Photopolymerized multifunctional sodium alginate-based hydrogel for antibacterial and coagulation dressings.

Trauma caused by tissue damage in clinical applications has posed a serious threat to public safety. Dressings with a single function cannot meet the needs of wound healing, but multifunctional dressings are difficult to achieve and obtain. To address this issue, this research designed a facile one-pot photo-crosslinking method to prepare multifunctional sodium alginate-based hydrogel dressings for effective wound healing. According to irregular wounds, sodium alginate-based hydrogel dressings can be quickly prepared anytime and anywhere. The structure and physicochemical properties of hydrogels are regulated by modulating the proportion of main components sodium alginate and acrylamide. The results showed the sodium alginate-based composite hydrogel as a candidate multifunctional dressing that exhibits excellent stretchability and compressibility, viscoelasticity, and suitable tissue-like adhesion. In vitro drug release and antibacterial experiments indicated that the hydrogel has effective antibacterial properties against S. aureus and P. aeruginosa. Furthermore, the haemostatic behaviour of the hydrogel was demonstrated using the coagulation activation test, whole blood-clotting test, and blood cell and platelet adhesion experiments. All these results demonstrated that the sodium alginate-based hydrogel had high application potential as a multifunctional medical dressing for wound healing.

Banana fibre-chitosan-guar gum composite as an alternative wound healing material.

Bio-composites, which can be obtained from the renewable natural resources, are fascinating material for use as sustainable biomaterials with essential properties like biodegradable, bio-compatibility as well cyto-compatibility etc. These properties are useful for bio-medical including wound healing applications. In this study, fibre obtained banana pseudo stem of banana plant, which is otherwise wasted, was used as a material along with chitosan and guar gum to fabricate a banana fibre-biopolymer composite patch. The physiochemical properties of the patches were examined using Fourier Transformed Infra-red spectrophotometer (FT-IR), tensile tester, Scanning Electron Microscope (SEM), contact angle tester, swelling and degradation studies. We further demonstrated that a herbal drug, Nirgundi could be loaded to the patch showed controlled its release at different pHs. The patch had good antibacterial property and supported proliferation of mouse fibroblast cells. The study thus indicates that banana fibre-chitosan-guar gum composite can be developed into an alternative wound healing material.

Arthroscopic knots: Suture and knot characterisation of modern polyblend suture materials.

Objective: The primary aim of this study was to explore the relationship between the biophysical structure and function of modern suture materials. Particularly the suture's ability to withstand the stressors of surgery and how the material properties affect knot stability. The secondary aim was to investigate the effect that different knots have on the suture material itself. This study builds on previous research assessing suture and knot characteristics but in modern Ultra High Molecular Weight Polyethylene (UHMWPE) materials currently in widespread clinical use in arthroscopic surgery. Methods: Three common UHMWPE sutures and one polyester suture were tested in both a dry and wet state using the Geelong, Nicky's, Surgeon's and Tautline knots. Tensile strength of knots was tested vertically at a 60 mm/min strain rate and 45 mm gauge length. Sutures were tied through a cannula around two 8 mm diameter circular bollards. Testing was conducted in a controlled environment temperature and humidity environment (20 ± 2 °C, 65 ± 2%). Results: No one knot type was optimal over all suture types. Mean tensile strength in both a dry and wet state and a low coefficient of variation (CV) in tensile strength in a wet state were considered as an indication of suitability. With Ethibond sutures this was the Geelong knot (CV:4.2%). With Orthocord sutures both the Geelong and Tautline knots (CV:4.2% and CV:11.9% respectively). With FiberWire sutures the Nickys and Tautline knots (CV:22.6% and CV:22.5% respectively). With ForceFiber sutures all four knots exhibited similar wet tensile strength with high variability showing that all should perform in a similar way invivo. Conclusions: This study demonstrates a statistically significant three-way interaction between polyblend suture materials, the knot and the environment. This has implications for knot security using the tested sutures in different environments, as one knot may not behave the same under all conditions.

pH-sensitive alginate hydrogel for synergistic anti-infection.

This work designed a pH-sensitive sodium alginate hydrogel for combating bacterial infection caused by tissue damage. The antibacterial hydrogels were prepared using sodium alginate, citric acid, and vancomycin by one-step in situ method. Vancomycin (Van) was loaded into hydrogels via reversible imine bonds for controlled drug delivery. The morphology, swelling properties, and antibacterial activity of hydrogel were characterized. The hydrogel shown strong water absorbent behavior and pH-dependent performance. The result under weak acid conditions, the drug release rate of van-loaded gel was faster than neutral and alkaline conditions and followed zero-order kinetic release model, and the cumulative release amount could reach 86.7 % over 320 min. The van-loaded gel had highly effective antibacterial activity in a weak acid environment, the combination of citric acid and vancomycin had a synergistic therapeutic effect for acute infection. The drug-loaded hydrogel shows good biocompatibility. Compared with gauze, the drug-loaded hydrogel exhibited good coagulation properties, high platelet adhesion, high fluid absorption capacity, and proper balance of fluid on the wound bed. This work proposed this simple alginate-based drug delivery system has potential applications in the field of clinical treatment of infections.

Textiles in soft robots: Current progress and future trends.

