Current Research Focus
My current research continues to be at the interface of physics and biomedicine with a translational focus, just as my past research.  Almost all the vital signs are biophysical properties: blood pressure, pulse rate, body temperature, etc. With collaborators from the School of Medicine, School of Pharmacy, Departments of Biology, Chemistry, and Mathematics of Creighton University, as well as international collaborators in the UK and Germany, I develop and use novel biophysical tools to discover new biomarkers that provide diagnostic information and new therapeutic options. I address the physician’s wish list in order to improve disease diagnosis, patient monitoring, drug development and testing, etc.   While these efforts seek to improve biomedicine using principles and tools of physics, I also aim at advancing the physics of complex systems such as living matter. In particular, I seek to understand how biological cells function as mechanical units, with material properties. 

My current research covers  6 clinically relevant themes: 

1. Radioimmunotherapy, RIT, against glioblastoma, using immune checkpoint blockers, Durvalumab, Pembrolizumab and Ipilimumab. When I asked my physician-clinical collaborator, Dr Chi Kevin Chang, MD, PhD, Radiation Oncologist at University of Nebraska Medicine, what is atop his wish list, he replied: “I and my colleagues in the Glioblastoma/Brain Cancers community, need reliable biomarkers for effective therapies”. Thus, I am developing biophysical markers to help provide insights regarding the positive and negative outcomes of clinical trials involving immunotherapeutic agents against brain cancers especially glioblastomas. My latest publications on this theme include (1,2): 

1.      Walter Y, et al. Development of In Vitro Assays for Advancing Radioimmunotherapy against Brain Tumors. Biomedicines. 2022. 

2.      Merrick M, et al. In vitro radiotherapy and chemotherapy alter migration of brain cancer cells before cell death. Biochem Biophys Reports. 2021.  

2. Nanoparticle-Mediated Radiotherapy, NPRT, against brain cancers. Here, I use bio-compatible carbon quantum dots, graphene quantum dots and pegylated CdSe ZnS quantum dots to simultaneously do two things, namely, quantify reactive oxygen species (ROS) and cause local dose escalation in the tumor through radiosensitization. The aim is to use substances which can be tuned to cross the blood brain barrier, which can be tagged to get localized in the tumor and which can be irradiated so that they produce more ROS, leading to local dose escalation. Some quantum dots meet these needs and may be helpful against GBM. 

There is one patent application from this effort: 

“Cancer Radiation Therapy with Biocompatible Quantum Dots for Simultaneous Dose Enhancement and Counter-Metastasis”, United States Patent and Trademark Office (USPTO) application number 17/970,720, Confirmation# 6513, dated 04/17/2023. 

Recent publications from this ongoing effort include (3,4): 

3.      Lee BH, Suresh S, Ekpenyong A. Fluorescence intensity modulation of CdSe/ZnS quantum dots assesses ROS during chemotherapy and radiotherapy for cancer cells. J Biophotonics. 2018 Dec 13;12(2):e201800172. 

4.      Djam KH, Lee BH, Suresh S, Ekpenyong AE. Quantum Dots for Assessment of Reactive Oxygen Species Accumulation During Chemotherapy and Radiotherapy. In: Methods in Molecular Biology. Humana Press Inc.; 2020. p. 293–303. 

3. Chemo-Radiotherapy and Nanoparticle-Mediated Drug Delivery. With collaborators in the school of pharmacy,  I measure the effects of new drug candidates on cellular biophysical properties such as cell migration, as potential markers for anti-metastatic efficacy. Several papers are under preparation and here is one publication from this effort (5): 

5.      Palliyage GH, et al. Novel Curcumin-Resveratrol Solid Nanoparticles Synergistically Inhibit Proliferation of Melanoma Cells. Pharm Res. 2021. 

4. Physics of Cancer (Physical Oncology). Here, I investigate the biophysical mechanisms behind chemotherapy-induced metastasis, where such drugs alter the mechanical properties of cancer cells in ways that inadvertently promote metastasis before cell death. This current investigation is at the heart of the Physics of Cancer, a new research frontier accentuated by the National Institutes of Health, through the Physical Sciences in Oncology network, which explores the mechanical properties of cancer cells and their role in cancer disease and metastasis. My Lab was among the first to report some inadvertent prometastatic effects of chemotherapies (the NIH is currently funding research into mechanisms of chemotherapy-induced-metastasis) and we have continued this exploration as can be seen from the following publications (6,7): 

6.      Prathivadhi-Bhayankaram S V, et al. Chemotherapy impedes in vitro microcirculation and promotes migration of leukemic cells with impact on metastasis. Biochem Biophys Res Commun. 2016. 

7.      Abraham A, et al. Microfluidic Microcirculation Mimetic for Exploring Biophysical Mechanisms of Chemotherapy-Induced Metastasis. Micromachines. 2023. 

5. Microfluidics Microcirculation Mimetic (MMM). I developed microfluidic mimetics to enable in vitro modelling of the human pulmonary microcirculation with potential impact on the clinical management of lung diseases and inflammatory disorders. Following very high impact publications(8,9) based on MMM, I am currently refining it and developing it into a marketable device for the patient-specific prognosis of sickle cell disease(10):  

8.      Chan CJ, et al. Myosin II Activity Softens Cells in Suspension. Biophys J. 2015 

9.      Ekpenyong AE, et al. Mechanical deformation induces depolarization of neutrophils. Sci Adv. 2017 

10.    Asuquo MI, et al. Microfluidic Microcirculation Mimetic as a Tool for the Study of Rheological Characteristics of Red Blood Cells in Patients with Sickle Cell Anemia. Appl Sci. 2022. 

6. Simulated Microgravity.I currently NASA-developed device to simulate microgravity, the condition of apparent weightlessness experienced by astronauts during space flights. While I seek countermeasures against the pathophysiological consequences of microgravity, in order to enhance space medicine, I also use microgravity as a variable to help terrestrial medicine. For instance, I am currently developing glioblastoma tissue spheroids for my 3D RIT and NPRT using microgravity. Here are recent publications (11,12): 

11.    Prasanth D, et al. Microgravity Modulates Effects of Chemotherapeutic Drugs on Cancer Cell Migration. Life. 2020. 

12.    McKinley S, et al. Simulated Microgravity-Induced Changes to Drug Response in Cancer Cells Quantified Using Fluorescence Morphometry. Life. 2023. 

7. Mathematical and Computational Modelling. To fit data and extract useful parameters from my experimental work and to extend theoretical framework, I do some modelling using fractional calculus, MATLAB routines, R codes, COMSOL Multiphysics, etc.