Design principles of ion-selective nano-structured membranes for the extraction of lithium ions It is predicted that the continuously increasing demand for the energy-critical element of lithium will soon exceed its availability, rendering it a geopolitically significant resource. The present work critically reviews recent reports on Li+ selective membranes. Particular emphasis has been placed on the basic principles of the materials’ design for the development of membranes with nanochannels and nanopores with Li+ selectivity. Fundamental and practical challenges, as well as prospects for the targeted design of Li+ ion-selective membranes are also presented, with the goal of inspiring future critical research efforts in this scientifically and strategically important field.
Transistor based chemical sensors for water contamination monitoring
Heavy metals such as Mercury, Lead are known to be an extremely toxic metal that can lead to irreversible damage to human, animal and plant life. Furthermore, they have a tendency to bio-accumulate in living organisms meaning that even a very low level of exposure to mercury over a long period of time can lead to adverse effects. Therefore, it is essential that heavy metal levels in drinking water and other bodies of water are monitored carefully. In situ techniques such as ISEs also have the added advantage that the sample is more likely to be representative of the environment and less likely to have degraded during transport from the field to the lab. However, for ISEs themselves, the underlying electrode configuration requiring a reference electrode and a filling solution limits their widespread use. Si-based ion selective field effect transistor (ISFET) devices have been investigated to solve the portability and robustness issues related to ISEs; however, chemical/thermal instability of silicon in aqueous solutions and the requirement for a reference electrode remain.
In this project with aim to develop AlGaN/GaN high electron mobility transistor-type structure chemical sensors by functionalizing the gate area with a polyvinyl chloride (PVC) based ion selective membrane to measure heavy metals in water. Sensors based on this technology are portable, robust and typically highly sensitive to the target analyte.
(a) A schematic of GaN-capped AlGaN/GaN ISFET sensor cross-section with deposited membrane. (b) A schematic of the device showing the terminals and membrane. (c) An optical image of the sensor showing the contact and active area. (d) An optical image of the device after packaging.
Selected other papers in this field:
 M. A. Amir Razmjou, Ehsan Hosseini, Asghar Habibnejad Korayem, Vicki Chen, "Design principles of ion selective nanostructured membranes for the extraction of lithium ions," Nature Communications, vol. 10, p. 5793, 2019.
 Y. Boroumand, A. Razmjou, P. Moazzam, F. Mohagheghian, G. Eshaghi, Z. Etemadifar, et al., "Mussel inspired bacterial denitrification of water using fractal patterns of polydopamine," Journal of Water Process Engineering, vol. 33, p. 101105, 2020.
 A. R. M Izzah Binti Mohammad, K Liang, M Asadnia, V Chen, "MOF-based enzymatic microfluidic biosensor via surface patterning and biomineralization," ACS applied materials & interfaces, vol. 11, pp. 1807-1820, 2019.
 M. Mansoorianfar, A. Khataee, Z. Riahi, K. Shahin, M. Asadnia, A. Razmjou, et al., "Scalable fabrication of tunable titanium nanotubes via sonoelectrochemical process for biomedical applications," Ultrasonics Sonochemistry, p. 104783, 2019.
 Z. Mehrabi, A. Taheri-Kafrani, M. Asadnia, and A. Razmjou, "Bienzymatic modification of polymeric membranes to mitigate biofouling," Separation and Purification Technology, p. 116464, 2019.
 M. Asadnia, M. Myers, N. D. Akhavan, K. O'Donnell, G. A. Umana-Membreno, U. Mishra, et al., "Mercury (II) selective sensors based on AlGaN/GaN transistors," Analytica chimica acta, vol. 943, pp. 1-7, 2016.
 T. M. Sanders, M. Myers, M. Asadnia, G. A. Umana-Membreno, M. Baker, N. Fowkes, et al., "Description of ionophore-doped membranes with a blocked interface," Sensors and Actuators B: Chemical, vol. 250, pp. 499-508, 2017.