Quantification of steal flow on Doppler ultrasound in patients with arteriovenous graft for hemodialysis.

PURPOSE: Arteriovenous fistula (AVF) is the preferred treatment for long-term hemodialysis patients to allow reliable vascular access. Arteriovenous graft (AVG) is monitored using Doppler sonography to check a vessel's condition and predict complications such as steal syndrome. In this study, we developed an analysis algorithm and method to quantify steal syndrome using Doppler sonography. METHODS: Doppler sonography was used to determine the pattern of anterograde and retrograde flow. The ratio of blood volumes was calculated with a vision analysis software. First, performance of the developed algorithm was validated by comparing it with commercial Doppler sonography data. Doppler sonography was performed for an artificial vessel to analyze the steal flow. RESULTS: A total of 58 patients with steal flow were enrolled in this study. Of these patients, 23 did not have a difference in fingertip temperature between both sides. The median difference in temperature of 35 patients was 0.8°C (range, 0.3-1.9°C). The ratio of retrograde flow volume/antegrade flow volume in patients with the presence of temperature difference was significantly higher compared to that in patients without the temperature difference (p < .001). The ROC curve for the difference in flow volume had an AUC of 0.770. The optimal cutoff of difference in the flow volume between the two groups was 0.24 (sensitivity of 91.4 % and specificity of 52.2%). The flow volume difference was significantly positively correlated to temperature difference (r = 0.487, p < .003). CONCLUSION: Our algorithm could measure steal flow volume of a bidirectional waveform by antegrade arterial flow and retrograde reversal flow.

Nanographene-Au fine-tuning to intensify plasmonic-resonance of polymeric hybrid bionanosystem for synergistic phototherapy and nerve photobiomodulation.

Here, we report the multi-photo-bioactivity of the plasmonic-nano graphitic coordinated polycaprolactone-based aligned nanofibrous scaffolds-based bionanosystem for photothermal breast and colon cancer therapies and peripheral nerve photobiomodulation. The size-optimized colloidal reduced graphene oxide (nRGO, 180 nm) nanosheets, for enhanced photothermal impact, were surface-functionalized with gold nanospheres (AuNPs) to prepare the nRGO@AuNP monodispersed nano-composite and then doped 2.0 mg of nRGO@AuNP in biocompatible and biodegradable polymer polycaprolactone (PCL) to fabricate the nRGO@AuNP-PCL (2.0 mg) plasmonic aligned nanofibrous scaffolds. More than 90% of cancer cells, breast cancer (MCF-7) as well as colon cancer (CT-26), ablated after 5 min of low NIR (808 nm) laser power (0.72 W/cm2) illumination with nRGO@AuNP-PCL (2.0 mg) aligned nanofibrous scaffolds. Besides, the nRGO@AuNP-PCL (2.0 mg) provided an extraordinary microenvironment for adhesion, nerve growth, proliferation, and differentiation of PC12 and S42 cells which mimics the natural extracellular matrix. The 2.5-fold increase in neurite length was observed with NIR illumination after 3 days whereas 1.7-fold was found without NIR illumination after 7 days in comparison to PCL (pure). The current findings will be useful to provide a new crucial approach for preparing biocompatible multifunctional composite plasmonic nanofibers as a highly efficient distinct platform for photothermal therapies and promising bioimplants to overcome the loss of sensation after cancer surgery through nerve photobiomodulation.

Amikacin sulphate loaded chitosan-diopside nanoparticles composite scaffold for infectious wound healing.

A wound dressing material should inhibit infections that may occur at the wound site, and at the same time, it should enhance the healing process. In this study, we developed an amikacin sulphate (AK) incorporated chitosan (Ch) and Diopside nanoparticles composite dressing (Ch-nDE-AK) for controlling wound infection and healing. The diopside nanoparticles (nDE) were prepared using sol-gel synthesis and characterized using XRD, FT-IR, and FESEM. nDE shows a size range of 142 ± 31 nm through FESEM analysis. Later, the developed composite dressing was characterized using SEM, EDS, and FT-IR analysis. Ch-nDE-AK dressing possesses a porous nature that will aid in easy cell infiltration and proliferation. The swelling studies indicated the expansion capability of the scaffold when applied to the injured site. Ch-nDE-AK scaffold showed a 69.6 ± 8.2 % amikacin sulphate release up to 7 days, which indicates the sustained release of the drug from Ch-nDE-AK scaffold. The drug release data was subjected to various kinetics models and was observed to follow the Higuchi model. The scaffold showed antibacterial activity against ATCC strains of S. aureus and E. coli for 7 days by in vitro. Ch-nDE-AK scaffold also showed antibacterial activity against S. aureus and E. coli clinical strains in vitro. The ex vivo antibacterial study confirmed the antibacterial ability of Ch-nDE-AK scaffold against S. aureus and E. coli. Ch-nDE-AK scaffold also exhibits anti-biofilm activity against S. aureus and E. coli. The Ch-nDE-AK scaffold showed cytocompatibility and cell attachment to fibroblast cells. Additionally, the scratch assay using fibroblast cells confirmed the role of the nDE in the scaffold, helping in cell migration. Thus, the developed Ch-nDE-AK dressing can potentially be used to treat infectious wound healing.

