Potential of an Amphiphilic Artificial Corneal Endothelial Layer as a Replacement Option for Damaged Corneal Endothelium.

Bullous keratopathy, a condition severely impacting vision and potentially leading to corneal blindness, necessitates corneal transplantation. However, the shortage of donor corneas and complex surgical procedures drive the exploration of tissue-engineered corneal endothelial layers. This study develops a transparent, amphiphilic, and cell-free membrane for corneal endothelial replacement. The membrane, securely attached to the posterior surface of the cornea, is created by mixing hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethylacrylate (EGDMA) in a 10:1 ratio. A 50 µL volume is used to obtain a 60 µm hydrophobic membrane on both sides, with one side treated with a polyvinylpyrrolidone (PVP) solution. The resulting membrane is transparent, foldable, biocompatible, amphiphilic, and easily handled. When exposed to 20% sulfur hexafluoride (SF6), the hydrophilic side of the membrane adheres tightly to the corneal Descemet's membrane, preventing water absorption into the corneal stroma, and thus treating bullous keratopathy. Histological test confirms its effectiveness, showing normal corneal structure and low inflammation when implanted in rabbits for up to 100 d. This study showcases the potential of this membrane as a viable option for corneal endothelial replacement, offering a novel approach to address donor tissue scarcity in corneal transplantation.

Effects of different drugs in combination with PKP/PVP on postoperative pain in patients with osteoporotic compression fractures: a network meta-analysis.

Objective: This study was designed to evaluate the postoperative pain effect and clinical efficacy of different drugs combined with PKP or PVP in treating osteoporotic vertebral compression fractures (OVCFs) through a systematic review and network meta-analysis. Methods: We searched five electronic databases, namely, MEDLINE (PubMed), EMBASE, Web of Science, Google Scholar, and the Cochrane Central Register of Controlled Trials online, for the treatment of OVCFs through March 2023 with keywords zoledronic acid (ZOL), teriparatide (TPTD or PTH 1-34), and calcitonin (CT) combined with PKP/PVP. The visual analog scale (VAS) and Oswestry Disability Index (ODI) were the primary outcomes of the network meta-analysis, and the secondary outcome was the diagnostic marker bone mineral density (BMD). Results: Eighteen studies involving 2,374 patients were included in this study. The network meta-analysis revealed that, in terms of reducing VAS scores, compared with PVP surgery alone, PVP combined with TPTD was most likely to be the treatment associated with the greatest pain relief [MD = -4.99, 95% CI = (-7.45, -2.52)]. In terms of reducing the ODI dysfunction score, compared with PKP combined with Cal, PKP combined with ZOL had the highest probability of being the best treatment option [MD = -9.11, 95% CI = (-14.27, -3.95)]. In terms of protecting against bone density loss, compared with PKP surgery alone, treatment with PKP combined with ZOL had the best effect [MD = 0.39, 95% CI = (0.13,0.65)]. Conclusions: Based on the network meta-analysis and SUCRA rankings, this study concluded that adding teriparatide has the advantage of reducing VAS pain scores compared with PVP alone and that adding zoledronate is a more effective treatment for reducing ODI scores compared with PKP combined with Cal and preserving BMD compared with PKP alone. However, additional high-quality studies are needed to verify our findings. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=358445, identifier CRD42022358445.

Tailoring ZnS nanostructures through precipitation-cum-hydrothermal synthesis for enhanced wastewater purification and antibacterial treatment.

