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Flexible piezoelectric energy harvesters (PEHs) have attracted extensive interest because of their ability to transform mechanical energy into electric power. Here, PEHs were fabricated using P(VDF-TrFE)-based piezoelectric composite films containing lead zirconate titanate (PZT) powder and –OH-functionalized graphene (HOG) nanosheets (HOG-P/P). Among all composites, a high open-circuit voltage (Voc) of approximately 50 Vp-p and a maximum power density of 1.4 μW/cm2 were obtained from a HOG-P/P PEH with 0.10 wt% HOG nanosheets and 15 wt% PZT under bending–releasing mode. Moreover, the PEH exhibited a stable voltage output after 3000 bending–releasing cycles. In addition, the PEH harvested mechanical energy from human body movements and generated an output voltage and current of 60 V and 8 μA during the finger bending–releasing process, lighting up 30 commercial white LEDs. The enhanced piezoelectric performance can be attributed to the introduction of HOG nanosheets and PZT powder. This work provides an effective strategy for improving the output performance of P(VDF-TrFE)-based PEHs.

Redox-responsive colloidal mesoporous silica nanoparticles (CMS) drug delivery systems based on fluorescence resonance energy transfer (FRET) was successfully designed for targeting and real-time monitoring in potential cancer therapy. FRET-CMS indicated the typical type IV isotherm with uniform distribution and wormhole arrangement of mesopores. In vitro release studies indicate the redox-sensitive drug release behaviors. Furthermore, the release of entrapped drugs in real time is monitored by the changed FRET signals of FRET-CMS, which is effectively controlled due to the eliminating FRET with the dissociation of FRET donor–acceptor pair. Fluorescent images of cellular uptake and cell viability test revealed that FRET-CMS enhanced significantly 6-MP accumulation in Hela cells with CD44 receptor over-expressed compared to MCF-7 cells due to the existence of hyaluronic acid and subsequently induced selective cytotoxicity to Hela cells. The obtained results illustrate that FRET-CMS may be a promising nanocarrier for drug delivery systems in cancer therapy.

Montmorillonite (MMT) clay modified with lanthanum (La) ions and Fe3O4 nanoparticles was proposed for the effective removal of phosphate ions from aqueous solution. Characterisation of the adsorbent using FTIR, SEM, XRD, XPS, XRF, BET and VSM techniques were carried out. The effects of initial phosphate concentration, contact time, dosage and pH on the phosphorus adsorption were investigated. La-MMT/Fe3O4 exhibited an excellent adsorption capacity of up to 14.35 mg/g, with 97.8% removal within 60 min. Langmuir isotherm model fits well with the equilibrium isotherm data, with a maximum adsorption capacity of 15.53 mg/g at room temperature. The kinetic study was well fitted with pseudo-second-order kinetics, and the adsorption rate was mainly controlled by liquid-film diffusion. The manufactured adsorbent was effectively regenerated using 0.1 M NaOH solutions, with 90.18% adsorption efficiency remaining after six adsorption/desorption cycles. These results demonstrate that La-MMT/Fe3O4 provides an example of regenerable high-performance adsorbents for removal of PO4 3− from wastewater.

Lead-free Na0.5K0.5NbO3 (KNN) piezoelectric ceramics is regarded as a potential candidate for PZT material, while high performance is difficult to be obtained due to its poor sinterability and non-stoichiometric component. In this work, oscillatory pressure-assisted hot pressing (OPAHP) is utilized to fabricate KNN ceramics with high density. The KNN ceramics sintered at 860 °C exhibits superior performance with piezoelectric parameter (d33) of 142 pC/N, electromechanical coupling factors (kp) of 0.41, and relative permittivity (eT33/e0) of 472–620. Additionally, hardness and flexural strength are measured as 3.55 GPa and 99.13 MPa, respectively. This work indicates that OPAHP technique is effective for fabricating KNN piezoelectric ceramics with high performance.

