Honey: An Advanced Antimicrobial and Wound Healing Biomaterial for Tissue Engineering Applications

Honey was used in traditional medicine to treat wounds until the advent of modern medicine. The rising global antibiotic resistance has forced the development of novel therapies as alternatives to combat infections. Consequently, honey is experiencing a resurgence in evaluation for antimicrobial and wound healing applications. A range of both Gram-positive and Gram-negative bacteria, including antibiotic-resistant strains and biofilms, are inhibited by honey. Furthermore, susceptibility to antibiotics can be restored when used synergistically with honey. Honey’s antimicrobial activity also includes antifungal and antiviral properties, and in most varieties of honey, its activity is attributed to the enzymatic generation of hydrogen peroxide, a reactive oxygen species. Non-peroxide factors include low water activity, acidity, phenolic content, defensin-1, and methylglyoxal (Leptospermum honeys). Honey has also been widely explored as a tissue-regenerative agent. It can contribute to all stages of wound healing, and thus has been used in direct application and in dressings. The difficulty of the sustained delivery of honey’s active ingredients to the wound site has driven the development of tissue engineering approaches (e.g., electrospinning and hydrogels). This review presents the most in-depth and up-to-date comprehensive overview of honey’s antimicrobial and wound healing properties, commercial and medical uses, and its growing experimental use in tissue-engineered scaffolds

Recent Advances in Enzymatic and Non-Enzymatic Electrochemical Glucose Sensing

From MDPI via Jisc Publications RouterHistory: accepted 2021-07-06, pub-electronic 2021-07-08Publication status: PublishedFunder: Engineering and Physical Sciences Research Council; Grant(s): EP/R513131/1The detection of glucose is crucial in the management of diabetes and other medical conditions but also crucial in a wide range of industries such as food and beverages. The development of glucose sensors in the past century has allowed diabetic patients to effectively manage their disease and has saved lives. First-generation glucose sensors have considerable limitations in sensitivity and selectivity which has spurred the development of more advanced approaches for both the medical and industrial sectors. The wide range of application areas has resulted in a range of materials and fabrication techniques to produce novel glucose sensors that have higher sensitivity and selectivity, lower cost, and are simpler to use. A major focus has been on the development of enzymatic electrochemical sensors, typically using glucose oxidase. However, non-enzymatic approaches using direct electrochemistry of glucose on noble metals are now a viable approach in glucose biosensor design. This review discusses the mechanisms of electrochemical glucose sensing with a focus on the different generations of enzymatic-based sensors, their recent advances, and provides an overview of the next generation of non-enzymatic sensors. Advancements in manufacturing techniques and materials are key in propelling the field of glucose sensing, however, significant limitations remain which are highlighted in this review and requires addressing to obtain a more stable, sensitive, selective, cost efficient, and real-time glucose sensor

ROS-releasing PVA sub-micron antimicrobial dressing with enhanced aqueous stability and mechanical properties

This study aimed to develop a biocompatible nanofibrous mesh for wound healing applications that is stable in aqueous environments. The mesh was produced by electrospinning RO-101-loaded polyvinyl alcohol (PVA) fibres and crosslinking them using glutaraldehyde (GA) vapour exposure. RO-101™ is a wound gel that produces therapeutic levels of hydrogen peroxide (H2O2). The results of Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed successful incorporation of RO-101 wound gel and crosslinking of the mesh, with average fibre diameters of 400 nm. The vapour crosslinking process resulted in enhanced mechanical strength and flexibility, improved aqueous stability, and an increase in contact angle compared to the uncrosslinked mesh whilst maintaining hydrophilicity. The vapour-crosslinked mesh also demonstrated sustained release of H2O2 at similar concentrations (1103 ± 199 μM g−1 mL−1) to the uncrosslinked mesh, but with a more gradual release. The developed mesh showed antimicrobial activity against S. aureus and its released H2O2 presented no cytotoxicity in human adipose-derived stem cells (hADSCs) metabolic activity. Overall, the developed mesh has potential for wound healing applications, providing a barrier against infection and promoting tissue regeneration

Biological perspectives and current biofabrication strategies in osteochondral tissue engineering

From Springer Nature via Jisc Publications RouterHistory: received 2019-09-26, accepted 2020-06-29, registration 2020-06-29, pub-electronic 2020-07-09, online 2020-07-09, pub-print 2020-12Publication status: PublishedFunder: Engineering and Physical Sciences Research Council; doi: http://dx.doi.org/10.13039/501100000266; Grant(s): EP/L014904/1Funder: Fundação para a Ciência e a Tecnologia; doi: http://dx.doi.org/10.13039/501100001871; Grant(s): PTDC/MEC-GIN/29232/2017, 0245_IBEROS_1_EAbstract: Articular cartilage and the underlying subchondral bone are crucial in human movement and when damaged through disease or trauma impacts severely on quality of life. Cartilage has a limited regenerative capacity due to its avascular composition and current therapeutic interventions have limited efficacy. With a rapidly ageing population globally, the numbers of patients requiring therapy for osteochondral disorders is rising, leading to increasing pressures on healthcare systems. Research into novel therapies using tissue engineering has become a priority. However, rational design of biomimetic and clinically effective tissue constructs requires basic understanding of osteochondral biological composition, structure, and mechanical properties. Furthermore, consideration of material design, scaffold architecture, and biofabrication strategies, is needed to assist in the development of tissue engineering therapies enabling successful translation into the clinical arena. This review provides a starting point for any researcher investigating tissue engineering for osteochondral applications. An overview of biological properties of osteochondral tissue, current clinical practices, the role of tissue engineering and biofabrication, and key challenges associated with new treatments is provided. Developing precisely engineered tissue constructs with mechanical and phenotypic stability is the goal. Future work should focus on multi-stimulatory environments, long-term studies to determine phenotypic alterations and tissue formation, and the development of novel bioreactor systems that can more accurately resemble the in vivo environment

