Degradable rosin-ester-caprolactone graft copolymers.

We have carried out the synthesis of side-chain rosin-ester-structured poly(ε-caprolactone) (PCL) through a combination of ring-opening polymerization and click chemistry. Rosin structures are shown to be effectively incorporated into each repeat unit of caprolactone. This simple and versatile methodology does not require sophisticated purification of raw renewable biomass from nature. The rosin properties have been successfully imparted to the PCL polymers. The bulky hydrophenanthrene group of rosin increases the glass-transition temperature of PCL by >100 °C, whereas the hydrocarbon nature of rosin structures provides PCL excellent hydrophobicity with contact angle very similar to polystyrene and very low water uptake. The rosin-containing PCL graft copolymers exhibit full degradability and good biocompatibility. This study illustrates a general strategy to prepare a new class of renewable hydrocarbon-rich degradable biopolymers.

Viraemia and Ebola virus secretion in survivors of Ebola virus disease in Sierra Leone: a cross-sectional cohort study.

BACKGROUND: In survivors of Ebola virus disease, clinical sequelae including uveitis, arthralgia, and fatigue are common and necessitate systematic follow-up. However, the infection risk to health-care providers is poorly defined. Here we report Ebola virus RT-PCR data for body site and fluid samples from a large cohort of Ebola virus survivors at clinic follow-up. METHODS: In this cross-sectional cohort study, consecutive survivors of Ebola virus disease attending Kerry Town survivor clinic (Freetown, Sierra Leone), who had been discharged from the Kerry Town Ebola treatment unit, were invited to participate. We collected and tested axillary, blood, conjunctival, forehead, mouth, rectal, semen, urine, and vaginal specimens for presence of Ebola virus using RT-PCR. We regarded samples to be positive for Ebola virus disease if the cycle threshold was 40 or lower. We collected demographic data from survivors of their age, sex, time since discharge from the treatment unit, and length of acute admission in the Ebola treatment unit using anonymised standard forms. FINDINGS: Between April 2, and June 16, 2015, of 151 survivors of Ebola virus disease invited to participate, 112 (74%) provided consent. The median age of participants was 21·5 years (IQR 14-31·5) with 34 (30%) participants younger than 16 years. 50 (45%) of 112 participants were male. We tested a total of 555 specimens: 103 from the axilla, 93 from blood, 92 from conjunctiva, 54 from forehead, 105 from mouth, 17 from the rectum, one from semen, 69 from urine, and 21 from the vagina. The median time from Ebola treatment unit discharge to specimen collection was 142 days (IQR 127-159). 15 participants had a total of 74 swabs taken less than 100 days from discharge. The semen sample from one participant tested positive for Ebola virus at 114 days after discharge from the treatment unit; specimens taken from the axilla, blood, conjunctiva, forehead, mouth, rectum, and urine of the same participant tested negative. All specimens from the other 111 participants tested negative. INTERPRETATION: Patients recovering from Ebola virus disease who do not meet the case definition for acute disease pose a low infection risk to health-care providers 6 weeks after clearance of viraemia. Personal protective equipment after this time might be limited to standard barrier precautions, unless contact with fluids from sanctuary sites is envisaged. FUNDING: Save the Children International, Public Health England.

Highly sensitive and multifunctional tactile sensor using free-standing ZnO/PVDF thin film with graphene electrodes for pressure and temperature monitoring.

We demonstrate an 80-µm-thick film (which is around 15% of the thickness of the human epidermis), which is a highly sensitive hybrid functional gauge sensor, and was fabricated from poly(vinylidene fluoride) (PVDF) and ZnO nanostructures with graphene electrodes. Using this film, we were able to simultaneously measure pressure and temperature in real time. The pressure was monitored from the change in the electrical resistance via the piezoresistance of the material, and the temperature was inferred based on the recovery time of the signal. Our thin film system enabled us to detect changes in pressure as small as 10 Pa which is pressure detection limit was 10(3)-fold lower than the minimum level required for artificial skin, and to detect temperatures in the range 20-120 °C.

Flexible FET-type VEGF aptasensor based on nitrogen-doped graphene converted from conducting polymer.

Graphene-based field-effect transistors (FETs) have been developed rapidly and are currently considered as an alternative for postsilicon electronics. In this study, polypyrrole-converted nitrogen-doped few-layer graphene (PPy-NDFLG) was grown on Cu substrate by chemical vapor deposition combined with vapor deposition polymerization and then transferred onto a flexible substrate. Furthermore, antivascular endothelial growth factor (VEGF) RNA aptamer conjugated PPy-NDFLG was integrated into a liquid-ion gated FET geometry to fabricate a high-performance VEGF aptamer-based sensor. Field-induced high sensitivity was observed for the analyte-binding events, eventually leading to the recognition of the target molecules at an unprecedentedly low concentration (100 fM). Additionally, the aptasensor had excellent reusability, mechanical bendability, and durability in the flexible process. The developed methodology describes, for the first time, the fabrication of N-doped graphene using conducting polymers including heteroatoms in their structures as the carbonization precursor and demonstrates its use in a high-performance, flexible FET-type aptasensor to detect vascular endothelial growth factor as a cancer biomarker.