Strong intramolecular charge-transfer effect strengthening naphthoquinone-based chemosensor: Experimental and theoretical evaluation.

An aminophenol-linked naphthoquinone-based fluorometric and colorimetric chemosensor 2-chloro-3-((3-hydroxyphenyl) amino) naphthalene-1,4-dione (2CAN-Dione) was synthesized for selective detection of Sn2+ ion in aqueous solution. The amine and conversion of carbonyl into carboxyl groups play a vital role in the sensing mechanism when Sn2+ is added to 2CAN-Dione. Comprehensive characterization of the sensor was carried out using standard spectral and analytical approaches. Because of the intramolecular charge transfer (ICT) effect and the turn-on sensing mode, the strong fluorometric emission towards Sn2+ was observed at about 435 nm. The chemosensor exhibited good selectivity for Sn2+ in the presence of coexisting metal ions. An improved linear connection was established with a low limit of detection (0.167 µM). FT-IR, 1H NMR, 13C NMR, and quantum chemistry methods were performed to verify the binding coordination mechanism. The chemosensing probe 2CAN-Dione was successfully employed in bioimaging investigations, demonstrating that it is a reliable fluorescent marker for Sn2+ in human cancer cells.

Magnetic Hydroxyapatite Composite Nanoparticles for Augmented Differentiation of MC3T3-E1 Cells for Bone Tissue Engineering.

Progressive aging harms bone tissue structure and function and, thus, requires effective therapies focusing on permanent tissue regeneration rather than partial cure, beginning with regenerative medicine. Due to advances in tissue engineering, stimulating osteogenesis with biomimetic nanoparticles to create a regenerative niche has gained attention for its efficacy and cost-effectiveness. In particular, hydroxyapatite (HAP, Ca10(PO4)6(OH)2) has gained significant interest in orthopedic applications as a major inorganic mineral of native bone. Recently, magnetic nanoparticles (MNPs) have also been noted for their multifunctional potential for hyperthermia, MRI contrast agents, drug delivery, and mechanosensitive receptor manipulation to induce cell differentiation, etc. Thus, the present study synthesizes HAP-decorated MNPs (MHAP NPs) via the wet chemical co-precipitation method. Synthesized MHAP NPs were evaluated against the preosteoblast MC3T3-E1 cells towards concentration-dependent cytotoxicity, proliferation, morphology staining, ROS generation, and osteogenic differentiation. The result evidenced that MHAP NPs concentration up to 10 µg/mL was non-toxic even with the time-dependent proliferation studies. As nanoparticle concentration increased, FACS apoptosis assay and ROS data showed a significant rise in apoptosis and ROS generation. The MC3T3-E1 cells cocultured with 5 µg/mL MHAP NPs showed significant osteogenic differentiation potential. Thus, MHAP NPs synthesized with simple wet chemistry could be employed in bone regenerative therapy.

Electroconductive Polythiophene Nanocomposite Fibrous Scaffolds for Enhanced Osteogenic Differentiation via Electrical Stimulation.

Biophysical cues are key distinguishing characteristics that influence tissue development and regeneration, and significant efforts have been made to alter the cellular behavior by means of cell-substrate interactions and external stimuli. Electrically conductive nanofibers are capable of treating bone defects since they closely mimic the fibrillar architecture of the bone matrix and deliver the endogenous and exogenous electric fields required to direct cell activities. Nevertheless, previous studies on conductive polymer-based scaffolds have been limited to polypyrrole, polyaniline, and poly(3,4-ethylenedioxythiophene) (PEDOT). In the present study, chemically synthesized polythiophene nanoparticles (PTh NPs) are incorporated into polycaprolactone (PCL) nanofibers, and subsequent changes in physicochemical, mechanical, and electrical properties are observed in a concentration-dependent manner. In murine preosteoblasts (MC3T3-E1), we examine how substrate properties modified by adding PTh NPs contribute to changes in the cellular behavior, including viability, proliferation, differentiation, and mineralization. Additionally, we determine that external electrical stimulation (ES) mediated by PTh NPs positively affects such osteogenic responses. Together, our results provide insights into polythiophene's potential as an electroconductive composite scaffold material.

