Three-dimensional biofabrication of an aragonite-enriched self-hardening bone graft substitute and assessment of its osteogenicity in vitro and in vivo

A self-hardening three-dimensional (3D)-porous composite bone graft consisting of 65 wt% hydroxyapatite (HA) and 35 wt% aragonite was fabricated using a 3D-Bioplotter®. New tetracalcium phosphate and dicalcium phosphate anhydrous/aragonite/gelatine paste formulae were developed to overcome the phase separation of the liquid and solid components. The mechanical properties, porosity, height and width stability of the end products were optimised through a systematic analysis of the fabrication processing parameters including printing pressure, printing speed and distance between strands. The resulting 3D-printed bone graft was confirmed to be a mixture of HA and aragonite by X-ray diffraction, Fourier transform infrared spectroscopy and energy dispersive X-ray spectroscopy. The compression strength of HA/aragonite was between 0.56 and 2.49 MPa. Cytotoxicity was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay in vitro. The osteogenicity of HA/aragonite was evaluated in vitro by alkaline phosphatase assay using human umbilical cord matrix mesenchymal stem cells, and in vivo by juxtapositional implantation between the tibia and the anterior tibialis muscle in rats. The results showed that the scaffold was not toxic and supported osteogenic differentiation in vitro. HA/aragonite stimulated new bone formation that bridged host bone and intramuscular implants in vivo. We conclude that HA/aragonite is a biodegradable and conductive bone formation biomaterial that stimulates bone regeneration. Since this material is formed near 37°C, it will have great potential for incorporating bioactive molecules to suit personalised application; however, further study of its biodegradation and osteogenic capacity is warranted. The study was approved by the Animal Ethical Committee at Tongji Medical School, Huazhong University of Science and Technology (IACUC No. 738) on October 1, 2017

High performance tunable piezoresistive pressure sensor based on direct contact between printed graphene nanoplatelet composite layers

This article details the development of a thin film piezoresistive screen printed pressure sensor on a flexible substrate using a composite ink based on functionalised graphene nanoplatelets (GNPs). The sensor operates through direct interfacial contact between two distinct films of the composite ink deposited over conductive substrates, without requiring any intermediate gap through spacers. The sensors showed consistent results and sensitivity forces ranging between 10 N to 2000 N. The piezoresistive range of the sensor can be tuned with the number of layers deposited per side

Enhanced liquid retention capacity within plastic food packaging through modified capillary recesses

A novel approach is proposed to isolate meat exudate in plastic packaging trays. This exudate is responsible for limiting meat shelf life, increasing meat loss and non-recycling plastic waste. This study explores the use of specially designed capillary recesses with integrated raised rims as a means of improving liquid retention capacity in thermoformed meat trays. The presence of raised recess rims is used to enhance the valving functionality of the recesses and restrict liquid drainage during and after recess inclination. This resulted in a considerable increase in liquid retention capabilities. For pork exudate, the retention capacity of recess samples (recess diameter: 9 mm) significantly increased (p < 0.05) from 0.79 g for recesses with no rims to 2.12 g for rim-integrated recesses. The corresponding retention capacity of a recess array after introducing these rims was 2921 ± 63 mL/m2. These recesses have comparable liquid scavenging performance to absorbent meat pads (3000 mL/m2) yet are integrated within the tray material. This proves the practicality of using rim-integrated recesses in plastic meat packaging to retain exudate away and ensure fully recyclable plastic packaging. The manufacturing of these recesses is integrated into the thermoforming process for the tray body

Facile fabrication of electrochemical ZnO nanowire glucose biosensor using roll to roll printing technique

A three electrode electrochemical enzymatic biosensor consisting of ZnO nanowires was successfully fabricated using flexographic printing technique. The incorporation of ZnO nanowires at the working electrode provides advantages such as simple functionalization and high surface area for enhanced sensitivity. The flexographic printing technique allows ultra-high throughput and low cost mass production of devices due to the roll-to-roll nature of the technique. Therefore, the techniques developed here are prudent to the development of technologies capable of meeting the vast market demand for biosensing. Carbon electrodes, silver/silver chloride reference electrodes and ZnO seed layer precursors were directly printed onto a flexible plastic substrate through flexographic printing. The printing process was optimised to allow a suitable seed layer to be formed on the porous printed-carbon electrode to allow selective growth of ZnO nanowires using a hydrothermal growth method. The ZnO nanowires were subsequently functionalised with glucose oxidase, which was used in this work to form a glucose sensor as an exemplary use of the device. The fabricated nanowire electrochemical biosensing devices showed a typical sensitivity of 1.2 ± 0.2 μA mM−1 cm−2 with a linear response to the addition of glucose over a concentration range of 0.1 mM to 3.6 mM

Improvement in liquid absorption of open-cell polymeric foam by plasma treatment for food packaging applications