This study presents a novel blend of synthesis techniques for shape-controlled ZnS nanoparticles. Zinc sulfide (ZnS) nanoparticles with distinct morphologies cauliflower-like microstructures (∼4.5 µm) and uniform nanospheres (200-700 nm) were synthesized through an innovative blend of precipitation and hydrothermal techniques. Capping with polyvinylpyrrolidone (PVP) significantly decreased crystallite size (3.93 nm-2.36 nm), modulated the band gap (3.57 eV-3.71 eV), and dramatically influenced morphology, highlighting the novelty of shape-controlled synthesis and its impact on optoelectronic and functional properties. X-ray diffraction confirmed crystallinity and revealed the size-controlling influence of PVP. UV-vis spectroscopy suggested potential tuning of optical properties due to band gap widening upon PVP capping. Field-emission scanning electron microscopy (FESEM) unveiled distinct morphologies: cauliflower-like microstructures for ZnS and uniform nanospheres (200-700 nm) for PVP-ZnS. Both structures were composed of smaller spherical nanoparticles, demonstrating the role of PVP in promoting controlled growth and preventing agglomeration. High-resolution transmission electron microscope (HRTEM) images depicted that the majority of nanoparticles maintain a spherical shape, though slight deviations from perfect sphericity can be discerned. Fourier-transform infrared (FTIR) spectroscopy confirmed that successful PVP encapsulation is crucial for shaping nanospheres and minimizing aggregation through steric hindrance. Photocatalytic activity evaluation using methylene blue (MB) dye degradation revealed significantly faster degradation by PVP-ZnS under ultraviolet (UV) irradiation (within 60 min as compared to 120 min for ZnS), showcasing its superior performance. This improvement can be attributed to the smaller size, higher surface area, and potentially optimized band gap of PVP-ZnS. Additionally, PVP-ZnS exhibited promising antibacterial activity against S. aureus and P. aeruginosa, with increased activity at higher nanoparticle concentrations.

Study of the Incorporation of Gel and Aloe vera Peel Extract in a Polymer Matrix Based on Polyvinylpyrrolidone.

The development of dressings based on electrospun membranes with polymers and plant extracts is an interesting approach to skin regeneration, providing elements to prevent contamination and a matrix that accelerates the healing process. We developed a membrane composed of polyvinylpyrrolidone (PVP), gel and Aloe vera peel extract via the electrospinning technique. Additionally, an optimal ratio of PVP/Av gel/Av skin extract was determined to facilitate membrane formation. Electrospun membranes were obtained with fiber diameters of 1403 ± 57.4 nm for the PVP and 189.2 ± 11.4 nm for PVP/Av gel/Av peel extract, confirming that the use of extracts generally reduced the fiber diameter. The incorporation of gel and peel extract of Aloe vera into the electrospun membrane was analyzed via FTIR and UV-Vis spectroscopies. FTIR revealed the presence of functional groups associated with phenolic compounds such as aloin, aloe-emodin, emodin and aloesin, which was confirmed by UV-Vis, revealing absorption bands corresponding to aloin, phenols and carbonyl groups. This finding provides evidence of the effective integration and prevalence of bioactive compounds of a phenolic and polysaccharide nature from the gel and the Av skin extract in the electrospun fibers, resulting in an advanced membrane that could improve and accelerate the healing process and protect the wound from bacterial infections.

Poly-vinyl-pyrrolidone capped luminescent zinc oxide nanocomposites as excellent tools for germicidal and photo-catalytic performances.

Alternate antibiotics developed through the involvement of nanomaterials are gaining interest due to their economical and lower toxicity concerns. A newly developed biopolymer-based polyvinylpyrrolidone/zinc oxide (PVP/ZnO) nanocomposite (NCs) was efficiently synthesized by an environment-friendly approach, utilizing onion and garlic peel extract as a bio-surfactant, zinc acetate as the source, PVP as the stabilizing agent, and sodium hydroxide as the precipitant. Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD) investigations verified the crystalline properties of ZnO, PVP, and PVP/ZnO-based NCs. The structure of the biopolymer-linked ZnO particles interpolated inside the PVP array was seen to have a layered and flaky structure, as validated by field emission scanning electron microscopy (FE-SEM) analysis, which revealed its occurrence in the nanometer range. The XRD examination verified that the surface topographical image of PVP/ZnO NCs had an average thickness of 21 nm. The PVP/ZnO nanocrystals demonstrated exceptional photocatalytic efficacy, with a breakdown rate of 88% and almost 92% for the methylene blue dye. Therefore, the PVP/ZnO matrix exhibits superior antibacterial activity compared to other extracts, resulting in greater microbial suppression. The results above indicate that the ZnO-intercalated PVP array has a stronger reinforcing effect than other components. Hence, PVP/ZnO nanocrystals exhibit enormous potential as a favorable substance for environmental and biomedical intentions.

"Five-Step" Vaporization of the Prostate Using 180-W XPS Greenlight Laser in Patients with Benign Prostatic Hyperplasia of Large Volume: Improved Efficacy and Safety.

