Functionalized Green Carbon dots for Specific Detection of Copper in Human Serum Samples and Living Cells.

Intracellular copper ion (Cu2+) is irreplaceable and essential in regulation of physiological and biological processes, while excessive copper from bioaccumulation may cause potential hazards to human health. Hence, effective and sensitive recognition is urgently significant to prevent over-intake of copper. In this work, a novel highly sensitive and green carbon quantum dots (Green-CQDs) were synthesized by a low-cost and facile one-step microwave auxiliary method, which utilized gallic acid, carbamide and PEG400 as carbon source, nitrogen source and surface passivation agent, respectively. The decreased fluorescence illustrated excellent linear relationship with the increasing of Cu2+ concentration in a wide range. Substantial surface amino and hydroxyl group introduced by PEG400 significantly improved selectivity and sensitivity of Green-CQDs. The surface amino chelation mechanism and fluorescence internal filtration effect were demonstrated by the restored fluorescence after addition of EDTA. Crucially, the nanosensor illustrated good cell permeability, high biocompatibility and recovery rate, significantly practical application in fluorescent imaging and biosensing of intracellular Cu2+ in HepG-2 cells, which revealed a potential and promising biological applications in early diagnosis and treatment of copper ion related disease.

Size-Related Pathway Flux Analysis of Ultrasmall Iron Oxide Nanoparticles in Macrophage Cell RAW264.7 for Safety Evaluation.

The endocytosis, intracellular transport, and exocytosis of different-sized nanoparticles were reported to greatly affect their efficacy and biosafety. The quantitation of endocytosis and exocytosis as well as subcellular distribution of nanoparticles might be an effective approach based on transport pathway flux analysis. Thus, the key parameters that could present the effects of three different-sized ultrasmall iron oxide nanoparticles (USIONPs) were systematically investigated in RAW264.7 cells. The endocytosis and exocytosis of USIONPs were related to their sizes; 15.4 nm of S2 could be quickly and more internalized and excreted in comparison to S1 (7.8 nm) and S3 (30.7 nm). In RAW264.7 cells, USIONPs were observed in endosomes, lysosomes, the Golgi apparatus, and autophagosomes via a transmission electron microscope. Based on flux analysis of intracellular transport pathways of USIONPs, it was found that 43% of S1, 40% of S2, and 44% of S3 were individually transported extracellularly through the Golgi apparatus-involved middle-fast pathway, while 24% of S1, 23% of S2, and 26% of S3 were transported through the fast recycling endosomal pathway, and the residues were transported through the slower speed lysosomal pathway. USIONPs might be transported via size-related endocytosis and exocytosis pathways. The pathway flux could be calculated on the basis of disturbance analysis of special transporters as well as their coding genes. Because there were rate differences among these transport pathways, this pathway flux could anticipate the intracellular remaining time and distribution of different-sized nanoparticles, the function exertion, and side effects of nanomaterials. The size of the nanomaterials could be optimized for improving functions and safety.

Molecularly imprinted solid-phase extraction combined with non-ionic hydrophobic deep eutectic solvents dispersed liquid-liquid microextraction for efficient enrichment and determination of the estrogens in serum samples.

Hormonal drugs in biological samples are usually in low concentration and highly intrusive. It is of great significance to enhance the sensitivity and specificity of the detection process of hormone drugs in biological samples by utilizing appropriate sample pretreatment methods for the detection of hormone drugs. In this study, a sample pretreatment method was developed to effectively enrich estrogens in serum samples by combining molecularly imprinted solid-phase extraction, which has high specificity, and non-ionic hydrophobic deep eutectic solvent-dispersive liquid-liquid microextraction, which has a high enrichment ability. The theoretical basis for the effective enrichment of estrogens by non-ionic hydrophobic deep eutectic solvent was also computed by simulation. The results showed that the combination of molecularly imprinted solid-phase extraction and deep eutectic solvent-dispersive liquid-liquid microextraction could improve the sensitivity of HPLC by 33∼125 folds, and at the same time effectively reduce the interference. In addition, the non-ionic hydrophobic deep eutectic solvent has a relatively low solvation energy for estrogen and possesses a surface charge similar to that of estrogen, and thus can effectively enrich estrogen. The study provides ideas and methods for the extraction and determination of low-concentration drugs in biological samples and also provides a theoretical basis for the application of non-ionic hydrophobic deep eutectic solvent extraction.

