Functionally graded additive manufacturing to achieve functionality specifications of osteochondral scaffolds

Osteoarthritis (OA) is a degenerative joint disease, characterized by cartilage loss and changes in bone at the interface of a joint resulting in pain, stiffness and reduced mobility. OA is one of the most prevalent chronic conditions as identified in Bone and Joint Decade. According to the World Health Organization, 40% of people over the age of 70 have OA. This joint disease affects around 0.4 billion people with patients in Europe accounting for up to 30%. The figure is set to increase with the ageing problem. Current non-surgical treatments for OA involve non-steroidal anti-inflammatory drug administration. Surgical treatments include osteotomy, abrasion arthroplasty, micro-fracture and autologous chondrocyte implantation (ACI). This is a two-stage surgical procedure with the associate costs and infection being the main concern. For small osteochondral defects, micro-fracture (MF) marrow stimulation and for large cartilaginous defects the autologous chondrocyte implantation are considered as necessary treatments. However, MF produces fibrocartilage not native hyaline cartilage. For defects that have progressed to a stage that affects the subchondral bone, other treatments are no longer effective and joint replacement operation is the only alternative. The demand for innovative therapeutic alternatives for complete healing of OA is significant. The treatment of cartilage and osteochondral (OC) defects remains a challenge since treatments so far have failed to achieve complete restoration of the properties of joint cartilage. Many new technologies, such as osteochondral tissue engineering, have been studied and applied to repair osteochondral defects. Commercially available osteochondral scaffolds have been used in patients with OC defects. However, no products have so far demonstrated to provide biomechanical properties suitable to promote the durable regeneration of large OC defects [1]. The main issue with these commercially available OC scaffolds is poor cartilage fill associated with fibrocartilage formation. The aim of this paper is to define the functionality and performance which would be required for intended clinical applications in the treatment of osteoarthritis and also to show that the capabilities of 3D bioprinting and functionally graded additive manufacturing scaffolds are suitable to meet most of these requirements.The authors would like to thank H2020-MSCARISE programme, as this work is part of developments carried out in BAMOS project, funded from the European Union’s Horizon 2020 research and innovation programme under Grant Agreement No. 734156.info:eu-repo/semantics/publishedVersio

Solitary bees as pollinators

Besides the wind, insects are the main pollinating agents and many of them are hymenopterans. However, among the 20,000 species of bees (Superfamily Apoidea), only a very restricted group has been domesticated for commercial crop pollination, including social and solitary species. The honey bee Apis mellifera L. has been the first domesticated pollinator species, anyway, many cultivated crops benefit largely from the activity of other pollinators, especially when honey bees cannot provide a sufficient pollination service. This occurrence is particularly frequent in crops blooming in early spring or in crops with flowers not enough attractive to honey bees, i.e. because of low nectar and pollen production or for particular flower shapes. In addition to these ecological aspects, which are the result of a long history of coevolution between insects and flowers, modern agriculture and the well-known difficulties that honey bees are suffering of, create new concern that a general decline in the native pollinator populations will have unavoidable consequences on crop production due to insufficient pollination service. The most striking contradiction of the “industrial” extensive monocultures is that on one side they put in forth the need of enormous number of pollinators to satisfy the vast number of flowers contemporarily ready to be pollinated; on the other side, they cancel from the agroecosystem uncultivated meadows, edges and forests, which serve as refuge and conservation areas. The immediate repercussion on pollinating insects is the lack of continuity in blooms: on large areas, flowers are extremely abundant during the short blooming period of the main crops and nearly almost absent in the remaining part of their reproductive season (what is called “green desert”). In addition, very often a dramatic reduction of adequate nesting sites and materials may strongly limit the reproductive success, while, up today, the knowledge about the acute and chronic effects of pesticides on native bees is still insufficient

Towards a sustainable management of bees of the subgenus Osmia (Megachilidae; Osmia) as fruit tree pollinators

International audienceThe limited pollination efficiency of honeybees (Apidae; Apis) for certain crop plants and, more recently, their global decline fostered commercial development of further bee species to complement crop pollination in agricultural systems. In particular, a number of mason bees (Megachilidae; Osmia) are among the most widely used alternative pollinators, and their utilisation has been fine-tuned specifically for pollination in fruit tree orchards. A successful management system should not only aim at optimising pollination efficiency but also consider the relevant biological and ecological requirements to achieve sustainable and healthy bee populations. Here, we review the factors influencing the rate of population increase during the implementation of Osmia bees as orchard pollinators. These factors include nesting material, release methods, and control of antagonists as well as methods optimising management of developmental stages to synchronize bee activity with orchard bloom and to minimize developmental mortality