Honey: an advanced antimicrobial and wound healing biomaterial for tissue engineering applications

Honey was used in traditional medicine to treat wounds until the advent of modern medicine. The rising global antibiotic resistance has forced the development of novel therapies as alternatives to combat infections. Consequently, honey is experiencing a resurgence in evaluation for antimicrobial and wound healing applications. A range of both Gram-positive and Gram-negative bacteria, including antibiotic-resistant strains and biofilms, are inhibited by honey. Furthermore, susceptibility to antibiotics can be restored when used synergistically with honey. Honey’s antimicrobial activity also includes antifungal and antiviral properties, and in most varieties of honey, its activity is attributed to the enzymatic generation of hydrogen peroxide, a reactive oxygen species. Non-peroxide factors include low water activity, acidity, phenolic content, defensin-1, and methylglyoxal (Leptospermum honeys). Honey has also been widely explored as a tissue-regenerative agent. It can contribute to all stages of wound healing, and thus has been used in direct application and in dressings. The difficulty of the sustained delivery of honey’s active ingredients to the wound site has driven the development of tissue engineering approaches (e.g., electrospinning and hydrogels). This review presents the most in-depth and up-to-date comprehensive overview of honey’s antimicrobial and wound healing properties, commercial and medical uses, and its growing experimental use in tissue-engineered scaffolds

Outcomes of elective liver surgery worldwide: a global, prospective, multicenter, cross-sectional study

Background: The outcomes of liver surgery worldwide remain unknown. The true population-based outcomes are likely different to those vastly reported that reflect the activity of highly specialized academic centers. The aim of this study was to measure the true worldwide practice of liver surgery and associated outcomes by recruiting from centers across the globe. The geographic distribution of liver surgery activity and complexity was also evaluated to further understand variations in outcomes. Methods: LiverGroup.org was an international, prospective, multicenter, cross-sectional study following the Global Surgery Collaborative Snapshot Research approach with a 3-month prospective, consecutive patient enrollment within January–December 2019. Each patient was followed up for 90 days postoperatively. All patients undergoing liver surgery at their respective centers were eligible for study inclusion. Basic demographics, patient and operation characteristics were collected. Morbidity was recorded according to the Clavien–Dindo Classification of Surgical Complications. Country-based and hospital-based data were collected, including the Human Development Index (HDI). (NCT03768141). Results: A total of 2159 patients were included from six continents. Surgery was performed for cancer in 1785 (83%) patients. Of all patients, 912 (42%) experienced a postoperative complication of any severity, while the major complication rate was 16% (341/2159). The overall 90-day mortality rate after liver surgery was 3.8% (82/2,159). The overall failure to rescue rate was 11% (82/ 722) ranging from 5 to 35% among the higher and lower HDI groups, respectively. Conclusions: This is the first to our knowledge global surgery study specifically designed and conducted for specialized liver surgery. The authors identified failure to rescue as a significant potentially modifiable factor for mortality after liver surgery, mostly related to lower Human Development Index countries. Members of the LiverGroup.org network could now work together to develop quality improvement collaboratives

Hybrid biomanufacturing systems applied in tissue regeneration

Scaffold-based approach is a developed strategy in biomanufacturing, which is based on the use of temporary scaffold that performs as a house of implanted cells for their attachment, proliferation, and differentiation. This strategy strongly depends on both materials and manufacturing processes. However, it is very difficult to meet all the requirements, such as biocompatibility, biodegradability, mechanical strength, and promotion of cell-adhesion, using only single material. At present, no single bioprinting technique can meet the requirements for tissue regeneration of all scales. Thus, multi-material and mixing-material scaffolds have been widely investigated. Challenges in terms of resolution, uniform cell distribution, and tissue formation are still the obstacles in the development of bioprinting technique. Hybrid bioprinting techniques have been developed to print scaffolds with improved properties in both mechanical and biological aspects for broad biomedical engineering applications. In this review, we introduce the basic multi-head bioprinters, semi-hybrid and fully-hybrid biomanufacturing systems, highlighting the modifications, the improved properties and the effect on the complex tissue regeneration applications.</p

Crystal Growth of 3D Poly(ε-caprolactone) Based Bone Scaffolds and Its Effects on the Physical Properties and Cellular Interactions

Extrusion additive manufacturing is widely used to fabricate polymer‐based 3D bone scaffolds. However, the insight views of crystal growths, scaffold features and eventually cell‐scaffold interactions are still unknown. In this work, melt and solvent extrusion additive manufacturing techniques are used to produce scaffolds considering highly analogous printing conditions. Results show that the scaffolds produced by these two techniques present distinct physiochemical properties, with melt‐printed scaffolds showing stronger mechanical properties and solvent‐printed scaffolds showing rougher surface, higher degradation rate, and faster stress relaxation. These differences are attributed to the two different crystal growth kinetics, temperature‐induced crystallization (TIC) and strain‐induced crystallization (SIC), forming large/integrated spherulite‐like and a small/fragmented lamella‐like crystal regions respectively. The stiffer substrate of melt‐printed scaffolds contributes to higher ratio of nuclear Yes‐associated protein (YAP) allocation, favoring cell proliferation and differentiation. Faster relaxation and degradation of solvent‐printed scaffolds result in dynamic surface, contributing to an early‐stage faster osteogenesis differentiation