Skin bioprinting: a novel approach for creating artificial skin from synthetic and natural building blocks

Significant progress has been made over the past few decades in the development of in vitro-engineered substitutes that mimic human skin, either as grafts for the replacement of lost skin, or for the establishment of in vitro human skin models. Tissue engineering has been developing as a novel strategy by employing the recent advances in various fields such as polymer engineering, bioengineering, stem cell research and nanomedicine. Recently, an advancement of 3D printing technology referred as bioprinting was exploited to make cell loaded scaffolds to produce constructs which are more matching with the native tissue. Bioprinting facilitates the simultaneous and highly specific deposition of multiple types of skin cells and biomaterials, a process that is lacking in conventional skin tissue-engineering approaches. Bioprinted skin substitutes or equivalents containing dermal and epidermal components offer a promising approach in skin bioengineering. Various materials including synthetic and natural biopolymers and cells with or without signalling molecules like growth factors are being utilized to produce functional skin constructs. This technology emerging as a novel strategy to overcome the current bottle-necks in skin tissue engineering such as poor vascularization, absence of hair follicles and sweat glands in the construct

Electrospun polymer nanocomposite scaffolds containing metal oxide nanoparticles for diabetic wound healing

It is very important to treat diabetic foot injuries at early stage since even minor wounds can turn into serious foot ulcers which can lead to the amputation of the entire foot if not treated early. The management of diabetic foot ulcers requires the use of appropriate wound dressings to provide a moist wound environment and protect from infection. Large number of polymeric materials has been tried for wound coverage applications with many successful outcomes, but the search for an ideal wound dressing material which can enhance diabetic wound healing is still continuing. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), commonly known as PHBV has got a lot of attention in biomedical applications due to its biocompatibility and biodegradability Electrospinning is a robust technique that can produce highly porous membranes composed of nano or submicron fibers from polymer solutions. Formation of active blood vessel network through an implanted wound dressing is one of the most important issues in the treatment of diabetic wounds. Ability of metal oxide nanostructures to promote angiogenesis and wound healing is already established. Thus, in the present work, electrospun PHBV wound dressings containing metal oxide nanoparticles were fabricated and characterized. Our results demonstrated that metal oxide nanoparticles in the wound dressings enhanced human cell adhesion and their migration. Further, angiogenic property of the membranes was enhanced as evident from chicken chorioallantoic membrane assay and leads to the enhancement of diabetic wound healing. Present study strongly suggest the potential application of metal oxide nanoparticles incorporated PHBV scaffolds in promoting angiogenesis and their effective use in diabetic wound healing.qscienc

CTGF Loaded Electrospun Dual Porous Core-Shell Membrane For Diabetic Wound Healing

Purpose: Impairment of wound healing is a major issue in type-2 diabetes that often causes chronic infections, eventually leading to limb and/or organ amputation. Connective tissue growth factor (CTGF) is a signaling molecule with several roles in tissue repair and regeneration including promoting cell adhesion, cell migration, cell proliferation and angiogenesis. Incorporation of CTGF in a biodegradable core-shell fiber to facilitate its sustained release is a novel approach to promote angiogenesis, cell migration and facilitate wound healing. In this paper, we report the development of CTGF encapsulated electrospun dual porous PLA-PVA core-shell fiber based membranes for diabetic wound healing applications. Methods: The membranes were fabricated by a core-shell electrospinning technique. CTGF was entrapped within the PVA core which was coated by a thin layer of PLA. The developed membranes were characterized by techniques such as Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) analysis. In vitro cell culture studies using fibroblasts, keratinocytes and endothelial cells were performed to understand the effect of CTGF loaded membranes on cell proliferation, cell viability and cell migration. A chicken chorioallantoic membrane (CAM) assay was performed to determine the angiogenic potential of the membranes. Results: Results showed that the developed membranes were highly porous in morphology with secondary pore formation on the surface of individual fibers. In vitro cell culture studies demonstrated that CTGF loaded core-shell membranes improved cell viability, cell proliferation and cell migration. A sustained release of CTGF from the core-shell fibers was observed for an extended time period. Moreover, the CAM assay showed that core-shell membranes incorporated with CTGF can enhance angiogenesis. Conclusion: Owing to the excellent cell proliferation, migration and angiogenic potential of CTGF loaded core-shell PLA-PVA fibrous membranes, they can be used as an excellent wound dressing membrane for treating diabetic wounds and other chronic ulcers.This article was made possible by the NPRP9-144-3-021 grant funded by the Qatar National Research Fund (a part of the Qatar Foundation). We also acknowledge the support provided by the Central Laboratories Unit (CLU), Qatar University, Qatar. The statements made herein are solely the responsibility of the authors. The publication of this article was funded by the Qatar National Library. The authors also acknowledge Huseyin Cagatay Yalcin and Ala-Eddin Al Moustafa for sharing resources during the initial stage of this project.Scopu

A novel in ovo model to study cancer metastasis using chicken embryos and GFP expressing cancer cells.