Oxidized Dextran/Chitosan Hydrogel Engineered with Tetrasulfide-Bridged Silica Nanoparticles for Postsurgical Treatment.

Tumor recurrence and wound microbial infection after tumor excision are serious threats to patients. Thus, the strategy to supply a sufficient and sustained release of cancer drugs and simultaneously engineer antibacterial properties and satisfactory mechanical strength is highly desired for tumor postsurgical treatment. Herein, A novel double-sensitive composite hydrogel embedded with tetrasulfide-bridged mesoporous silica (4S-MSNs) is developed. The incorporation of 4S-MSNs into oxidized dextran/chitosan hydrogel network, not only enhances the mechanical properties of hydrogels, but also can increase the specificity of drug with dual pH/redox sensitivity, thereby allowing more efficient and safer therapy. Besides, 4S-MSNs hydrogel preserves the favorable physicochemical properties of polysaccharide hydrogel, such as high hydrophilicity, satisfactory antibacterial activity, and excellent biocompatibility. Thus, the prepared 4S-MSNs hydrogel can be served as an efficient strategy for postsurgical bacterial infection and inhibition of tumor recurrence.

Construction of optical dual-mode sensing platform based on green emissive carbon quantum dots for effective detection of ClO- and cellular imaging.

Hypochlorite (ClO-) is an important redox regulator in reactive oxygen species, which play a considerable role in oxidative stress and related diseases. Hence, accurate and sensitive monitoring of ClO- concentration was urgently needed in the fields of life sciences, food and environment. Bright green fluorescent carbon quantum dots (G-CQDs) were synthesized utilizing one-step hydrothermal method with citric acid and acriflavine precursors. Through TEM, FTIR, XPS and zeta potential characterization procedures, G-CQDs illustrated uniformly dispersed and significant number of -NH2 and -OH on the surface. Meanwhile, the fluorescence and colorimetric analysis exhibited wide linear range and low detection limit response to ClO-. The fluorescence changes of G-CQDs were identified via smartphone to realize mobile sensing of ClO-. Subsequently, G-CQDs was applied for visualization and quantitative detection of ClO- in drinking water samples with satisfactory recovery rate. More importantly, G-CQDs demonstrated good water solubility, optical stability and excellent biocompatibility, which offered a promising analysis approach in cell imaging and exogenous ClO- detection in living cells. G-CQDs illustrated bright prospect and great potential in practical application of ClO- associated disease prevention and early clinical diagnosis.

Positive interactions among Corynebacterium glutamicum and keystone bacteria producing SCFAs benefited T2D mice to rebuild gut eubiosis.

Accumulating evidences strongly support the correlations between the compositions of gut microbiome and therapeutic effects on Type 2 diabetes (T2D). Notably, gut microbes such as Akkermansia muciniphila are found able to regulate microecological balance and alleviate dysmetabolism of mice bearing T2D. In order to search out similarly functional bacteria, bacteriophage MS2 with a good specificity to bacteria carrying fertility (F) factor were used to treat T2D mice. Based on multi-omics analysis of microbiome and global metabolism of mice, we observed that gavage of bacteriophage MS2 and metformin led to a significant increase in the abundance of Corynebacterium glutamicum and A. muciniphila, respectively. Consequently, the gut microbiota were remodeled, leading to variations in metabolites and a substantial increase in short-chain fatty acids (SCFAs). In which, the amount of acetate, propionate, and butyrate presented negative correlations to that of proinflammatory cytokines, which was beneficial to repairing the intestinal barriers and improving their functions. Moreover, main short fatty acid (SCFA) producers exhibited positive interactions, further facilitating the restoration of gut eubiosis. These findings revealed that C. glutamicum and its metabolites may be potential dietary supplements for the treatment of T2D. Moreover, our research contributes to a novel understanding of the underlying mechanism by which functional foods exert their anti-diabetic effects.

DNA binding peptide CF-14 enhances bactericidal efficacy of eugenol/carvacrol nanoparticles to Escherichia coli.