To effective capture and universal enrichment of His-tagged protein, polyacrylic acid (PAA) brushes were used to encapsulate Fe3O4 nanoparticles, connect NTA, and Ni2+ to prepare magnetic beads. These materials provide many advantages, such as excellent stability, tuneable particle size, and a surface for further functionalisation with biomolecules. His-tagged green fluorescence protein (GFP) was separated efficiently, and the binding capacity of Fe3O4/MPS@PAA/NTA-Ni2+ was 93.4 mg/g. Compared with High-Affinity Ni-NTA Resin and Ni-NTA Magnetic Agarose Beads, Fe3O4/MPS@PAA/NTA-Ni2+ nanocomposites exhibited higher separation efficiency and binding capacity towards His-tagged GFP. Moreover, the selectivity and recyclability of them for the target proteins were maintained well after six cycles. This study would widen the application of PAA in constructing multifunctional nanocomposites for biomedical fields.

To solve the problem of the hard and brittle mechanical properties of poly(l-lactide) (PLLA), a novel pectinate polymethylphenylsilane-co-poly(e-caprolactone) (PCL-PMPS-PCL) has been designed to modify PLLA via the hydrolysis polycondensnsation of methylphenyldimethoxysilane and ring-opening polymerization of e-caprolactone. The triblock copolymer is characterized with 1HNMR and GPC. It is harmonized with PLLA in chloroform to make smooth blending film. Incorporation of PCL-PMPS-PCL lowers Tg of PLLA, enhances the macromolecular mobility, and facilitates PLLA to form defective crystals. Compared to the brittle PLLA, the cross section of blends is rough and uneven. With the blending amount of PCL-PMPS-PCL going up, the tensile strength curve has a downward glacis, while the elongation at a break climbs upward, and reaches 25% at 10 wt%, exhibiting that the typical characteristics of ductile material. At the same time, the tensile strength for 10 wt% PCL-PMPS-PCL/PLLA reserve about 60 MPa, so PCL-PMPS-PCL can serve as a candidate of plasticizing PLLA.

A mild chemistry route was developed to prepare carbonaceous nanofibers-titanium dioxide (CNF-TiO2) nanocomposites for removal of dye pollutants. In the process of the template-directed hydrothermal carbonization (HTC), ultrathin Te nanowires were adopted as templates and glucose as the carbon source, and TiO2 was decorated on CNF via the hydrolysis of tetrabutyltitanate in the presence of CNF in ethanol. The as-prepared materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) and X-ray diffraction (XRD). SEM and TEM observations displayed that TiO2 nanoparticles were anchored on the CNF. EDX and XRD data confirmed that the assynthesized samples were CNF-TiO2, and TiO2 belonged to anatase titania. Taking advantage of combined benefits of carbonaceous nanofibers and titanium dioxide, these CNF-TiO2 nanocomposites exhibited higher removal efficiency in a short time and showed good reusability. It was showed that over 97% of Rhodamine B could be removed in 15 min without generating the solid and liquid wastes. The removal efficiency of dyes was still over 80% after reuse in five cycles. All the results demonstrate that the as-prepared CNF-TiO2 composites are effective materials for fast and effective removal of dye pollutants and thus can provide a new platform for dye decontamination.