Silver nanoparticles decorated reduced graphene oxide: Eco-friendly synthesis, characterization, biological activities and embryo toxicity studies.

This study was aimed on the eco-friendly synthesis of silver nanoparticles (AgNPs), reduced graphene oxide (rGO) and AgNPs decorated rGO (rGO/AgNPs) nanocomposite and appraisal of their bioactivities and toxicity. As-prepared nanomaterials were established through high resolution X-ray diffraction (HR-XRD), high resolution transmission electron microscopy (HR-TEM), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, UV-Vis. spectroscopy and Fourier transform infrared spectroscopy (FT-IR). In this study, leaves extract, graphene oxide (GO) and rGO did not show antibacterial and anticancer activities; no significant embryo toxicity was recorded. On the other hand, AgNPs displayed good antibacterial and anticancer activities; however, higher toxic effects were observed even at the lowest test concentration (0.7 µg/ml). In case of rGO/AgNPs nanocomposite, significant antibacterial activity together with low cytotoxicity was noticed. Interestingly, the embryo toxicity of AgNPs was significantly reduced by rGO, implying the biocompatible nature of as-synthesized nanocomposite. Taken together, these results clearly suggest that rGO/AgNPs nano hybrid composite could be developed as the promising biomaterial for future biomedical applications.

A dual-channel colorimetric and ratiometric fluorescence chemosensor for detection of Hg2+ ion and its bioimaging applications.

A new colorimetric and ratiometric fluorescence chemosensor 4-((3-(octadecylthio)-1,4-dioxo-1,4-dihydronaphthalen-2-yl)amino)benzenesulfonamide (4DBS) was synthesized and investigated for the selective detection of Hg2+ in DMSO-H2O (9:1, v/v) solution. The chemosensor was efficiently synthesized in two steps via Michael-like addition and nucleophilic substitution reactions. The ratiometric fluorescence turn-on response was obtained towards Hg2+, and its fluorescence emission peak was red-shifted by 140 nm with an associated color change from light maroon to pale yellow due to the intramolecular charge transfer effect. The formed coordination metal complex was further evaluated by FT-IR, 1H NMR, and quantum chemical analyses to confirm the binding mechanism. The detection process was sensitive/reversible, and the calculated limit of detection for Hg2+ was 0.451 µM. Furthermore, 4DBS was effectively utilized as a bioimaging agent for detection of Hg2+ in live cells and zebrafish larvae. Additionally, 4DBS showed distinguishing detection of Hg2+ in cancer cells in comparison with normal cells. Thus, 4DBS could be employed as an efficient bioimaging probe for discriminative identification of human cancer cells.

Simple Colorimetric and Fluorescence Chemosensing Probe for Selective Detection of Sn2+ Ions in an Aqueous Solution: Evaluation of the Novel Sensing Mechanism and Its Bioimaging Applications.

An easily accessible colorimetric and fluorescence probe 4-((3-chloro-1,4-dioxo-1,4-dihydronaphthalen-2-yl)amino)benzenesulfonamide (4CBS) was successfully developed for the selective and sensitive detection of Sn2+ in an aqueous solution. The sensing mechanism involves reduction of -C═O into -C-OH groups in 4CBS upon the addition of Sn2+, which initiates the fluorescence turn-on mode. A better linear relationship was achieved between fluorescence intensity and Sn2+ concentration in the range of 0-62.5 µM, with a detection limit (LOD) of 0.115 µM. The binding mechanism of 4CBS for Sn2+ was confirmed by Fourier transform infrared analysis, NMR titrations, and mass (electrospray ionization) spectral analysis. Likewise, the proposed sensing mechanism was supported by quantum chemical calculations. Moreover, bioimaging studies demonstrated that the chemosensing probe 4CBS is an effective fluorescent marker for the detection of Sn2+ in living cells and zebrafish. Significantly, 4CBS was able to discriminate between Sn2+ in human cancer cells and Sn2+ in normal live cells.

Regenerated cellulose nanofiber reinforced chitosan hydrogel scaffolds for bone tissue engineering.

Natural hydrogel scaffolds usually exhibit insufficient mechanical strength which remains a major challenge in bone tissue engineering. In this study, the limitation was addressed by incorporating regenerated cellulose (rCL) nanofibers into chitosan (CS) hydrogel. The rCL nanofibers were regenerated from deacetylation of electrospun cellulose acetate (CA) nanofibers. As-prepared rCL/CS composite scaffold showed unique porous morphology with rCL nanofibers imbibed CS matrix. The compressive strength test exhibited that the rCL/CS scaffold have higher compressive strength compared to pure CS. The rCL/CS scaffold showed increased biomineralization and enhanced pre-osteoblast cell (MC3T3-E1) viability, attachment, and proliferation. The alkaline phosphatase (ALP) and alizarin red (ARS) staining results suggested that the osteogenic differentiation ability was improved in rCL/CS composite scaffold. Hence, the novel fabrication idea and the obtained results suggested that the rCL/CS composite hydrogel scaffolds could be a promising three-dimensional bio-scaffold for bone tissue engineering.