To evaluate the bactericidal action of antimicrobial peptide CF-14, Eugenol (EU) and carvacrol (CAR) nanoparticles (NPs) less than 200 nm were surface-modified with CF14, gaining approximately 200 nm of EU-CF and CAR-CF NPs with swollen morphology. EU-CF and CAR-CF NPs were bactericidal to E. coli at dosage of 0.09% and 0.07% (v/v), respectively; while they were just bacteriostatic to Staphylococcus aureus at 0.10% and 0.08% (v/v). Spectral variations in bacterial carbohydrates (1185-900 cm-1), lipids (3000-2800 cm-1) and DNA (1500-1185 cm-1) were obvious as evident from Fourier transform infrared spectroscopy (FTIR). A higher percentage of membrane damaged (non-revivable) E. coli than S. aureus was found, which indicated electrostatic interactions between Gram-negative E. coli with cationic CF conjugated NPs leading to DNA disintegration. Interestingly, EU-CF and CAR-CF NPs inhibited E. coli growth in orange juice without impacting flavour compounds.

Photo-crosslinked enhanced double-network hydrogels based on modified gelatin and oxidized sodium alginate for diabetic wound healing.

The diabetic wound is hard to repair due to bacterial infection, lasting inflammation, and so on. Therefore, it is vital to fabricate a multi-functional hydrogel dressing for the diabetic wound. In this study, a kind of dual-network hydrogel loaded with gentamicin sulfate (GS) based on sodium alginate oxide (OSA) and glycidyl methacrylate gelatin (GelGMA) was designed through the Schiff base bonding and photo-crosslinking to promote the diabetic wound healing. The hydrogels exhibited stable mechanical properties, high water absorbency, and good biocompatibility and biodegradability. Antibacterial results showed that gentamicin sulfate (GS) had a remarkable antibacterial effect on Staphylococcus aureus and Escherichia coli. In a diabetic full-thickness skin wound model, the GelGMA-OSA@GS hydrogel dressing dramatically decreases inflammation and accelerated re-epithelialization and granulation tissue formation, promising applications in promoting diabetic wound healing.

Dummy-template Pickering emulsion imprinted microspheres online pretreatment and analysis for the estrogens in cosmetics.

Estrogens are a class of steroid hormone with strong physiological activity. Due to the pronounced beauty effect, such drugs are highly susceptible to illegal addition and cause other adverse effects. To avoid template leakage and the negative impacts on the environment caused by the estrogens, diosgenin was selected as the dummy template due to its similar skeleton structure. The Pickering emulsion polymerization was used to obtain the dummy-template molecularly imprinted polymers (dt-MIPs). Scanning electron microscopy, optical microscopy, specific surface area testing, Fourier transform infrared spectroscopy and adsorption experiments were used to characterize the apparent morphology and the recognition performance of the microspheres. Then, the prepared microspheres and commercial fillers were used to construct an on-line solid phase extraction (on-line SPE) analytical system coupled with HPLC via a two-position switching valve. On-line solid phase extraction-HPLC analytical methods were established and verified, for the simultaneous determination of four estrogens in cosmetic samples. The accuracy and precision RSDs for the established methods using the imprinted sorbents were 92.00-104.02% and less than 9.12%, respectively. All four estrogens exhibited good linearity in the range of 0.05 to 5 µg/mL with a coefficient of determination R2 greater than 0.9810. The method comparison results suggest that the established analytical method is simple in pre-treatment, easy to automate, and has excellent sensitivity to meet the analytical requirements of complex samples.

Novel Green Fluorescent Probe Stem From Carbon Quantum Dots for Specific Recognition of Tyrosinase in Serum and Living Cells.

Tyrosinase (TYR), an important biomarker for melanoma, offered significant information early detection of melanoma and may decrease the likelihood of mortality. Therefore, this article constructed a highly sensitive and selective green fluorescent functionalized carbon quantum dots (TYR-CQDs) for tyrosinase (TYR) activity detection by one-step hydrothermal protocol utilizing catechol, citric acid and urea as precursors. The prepared TYR-CQDs illustrated excellent linear relationship and broad linear range with a low detection limit, which exhibited high accuracy and recovery in quantitative determination of TYR in human serum samples. Furthermore, the TYR-CQDs had successfully realized intracellular TYR detection owing to excellent biocompatibility, high anti-interference ability and good cellular imaging capability, suggesting the potential biomedical applications in early diagnosis of melanoma and other tyrosinase-related diseases.