Soft robotics have substantial benefits of safety, adaptability, and cost efficiency compared to conventional rigid robotics. Textiles have applications in soft robotics either as an auxiliary material to reinforce the conventional soft material or as an active soft material. Textiles of various types and configurations have been fabricated into key components of soft robotics in adaptable formats. Despite significant advancements, the efficiency and characteristics of textile actuators in practical applications remain unsatisfactory. To address these issues, novel structural and material designs as well as new textile technologies have been introduced. Herein, we aim at giving an insight into the current state of the art in textile technology for soft robotic manufacturing. We firstly discuss the fundamental actuation mechanisms for soft robotics. We then provide a critical review on the recently developed functional textiles as reinforcements, sensors, and actuators in soft robotics. Finally, the future trends and current strategies that can be employed in textile-based actuator manufacturing process have been explored to address the critical challenges in soft robotics.

Effect of sonochemical scouring on the surface morphologies, mechanical properties, and dyeing abilities of wool fibres.

Ultrasonics has the potential to reduce the cost and environmental impact of textile processing. This work investigates the effects of ultrasonic irradiation during wool scouring on fibre surface morphologies, fibre mechanical properties, and fibre dyeing abilities. A range of ultrasonic frequencies were used in the scouring bath to examine the forms of fibre cuticle damage. It is observed that wool fibres underwent ultrasonic irradiation at a low frequency have severe modifications of the fibre surface structure. Despite some visible disruptions to the fibre scale structure however, ultrasonic irradiation has shown a negligible impact on the fibre mechanical properties, especially bending abrasion resistance which depends largely on the fibre surface conditions, and is responsible for the handle and pilling propensity of the resultant fabrics. Dyeing abilities were investigated on wool samples using commercially available acid dye and reactive dye. It is found that ultrasonically scoured wool has a quicker dye uptake in the early stage of low temperature dyeing for both acid dye and reactive dye, than the conventionally scoured wool.

Validation of the abrasion resistance test protocols and performance criteria of EN13595: The probability of soft tissue injury to motorcycle riders by abrasion resistance of their clothing.

INTRODUCTION: Motorcyclists represent an increasing proportion of road users globally and are increasingly represented in crash statistics. Soft tissue injuries are the most common type of injuries to crashed motorcyclists. These injuries can be prevented through the use of protective clothing designed for motorcycle use. However, the quality of such clothing is not controlled in many countries around the world. A European Standard was developed to assess the performance of clothing but as this is not mandatory, clothing certified to this Standard is difficult to obtain. Given the importance of this Standard, and that it has been validated only once, further validation work is required. METHODS: In-depth crash investigation data were used to investigate the relationship between the abrasion resistance performance of clothing and real-world injury outcome. Clothing was collected from riders who crashed on public roads in Sydney and Newcastle, Australia. This clothing was tested according to the EU Standard and the time to hole was recorded. Hospital medical records were reviewed and the association between a rider suffering a soft tissue injury and the time-to-hole for the garment was examined. RESULTS: The probability of soft tissue injury for Level 1 Standard garments was between 40-60%, but more than 60% of garments tested failed to meet the minimum requirement. CONCLUSIONS: The findings of this study provide qualified support for the Standard, with a marginal association between time-to-hole and injury being found. PRACTICAL IMPLICATIONS: This work supports the need for improved safety performance and an increased number of high performing garments being available to motorcyclists.

Bending and abrasion fatigue of common suture materials used in arthroscopic and open orthopedic surgery.

In orthopedic surgery, the reattachment of tendon to bone requires suture materials that have stable and durable properties to allow time for healing at the tendon-bone interface. The suture, not rigidly restrained within the anchor eyelet, is free to move during surgery and potentially after surgery with limb motion. During such movement, the suture is subjected to bending and frictional forces that can lead to fatigue-induced failure. We investigated some common contemporary commercial number-two-grade suture materials and evaluated their resistance to bending abrasion fatigue and the consequent failure. Sutures were oscillated over a stainless steel wire at low frequency under load. Number of abrasion cycles to failure, changes in suture morphology, and fatigue-failure method was recorded for each material. Suture structure had a significant effect on abrasion resistance, with braided sutures containing large numbers of fine high tenacity core filaments performing 15-20 times better than other braided suture structures. Ultra high molecular weight polyethylene (UHMWPE) core filaments resisted bending abrasion failure better than other core materials due to the load spreading and abrasion resistance of these filaments. Sutures with UHMWPE cores also had high resistance to tensile failure. Limited correlation was observed between tensile strength and abrasion resistance.

The effects of ultrasonic agitation in laundering on the properties of wool fabrics.

This paper investigates the use of ultrasonic agitation as a method for reducing felting and area shrinkage during the laundering of wool fabric. Work was conducted to evaluate the changes in fibre and fabric properties after repeated exposure to ultrasonic agitation, and also the effectiveness of ultrasonic treatment to remove common stains. Fabric colour, appearance, tensile strength, dimensional stability and thickness were measured before and after each test. Ultrasonic agitation produced fine cracks in the scale structure of the fibre, but these had negligible effects on the strength and colour when compared to hand washing. Ultrasonic agitation caused less fibre migration than hand washing, with a reduced rate of thickness increase and felting. Ultrasonic agitation increased the level of stain removed from the fabric when compared with hand washing.