Research in the Wang lab falls within the field of nanobioelectronics, focusing mostly on the design of wearable biosensors and nano- and micromotors for drug delivery and microchip diagnostics. The Wang group’s work on nano- and micromotors have advanced the field significantly towards the dream of autonomous machines capable of navigating the circulation to deliver drugs or test for the presence of disease biomarkers (à la Fantastic Voyage). Their designs have demonstrated the feasibility of nano- and micromotors that rely on local chemical fuel or ultrasound or magnetic actuation to travel rapidly and carry cargo, whereas the vast majority of the field until recently focused on peroxide-driven machines. Excitingly, they have introduced the first water-driven micromotor, in which water reacts with aluminum to produce hydrogen microbubbles, which move efficiently in human serum. Recent contributions to fuel-free nanomotors include the development of magnetically guided ultrasound-powered nanowires capable of towing cargo (see figure below) and of magnetically-powered flexible nanowire motors capable of high-speed propulsion.
Just as important as the Wang lab’s fundamental advances in the field are their demonstrations of micromotor applications that could rapidly become useful to diagnose disease. For example, they have shown that micromachines are capable of capturing and transporting cancer cells in biological media, which could allow rapid, sensitive detection of circulating tumor cells in blood to improve the accuracy of cancer staging. In addition, their incorporation of tubular micromotors into a microchip enabled quantification of a specific protein, and could lead to on-chip immunoassays with no external power requirement.
Even more practical is their development of wearable sensors to measure the concentrations of biochemical species in sweat, which was previously only possible by collecting samples and analyzing them in the lab, preventing real-time observation of electrolyte and metabolite changes. They have demonstrated the ability of temporary tattoo sensors to measure the dynamics of sodium (an indicator of electrolyte balance), lactate (indicating a switch to anaerobic metabolism during endurance exercise), and pH, which should make biochemical assessment of athletic performance more widely feasible.
Bandodkar AJ, Nuñez-Flores R, Jia W, Wang J. All-printed stretchable electrochemical devices. Adv Mater 2015; online Apr 9.
Garcia-Gradilla V, Orozco J, Sattayasamitsathit S, Soto F, Kuralay F, Pourazary A, Katzenberg A, Gao W, Shen Y, Wang J. Functionalized ultrasound-propelled magnetically guided nanomotors: toward biomedical applications. ACS Nano 2013; 7(10): 9232-40.
W Gao, A Pei, J Wang. Water-driven micromotors, J Am Chem Soc 2012; 6 (9): 8432–8438.
S Balasubramanian, D Kagan, CM Hu, S Campuzano, M J Lobo-Castañon, N Lim, DY Kang, M Zimmerman, L. Zhang, J Wang. Micromachine enables capture and isolation of cancer cells in complex media, Angew Chemie Int Ed 2011; 50(18): 4161-64.