Cancer metastasis is the leading cause of cancer-related mortality worldwide. To date, several in vitro methodologies have been developed to understand the mechanisms of cancer metastasis and to screen various therapeutic agents against it. Nevertheless, mimicking an in vivo microenvironment in vitro is not possible; while in vivo experiments are complex, expensive and bound with several regulatory requirements. Herein, we report a novel in ovo model that relies on chicken embryo to investigate cancer cell invasion and metastasis to various organs of the body. In this model, we directly inject green fluorescent protein (GFP) expressing cancer cells to the heart of chicken embryo at 3 days of incubation, then monitor cell migration to various organs. To this end, we used a simple tissue processing technique to achieve rapid imaging and quantification of invasive cells. We were able to clearly observe the migration of GFP expressing cancer cells into various organs of chicken embryo. Organ specific variation in cell migration was also observed. Our new slide pressing based tissue processing technique improved the detectability of migrated cells. We herein demonstrate that the use of GFP expressing cancer cells allows easy detection and quantification of migrated cancer cells in the chicken embryo model, which minimizes the time and effort required in this types of studies compared to conventional histopathological analysis. In conclusion, our investigation provides a new cancer metastasis model that can be further improved to include more complex aspects, such as the use of multiple cell lines and anti-metastatic agents, thus opening new horizons in cancer biology and pharmaceutical research

Loop-mediated isothermal amplification (Lamp): A rapid, sensitive, specific, and cost-effective point-of-care test for coronaviruses in the context of covid-19 pandemic

The rampant spread of COVID-19 and the worldwide prevalence of infected cases demand a rapid, simple, and cost-effective Point of Care Test (PoCT) for the accurate diagnosis of this pandemic. The most common molecular tests approved by regulatory bodies across the world for COVID-19 diagnosis are based on Polymerase Chain Reaction (PCR). While PCR-based tests are highly sensitive, specific, and remarkably reliable, they have many limitations ranging from the requirement of sophisticated laboratories, need of skilled personnel, use of complex protocol, long wait times for results, and an overall high cost per test. These limitations have inspired researchers to search for alternative diagnostic methods that are fast, economical, and executable in low-resource laboratory settings. The discovery of Loop-mediated isothermal Amplification (LAMP) has provided a reliable substitute platform for the accurate detection of low copy number nucleic acids in the diagnosis of several viral diseases, including epidemics like Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS). At present, a cocktail of LAMP assay reagents along with reverse transcriptase enzyme (Reverse Transcription LAMP, RT-LAMP) can be a robust solution for the rapid and cost-effective diagnosis for COVID-19, particularly in developing, and low-income countries. In summary, the development of RT-LAMP based diagnostic tools in a paper/strip format or the integration of this method into a microfluidic platform such as a Lab-on-a-chip may revolutionize the concept of PoCT for COVID-19 diagnosis. This review discusses the principle, technology and past research underpinning the success for using this method for diagnosing MERS and SARS, in addition to ongoing research, and the prominent prospect of RT-LAMP in the context of COVID-19 diagnosis

Electrospun polylactic acid/date palm polyphenol extract nanofibres for tissue engineering applications

In this study, a set of polylactic acid (PLA)/polyphenol extracted from date palm fruit (DP) blends were prepared by electrospinning process to be used as cell culture scaffolds for tissue engineering applications. For this purpose, PLA/DP blends with variable composition were dissolved in dichloromethane/dimethylformamide (70:30, v/v) mixture and then electrospun to obtain the fibres. Contact angle measurements, dynamic mechanical analysis, mechanical tensile and scanning electron microscopy (SEM) tools were used to study the physico-mechanical properties of the electrospun scaffolds. The results revealed that scaffolds became more hydrophilic with addition of DP. Increasing the polyphenol concentration caused the tensile strength and Young's modulus to decrease. The SEM graphs indicated a decrease in fibre diameter with increasing DP content. In addition, it was found that both cell proliferation and cell viability were enhanced with increased DP concentration within the scaffolds. The scratch test shows that there is an enhancement in cell migration through the scratch for PLA/DP scaffolds; again, higher DP content resulted better migration. Our results suggest that improved mechanical properties, decreased fibre diameter and enhanced hydrophilicity with addition of DP improved cell migration and cell adhesion for the scaffolds. Overall, these results demonstrate that DP is a potential natural cell-friendly product for tissue engineering applications such as tissue regeneration or wound healing assays