In-situ polymerized polypyrrole nanoparticles immobilized poly(ε-caprolactone) electrospun conductive scaffolds for bone tissue engineering.

Despite intensive attempts to fabricate polypyrrole nanoparticles (PPy-NPs) incorporated nanofibrous scaffolds, a low-cost facile strategy is still demanded. Herein, we developed a novel strategy- in-situ polymerization of PPy-NPs and immobilized them into the PCL polymeric matrix in a single step. For the in-situ polymerization of PPy-NPs, ferric chloride hexahydrate (FeCl3.6H2O) was introduced as an oxidant into the blended solution of PCL and pyrrole monomers. Due to the chemical oxidative polymerization process, the clear solution changed into a black PCL/PPy solution. After electrospinning the solution, PCL/PPy composite nanofibers were fabricated. The immobilization of PPy-NPs into PCL matrix was clearly revealed by Bio-TEM images. The Field emission scanning electron microscopy (FESEM) results exhibited that the PCL/PPy scaffolds showed significantly decreased fiber diameter. The atomic force microscopy (AFM) study showed increased surface roughness in the PCL/PPy scaffolds. The mechanical strength test of PCL/PPy scaffolds showed improved Young's Modulus (YM = 2 to 4-folds) and tensile strength (TS = 3 to 4-folds). As well as the YM and TS were gradually increased with increased concentration of PPy-NPs in composite scaffolds. The conductivity measurement conducted on polymeric solution and electrospun scaffolds showed an increasing trend of conductive property in the PCL/PPy solution and scaffolds too. The surface wettability test exhibited decreased water contact angle measurement from 126° for pure PCL to 93° for the PCL/PPy-200 composite scaffold. The biomineralization test conducted by simulated body fluid (SBF) incubation showed enhanced calcium-phosphate crystal deposition on the PCL/PPy scaffolds. The CCK-8 assay and confocal laser scanning microscopic (CLSM) imaging conducted without and with electrical stimulation (ES) displayed enhanced cell adhesion, growth, and proliferation of MC3T3-E1 cells on the PCL/PPy conductive scaffolds. Furthermore, ALP and ARS staining assays showed significant enhancement of the calcium-phosphate deposition on the PCL/PPy scaffolds after ES treatment. Hence, the current study provides a novel strategy for the fabrication of PCL/PPy conductive scaffolds with enhanced bioactivity, biocompatibility, and osteogenic differentiation under electrical stimulation confirmed its promising application towards bone tissue engineering.

Albumin-induced exfoliation of molybdenum disulfide nanosheets incorporated polycaprolactone/zein composite nanofibers for bone tissue regeneration.

The two-dimensional (2D) nanomaterial incorporated polymeric matrix is being widely used as a promising reinforcement material for next-generation bone tissue engineering application. In this study, the albumin-induced exfoliated 2D MoS2 nanosheets were incorporated into polycaprolactone (PCL)/zein (PZ) composite polymeric network via electrospinning technique, and the PCL/zein/MoS2 (PZM) composite nanofibrous scaffolds were fabricated. The incorporation of different concentrations of MoS2 into PZ composite was evaluated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), mechanical strength (in dry and wet state), and contact angle test. Moreover, the in vitro biocompatibility, cell attachment, and proliferation behavior of the composite scaffolds were evaluated on pre-osteoblasts (MC3T3-E1) cell lines as a model. In addition, biomineral crystal deposition was determined via simulated body fluid (SBF) incubation and Alizarin Red S (ARS) assay. The results showed that the PZM composite nanofibrous scaffold exhibited improved fiber morphology and increased wettability, compared to the PZ. Furthermore, the PZM-0.02 composite nanofibrous scaffold showed improved Young's modulus for both dry and wet state compared to other scaffolds. The in vitro biocompatibility and alkaline phosphatase (ALP) assay showed better cell attachment, proliferation and differentiation on the PZM scaffold over the PZ only. In addition, the in vitro SBF biomineralization and ARS test showed improved calcium-phosphate deposition on the PZM composite scaffold. The overall results suggest that the albumin-induced exfoliated MoS2 nanosheets incorporated PZ polymeric nanofibrous scaffold may be a potential biomaterial for bone tissue engineering application.