Research 

Research Interests

The overarching goal of my research has been the development of miniaturized devices by building on exciting physical and material properties. These devices are small enough to be ingested in the body and carry out functions ranging from microsurgery, drug delivery to local sensing.  


Various physiological barriers and clearance mechanisms in the body make it difficult to achieve an intended pharmacokinetic profile of a drug. For example, extended release polymeric patch or micro/nanoparticulate drug formulations are naturally removed from the gastrointestinal tract within a few hours, thus rendering them ineffective. To solve this problem, one can take inspiration from gut parasites, which reside in the GI tract for several years. Stimuli responsive shape morphing drug delivery devices can be used to mimic these parasites like hookworms or tapeworms and can be designed to resist the gastrointestinal clearance. These drug delivery devices, which are often fabricated using microfabrication principles, can actively generate forces, while changing their shape and size. I envision to harness this force to overcome the natural barriers in the body for enhanced efficacy in drug delivery. 

"Autonomous untethered microinjectors for gastrointestinal delivery of insulin " by A Ghosh, W Liu, L Li, G Pahapale, SY Choi, L Xu, Q Huang, R Zhang, Z Zijiang, FM Selaru, DH Gracias; ACS Nano, 2022

"Gastrointestinal-resident, shape-changing microdevices extend drug release in vivo"  by A Ghosh, L Li, L Xu, RP Dash, N Gupta, J Lam, Q Jin, VA Akshintala, G Pahapale, W Liu, A Sarkar, R Rais, DH Gracias and FM Selaru; Science Advances, 2020


Surgical operations have evolved over the years towards minimally invasive techniques, which significantly reduce post operative trauma and improves patient quality of life. However a big limitation of modern day minimally invasive surgery is the use of tethers for navigation of the end effector tool as well as for the delivery of power. My research focus thus encompasses the development of new micro tools, which can carry out microsurgical tasks in a completely untethered manner. The challenges are two fold: untethered navigation of the microtools, which can be achieved by external biocompatible fields like magnetic or ultrasound and the more challenging problem of actuation of the micro tool appendages, which can be achieved for example by utilizing pre stressed thin film microactuators. However, there is a tremendous scope of innovation and exploration, where other forms of energy can be utilized to develop wireless micromachines and tools to augment present day microsurgical operations.

"Magnetic Resonance Guided Navigation of Untethered Microgrippers" by A Ghosh, Y Liu, D Artemov and DH Gracias; Advanced Healthcare Materials, 2020.


Moving micro/nanoscale objects in a fluid is difficult because of the tremendous amount of viscous dissipation that needs to be overcome at low Reynold's number environments. Successful locomotion can be however achieved by biomimetic helical propulsion, similar to the bacteria Escherichia coli. Artificial nanoscale helices can be fabricated by advanced physical vapor deposition techniques like Glancing Angle Deposition which can produce billions of swimmers in parallel. The swimmers are controlled by external rotating magnetic fields and their swimming dynamics show diverse configurations and thermal fluctuations. The mobile nanoswimmers which can traverse at speeds of tens of microns per second, can be utilized to dynamically measure the local rheological properties of a complex heterogeneous fluid. Apart from rheology, such controlled nanoscale probes can be applied for various other local measurement applications, which has a broad relevance to the field of biosensing. 

"Helical Nanomachines as Mobile Viscometers" by A Ghosh, D Dasgupta, M Pal, KI Morozov, AM Leshansky and A Ghosh; Advanced Functional Materials, 2018.