Sagar Regmi

Dr. Sagar Regmi

Case Western Reserve University, Cleveland, Georgia, USA
+1
orcid
Postdoctoral Scholar, School of Medicine, Case Western Reser...

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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5 January 2017 in Scientific Reports
Verified
Journal Article
Open access
Sagar RegmiSagar Regmi
Sagar Regmi
AFAfu Fu
Afu Fu
KLKathy Qian Luo
Kathy Qian Luo
Circulating tumor cells (CTCs) are the primary targets of cancer treatment as they cause distal metastasis. However, how CTCs response to exercise-induced high shear stress is largely unknown. To study the effects of hemodynamic microenvironment on CTCs, we designed a microfluidic circulatory system that produces exercise relevant shear stresses. We explore the effects of shear stresses on breast cancer cells with different metastatic abilities, cancer cells of ovarian, lung and leukemic origin. Three major findings were obtained. 1) High shear stress of 60 dynes/cm2 achievable during intensive exercise killed more CTCs than low shear stress of 15 dynes/cm2 present in human arteries at the resting state. 2) High shear stress caused necrosis in over 90% of CTCs within the first 4 h of circulation. More importantly, the CTCs that survived the first 4 h-circulation, underwent apoptosis during 16–24 h of post-circulation incubation. 3) Prolonged high shear stress treatment effectively reduced the viability of highly metastatic and drug resistant breast cancer cells. As high shear stress had much less damaging effects on leukemic cells mimicking the white blood cells, we propose that intensive exercise may be a good strategy for generating high shear stress that can destroy CTCs and prevent cancer metastasis.

27 June 2022 in Biosensors
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Journal Article
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Sagar RegmiSagar Regmi
Sagar Regmi
CPChetan Poudel
Chetan Poudel
RARameshwar Adhikari
Rameshwar Adhikari
KLKathy Qian Luo
Kathy Qian Luo
Taking the life of nearly 10 million people annually, cancer has become one of the major causes of mortality worldwide and a hot topic for researchers to find innovative approaches to demystify the disease and drug development. Having its root lying in microelectronics, microfluidics seems to hold great potential to explore our limited knowledge in the field of oncology. It offers numerous advantages such as a low sample volume, minimal cost, parallelization, and portability and has been advanced in the field of molecular biology and chemical synthesis. The platform has been proved to be valuable in cancer research, especially for diagnostics and prognosis purposes and has been successfully employed in recent years. Organ-on-a-chip, a biomimetic microfluidic platform, simulating the complexity of a human organ, has emerged as a breakthrough in cancer research as it provides a dynamic platform to simulate tumor growth and progression in a chip. This paper aims at giving an overview of microfluidics and organ-on-a-chip technology incorporating their historical development, physics of fluid flow and application in oncology. The current applications of microfluidics and organ-on-a-chip in the field of cancer research have been copiously discussed integrating the major application areas such as the isolation of CTCs, studying the cancer cell phenotype as well as metastasis, replicating TME in organ-on-a-chip and drug development. This technology’s significance and limitations are also addressed, giving readers a comprehensive picture of the ability of the microfluidic platform to advance the field of oncology.

13 June 2016 in Nucleic Acids Research
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Journal Article
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BNBeatrice De Nicola
Beatrice De Nicola
CLChristopher J. Lech
Christopher J. Lech
BHBrahim Heddi
Brahim Heddi
Sagar RegmiSagar Regmi
Sagar Regmi
IFIlaria Frasson
Ilaria Frasson
APAnh Tuân Phan
Anh Tuân Phan
The long terminal repeat (LTR) of the proviral human immunodeficiency virus (HIV)-1 genome is integral to virus transcription and host cell infection. The guanine-rich U3 region within the LTR promoter, previously shown to form G-quadruplex structures, represents an attractive target to inhibit HIV transcription and replication. In this work, we report the structure of a biologically relevant G-quadruplex within the LTR promoter region of HIV-1. The guanine-rich sequence designated LTR-IV forms a well-defined structure in physiological cationic solution. The nuclear magnetic resonance (NMR) structure of this sequence reveals a parallel-stranded G-quadruplex containing a single-nucleotide thymine bulge, which participates in a conserved stacking interaction with a neighboring single-nucleotide adenine loop. Transcription analysis in a HIV-1 replication competent cell indicates that the LTR-IV region may act as a modulator of G-quadruplex formation in the LTR promoter. Consequently, the LTR-IV G-quadruplex structure presented within this work could represent a valuable target for the design of HIV therapeutics.

28 August 2020 in International Journal of Biomaterials
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Journal Article
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KMKomal Prasad Malla
Komal Prasad Malla
Sagar RegmiSagar Regmi
Sagar Regmi
ANAchyut Nepal
Achyut Nepal
SBSitaram Bhattarai
Sitaram Bhattarai
RYRam Jeewan Yadav
Ram Jeewan Yadav
RARameshwar Adhikari
Rameshwar Adhikari
A novel natural hydroxyapatite (HAp) bioceramic was extracted from the ostrich cortical bone by the thermal decomposition method. HAp was characterized by different analytical tools such as thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM). Removal of organic impurities from the bone powder was confirmed by TGA analysis. FTIR spectra of HAp confirmed the presence of the major functional groups such as phosphate (PO43−), hydroxyl (OH−), and carbonate (CO32−) in the bioceramic. The XRD data revealed that the HAp was the crystalline phase obtained by calcination of the bone powder at 950°C, and the SEM analyses confirmed the typical plate-like texture of the nanosized HAp crystals.

30 January 2019 in Journal of Biophotonics
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Journal Article
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Jian JuJian Ju
Jian Ju
Sagar RegmiSagar Regmi
Sagar Regmi
AFAfu Fu
Afu Fu
SLSierin Lim
Sierin Lim
Quan LiuQuan Liu
Quan Liu

6 August 2022 in Biosensors
Verified
Journal Article
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Jian JuJian Ju
Jian Ju
LLLin Li
Lin Li
Sagar RegmiSagar Regmi
Sagar Regmi
XZXinyu Zhang
Xinyu Zhang
STShixing Tang
Shixing Tang
Significant advanced have recently been made in exploiting microneedle-based (MN-based) diabetes devices for minimally invasive wearable biosensors and for continuous glucose monitoring. Within this emerging class of skin-worn MN-based sensors, the ISF can be utilized as a rich biomarker source to diagnose diabetes. While initial work of MN devices focused on ISF extraction, the recent research trend has been oriented toward developing in vivo glucose sensors coupled with optical or electrochemical (EC) instrumentation. This outlook highlights the essential characteristics of the sensing mechanisms, rational design, sensing properties, and applications. Finally, we describe the opinions about the challenge and prospects of optical and EC MN-based device platforms for the fabrication of wearable biosensors and their application potential in the future.