Thermosensitive molecularly imprinted polymer coupled with HPLC for selective enrichment and determination of matrine in traditional Chinese medicine.

In this study, a temperature-sensitive molecularly imprinted polymer was prepared by using the bifunctional monomer with the critical phase transition characteristics. Infrared spectrometry, scanning electron microscopy, and specific surface area testing were used to characterize the polymers. Then, the recognizing properties of the polymers were studied. Based on the prepared smart polymers, an SPE-HPLC analytical method for the determination of quinolizidine alkaloids in the extracts of Sophora flavescens was established and verified. Finally, the smart polymers were applied to the enrichment of quinolizidine alkaloids in plant extracts. By changing the temperature and solvents of the solid phase extraction conditions, the extraction process can increase the concentration of quinolizidine alkaloids by 4.3 to 5.2 folds. The extraction process has mild conditions and less time consumption, avoiding the use of a large number of toxic reagents, which indicate that the extraction process are more efficient and environmentally friendly.

Biocompatible sulfur nitrogen co-doped carbon quantum dots for highly sensitive and selective detection of dopamine.

In this work, sulfur and nitrogen co-doped carbon quantum dots (S,N-CQDs) were prepared via one-pot hydrothermal treatment of EDTA disodium and sodium sulfide. The prepared S,N-CQDs were characterized by TEM, XRD, FT-IR, XPS, UV-vis absorption and fluorescence spectra to characterize their morphology, crystal structure, functional groups, elemental composition, and optical properties. It was found that S and N elements were successfully doped into the CQDs and the morphology was approximately spherical with an average particle size of 2.16 nm, in which the excitation/emission wavelengths were 350 and 420 nm, respectively. Compared with single element doped CQDs, double element doped CQDs have a higher quantum yield and excellent optical stability. Cell experiments showed that S,N-CQDs had good biocompatibility because they had no obvious toxicity on both normal cell lines and cancer cell lines. More importantly, based on the synergy of static quenching and dynamic quenching, the S,N-CQDs were used as effective fluorescent probes for sensitive detection of DA, with high anti-interference and low limit of detection. Based on the good biocompatibility of S,N-CQDs, the detection of dopamine in actual serum samples were carried out and the results showed an excellent recovery rate. Therefore, this work provides a dopamine sensor with a practical application prospect.

The toxicity mechanism of different sized iron nanoparticles on human breast cancer (MCF7) cells.

The toxicity mechanism of superparamagnetic iron oxide nanoparticles (SPIONs) were examined multidimensionally to reduce the toxicity risks. A higher dosage and more suitable size of SPIONs enhanced the uptake amount into MCF7 cells, leading to a higher specific uptake rate of SPIONs with the formation of more reactive oxygen species (ROS). ROS was an intrinsic factor of cell death. Interestingly, the smaller SPIONs (S1) liked to produce more ROS in mitochondria to damage mitochondria, while the larger SPIONs (S2 and S3) promoted ROS yield in plasma to destroy cytomembrane. Furthermore, ROS synthesis pathways were the partial of cell death pathways, and ferroptosis pathway was the main contributor to mitochondrial and cytomembrane damage. Meanwhile, ROS amount was well coincided to gene expression level of these cell death pathways, which inferred RNA-seq might be a new method to evaluate the oxidative stress and potential toxicity of nanomaterials.

Fluorescent recognition and selective detection of nitrite ions with carbon quantum dots.

The nitrite ion (NO2-) is a vital inorganic species that occurs both in natural ecological systems and human bodies. The high concentration of NO2- can be harmful for animal and human health. It is important to develop a simple, sensitive, reliable, and economic methodology to precisely monitor NO2- in various environmental and biological fields. Thus, a novel nitrite biosensor based on carbon quantum dots (PA-CDs) has been constructed and prepared via a high-efficiency, one-pot hydrothermal route using primary arylamines (PA) such as m-phenylenediamine. The device exhibits bright green fluorescence and a high quantum yield of 20.1% in water. In addition, the PA-CDs also possess two broad linear ranges: 0.05-1.0 µM and 1.0-50 µM with a low detection limit of 7.1 nM. The classical diazo reaction is firstly integrated into the PA-CD system by primary arylamines, which endows the system with high sensitivity and specific selectivity towards nitrite. Importantly, the nanosensor can detect NO2- in environmental water and serum samples with high fluorescence recoveries, demonstrating its feasibility in practical applications. This work broadens a new method to fabricate novel nanosensors and provides a prospective application for fluorescent carbon quantum dots (CDs). Graphical abstract.