Objective: To evaluate the safety and efficacy of 180-W XPS Greenlight laser "Five-step" photoselective vaporization of the prostate (PVP) in patients with benign prostatic hyperplasia (BPH) with prostate volume (PV) > 80 mL. Background: In patients with BPH with large PV, PVP often results in bleeding, unclear visual field, additional damage, and insufficient tissue vaporization. Methods: This single-center, retrospective study enrolled patients with BPH with PV > 80 mL treated with the Five-step PVP or the Conventional PVP from January 2018 to June 2021. Comorbidities, high-risk habits, and operative parameters were analyzed and compared. The short-term functional outcomes and postoperative complications were recorded over the 24-month follow-up. Results: Two hundred eligible patients were divided into the Five-step PVP and Conventional PVP groups (n = 100 each). These groups showed no differences in comorbidities, living habits, baseline perioperative parameters, operative time, lasing time, or energy use. However, a higher energy density (3.95 [interquartile range (IQR) 3.37, 4.52] vs 3.68 [IQR 3.17, 4.20] kJ/mL) and energy-time ratio (7.23 [IQR 6.12, 8.52] vs 6.72 [IQR 5.51, 7.87] kj/min p = 0.034) were obtained in the Five-step PVP group. Subgroup analysis of patients with PV ≥120 mL showed similar results. The short-term functional outcomes were similar between the two study groups with significant improvement from baseline, but the total prostate-specific antigen levels at 1 and 6 months were lower in the Five-step PVP group. Further, incidences of intraoperative bleeding, bladder mucosa injury, postoperative hematuria, and urinary tract infection were lower in the Five-step PVP group. In the Conventional PVP group, four patients required conversion to transurethral resection of the prostate in surgery and two patients required retreatment during the 24-month follow-up. Conclusions: The 180-W XPS Greenlight laser Five-step PVP has advantages of less bleeding, high vaporization efficiency, and low rates of perioperative complications, and, therefore, it is a promising treatment to improve short-term functional outcomes for patients with BPH with large PV.

A proof of concept model to calculate white and grey matter AIS injuries in pedestrian collisions.

In the real world, the severity of traumatic injuries is measured using the Abbreviated Injury Scale (AIS) and is often estimated, in finite element human computer models, with the maximum principal strains (MPS) tensor. MPS can predict when a serious injury is reached, but cannot provide any AIS measures lower and higher from this. To overcome these limitations, a new organ trauma model (OTM2), capable of calculating the threat to life of any organ injured, is proposed. The OTM2 model uses a power method, namely peak virtual power, and defines brain white and grey matters trauma responses. It includes human age effect (volume and stiffness), localised impact contact stiffness and provides injury severity adjustments for haemorrhaging. The focus, in this case, is on real-world pedestrian brain injuries. OTM2 model was tested against three real-life pedestrian accidents and has proven to reasonably predict the post mortem (PM) outcome. Its AIS predictions are closer to the real-world injury severity than the standard maximum principal strain (MPS) methods currently used. This proof of concept suggests that OTM2 has the potential to improve forensic predictions as well as contribute to the improvement in vehicle safety design through the ability to measure injury severity. This study concludes that future advances in trauma computing would require the development of a brain model that could predict haemorrhaging.

Safety Assessment of Vinylpyrrolidone Polymers as Used in Cosmetics.

The Expert Panel for Cosmetic Ingredient Safety (Panel) reviewed the safety of 30 vinylpyrrolidone polymers as used in cosmetic products; most of these ingredients have the reported cosmetic function of film former in common. The Panel reviewed data relevant to the safety of these ingredients, and determined that 27 vinylpyrrolidone polymers are safe in cosmetics in the present practices of use and concentration described in the safety assessment. The Panel also concluded that the available data are insufficient to make a determination that 3 vinylpyrrolidone polymers (all urethanes) are safe under the intended conditions of use in cosmetic formulations.

Nanofibrous Conductive Sensor for Limonene: One-Step Synthesis via Electrospinning and Molecular Imprinting.

