-Stable Upconversion.

Photon upconversion (UC) based on triplet-triplet annihilation is a very promising phenomenon with potential application in several areas, though, due to the intrinsic mechanism, the achievement of diffusion-limited solid materials with air-stable UC is still a challenge. Herein, we report UC coordination polymer nanoparticles (CPNs) combining sensitizer and emitter molecules especially designed with alkyl spacers that promote the amorphous character. Beyond the characteristic constraints of crystalline MOFs, amorphous CPNs facilitate high dye density and flexible ratio tunability. To show the universality of the approach, two types of UC-CPNs are reported, exhibiting highly photostable UC in two different visible spectral regions. Given their nanoscale, narrow size distribution, and good chemical/colloidal stability in water, the CPNs were also successfully printed as anticounterfeiting patterns and used to make highly transparent and photostable films for luminescent solar concentrators, both showing air-stable UC.

A smartphone-integrated colorimetric quantitative analysis platform based on oxidase-like Ce(IV)-ATP-Tris CPNs/CNF test strip for detection of inorganic arsenic in rice

Herein, a colorimetric sensing system based on cerium(IV) coordination polymer nanoparticles (Ce(IV)-ATP-Tris CPNs) was proposed for As(V) detection. Ce(IV)-ATP-Tris CPNs show excellent oxidase-like activity, triggering 3,3′,5,5′-tetramethylbenzidine (TMB) chromogenic reaction. With addition of ascorbic acid 2-phosphate (AAP) and acid phosphatase (ACP), ACP can hydrolyze AAP to produce antioxidative ascorbic acid (AA), inhibiting TMB chromogenic reaction. After that, introduction of As(V) can inhibit ACP, recovering TMB chromogenic reaction. Therefore, sensitive and selective As(V) detection is achieved. Moreover, Ce(IV)-ATP-Tris CPNs were transformed into cellulose nanofiber (CNF) to form test strip (Ce(IV)-ATP-Tris CPNs/CNF). Inorganic arsenic in rice can be detected by test strip, color of that can be measured by smartphone-integrated colorimetric quantitative analysis platform. Given this, rapid and convenient strip test of inorganic arsenic in rice by using this platform was achieved. Hence, this platform possesses great application potential in the field of inorganic arsenic in rice, even food safety.

PH‐Responsive Charge‐Convertible N‐Succinyl Chitosan‐Quercetin Coordination Polymer Nanoparticles for Effective NIR Photothermal Cancer Therapy

AbstractIn recent years, a combination of photothermal therapy (PTT) with chemotherapy has emerged as a new promising strategy to achieve synergistic cancer therapeutic efficacy. Coordination polymer nanocomposites (CPNs) are a new generation of photothermal agents (PTAs) for cancer therapy owing to their high photothermal transduction efficiency, excellent biocompatibility as well as biodegradability and bioactivity. In this study, a robust and scalable synthesis of pH‐sensitive charge convertible NSC‐Fe‐Que coordination polymer nanoparticles (CPNs) based on the coordination reaction between Fe3+, anti‐cancer prodrug quercetin (Que), and pH‐sensitive zwitterionic biopolymer N‐succinyl chitosan (NSC) is reported. The as‐prepared CPNs exhibit slightly negative zeta potential at neutral pH while positive zeta potential at pH 6.5, which ensures long blood circulation and high accumulation in the tumor region. NSC‐Fe‐Que CPNs exhibited strong absorption in NIR (500–850 nm) region and displayed a good anticancer effect against A549 cells attributing to the chemo‐photothermal synergistic effect. This study demonstrated that the NSC‐Fe‐Que CPNs hold great promise as an effective thermo‐chemotherapy agent for combination therapy against cancer.