A Probe for Fluorescence Detection of the Acetylcholinesterase Activity Based on Molecularly Imprinted Polymers Coated Carbon Dots.

This paper presents a new probe for fluorescence detection of the acetylcholinesterase (AChE) activity based on molecularly imprinted polymer (MIP) coated carbon dots (C-dots) composite. The C-dots were hydrothermally synthesized with grafted silica surface and sealed with molecularly imprinted polymers in silica pores (MIP@C-dots) in situ. Removed the original template molecules, the MIP@C-dots composite exhibits quite high selectivity for acetylthiocholine (ACh). With AChE, its substrate ACh will be hydrolyzed into thiocholine and the fluorescence signals exhibit a dramatic decrease at 465 nm, Under optimal conditions, the fluorescent probe shows sensitive responses to AChE in the range of 0.01-0.6 mU/mL. The detection limits of AChE are as low as 3 µU/mL. These experiments results validate the novel fluorescent probe based on MIP@C-dots composite, paving a new way to evaluation of AChE activity and Screening inhibitors.

Fabrication of Konjac glucomannan-based composite hydrogel crosslinked by calcium hydroxide for promising lacrimal plugging purpose.

Swelling, mechanical strength, flexibility, and toughness are important parameters in hydrogel preparation for application in the human body. Herein, composite hydrogels were prepared using a mix of Konjac glucomannan (KGM), sodium alginate (SA), and polyvinyl alcohol (PVA) cross-linked by calcium hydroxide. The PVA/KGM/SA composite hydrogel showed a suitable swelling ratio and rate, as well as elasticity and flexibility. In addition, the elongation at break was 660.3%, with a breaking strength of 87.25 kPa and a compression modulus of 1.660 MPa. Rheological studies showed that the composite hydrogel was composed of a multiply cross-linked network involving chemical and physical interactions, thereby affecting the elasticity and flexibility of the gel. Interestingly, the composite gel network was reformed when the temperature decreased. In rabbit models of dry eye, the hydrogel effectively maintained the normal tear meniscus height and increased the low tear meniscus area. The results therefore showed that the PVA/KGM/SA gels not only provide a simple, effective, and safe method for the preparation of hydrogels, but also have potential applications in the treatment of dry eye syndrome.

Effects of core size and PEG coating layer of iron oxide nanoparticles on the distribution and metabolism in mice.

INTRODUCTION: In vivo distribution of polyethylene glycol (PEG)ylated functional nanoparticles is vital for determining their imaging function and therapeutic efficacy in nanomedicine. However, contradictory results have been reported regarding the effect of core size and PEG surface of the nanoparticles on biodistribution. METHODS: To clarify this ambiguous understanding, using iron oxide nanoparticles (IONPs) as a model system, we investigated the effect of core size and PEG molecule weights on in vivo distribution in mice. Three PEGylated IONPs, including 14 nm IONP@PEG2,000, 14 nm IONP@PEG5,000, and 22 nm IONP@PEG5,000, were prepared with a hydrodynamic size of 26, 34, and 81 nm, respectively. The blood pharmacokinetics and tissue distribution were investigated in detail. RESULTS: The results indicated that the PEG layer, rather than core size, played a dominant role in determining the half-life time of IONPs. Specifically, increased molecular weight of the PEG layer led to a longer half-life time. These PEGylated IONPs were mainly excreted by liver clearance. While the PEG molecular layer constituted the key factor to determine the clearance ratio, core size affected the clearance rate. CONCLUSION: Complete blood count analysis and histopathology suggested excellent biocompatibility of PEGylated IONPs for future clinical trials.

AMF responsive DOX-loaded magnetic microspheres: transmembrane drug release mechanism and multimodality postsurgical treatment of breast cancer.