Dose-dependent effects of gamma irradiation on the materials properties and cell proliferation of electrospun polycaprolactone tissue engineering scaffolds

Electrospun membranes of polycaprolactone are widely used for biomedical applications like wound dressings and tissue engineering scaffolds. It is important to sterilize this material using the most accepted method, the gamma irradiation. In this study, we have evaluated the sterilizability of electrospun polycaprolactone membranes with gamma radiation of varying doses. The irradiated materials were assessed for the changes in morphology, crystallinity, surface degradation, hydrophilicity, mechanical property, sterility and the cell proliferation. Our results demonstrate that electrospun polycaprolactone can be effectively sterilized by gamma irradiation, however a higher dose of radiation affect the materials properties. The irradiated membranes showed improved hydrophilicity and fibroblast cell proliferation.Department of Biotechnology (DBT), Government of India, New Delhi.MSUB IPLSARE program.http://www.tandfonline.com/loi/gpom202016-01-31hb201

Experimental evidence that livestock grazing intensity affects cyclic vole population regulation processes

Peer reviewedPublisher PD

Rwanda Nutrition, Markets and Gender Analysis 2015: An integrated approach towards alleviating malnutrition among vulnerable populations in Rwanda

The Nutrition, Markets and Gender (NMG) Survey was conducted in Rwanda to investigate the causes of malnutrition in children under 24 months. The NMG Survey was informed by the 2010 Demographic Health Survey (DHS) for Rwanda that gave some insight into the knowledge and trend of malnutrition in the country for the period 2005 to 2010. The DHS results indicated a 6 percent decline in stunting among children under the age of five years. The key findings from the 2014/2015 DHS that followed the same delineation as the DHS 2010 provided the most current status of malnutrition in Rwanda and showed further overall improvements in child growth outcomes with 37.9 percent of children under five years classified as stunted. These results again indicated a 6.3 percent decline in stunting among children under the age of five years for the period 2010 to 2015. This progressive trend is a testament to the country’s commitments to prioritise nutrition issues and nutrition programmes in its development agenda. The Government of Rwanda, through the Ministry of Health, has prioritised malaria control, nutrition education, and better public healthcare. However, in spite of the advancements made, the consensus is that high rates of chronic malnutrition among children still prevail. Thus a better understanding of risk factors that contribute to child malnutrition at the household level in Rwanda was needed to strengthen the fight against malnutrition in the country. The ‘Comprehensive Food Security and Vulnerability and Nutrition Analysis’ – CFSVA 2012 – report produced by the Ministry of Agriculture and Animal Resources (MINAGRI), the National Institute of Statistics of Rwanda (NISR) and the World Food Programme (WFP) acknowledged that vulnerable households are increasingly reliant on markets as a source of food; providing on average 65 percent of the food consumed by a household. It is therefore clear that household nutrition outcomes in such households are dependent on markets. In addition, it is widely accepted that gender dynamics influence decision-making in the household. Thus gender dynamics affect decisions related to food, care, markets, and health. Therefore this survey focused on nutrition, markets, and gender to determine the factors that influence the nutrition status of children under 24 months. Moreover, a disconnect between agricultural production and nutrition outcomes was revealed in the CFSVA 2012 report that indicated that the northern agricultural zones, considered the bread basket of the country, had stunting rates of up to 66 percent in children under 60 months

BAN antenna design using ferrite polymer composite

Wearable antennas are an integral part of body area networks (BAN). Antenna design for BAN applications is a challenging task since the antennas have to be small, efficient and must not be affected by the wearer's body. This makes isolation of antenna a matter of importance. Ferrites form an opaque media for microwave at the ISM frequencies and hence it could be used for the isolation of antenna from surroundings. Thin polymeric ferrite sheets are used to reduce body influence in BAN perspective