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Purpose – Real-time monitoring of wound or injured tissues is critical for speedy recovery, and the onset of a cascade of biochemical reactions provides potential biomarkers that facilitate the process of wound monitoring, e.g. pH, temperature, moisture level, bacterial load, cytokines, interleukins, etc. Among all the biomarkers, pH has been known to have a profound impact on the wound healing process, and is used to determine the incidence of bacterial infection of the wound (persistently elevated alkaline pH), proteolytic activity at the site of injury, take rate in skin grafting, wound healing stage and preparation for wound debridement. Design/methodology/approach – This review highlights the significance of pH in determination of clinical parameters and for selection of an appropriate treatment regime, and it presents an in-depth analysis of the designs and fabrication methods that use integrated pH sensors, which have been reported to date for the real-time monitoring of wound healing. Findings – For an expedited wound healing process, the significance of pH mandated the need of an integrated sensor system that would facilitate real-time monitoring of healing wounds and obviate the requirement of redressing or complicated testing procedures, which are both labor-intensive and painful for the patient. The review also discussed different types of sensor systems which were developed using hydrogel as a pH-responsive system coupled with voltammetry, potentiometry, impedimetric and flex-circuit inductive transducer systems. All of the mentioned devices have considerable potential for clinical applications, and there is need of in vivo testing to validate their efficiency and sensitivity under practical scenarios. Originality/value – This manuscript is an original review of literature, and permission has been granted to use the figures from previously published papers.

Wounds are of a variety of types and each category has its own distinctive healing requirements. This realization has spurred the development of a myriad of wound dressings, each with specific characteristics. It is unrealistic to expect a singular dressing to embrace all characteristics that would fulfill generic needs for wound healing. However, each dressing may approach the ideal requirements by deviating from the ‘one size fits all approach’, if it conforms strictly to the specifications of the wound and the patient. Indeed, a functional wound dressing should achieve healing of the wound with minimal time and cost expenditures. This article offers an insight into several different types of polymeric materials clinically used in wound dressings and the events taking place at cellular level, which aid the process of healing, while the biomaterial dressing interacts with the body tissue. Hence, the significance of using synthetic polymer films, foam dressings, hydrocolloids, alginate dressings, and hydrogels has been reviewed, and the properties of these materials that conform to wound-healing requirements have been explored. A special section on bioactive dressings and bioengineered skin substitutes that play an active part in healing process has been re-examined in this work.

Oesophageal cancer is the ninth leading cause of malignant cancer death and its prognosis remains poor, ranking as the sixth most frequent cause of death in the world. This research work aims to adopt an Auxetic (rotating-squares) geometry device, that had previously been examined theoretically and analysed by Grima and Evans (J Mater Sci Lett 19(17):1563-1565, 2000), to produce a novel Auxetic oesophageal stent and stent-grafts relevant to the palliative treatment of oesophageal cancer and also for the prevention of dysphagia. This paper discusses the manufacture of a small diameter Auxetic oesophageal stent and stent-graft. The oral deployment of such an Auxetic stent would be simplest if a commercial balloon dilatational catheter was used as this obviates the need for an expensive dedicated delivery system. A novel manufacturing route was employed in this research to develop both Auxetic films and Auxetic oesophageal stents, which ranged from conventional subtractive techniques to a new additive manufacturing method. Polyurethane was selected as a material for the fabrication of Auxetic films and Auxetic oesophageal stents because of its good biocompatibility and non-toxicological properties. The Auxetic films were later used for the fabrication of seamed Auxetic oesophageal stents. The flexible polyurethane tubular grafts were also attached to the inner luminal side of the seamless Auxetic oesophageal stents, in order to prevent tumour in-growth. Scanning electron microscopy was used to conduct surface morphology study by using different Auxetic specimens developed from different conventional and new additive manufacturing techniques. Tensile testing of the Auxetic films was performed to characterise their mechanical properties. The stent expansion tests of the Auxetic stents were done to analyse the longitudinal extension and radial expansion of the Auxetic stent at a range of radial pressures applied by the balloon catheter, and to also identify the pressure values where the Auxetic stent fails. Finite element models of both Auxetic film and Auxetic stent were developed, and the results were compared with experimental results with a good agreement. The tensile testing of the Auxetic polyurethane films revealed that the Poisson's ratio of the sample ranged between -0.87 and -0.963 at different uniaxial tensile load values. From the stent expansion test, it was found that the Auxetic oesophageal stent radially expanded from 0.5 to 5.73 mm and longitudinally extended from 0.15 to 1.83 mm at a range of applied pressure increments (0.5-2.7 bar) from the balloon catheter.

This article presents a scheme for the analysis of an unsteady axisymmetric flow of incompressible Newtonian material in the form of liquid squeezed between two circular plates. The scheme combines traditional perturbation technique with homotopy using an adaptation of the Laplace Transform. The proposed method is tested against other schemes such as the Regular Perturbation Method (RPM), Homotopy Perturbation Method (HPM), Optimal Homotopy Asymptotic Method (OHAM), and the fourth-order Explicit Runge-Kutta Method (ERK4). Comparison of the solutions along with absolute residual errors confirms that the proposed scheme surpasses HPM, OHAM, RPM, and ERK4 in terms of accuracy. The article also investigates the effect of Reynolds number on the velocity profile and pressure variation graphically.

