While tactile sensors were heralded in the late 1980s as the major development of the coming decade, there was a downward trend that followed. However, with advancement in robotics and computing, tactile sensing has made a comeback.
A tactile sensor is basically able to detect changes in parameters like shape, texture, temperature, vibration, shear/normal forces and touch.
One of the important modern usages of tactile sensing is in the domain of biomedical applications and systems for unstructured environments. Many times a current sensor is relied on for such a project and these sensors are later adjusted as per the system requirement.
Advancement in nanotechnology is a major boost where tactile sensors can be inserted in different biopolymers and grafted in the skin. Various materials are used in the production of such biopolymers–successful ones include hyaluronic acid along with chondroitin sulfate.
Such grafts that are adjusted with sensors are being used in the case of burn victims. Normally, it’s difficult for skin regeneration for second and third degree burns, but nano-sheaths have allowed professionals to achieve such grafts.
The defining goal of biomedical (tissue) engineering is to make a bio-system that is able to restore, maintain and improve the tissue function.
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Gelatin chondroitin 6-sulfate hyaluronic acid (gelatin C6S HA) is a biopolymer which can effectively mimic the extracellular matrix of the skin. The polymer can provide an ideal environment for cell growth, leading to development of real skin tissue.
The reason why a number of synthetic skin based applications are not successful is that they are grown in 2D monolayers. The skin cell behavior depends on the cell itself and its neighbors along with the extra cellular matrix.
2D monolayers aren’t able to completely encapsulate the complexity of the microenvironment. These cells are generally devoid of some important signals, regulators and phenotypes that are important for normal skin function. However, using tactile sensors, these issues can be circumvented.
A well described example is the case of engineering mouse with human ear using tactile sensors. This study involved the usage of chondrocytes in combination with a polymer, polyglycolic acid to form a scaffold (has tactile sensors), and mimic the human ear. This ear was then transplanted in a nude mouse. After the reconstruction surgery, new cartilage develops within a 12 week time period.
As far as recent models are concerned, there’s the example of a tissue engineering airway. The methodology focuses on removal of all antigens from a donor trachea. The wind pipe provides with them a matrix in which autogenic cells are seeded. The engineering wind pipe is surgically transplanted in the patient. The engineering wind pipe is functional within a four month time period, and till now has indicated a natural appearance with good mechanical functionality.
The strength of the engineered tissue can be increased with the help of elctrospun protein fiber. In studies, coaxial electrospinning has been used to combine a synthetic core to gelatin fiber. The result was more strength of the scaffold without disrupting its biologically active shell. And if a tactile sensor is added, it’s possible to improve the efficiency of the system.
All of this shows how science is heavily emerging as an integrated approach, with a number of sectors merging together.