Objective Real-time locating systems (RTLS) enable contact tracing and hand hygiene reminders, to improve hospital safety. Successful implementation requires healthcare personnel (HCP) to carry RTLS tags continuously. We assessed for determinants of HCP’s willingness to use RTLS tags during routine inpatient care, and evaluated concerns using mixed-methods analysis. Materials and Methods We conducted a cross-sectional study in the 330-bed purpose-built National Centre for Infectious Diseases in Singapore, from January 15 through February 4, 2020. The anonymous survey comprised 24 questions based on constructs from behavioral models and an open-ended question. Principal component analysis was performed to derive the latent factor structure applied in the multivariable logistic regression analysis. Concerns were analyzed using thematic analysis. Results Of 260 HCP (nurses [40.8%], ancillary and administrative staff [23.1%], allied health professionals [18.5%], and physicians [17.7%]), 75% were willing to use the RTLS tag. After adjusting for age, gender, healthcare professional group, and duration of practice, the acceptance of the use of the RTLS tag (adjusted OR 11.28 [95% CI 4.39–29.00], P Conclusion More communications on the intentions and data protection standards of the RTLS, and accessory enhancements for HCP’s convenient and sustained use of the RTLS tag are crucial, to optimize RTLS’s usefulness during the COVID-19 pandemic.

BackgroundEffective contact tracing is labor intensive and time sensitive during the COVID-19 pandemic, but also essential in the absence of effective treatment and vaccines. Singapore launched the first Bluetooth-based contact tracing app—TraceTogether—in March 2020 to augment Singapore’s contact tracing capabilities.ObjectiveThis study aims to compare the performance of the contact tracing app—TraceTogether—with that of a wearable tag-based real-time locating system (RTLS) and to validate them against the electronic medical records at the National Centre for Infectious Diseases (NCID), the national referral center for COVID-19 screening.MethodsAll patients and physicians in the NCID screening center were issued RTLS tags (CADI Scientific) for contact tracing. In total, 18 physicians were deployed to the NCID screening center from May 10 to May 20, 2020. The physicians activated the TraceTogether app (version 1.6; GovTech) on their smartphones during shifts and urged their patients to use the app. We compared patient contacts identified by TraceTogether and those identified by RTLS tags within the NCID vicinity during physicians’ 10-day posting. We also validated both digital contact tracing tools by verifying the physician-patient contacts with the electronic medical records of 156 patients who attended the NCID screening center over a 24-hour time frame within the study period.ResultsRTLS tags had a high sensitivity of 95.3% for detecting patient contacts identified either by the system or TraceTogether while TraceTogether had an overall sensitivity of 6.5% and performed significantly better on Android phones than iPhones (Android: 9.7%, iPhone: 2.7%; PConclusionsTraceTogether had a much lower sensitivity than RTLS tags for identifying patient contacts in a clinical setting. Although the tag-based RTLS performed well for contact tracing in a clinical setting, its implementation in the community would be more challenging than TraceTogether. Given the uncertainty of the adoption and capabilities of contact tracing apps, policy makers should be cautioned against overreliance on such apps for contact tracing. Nonetheless, leveraging technology to augment conventional manual contact tracing is a necessary move for returning some normalcy to life during the long haul of the COVID-19 pandemic.

The (1 − 2x)NBT–xKBT–xBT ternary piezoelectric system has been extensively studied in recent years. However, its electrical performance is far inferior to lead-based counterparts, and could not meet the requirements for practical applications. In this contribution, the 0.92NBT–0.04KBT–0.04BT (abbreviated as NKBT4) ceramics were prepared by traditional solid-state method. The effects of doped cobalt content on the structure and electrical performance of NKBT4 ceramics were studied systematically. The content of Co2O3 affects the average grain size, maximum dielectric constant, piezoelectric properties and the ferroelectric responses of the ceramics. It was found that the introduction of cobalt did not affect the phase structure of the ceramics, but is beneficial for the improvement of the dielectric and piezoelectric properties. When x = 0.2, the piezoelectric coefficient (d33) is around 130 pC/N, which is greatly improved compared to pure NKBT4 ceramics. Besides, a relatively high dielectric constant (er = 1150) was obtained at the same composition. This work paves a new way for the further development of high performance lead-free piezoelectric ceramics.

