International Journal of Biological Macromolecules 110 (2018) 392–398 Contents lists available at ScienceDirect International Journal of Biological Macromolecules j ourna l ho me pa g e: www.elsevier.com/locate/ijbiomac Glycol chitosan assisted in situ reduction of gold on polymeric template for anti-cancer theranostics Asifkhan Shanavas a,∗,1 , Aravind Kumar Rengan b,1 , Deepak Chauhan c , Liya George c , Mukti Vats c , Navneet Kaur a , Pranjali Yadav a , Purvi Mathur a , Swaroop Chakraborty a , Appidi Tejaswini b , Abhijit De d , Rohit Srivastava c,∗ a Institute of Nano Science and Technology, Mohali, Punjab, India b Department of Biomedical Engineering, Indian Institute of Technology Hyderabad, Telangana, India c Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, India d Molecular Functional Imaging Lab, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Navi Mumbai, India a r t i c l e i n f o Article history: Received 12 August 2017 Received in revised form 1 November 2017 Accepted 19 November 2017 Available online 22 November 2017 Keywords: PLGA Glycol chitosan Gold Nanoshell Polypods Photothermal therapy X-ray/CT a b s t r a c t Multifunctional biodegradable nanomaterials that could be used for both imaging and therapy are being researched extensively. A simple technique to synthesize multifunctional nanoparticles without compro- mising on any of their functionality is a challenge. We have attempted to optimize a two-step procedure of gold coated polymeric template involving 1) Single pot synthesis of PLGA nanoparticles with cationic surface charge using glycol chitosan and 2) in situ gold coating for formation of gold coated PLGA nanoshell (AuPLGA-NS). These gold-coated PLGA nanoparticles were explored for photothermal therapy (PTT) and as X-ray/CT contrast agents. Biocompatibility and photothermal cytotoxicity of AuPLGA-NS were eval- uated in-vitro and results confirmed the therapeutic efficacy of these particles resulting in 80% cancer cell death. Besides, it also showed potential X-ray/CT imaging ability with contrast equivalent to that of Iodine. The results demonstrated that these gold-coated PLGA nanoparticles synthesized by a simple approach could be used as a multifunctional nanosystem for cancer theranostics. © 2017 Elsevier B.V. All rights reserved. 1. Introduction Gold nanoparticles has attracted much attention due to their unique physical properties combined with chemical inertness, bio- compatibility and surface properties which permits conjugation with different chemical moieties [1]. Gold nanoparticles are also well known for their tunable surface plasmon resonance (SPR) ranging from 500 nm to 900 nm. SPR finds application in various techniques like SERS imaging, photothermal therapy, etc. [2,3]. Gold nanoshells are unique structures with very large optical absorption and scattering cross section that helps in absorption or scatter- ing of light specifically at visible and near infrared (NIR) regions of electromagnetic spectrum. NIR absorption of gold nanostructures qualifies them to be used as diagnostic agents and for deep tissue therapy, as there is very low absorption or scattering from tissue ∗ Corresponding authors. E-mail addresses: asifkhan@inst.ac.in (A. Shanavas), rsrivasta@iitb.ac.in (R. Srivastava). 1 Equally contributing authors. components between 650 nm to 1350 nm. This allows the pene- trating light energy to be specifically absorbed by the nanoshells only which will be transduced into thermal radiation increasing the local tissue temperature above 42 ◦ C. This photothermal phe- nomenon has been extensively utilized for specific ablation of solid tumor tissues [4,5]. Gold nanoshells were previously prepared by seed mediated growth method, where a dielectric core such as silica nanopar- ticle is first decorated with gold nanoseeds followed by further growth of gold to produce a continuous shell [6]. The thickness and roughness of the shell allows them to absorb at NIR region of the spectrum. For biomedical applications, apart from silica tem- plates polymeric templates such as Poly (lactic-co-glycolic acid) (PLGA) nanoparticles were used for gold nanoshell fabrication to allow encapsulation of a drug molecule in the biodegradable core. Gold coated PLGA nanoparticles exhibiting NIR absorbance were first reported by Yang et al., in 2009 where they functionalized Doxorubicin loaded PLGA nanoparticles with cysteamine providing a thiol group for gold nanoseeds to cling onto for further growth to provide a continuous nanoshell on the polymeric nanoparti- https://doi.org/10.1016/j.ijbiomac.2017.11.127 0141-8130/© 2017 Elsevier B.V. All rights reserved.