Detecting volatile organic compounds (VOCs) emitted from different plant species and their organs can provide valuable information about plant health and environmental factors that affect them. For example, limonene emission can be a biomarker to monitor plant health and detect stress. Traditional methods for VOC detection encounter challenges, prompting the proposal of novel approaches. In this study, we proposed integrating electrospinning, molecular imprinting, and conductive nanofibers to fabricate limonene sensors. In detail, polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) served here as fiber and cavity formers, respectively, with multiwalled carbon nanotubes (MWCNT) enhancing conductivity. We developed one-step monolithic molecularly imprinted fibers, where S(-)-limonene was the target molecule, using an electrospinning technique. The functional cavities were fixed using the UV curing method, followed by a target molecule washing. This procedure enabled the creation of recognition sites for limonene within the nanofiber matrix, enhancing sensor performance and streamlining manufacturing. Humidity was crucial for sensor working, with optimal conditions at about 50% RH. The sensors rapidly responded to S(-)-limonene, reaching a plateau within 200 s. Enhancing fiber density improved sensor performance, resulting in a lower limit of detection (LOD) of 137 ppb. However, excessive fiber density decreased accessibility to active sites, thus reducing sensitivity. Remarkably, the thinnest mat on the fibrous sensors created provided the highest selectivity to limonene (Selectivity Index: 72%) compared with other VOCs, such as EtOH (used as a solvent in nanofiber development), aromatic compounds (toluene), and two other monoterpenes (α-pinene and linalool) with similar structures. These findings underscored the potential of the proposed integrated approach for selective VOC detection in applications such as precision agriculture and environmental monitoring.

Effect of saline perfusion before catheter removal in patients with BPH treated with GreenLight laser photoselective vaporization of the prostate.

OBJECTIVE: To investigate the effect of saline perfusion before catheter removal in patients with benign prostatic hyperplasia (BPH) treated with GreenLight laser photoselective vaporization of the prostate (PVP). MATERIALS AND METHODS: Patients (n=200) with BPH treated with PVP were divided into perfusion (n=100) and control (n=100) groups. For the perfusion group, saline (200 mL or the maximum capacity tolerated) was irrigated into the bladder after standardized external urethral disinfection, and the catheter was removed. Catheter removal was routinely performed in the control group. Perioperative adverse events and clinical outcomes were compared between the groups. RESULTS: Patients in the perfusion group had a shorter waiting time [3 (0-4) vs. 15 (8.75-26) min; P<0.001] and a better satisfaction grade [24 (21.75-26) vs. 23 (20-25); P=0.016] for first urination than those in the control group. The perfusion group exhibited lower anxiety levels regarding first urination than the control group [1 (1-2) vs. 1.5 (1-2), respectively; P=0.012]. Urinalysis revealed that the perfusion group had significantly lower white blood cell (WBC) count than the control group on the day [25.5 (8-37.75) vs. 43.5 (24.0-64.75); P<0.001] and 2 weeks [20.5 (11-27) vs. 31.0 (20-42); P<0.001] after catheter removal. No significant differences in treatment-related adverse events were observed [perfusion (n=15), control (n=20)]. CONCLUSION: Saline perfusion before catheter removal in patients with BPH treated with PVP could shorten the waiting time for first urination, improve patient anxiety and satisfaction and reduce postoperative urinary WBC levels.

Fabrication of bacterial cellulose/PVP nanofiber composites by electrospinning.

This study aimed to address a significant challenge in the application of bacterial cellulose (BC) within tissue engineering and regenerative medicine by tackling its inherent insolubility in water and organic solvents. Our team introduced a groundbreaking approach by utilizing zinc sulfate (ZnSO4) as a solvent to render BC soluble, a novel contribution to the literature. Subsequently, the obtained soluble BC was combined with varying concentrations of polyvinylpyrrolidone (PVP). Notably, we pioneered the fabrication of BC/PVP composite scaffolds with customizable fiber surface morphology and regulated degradation rates through the electrospun technique. Several key parameters, such as PVP concentration (8%, 15%, 12%, and 20% w/v), applied voltage (22, 15, and 12 kV), and a fixed nozzle-collector distance of 10 cm with a flow rate of 0.9 mL/h, were systematically evaluated so as to find the optimum parameter created BC/PVP product with electrospun. For electrospun BC/PVP products, a voltage of 12 kV was found to be optimal. Intriguingly, our findings revealed enhanced cell adhesion and proliferation in BC/PVP electrospun products compared with using PVP membranes alone. Specifically, cell viability for PVP and PVP/BC electrospun products was determined as 50.73% and 79.95%, respectively. In terms of thermal properties, the BC/PVP electrospun product exhibited a mass loss of 82.6% at 380°C, while PVP alone experienced 90.2% mass loss at around 280°C. Furthermore, the protein adhesion capacities were measured at 62.3 ± 1.2 µg for PVP and 99.4 ± 2 µg for BC/PVP electrospun products, whereas product showed no biodegradation over 28 days and had notable water retention capacity. In conclusion, our research not only successfully attained nanofiber morphology but also showcased enhanced cell attachment and proliferation on the BC/PVP electrospun product.