For a graphG=(V,E), a bijectionffromV(G)∪E(G)→{1,2,…,|V(G)|+|E(G)|}is called(a,d)-edge-antimagic total ((a,d)-EAT) labeling ofGif the edge-weightsw(xy)=f(x)+f(y)+f(xy),xy∈E(G), form an arithmetic progression starting fromaand having a common differenced, wherea>0andd≥0are two fixed integers. An(a,d)-EAT labeling is called super(a,d)-EAT labeling if the vertices are labeled with the smallest possible numbers; that is,f(V)={1,2,…,|V(G)|}. In this paper, we study super(a,d)-EAT labeling of cycles with some pendant edges attached to different vertices of the cycle.

The electrospinning method for scaffold production has emerged as a technique of great versatility within the field of tissue engineering. It is a relatively simple technique that enables scaffolds to be manufactured of the required specifications without much ado. Bone scaffolds are challenging in their requirements for mechanical strength and degradability. Polymeric materials can be most efficiently tailored to meet these demands for such scaffolds. This review focuses on the existing technologies involved in the fabrication of polymeric fibrous and porous scaffolds in bone tissue engineering and regenerative medicine applications, as well as on the emerging technologies that are more promising.

One of the important mechanical properties of materials is Poisson’s ratio, which is positive for most of the materials. However, certain materials exhibit “auxetic” properties; that is, they have a negative Poisson’s ratio. Thus auxetic and non-auxetic materials exhibit different deformation mechanisms. A specific microscopic structure in the auxetic materials is important for maintaining a negative Poisson’s ratio. Based on their distinct nature auxetic materials execute certain unique properties in contrast to other materials, which are reviewed in this paper. Thus auxetic materials have important applications in the biomedical field which are also a part of this review article. Many auxetic materials have been discovered, fabricated, and synthesized which differ on the basis of structure, scale and deformation mechanism. The different types of auxetic materials such as auxetic cellular solids, microscopic auxetic polymers, molecular auxetic materials, and auxetic composites have been reviewed comprehensively in this paper. Modeling of auxetic structures is of considerable importance and needs appropriate stress strain configurations; thus different aspects of auxetic modeling have also been reviewed. Packing parameters and relative densities are of prime importance in this regard. This review would thus help the researchers in determining and deciding the various aspects of auxetic nature for their products.

Oesophageal cancer is the ninth leading cause of malignant cancer death and its prognosis remains poor. Dysphagia which is an inability to swallow is a presenting symptom of oesophageal cancer and is indicative of incurability. The goal of this study was to design and manufacture an Auxetic structure film and to configure this film as an Auxetic stent for the palliative treatment of oesophageal cancer, and for the prevention of dysphagia. Polypropylene was used as a material for its flexibility and non-toxicity. The Auxetic (rotating-square geometry) structure was made by laser cutting the polypropylene film. This flat structure was welded together to form a tubular form (stent), by an adjustable temperature control soldering iron station: following this, an annealing process was also carried out to ease any material stresses. Poisson’s ratio was estimated and elastic and plastic deformation of the Auxetic structure was evaluated. The elastic and plastic deformation behaviours of the Auxetic polypropylene film were evaluated by applying repetitive uniaxial tensile loads. Observation of the structure showed that it was initially elastically deformed, thereafter plastic deformation occurred. This research discusses a novel way of fabricating an Auxetic structure (rotating-squares connected together through hinges) on Polypropylene films, by estimating the Poisson’s ratio and evaluating the plastic deformation relevant to the expansion behaviour of an Auxetic stent within the oesophageal lumen.

The intramedullary nailing as a fixation device has a long history, which dates back to the 16th century and has evolved in various aspects. Now, it has become a gold standard for the treatment for diaphyseal fractures, with a good success rate, however the technique still has some drawbacks associated with it, but continued research regarding new mechanisms and devices can overcome these drawbacks. New osteosynthetic devices, such as intramedullary bone stents can be superior to current fixation devices, as they have a modulus of elasticity closer to that of bone, cause minimum soft tissue damage and trauma. Moreover, they can overcome complications posed by conventional devices, such as stress shielding and an inadequate blood supply. This review focuses on an evolutionary perspective of intramedullary devices used surgically for the repair of long bone diaphyseal fractures.

Internal fixation has been playing a pivotal role in orthopedic surgical procedures, yet the evolution of these devices has been relatively short. There is an uprising increase in the instance of trauma and injury. Therefore to accurately ensure the fracture management; fixation or reduction of fracture to reinstate anatomical associations while maintaining the stability of the fixation device and to preserve the blood supply of soft tissues and bone is advantageous. Internal fixation devices offer sustenance until the bone is entirely rehabilitated. These can also be kept throughout the life time of a recipient. This review focuses on an evolutionary perspective of different devices used surgically for the repair of long bone fractures.

Cardiovascular heart disease is one of the leading healthcare problems in this present era and need much care to prevent from this problem. The main reason for this problem is the accumulation of fats or plaque that blocks coronary arteries of heart which in turn resist the flow of blood to the heart walls and cause serious complications. The advancement in biomedical engineering and fabrication technology along with implantation technique made it possible and convenient to minimize the problems of coronary heart diseases. Small medical implantable device such as coronary stent which is a mesh like tube structure is one such emerging and stunning application which could be implanted in coronary artery with desirable yield and controllability. In this paper we have reviewed about causes of heart arteries blockage due to atherosclerosis and stenosis, about coronary stents implantation technique and different types of coronary stents available in present scenario.