To take advantage of the polymer’s special properties, we synthesized PVDAT coated polystyrene (PVDAT@PS) microspheres through semi-continuous precipitation polymerization, and demonstrated the possibility of controlling the size of microspheres by using different sized PS cores. Mechanism of the microsphere synthesis was investigated. Preliminary application studies indicated that the synthesized microspheres adsorbed double-stranded DNAs (dsDNAs) comprising A-T base pairs in pH7.4 phosphate buffered saline, and the adsorption capacity was in a range of 3.28mg to 5.58mg per gram PVDAT@ PS microspheres depending on A-T base pair percentage and chain length of the dsDNAs.

A safe, efficient and inexpensive multifunctional nanoplatform is urgently needed for cancer diagnosis and treatment. Herein, we report the first example of fabrication of gadolinium-functionalized Fe3O4@polydopamine nanocomposites and evaluate their potential application in T1/T2 dual-modal magnetic resonance imaging-guided photothermal therapy in vitro. This was achieved by encapsulating iron oxide nanoparticles with polydopamine, and then grafting gadolinium chelates onto the surface of Fe3O4@polydopamine nanocomposites. The as-prepared nanocomposites, composed of low cost Fe3O4, polydopamine and gadolinium complexes, showed high stability and good biocompatibility. More importantly, these nanocomposites exhibited high photothermal conversion efficiency, with the temperature reaching 43.0 °C at a concentration of 0.35 mg mL−1 under near-infrared irradiation for a few minutes. Furthermore, according to the magnetic resonance imaging results, these nanocomposites could induce an efficient contrast enhancement for both T1 and T2 imaging at low concentrations of Gd and Fe. This provides a new platform for the development of new diagnosis and therapeutic agents.

A near infrared (NIR) and pH dual-responsive nanocomposite, composed of a lanthanide-doped upconversion nanoparticle (UCNP) core and a transformable poly-o-nitrobenzyl shell, was prepared by the distillation precipitation polymerization and template method. The poly-o-nitrobenzyl shell can undergo hydrophobic-hydrophilic transformation upon an irradiation of 980 nm, rendering the capability of NIR-activated drug release. The anticancer drug, doxorubicin (DOX), can be loaded into these nanocomposites with a loading efficiency of 7.23 wt%. Furthermore, pH responsiveness caused by the hydrogen bond and charge interactions between DOX and nanocapsules can trigger the release of drugs at low pH. Under visible light irradiation and neutral (pH 7.4) conditions, the cumulative release of DOX was only 8.35% after 300 min, while it reached 59.5% under the synergistic effect of NIR irradiation and acidic conditions. The Baker-Lonsdale model was used to describe the drug release kinetics of this system, and the diffusion coefficient (3DCs/r02C0) and R2 under different conditions were determined to be 4.15 × 10−6 and 0.98 (pH 7.4 and visible light), 2.64 × 10−5 and 0.99 (NIR light), 3.26 × 10−5 and 0.97 (pH 4.5 and visible light), 2.59 × 10−4 and 0.99 (pH 4.5 and NIR light), respectively. This controlled release feature makes the nanocomposite a promising therapeutic agent for treating diseases.

Stormwater runoff management is challenging in a highly urbanised tropical environment due to the unique space constraints and tropical climate conditions. A modular bioretention tree (MBT) with a small footprint and a reduced on-site installation time was explored for application in a tropical environment. Tree species used in the pilot studies were Talipariti tiliaceum (TT1) and Sterculia macrophylla (TT2). Both of the MBTs could effectively remove total suspended solids (TSS), total phosphorus (TP), zinc, copper, cadmium, and lead with removal efficiencies of greater than 90%. Total nitrogen (TN) removal was noted to be significantly higher in the wet period compared to the dry period (p &lt, 0.05). Variation in TN removal between TT1 and TT2 were attributed to the nitrogen uptake and the root formation of the trees species. A field study MBT using Talipariti tiliaceum had a very clean effluent quality, with average TSS, TP, and TN effluent EMC of 4.8 mg/L, 0.04 mg/L, and 0.27 mg/L, respectively. Key environmental factors were also investigated to study their impact on the performance of BMT. It was found that the initial pollutant concentration, the dissolved fraction of influent pollutants, and soil moisture affect the performance of the MBT. Based on the results from this study, the MBT demonstrates good capability in the improvement of stormwater runoff quality.

