Biomaterials as Chemical Sensors

Recently, biomaterials have been used in a wide array of applications such as drug delivery, tissue engineering, and therapeutic, they are now being applied even as a chemical sensor for detecting internal and external environment (Sun et al. 2018). A variation of the biosensor can be achieved by modifying the materials, for example, the sensor consists of hyaluronic acid that can be used to detect cancer due to abundant CD44 receptors on the tumor microenvironment (Bhattacharya et al. 2017 a). Other solid examples are the use of boronic functional group to quantify the glucose or the use of redox-responsive system that prefers oxidation-reduction precursors such as ROS (H2O2), protein (cysteine), or antioxidant (GSH) (Schumacker 2006, Rusin et al. 2004, Jung et al. 2018, Zhou et al. 2018). Every stimulant located inside the system, such as the cellular microenvironment, can be defined as internal stimuli, while the stimuli that are found or originate from outside of the system, can be described as external stimuli. For cancer optical diagnosis using fluorescence nanoparticles, several internal factors have been analyzed in the past 20 years, such as pH, the redox level, the overexpress enzyme or protein, or any other abnormal status that separate healthy condition and tumor. On the other hand, temperature, heat, light, magnetic field, and electronic field are identified as external trigger (Schumacker 2006, Rusin et al. 2004, Jung et al. 2018, Zhou et al. 2018, Mazrad et al. 2018). As the amount of stimuli is massively present, the huge possibility for biomaterials sensing not only for 2-D but also prospect for 3-D application including prosthetic, actuating, and human motion is also implied.