Received August 6, 2018, accepted September 12, 2018, date of publication October 1, 2018, date of current version October 25, 2018. Digital Object Identifier 10.1109/ACCESS.2018.2872768 Label-Free Cancer Cells Detection Using Optical Sensors MAHMOUD AL AHMAD 1 , (Senior Member, IEEE), ADEL NAJAR 2 , AMINE EL MOUTAOUAKIL 1 , NIDA NASIR 1 , MINAS HUSSEIN 1 , SHAIMA RAJI 1 , AND ALI HILAL-ALNAQBI 3 1 Electrical Engineering Department, College of Engineering, United Arab Emirates University, Al Ain 15551, United Arab Emirates 2 Physics Department, College of Science, United Arab Emirates University, Al Ain 15551, United Arab Emirates 3 Electromechanical Technology, Abu Dhabi Polytechnic, Abu Dhabi 111499, United Arab Emirates Corresponding author: Mahmoud Al Ahmad (m.alahmad@uaeu.ac.ae) This work was supported by funds from UAE University under Grant G00001962 and Grant G00002190. ABSTRACT Rapid and accurate label-free-based discrimination techniques between normal and cancer cells play an important role in non-invasive screening systems. Significant differences in cell composition for normal and cancer cells have been reported. Their interaction with light will cause a change in the optical absorption and transmission response. Hence, the advances in optical absorption methods along with signal processing could provide fingerprints that enable such discriminations and classifications. Here, we discriminate and identify several types of cells, such as BEAS-2B, HCC-827, THLE2, Hep G2, MCF 10A, and MDA MB231, in addition to HeLa and HEK-293T; each suspended in a homogeneous solution without labeling and using optical absorption-based method. Empirically, the cancer cells exhibit higher transmittance intensity when compared to normal ones from the same tissue type. Furthermore, the cells (both cancer and normal types) exhibit higher transmittance as per the following order: liver, lung, and breast. However, the normal cell suspensions exhibit higher optical absorption than cancer cells. The modifications of the optical response from normal to cancer state were explained mainly by morphological changes, modification of its physiological and biochemical properties that affect the refractive index and allowing them to be differentiated from each other. INDEX TERMS Label free, detection, cells, sensors, optical, cancer. I. INTRODUCTION The rapid and uncontrolled growth of cancer cells causes deficiency by stopping body’s control mechanism from func- tioning. The screening and distinction between healthy and cancer cells require new, rapid and efficient methods and techniques. Non-invasive screening systems are very critical and have not been developed yet. The efficiency of opti- cal techniques resides in their ability to provide real-time measurements at a lower cost compared to other detection techniques. Sensor array methods are useful for many bio-analyses. An array of nanoparticles and conjugated polymers releases the fluorescent polymer from the gold-nanoparticle quencher when it comes in contact with bacteria. Hence variant fluo- rescence responses generated by the bacterial surfaces gives an efficient detection and identification [1]. Contrast agents like folate-substituted poly (p-phenyleneethynylene) (PPE) can be used to image KB cancer cells with high selec- tivity and with minimal cytotoxicity to normal cells [2]. Nose-based polymer sensor arrays show a noble approach for advanced diagnostic and biophysical processes involving cell surfaces. It is used to distinguish among normal, cancerous and metastatic cells having similar genetic background, in an easy way, without any need of knowledge related to the exact receptors or ligands in order to distinguish between cell states, types and status [3]. Helen et al. give another example of ultra-sensitive magnetic field sensors where anti- body conjugated magnetic nanoparticle reagents are used in breast tumor cell detection. These cells were sensed using Superconducting Quantum Interference Device (SQUID) that is based on the promising, viable and fast magnetic relaxom- etry technique [4]. To achieve this, they identified a set of breast cancer cell lines using various levels of plasma mem- brane such as human epidermal growth factor-like receptor 2 (Her2) using the flow cytometry. Carbodiimide method was used to conjugate Anti-Her2 antibody to super-paramagnetic iron (II, III) oxide nanoparticles. Those labeled particles were incubated with cancerous cell lines and envisioned by VOLUME 6, 2018 2169-3536  2018 IEEE. Translations and content mining are permitted for academic research only. Personal use is also permitted, but republication/redistribution requires IEEE permission. See http://www.ieee.org/publications_standards/publications/rights/index.html for more information. 55807