Free-moving meat exudate in plastic packaging is perceived as unhygienic and unattractive by consumers. It facilitates the deterioration of meat quality and safety, increasing meat waste and loss. This work discusses an innovative approach in scavenging meat exudate within commercial plastic packaging. This involves improving the liquid absorption capabilities of open-cell polystyrene (PS) foam through the application of oxygen plasma treatment rather than chemical wetting agents. The excited plasma species diffuse into the porous foam structure introducing polar oxygen groups onto the pore walls and improves their surface hydrophilicity. Hence, the foam pores, with enhanced wettability towards water-based liquids, are proposed to have a larger sucking capillary pressure thus increasing the absorption capacity of the porous PS foam. The specific liquid absorption capacity of PS foam sheets (thickness: 5 mm) increased from 1.09 g g-1 (grams of exudate simulant liquid absorbed per gram of PS foam) to 8.78 g g-1 as a result of plasma treatment; an 8-fold increase in liquid capacity (g g-1) that persisted even 60 days post treatment. This study demonstrates the practicality of using plasma treatment as a non-chemical and efficient technology in scavenging meat and food exudates in plastic packagin

Effect of plasma treatment on improving liquid retention capacity of capillary recesses for food packaging applications

Liquid residue is a major issue in fresh food packaging, especially for meat products. This work investigates capillary recesses directly integrated into PET packaging film, with targeted plasma treatment of the recesses to enhance their liquid retention capacity. Localised oxygen plasma treatment (oxygen flow rate: 80 cm3/min, pressure: 0.14 mbar, power: 240 W) of PET recesses introduced polar oxygen groups onto their surface and increased their wettability. It is proposed that the difference in wetting characteristics of the recesses and rest of the packaging surface enhanced the capillary valve effect, which dramatically increased the liquid retention capacity. Untreated recess samples (diameter: 9 mm) had retention capacity of around 0.70 g, which increased to 1.50 g after localised O2 plasma treatment. Even after aging of over 60 days, the plasma-treated recesses maintained the enhanced retention capabilities. The estimated resulting retention capacity of recesses of diameter 9 mm was 2972 ± 62 mL/m2, which is comparable with conventional absorbent pads (3000 mL/m2). This demonstrated the viability of applying plasma treatment in food packaging to effectively isolate any excessive exudate using only the packaging film

Lengthening Temporalis Myoplasty: Objective Outcomes and Site-Specific Quality-of-Life Assessment

Objective Evaluate outcomes of the lengthening temporalis myoplasty in facial reanimations. Study Design Case series with planned data collection. Setting Ospedali Riuniti, Bergamo, and AOUC Careggi, Florence, Italy. Subjects and Methods From 2011 to 2016, 11 patients underwent lengthening temporalis myoplasty; demographic data were collected for each. Pre- and postoperative photographs and videos were recorded and used to measure the smile angle and the excursion of the oral commissure, according to the SMILE system (Scaled Measurements of Improvement in Lip Excursion). All patients were tested with the Facial Disability Index, and they also completed a questionnaire about the adherence to physiotherapy indications. Results All patients demonstrated a significant improvement in functional parameters and in quality of life. On the reanimated side, the mean z-line and a-value, measured when smiling, significantly improved in all patients: from 22.6 mm (95% CI, 20.23-25.05) before surgery to 30.9 mm (95% CI, 27.82-33.99) after surgery ( P < .001) and from 100.5° (95% CI, 93.96°-107.13°) to 111.6° (95% CI, 105.63°-117.64°; P < .001), respectively. The mean postoperative dynamic gain, passing from rest to a full smile at the reanimated side, was 3.1 mm (95% CI, 1.30-4.88) for the z-line and 3.3° (95% CI, 1.26°-5.29°) for the a-value. The Facial Disability Index score increased from a preoperative mean of 33.4 points (95% CI, 28.25-38.66) to 49.9 points (95% CI, 47.21-52.60) postoperatively ( P < .001). Conclusions The lengthening temporalis myoplasty can be successfully used for smile reanimation, with satisfying functional and quality-of-life outcomes

Vertically Aligned Graphene Prepared by Photonic Annealing for Ultrasensitive Biosensors

Graphene exhibits excellent physical, electronic, and chemical properties that are highly desirable for biosensing applications. However, most graphene biosensors are based on graphene lying flat on a substrate and therefore do not utilize its maximum specific surface area for ultrasensitive detection. Herein, we report the novel use of photonic annealing on a flexographically printed graphene–ethyl cellulose composite to produce vertically aligned graphene (VAG) biosensors for ultrasensitive detection of algal toxins in drinking water. These VAG structures, which maximized the specific surface area of graphene, were formed by partial removal of the polymeric binder upon applying intense pulsed light on the printed graphene. A label-free and low-cost VAG biosensor based on a non-faradaic electrochemical impedance spectroscopy technique was fabricated. The biosensor exhibited a limit of detection of 1.2 ng/L for microcystin-LR in local tap water. Such an ultrasensitive VAG biosensor is suitable for low-cost mass production using an integrated roll-to-roll flexographic printing with rapid photonic annealing technique