In situ bioprinting
One of the promising applications of bioprinting is to pattern de novo tissue directly onto the desired location in the body, such as chronic wounds in the skin or bone defect. With the aid of medical imaging, the topology of printed tissue can be designed to fit into the wound/defects such that heterotypic cellular structure, hydrogels, and soluble factors can be precisely deposited inside the defects. This approach would minimize the gap between implant-host interfaces and provide well-defined structure during the healing process, which can effectively recruit desired cells from surrounding tissues where the patient’s body act as a natural bioreactor (Vivian and Dai, 2016). In a recent proof-of-concept study, Albana et al 2019, demonstrated precise delivery of autologous/allogeneic dermal fibroblasts and epidermal keratinocytes directly into an injured area in animals, replicating the layered skin structure. Excisional wounds bioprinted with layered autologous dermal fibroblasts and epidermal keratinocytes in a hydrogel carrier showed rapid wound closure, reduced contraction and accelerated re-epithelialization. These results showed the feasibility of in situ bioprinting of skin and its potential applications for regeneration of various body parts. A successful in situ bioprinting technique could rapidly accelerate healing using cell therapy, where cells can be isolated from a small biopsy [Normand and Karasek, 1995].