DOX-loaded magnetic alginate-chitosan microspheres (DM-ACMSs) were developed as a model system to evaluate alternating magnetic field (AMF)-responsive, chemo-thermal synergistic therapy for multimodality postsurgical treatment of breast cancer. This multimodality function can be achieved by the combination of DOX for chemotherapy, with superparamagnetic iron oxide nanoparticles (SPIONs) as magnetic hyperthermia agents and drug release trigger. Both moieties are encapsulated in ACMSs which also allow on-demand drug release. It is demonstrated that the optimized SPION content in DM-ACMSs is about 0.29 mg Fe, at which DM-ACMSs could exhibit the best hyperthermia performance. Under a remote AMF, DM-ACMs can quickly reach a 22.5% cumulative drug release in the tumor site within 10 min upon exposure under AMF, whereas only 0.2% DOX is released in the absence of AMF. Furthermore, a comparison study of AMF and water bath as heating source indicates that the cumulative drug release amount upon AMF exposure is twice that by water bath heating. Further analysis revealed that the AMF stimulated drug release is driven by both thermal and concentration gradient from inside to outside, which can be well-described by the coupling mechanism of mass and heat transfer using the Soret diffusion model. In vitro cytotoxicity tests on MCF-7 breast cancer cells show that the combined therapy based on DM-ACMSs leads to 95.5% cell death, about 1.5-fold and 1.1-fold higher than that of single magnetic hyperthermia or chemotherapy, respectively. The in vivo anti-tumor effect on tumor-bearing mice demonstrates that the residual tumor disappears in 12 days after chemo-thermal synergistic treatment using DM-ACMSs, and there is no recurrence in the entire experiment period (40 days) as compared to 25 days recurrence for single-modality treatment. Our results not only provide an innovative DM-ACMSs system as a stimuli-responsive, synergistic chemo-thermal therapy platform for efficient reduction in the recurrence of breast cancer, but also provide insight into the intricate interplay of the functional components in magnetic hydrogel microspheres.

Enhancement of membrane stability on magnetic responsive hydrogel microcapsules for potential on-demand cell separation.

It is of high interest to obtain hydrogel membranes with optimum mechanical stability, which is a prerequisite to the successful fabrication of hydrogel microcapsules for cell separation. In this work, we developed magnetic responsive alginate/chitosan (MAC) hydrogel microcapsules by co-encapsulation of microbial cells and superparamagnetic iron oxide nanoparticles (SPIONs) reacting under a high voltage electrostatic field. We investigated the influence of the molecular weight of chitosan, microcapsules size, and membrane crosslinking time on the swelling behavior of microcapsules as an indicator of stability of the membranes. The results demonstrated that the suitable membrane stability conditions were obtained by a crosslinking of the microspheres with a chitosan presenting a molecular weight of 70kDa for 15-30min resulting in a membrane thickness of approximately 30mm. Considering the need of maintaining the cells inside the microcapsules, fermentation at 37°C and at neutral pH was favorable. Moreover, the MAC microcapsules sizing between 300 and 380µm were suitable for immobilizing Bacillus licheniformis in a 286h multiple fed-bath operation with no leakage of the SPIONs and cells. Overall, the results of this study provided strategies for the rational design of magnetic microcapsules exhibiting suitable mechanical stable membranes.

Lipid nanoparticles for hepatic delivery of small interfering RNA.

Clinical application of small interfering RNA (siRNA) requires safe and efficient delivery in vivo. Here, we report the design and synthesis of lipid nanoparticles (LNPs) for siRNA delivery based on cationic lipids with multiple tertiary amines and hydrophobic linoleyl chains. LNPs incorporating the lipid containing tris(2-aminoethyl)amine (TREN) and 3 linoleyl chains, termed TRENL3, were found to have exceptionally high siRNA transfection efficacy that was markedly superior to lipofectamine, a commercial transfection agent. In addition, inclusion of polyunsaturated fatty acids, such as linoleic acid and linolenic acid in the formulation further enhanced the siRNA delivery efficiency. TRENL3 LNPs were further shown to transport siRNA into the cytosol primarily via macropinocytosis rather than clathrin-mediated endocytosis. The new LNPs have demonstrated preferential uptake by the liver and hepatocellular carcinoma in mice, thereby leading to high siRNA gene-silencing activity. These data suggest potential therapeutic applications of TRENL3 mediated delivery of siRNA for liver diseases.