Dissolving microarray patches for transdermal delivery of risperidone for schizophrenia management.

Schizophrenia is a psychiatric disorder that results from abnormal levels of neurotransmitters in the brain. Risperidone (RIS) is a common drug prescribed for the treatment of schizophrenia. RIS is a hydrophobic drug that is typically administered orally or intramuscularly. Transdermal drug delivery (TDD) could potentially improve the delivery of RIS. This study focused on the development of RIS nanocrystals (NCs), for the first time, which were incorporated into dissolving microneedle array patches (DMAPs) to facilitate the drug delivery of RIS. RIS NCs were formulated via wet-media milling technique using poly(vinylalcohol) (PVA) as a stabiliser. NCs with particle size of 300 nm were produced and showed an enhanced release profile up to 80 % over 28 days. Ex vivo results showed that 1.16 ± 0.04 mg of RIS was delivered to both the receiver compartment and full-thickness skin from NCs loaded DMAPs compared to 0.75 ± 0.07 mg from bulk RIS DMAPs. In an in vivo study conducted using female Sprague Dawley rats, both RIS and its active metabolite 9-hydroxyrisperidone (9-OH-RIS) were detected in plasma samples for 5 days. In comparison with the oral group, DMAPs improved the overall pharmacokinetic profile in plasma with a âˆ¼ 15 folds higher area under the curve (AUC) value. This work has represented the novel delivery of the antipsychotic drug, RIS, through microneedles. It also offers substantial evidence to support the broader application of MAPs for the transdermal delivery of poorly water-soluble drugs.

Liraglutide alleviated alpha-pyrrolidinovalerophenone (α-PVP) induced cognitive deficits in rats by modifying brain mitochondrial impairment.

The use of NPS compounds is increasing, and impairment in spatial learning and memory is a growing concern. Alpha-pyrrolidinovalerophenone (α-PVP) consumption, as a commonly used NPS, can impair spatial learning and memory via the brain mitochondrial dysfunction mechanism. Liraglutide isone of the most well-known Glucagon-Like Peptide 1 (GLP-1) agonists that is used as an anti-diabetic and anti-obesity drug. According to current research, Liraglutide likely ameliorates cognitive impairment in neurodegenerative conditions and substance use disorders. Hence, the purpose of this study is examining the effect of Liraglutide on α-PVP-induced spatial learning and memory problems due to brain mitochondrial dysfunction. Wistar rats (8 in each group) received α-PVP (20 mg/kg/d for 10 consecutive days, intraperitoneally (I.P.)). Then, Liraglutide was administered at 47 and 94 µg/kg/d, I.P., for 4 weeks following the α-PVP administration. The Morris Water Maze (MWM) task evaluated spatial learning and memory 24 h after Liraglutide treatment. Bedside, brain mitochondrial activity parameters, including reactive oxygen species (ROS) level, mitochondrial membrane potential (MMP), cytochrome c release, mitochondrial outer membrane damage and swelling, and brain ADP/ATP ratio, were studied. Our results showed that Liraglutide ameliorated α-PVP-induced spatial learning and memory impairments through alleviating brain mitochondrial dysfunction (which is indicated by increasing ROS formation, collapsed MMP, mitochondrial outer membrane damage, cytochrome c release, mitochondrial swelling, and increased brain ADP/ATP ratio). This study could be used as a starting point for future studies about the possible role of Liraglutide in ameliorating mitochondrial dysfunction leading to substance use disorder- induced cognitive impairment.

QbD Assisted Systematic Review for Optimizing the Selection of PVP as a Ternary Substance in Enhancing the Complexation Efficiency of Cyclodextrins: a Pilot Study.