In this study, core–shell Fe3O4@Au nanoparticles with good chemical stability and tunable particle size were synthesized via Au–S bonding, which overcomes the challenges encountered for the reported preparation of Fe3O4@Au. The surface of nanoparticles was investigated by TEM, XRD, XPS, FT-IR, VSM and DLS which characterized the size, morphology, chemical lattice, elemental analysis, functional groups, magnetic strength, and size distribution. The results showed that Fe3O4@Au/NTA-Ni2+ magnetic nanocomposites were spherical with an average diameter of 469.5 nm, and superparamagnetic with saturation magnetization of 7 emu/g. The magnetic nanocomposites were directly utilized for one-step purification of His-tagged proteins from Description Escherichia coli lysate. The as-separated proteins were qualitatively validated by gel analysis and quantitatively measured by UV–visible spectroscopy. The binding capacity of Fe3O4@Au/NTA-Ni2+ towards His-tagged proteins was 48.3 mg/g. The target proteins were separated with high purity and separation efficiency up to 96.6%. Their specificity and enrichment ability were maintained during six cycles of adsorption–elution operations. The advantages of this novel nanoparticle can open a window for the multifunction of nanomaterials and their biological application.

Many studies have reported that silver has excellent antibacterial properties. However, silver ions can easily react with oxygen to form Ag2O, thus leading to a color change and a reduction in its anti-microbial characteristics. In this study, silver triethanolamine- (ST) loaded PVB/CO solution was prepared as a potential candidate liquid bandage. PVB/CO/ST retained high transparency after exposure to light for 12 months, which allowed convenient inspection of the wound bed without removal of the dressing. The PVB/CO/ST film exhibited favorable properties, such as speed of drying, excellent tensile strength and elongation characteristics and water vapor transmission rate (WVTR). It was comfortable and waterproof, and therefore effective at preventing bacterial invasion, providing effective biosafety. PVB/CO/ST solution-treated wounds exhibited accelerated healing and reduced inflammation in a nude mouse mode. Our data suggested that PVB/CO/ST solution could serve as a promising liquid bandage for treatment of minor trauma.

To create novel materials of skin tissue engineering, the blends of tannin-grafted poly(ɛ-caprolactone) (TA-g-PCL) and poly(l-lactic acid) (PLLA) have been prepared by electrospinning, and their corresponding characteristics are evaluated such as morphology, FTIR, thermodynamics, mechanics, wettability, as well as biocompatibility. TA-g-PCL and PLLA can be well blended to make smooth fibers, and fibrous diameter turns thinner with blending TA-g-PCL. At 15 wt%, the fibrous membrane shows higher tensile strength and elongation at a break than the other samples due to its best crystallinity. Membranous wettability drops with blending TA-g-PCL, but it increases sharply after incorporating PF108. At the same time, PLLA/TA-g-PCL fiber membrane is biocompatible. The biodegradable PLLA/TA-g-PLLA membrane is a promising candidate as skin tissue engineering.

Electroactive polypyrrole (PPy) are highly attractive for a number of biomedical applications such as tissue engineering. To improve interfacial compatibility of PPy with biopolyesters, poly (ɛ-caprolactone) grafted PPy (PPy-g-PCL) are synthesized in this work and characterized with Fourier transform infrared and nuclear magnetic resonance. PPy-g-PCL exhibits good conductivity and electrochemical activity. It is also blended with poly (glycolide-lactide) to make aligned fiber membranes via drum at the speed of 1500 r/min. The relationships of blending ratio with the fibrous structure, thermal stability, wettability, and mechanical properties are clarified. The results show that blending PPy-g-PCL has no significant effect on the fibrous morphology, but fibers trends aligned architecture as the blend ratio of poly (glycolide-lactide)/PPy-g-PCL exceeds 70/30. The membranous thermal and mechanical stability are modified. The membranous hydrophilicity significantly enhances with PPy-g-PCL amount increasing. Then the fiber membrane with topographical and electrical cues is qualified as the application of tissue engineering. Copyright © 2016 John Wiley & Sons, Ltd.

