[18p-E204-1~16] 3.1 Basic optics and frontier of optics

▲ [18p-E204-13] Optical trapping force investigation of viable and apoptotic THP-1 monocytes

〇(M2)Ric John Ombid Ombid¹, Glenn Oyong¹, Romeric Pobre¹ (1.De La Salle University)

Keywords:Optical trapping, cancer, THP-1

We report the utility of optical tweezers in determining the optical force as a profiling factor between viable and apoptotic cells. THP-1 monocytic leukemia cell lines were purchased from ATCC (Manassas, VA, USA) and cultured in complete Dulbecco’s modified Eagle’s medium. The trypan blue tested viable THP-1 cells (99% viability) were freshly mounted onto the glass slides, while old culture apoptotic cells (20% viable) were also investigated. The THP-1 monocytes (~10 μm) have experimented at room temperature using a 980 nm laser at 100 mW. Its thermal fluctuations were recorded by the quadrant photodiode and trap stiffness was determined by fitting a Lorentzian to the power spectrum. The optical force was measured through Hooke’s Law: F= -kx, where F is the applied force, k is the trap stiffness, and x is the displacement. Viable THP-1 cells were perfectly spherical in shape while apoptotic cells demonstrated cell membrane blebbing. Trapping force was respectively measured affording values that were higher for viable cells compared to apoptotic cells.