Inclusion complexes require higher concentration of Beta cyclodextrins (ßCD) resulting in increased formulation bulk, toxicity, and production costs. This systematic review offers a comprehensive analysis using Quality by design (QbD) as a tool to predict potential applications of Polyvinylpyrrolidone (PVP) as a ternary substance to address issues of inclusion complexes. We reviewed 623 documents from 2013 to 2023 and Eighteen (18) research papers were selected for statistical and meta-analysis using the QbD concept to identify the most critical factors for selecting drugs and effect of PVP on inclusion complexes. The QbD analysis revealed that Molecular weight (MW), Partition coefficient (Log P), and the auxiliary substance ratio directly affected complexation efficiency (CE), thermodynamic stability in terms of Gibbs free energy (ΔG), and percent drug release. However, Stability constant (Ks) remained unaffected by any of these parameters. The results showed that low MW (250), median Log P (6), and a ßCD: PVP ratio of 2:3 would result in higher CE, lower G, and improved drug release. PVP improves drug solubility, enhances delivery and therapeutic outcomes, and counteracts increased drug ionization due to decreased pH. In certain cases, its bulky nature and hydrogen bonding with CD molecules can form non-inclusion complexes. The findings of the study shows that there is potential molecular interaction between PVP and ß-cyclodextrins, which possibly enhances the stability of inclusion complexes for drug with low MW and log P values less than 9. The systematic review shows a comprehensive methodology based on QbD offers a replicable template for future investigations into drug formulation research.

CS/PVP Hydrogel-Based Nanocapillary for Monitoring Bacterial Growth and Rapid Antibiotic Susceptibility Testing.

Infection with drug-resistant bacteria poses a significant threat to human health. Judicious use of antibiotics could reduce the likelihood of bacterial resistance, which can be evaluated through antibiotic susceptibility testing (AST). This paper focuses on the application of a needle-like nanocapillary tip filled with chitosan (CS)/polyethylene pyrrolidone (PVP) hydrogel based on its specific pH-sensitive properties. The gel-filled nanocapillary has the potential to be used for electrical pH detection with a sensitivity of 3.06 nA/pH and a linear range from 7.3 to 4.3. Such sensitivity for pH measurement could be extended for monitoring of bacterial (such as Escherichia coli and Streptococcus salivarius) growth because of the relationship between pH and bacterial growth. Bacterial growth curves obtained using the hydrogel-filled nanocapillary showed good agreement with the OD600 method. Moreover, this device could be applied for rapid AST for tetracycline and norfloxacin on E. coli with minimum inhibitory concentrations of 2 and 0.125 µg/mL, respectively. This study expands the application of the hydrogel-based nanocapillary for bacterial research by monitoring changes in pH values.

Design and development of a soluble PDA-Emodin-PVP-MN patch and its anti-obesity effect in rats.

Emodin has been proven to have weight-reducing and lipid-lowering effects. In order to make emodin play a better anti-obesity role, we designed and developed an emodin loaded dissolving microneedle patch, in which emodin existed in the form of emodin-polyvinylpyrrolidone co-precipitate (Emodin-PVP). Meanwhile, polydopamine (PDA) was added to the microneedle patch (PDA-Emodin-PVP-MN) for photothermal-enhanced chemotherapy of obesity. The average weight of the patch was 0.1 ± 0.05 g and the drug loading was 0.37 ± 0.031 mg. After 5 min of NIR irradiation (808 nm, 0.6 W/cm2), the rat abdominal temperature could reach 48 ℃, and the cumulative release of emodin reached 96.25%. The diffusion coefficient of emodin in the in vitro agar diffusion experiment was 249.27 mm2 h-1. No obvious toxicity was observed in hemolysis test, CCK-8 assay and microscopic histopathological analysis. The patch significantly reduced the percent of body weight ( P < 0.01), lipid-body ratio ( P < 0.001), serum FFAs ( P < 0.01) and the cell volume of peritesticular adipose tissue in the high-fat diet induced obese rats, indicating the patch had good anti-obesity effect. The mechanism of action may be related to the up-regulation of HSL and LPL protein levels in rat peritesticular adipose tissue.

Self-powered stable high-performance UV-Vis-NIR broadband photodetector based on PVP-Cobalt@Carbon nanofibers/n-GaAs heterojunction.

