Table 1.

Potential of alternative transplantology technologies.

	3D bioprinting [25,26]	Nanotechnology in transplantology [27]	Cells encapsulation [28]	Organoids [29]
Applied technique	Bioprinting is a technology where bioinks and biomaterials, mixed with cells, are 3D printed to construct living tissue models. Construction of many tissues/organs (skin, blood vessel, adipose tissue, bone/cartilage, heart, liver, kidney, muscle, and nerve)	Nanotechnology in stem-cell-based therapy is applied in neurodegenerative disease, anti-tumor, and gene delivery	Cell encapsulation technology involves immobilization of cells within a polymeric semi-permeable membrane. Therapeutic applications (diabetes, cancer, liver and pancreatic disease, heart diseases, monoclonal antibody therapy)	Organoids are self-organized three-dimensional tissue cultures that are derived from stem cells. Ideal model for preclinical drug toxicity evaluation. Application in regenerative medicine (repair damaged tissues and organs)
Resolution	30–200 μm	1–100 nm	Capsule permeability <1 μm	>500 μm
Materials used	Hydrogels, decellularized matrix components, tissue spheroids and strands, cell pellet, and nanocomposites	Non-toxic and biodegradable nanomaterials such collagen nanofiber, carbon nanofiber, graphene, Quantum dots, gelatin-hydroxyapatite, gold nanoparticles, liposomes.	Microcapsules made of polimer (alginate), cellulose sulphate, collagen, chitosan, gelatin, and agarose	Stem cells are seeded on matrices of biological origin (matrigel, hydrogels)
Cell viability	>90%	No data available.	<50%	80–90%
Cost/ease of operation	Low/medium	High/medium	Mediumlow	Low/medium
Implemantation potential/applicable	High	Medium	High	Medium
Selected disadvantages	Functionalization is the core factor of 3D bioprinting. Bioinks need to possess good biocompatibility and mechanical property	High concentrations of reagents may cause artifacts. Barriers to clinical implementation of nanoparticles	Inflammatory response, and consequently, to rejection of the transplant	Heterogeneity of cultured organoids. Potential tumorigenicity of using matrix gel in organoid culture. Organoid cultivation is time- and labor-intensive
Future perspective	Future bioprinters could be made clinician-friendly, easy to use and maintain, and customized for specific types of tissues	Personalized immunosuppressive regimens to avoid graft rejection. Cell-specific drug targeting in therapy diseases	Cell encapsulation could the former allows a sustained and controlled delivery of therapeutic molecules that prevent immune response while permitting easy in vivo transplantation	Good preclinical model for human disease research and drug development – personalized medicine