Biosensors constitute selective, sensitive, and rapid tools for disease diagnosis in tissue engineering applications. Compared to standard enzyme-linked immunosorbent assay (ELISA) analytical technology, biosensors provide a strategy to real-time and on-site monitor micro biophysiological signals via a combination of biological, chemical, and physical technologies. This review summarizes the recent and significant advances made in various biosensor technologies for different applications of biological and biomedical interest, especially on tissue engineering applications. Different fabrication techniques utilized for tissue engineering purposes, such as computer numeric control (CNC), photolithographic, casting, and 3D printing technologies are also discussed. Key developments in the cell/tissue-based biosensors, biomolecular sensing strategies, and the expansion of several biochip approaches such as organs-on-chips, paper based-biochips, and flexible biosensors are available. Cell polarity and cell behaviors such as proliferation, differentiation, stimulation response, and metabolism detection are included. Biosensors for diagnosing tissue disease modes such as brain, heart, lung, and liver systems and for bioimaging are discussed. Finally, we discuss the challenges faced by current biosensing techniques and highlight future prospects of biosensors for tissue engineering applications.

A crucial step in creating reliable in vitro platforms for neural development and disorder studies is the reproduction of the multicellular three-dimensional (3D) brain microenvironment and the capturing of cell-cell interactions within the model. The power of self-organization of diverse cell types into brain spheroids could be harnessed to study mechanisms underlying brain development trajectory and diseases. A challenge of current 3D organoid and spheroid models grown in petri-dishes is the lack of control over cellular localization and diversity. To overcome this limitation, neural spheroids can be patterned into customizable 3D structures using microfabrication. We developed a 3D brain-like co-culture construct using embedded 3D bioprinting as a flexible solution for composing heterogenous neural populations with neurospheroids and glia. Specifically, neurospheroid-laden free-standing 3D structures were fabricated in an engineered astrocyte-laden support bath resembling a neural stem cell niche environment. A photo-crosslinkable bioink and a thermal-healing supporting bath were engineered to mimic the mechanical modulus of soft tissue while supporting the formation of self-organizing neurospheroids within elaborate 3D networks. Moreover, bioprinted neurospheroid-laden structures exhibited the capability to differentiate into neuronal cells. These brain-like co-cultures could provide a reproducible platform for modeling neurological diseases, neural regeneration, and drug development and repurposing.

Many animals such as snails and Chinese giant salamanders can secrete mucus for moisturizing, eliminating swelling and inflammation, and promoting wound healing; this implies that high viscous bio-functional materials inspired by mucus may show potential for biomedical applications. Herein, we developed a maltose-like injectable nanocomposite via the combination of chitosan polysaccharide and clay rectorite for hemostasis. Through the hemostatic property of rectorite, the viscous nanocomposite decreased the in vitro clotting time by 43%. Moreover, an in vitro porcine skin model confirmed that the viscous nanocomposite can stably adhere on skin and impede blood bleeding successfully. Importantly, the internal structure of the nanocomposites, chitosan intercalating into rectorite interlayers, provided a physical cross-linked network to decrease the release of rectorite from the nanocomposite and its invasion into the blood. Therefore, this viscous injectable nanocomposite provided a concept for a facile and sustainable biomaterial for skin hemostasis.