Copyright © 2017 American Scientific Publishers All rights reserved Printed in the United States of America Article Journal of Nanoscience and Nanotechnology Vol. 17, 8557–8561, 2017 www.aspbs.com/jnn Functionalization of Carbon Nanotubes by a Facile Chemical Method and Its Application in Anti-Diabetic Activity Sher Zaman 1 2 ∗† , Saghir Hussain 3 4† , Faheem K. Butt 5 6 ∗ , Xin Jianguo 2 , and Changjin Zhu 4 1 Department of Physics, Karakorum International University, Gilgit, 15100, Pakistan 2 Research Centre for Laser Technology and Applications, School of Optoelectronics, Beijing Institute of Technology, Beijing 100081, China 3 Institute of Chemical Sciences, Bahauddin Zakariya University, Multan, 60800, Pakistan 4 Department of Applied Chemistry, Beijing Institute of Technology, No. 5, Zhongguancun South Street, 100081, Beijing, China 5 Department of Physics, The University of Lahore, Lahore, 53700, Pakistan 6 Physik-Department, ECS, Technische Universität München, Garching, 85748, Germany Diabetes is a chronic metabolic disease caused by hyperglycemia. We report first time the anti- diabetic activity of functionalized carbon nanotubes (FCNT). The multiwall carbon nanotubes (MWCNTs) were functionalized by using 95% concentrated nitric acid by refluxing. The func- tional groups on the surface of MWCNT were investigated by high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spec- troscopy (XPS). FCNT showed 41.2% aldose reductase inhibition in vitro activity; further its docking study revealed that the carboxylic group played a significant role in inhibition. These studies pave the way for new opening of research for MWCNT in anti-diabetic activity. Keywords: Functionalized Carbon Nanotubes, Anti-Diabetic Activity, Aldose Reductase, Docking Modulation. 1. INTRODUCTION The increasing interest in nanomaterials based drug dis- covery constitutes an important area in nanomedicine. A large number of organic compounds and their deriva- tives with inorganic materials have been used in different kind of nanomedicine. 1 2 Carbon nanotubes (CNT) have attracted significant attention due to their potential appli- cations not only in semiconductor industry but also in pharmaceutical industry by introducing new and highly effective medicine. 3 The modifications of carbon nanotubes make it soluble in organic and inorganic solvent which can be used in cancer therapy, and many other biologi- cal applications. 1 4 5 Therefore CNT is gradually playing an important role in the emerging field of nanomedicine. In this article we tested the activity of FCNT first time against the target Aldose Reductase enzyme (ALR2, EC 1.1.1.21) and evaluated as for best anti-diabetic agent. ∗ Authors to whom correspondence should be addressed. † These two authors contributed equally to this work. Diabetes mellitus (DM) is a complex metabolic disor- der characterized by an elevated level of blood glucose called hyperglycemia. The polyol pathway of glucose metabolism is activated in the hyperglycemia, which sub- sequently results in the development of long-term diabetic complications including retinopathy, nephropathy,neuropa- thy, cataract and stroke. 6–8 Aldose Reductase (ALR2, EC 1.1.1.21) is a member of aldo-keto reductase super fam- ily, which plays a major role in the development of long- term diabetic complications. Several lines of evidence suggest that the primary cause of long-term diabetic com- plications is due to the activation of ALR2 and conse- quent imbalance of -nicotinamide adenine dinucleotide phosphate reduced and oxidized form (NADPH/NADP +  and -nicotinamide adenine dinucleotide oxidized and reduced form (NAD + /NADH) coenzymes ratio resulting the oxidative stress inside the cell along with overpro- duction of fructose. Thus inhibition of ALR2 represents the strategy and an attractive approach to block and delay the progression and development of pathogenesis of J. Nanosci. Nanotechnol. 2017, Vol. 17, No. 11 1533-4880/2017/17/8557/005 doi:10.1166/jnn.2017.15178 8557