ORIGINAL PAPER Enhancing the radiotherapeutic index of gamma radiation on cervical cancer cells by gold nanoparticles Priya Yadav 1 & Arghya Bandyopadhyay 1,2 & Anindita Chakraborty 3 & Sk. Manirul Islam 4 & Keka Sarkar 1 Received: 26 August 2018 /Accepted: 21 May 2019 # Springer Nature Switzerland AG 2019 Abstract Nanotechnology has the impending ability to improve the therapeutic potential of drugs and radiation-based treatment ap- proaches for reducing cancerous cell death while curtailing collateral toxicity to non-cancerous cells. Among all metal nanomaterials, gold nanoparticles (AuNPs) are establishing themselves as an excellent radiosensitizer and serve as a multimodal modality due to their unique physicochemical properties. The primordial purpose of the work is to evaluate the synergistic effect and molecular level interaction of gamma (γ) radiation on human cervical cancer cell (HeLa) in the presence of AuNPs. Biocompatible AuNPs in combination with γ-radiation were found to exhibit elated cytotoxic effects on cancer cells as evidenced by cell-based assays. The implication of AuNPs facilitates the minimization of radiation dose employment on cultured cells. As per our experimental evaluation, the modus operandi of dual effectors ascertained that a higher amount of reactive oxygen species (ROS) plays a key role in cellular functionality collapse. In that scenario, it can be concluded that AuNP-mediated radiosensitization proved to be the plausible candidate for preclinical testing in nanoparticle-based radiotherapy. Keywords Gold nanoparticles . Cancer . Radiosensitization . Ionizing radiation . Gamma radiation . Oxidative stress Introduction Nanotechnology has emerged as a prevailing area in medical and healthcare research during the last decade. Nanosystem offers the advantage to deliver the anticancer drugs selectively to cancer cells and also enhance the therapeutic potential of the same [1–3], which is not indifferent in the case of radiation-mediated treatment [4–6]. As stated, nanotechnolo- gy is also proved improvement to the pharmacokinetics and eliminates the systemic toxicities along with the inadequacy of chemo- and radiotherapy. Nanotechnology-based cancer ther- apy is not limited to drug delivery but also extends to other treatment modalities such as nanopermitted immuno-, ther- mal, and radiation therapy based on nanomaterial type, shape, size, and properties. These properties, enabling nanoparticles to, offer the therapeutic as well as diagnostic significance. Conventional cancer therapy including radiation leads to sev- eral side effects, like uncontrolled damage to encompass healthy cells and tissues along with developing resistance to- wards chemo-therapeutants and ionizing radiations (IR) [7]. Different radiations such as X-ray, γ-rays, neutrons, and α- and β-particles are utilized in radiation-based therapy to treat cancer. These ionizing radiation–based treatments mainly oc- cur through direct interaction with target site or indirectly by the generation of an enormous amount of free radicals within the cancer cells. Chen and coworkers demonstrated in their research that the shape of nanostructures and surface functionalizations critically persuade the radio-sensitizing ability of gold nanomaterials in vitro due to the difference in the cellular internalization of nanomaterials [8, 9]. Apart from Priya Yadav and Arghya Bandyopadhyay contributed equally to this work. Electronic supplementary material The online version of this article (https://doi.org/10.1007/s13404-019-00260-2) contains supplementary material, which is available to authorized users. * Keka Sarkar keka@klyuniv.ac.in 1 Department of Microbiology, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India 2 Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, West Bengal 741246, India 3 Radiation Biology, UGC-DAE CSR (Kolkata Centre), Kolkata, West Bengal 700098, India 4 Department of Chemistry, University of Kalyani, Kalyani, Nadia, West Bengal 741235, India Gold Bulletin https://doi.org/10.1007/s13404-019-00260-2