Magnetic nanoparticle (NPs) and fluorescent NP pairs were designed for myoglobin (Myo) detection in human blood. Magnetic NPs MNP@SiO2@BSA@Au with about 200 nm diameter (by TEM) were prepared through a layer by layer technique following by adsorption of anti-Myo antibody 4E2 on a Au surface. The MNPs were well dispersed in an aqueous solution. Fluorescent NPs were prepared by conjugating fluorescent Rhodamine Red-X (RhX) and another Myo antibody 7C3 on silica NPs with a final diameter of 80 nm. In the presence of Myo, magnetic NPs bearing 4E2 and fluorescent NPs bearing 7C3 form a sandwich structure, which can be separated from blood under a magnetic field. The concentration of Myo is quantified by the fluorescence intensity of SNP@RhX NPs in the sandwich structure. The calibration curve of the Myo showed a linear range between 0 and 250 ng mL−1 (R2 = 0.993). The minimum detectable concentration was 0.28 ng mL−1. The immunomagnetic separation based fluorescence immunoassay offered a simple and accurate way to determine Myo in human blood in 30 min.

Flexible piezoelectric nanogenerators based on organic-inorganic composite have attracted intensive attention for harvesting mechanical energy. However, charge annihilation situated in defect and stacking gap of inorganic nanofillers, which originates from its uneven dispersion within polymer matrix, constrains the practical application of composite piezoelectric nanogenerators. Herein, the usage of organic phosphonic acid in surface coating to improve the dispersion of BaTiO3 is reported, implementing 2-phosphonobutane-1,2,4-tricarboxylic acid (PBTCA) as proof of concept modifier. The coating with organic phosphonic acid on surface effectively improves the distribution of BaTiO3, mainly resulting from the strong chelating ability of reactive groups to organic matrix. Moreover, the well-distributed BaTiO3 promotes the stress transmission efficiency of composite via diminishing the density of defects and gaps. Benefited from these, the piezoelectric nanogenerator with modified BaTiO3 outputs a remarkable performance with a high voltage of 45 V even after 10,000 cycles and power density of 0.76 μW/cm2, much better than the unmodified counterpart. This work helps unravel that manipulating surface chemistry of nanofiller could be effective in improving the performance of organic-inorganic composite piezoelectric nanogenerators.

Synergistic photothermal therapy (PTT) and chemotherapy is an efficient strategy for tumor therapy. However, it is still a challenge to design a smart delivery system able to release a drug at the appropriate time and site of action. Here, we have synthesized photosensitive molecule 7-(double dodecylamine)-4-hydroxymethylcoumarin which was introduced in a nanocarrier GNR@SiO2-DOX@CouC12-HA (GSDCH) to achieve manually controlled drug release. The specific nanocarrier was fabricated using a GNR core for photothermal therapy, a mesoporous silica shell for drug loading, and the coumarin moiety as a blocking agent and intelligent controlled switch. In addition, cellular uptake of GSDCH by HeLa cells can be achieved effectively with the help of hyaluronic acid (HA). Owing to the controlled and targeted drug release properties, the GSDCH with photothermal- and chemo-therapy showed significantly enhanced therapeutic efficiency for HeLa tumor-bearing mice compared to the results of single therapy alone. It indicated that the GSDCH had great potential in tumor therapy with negligible systematic toxicity.

This paper serves to communicate concerns including misleading presentation of information and the use of incomplete monitoring data in a recent journal article by Lim and Lu (2016) published in the Journal of Hydrology.