The self-powered PVP-Co@C nanofibers/n-GaAs heterojunction photodetector (HJPD) was fabricated by electrospinning of the nanofibers onto GaAs. An excellent rectification ratio of 6.60 × 106was obtained fromI-Vmeasurements of the device in the dark. TheI-Vmeasurements of the fabricated device under 365 nm, 395 nm and 850 nm lights, as well asI-Vmeasurements in visible light depending on the light intensity, were performed. The HJPD demonstrated excellent photodetection performance in terms of a good responsivity of âˆ¼225 mA W-1(at -1.72 V) and at zero bias, an impressive detectivity of 6.28 × 1012Jones, and a high on/off ratio of 8.38 × 105, all at 365 nm wavelength. In addition, the maximum external quantum efficiency and NPDR values were 3495% (V = -1.72 V) and 2.60 × 1010W-1(V= 0.0 V), respectively, while the minimum NEP value was ∼10-14W.Hz-1/2for 365 nm atV= 0.V volts. The HJPD also exhibited good long-term stability in air after 30 d without any encapsulation.

Structural, Optical and Dielectric Properties of Some Nanocomposites Derived from Copper Oxide Nanoparticles Embedded in Poly(vinylpyrrolidone) Matrix.

Polymer nanocomposite films based on poly(vinyl pyrrolidone) incorporated with different amounts of copper oxide (CuO) nanoparticles were prepared by the solution casting technique. The PVP/CuO nanocomposites were analyzed by X-ray diffractometry (XRD), scanning electron microscopy, UV-Visible absorption spectroscopy and dielectric spectroscopy. The XRD analysis showed that the monoclinic structure of cupric oxide was maintained in the PVP host matrix. The key optical parameters, such as optical energy gap Eg, Urbach energy EU, absorption coefficient and refractive index, were estimated based on the UV-Vis data. The optical characteristics of the nanocomposite films revealed that their transmittance and absorption were influenced by the addition of CuO nanoparticles in the PVP matrix. Incorporation of CuO nanoparticles into the PVP matrix led to a significant decrease in band gap energy and an increase in the refractive index. The dielectric and electrical behaviors of the PVP/CuO nanocomposites were analyzed over a frequency range between 10 Hz and 1 MHz. The effect of CuO loading on the dielectric parameters (dielectric constant and dielectric loss) of the metal oxide nanocomposites was also discussed.

Nanomaterials-incorporated polymeric microneedles for wound healing applications.

There is a growing and urgent need for developing novel biomaterials and therapeutic approaches for efficient wound healing. Microneedles (MNs), which can penetrate necrotic tissues and biofilm barriers at the wound and deliver active ingredients to the deeper layers in a minimally invasive and painless manner, have stimulated the interests of many researchers in the wound-healing filed. Among various materials, polymeric MNs have received widespread attention due to their abundant material sources, simple and inexpensive manufacturing methods, excellent biocompatibility and adjustable mechanical strength. Meanwhile, due to the unique properties of nanomaterials, the incorporation of nanomaterials can further extend the application range of polymeric MNs to facilitate on-demand drug release and activate specific therapeutic effects in combination with other therapies. In this review, we firstly introduce the current status and challenges of wound healing, and then outline the advantages and classification of MNs. Next, we focus on the manufacturing methods of polymeric MNs and the different raw materials used for their production. Furthermore, we give a summary of polymeric MNs incorporated with several common nanomaterials for chronic wounds healing. Finally, we discuss the several challenges and future prospects of transdermal drug delivery systems using nanomaterials-based polymeric MNs in wound treatment application.

Detection of polyvinylpyrrolidone in Daphnia magna: Development of a refractive index quantification method for water-soluble polymers in aquatic organisms.

The water-soluble polymer polyvinylpyrrolidone (PVP) is an established ingredient in pharmaceutical and personal care product (PPCP) formulations. Due to its high usage and lack of biodegradability, it has been detected up to 7.0 mg L-1 in wastewater and 0.1 mg L-1 in the receiving freshwaters, with several studies showing detrimental sublethal effects in a range of aquatic species. A lack of simple analytical methods to detect and quantify PVP currently impacts further investigation into the cause of these sublethal effects. In this paper we propose a refractive index gel-permeation chromatography (GPC) method to quantify PVP, which includes the processing of raw chromatograms using line deconvolution to calculate peak area. The method was then applied to Daphnia magna exposed to PVP for 48 h. A limit of detection (LOD) and limit of quantification (LOQ) of 0.05 and 0.2 mg mL-1 respectively was determined, with a recovery of 78 % from spiked Daphnia magna. PVP was detected in the samples above the LOD but below the LOQ. This suggests PVP is ingested by Daphnia magna, which warrants further investigation into whether bioaccumulation of PVP could be causing the sublethal effects seen in other studies.