Cancers 2021, 13, 6114. https://doi.org/10.3390/cancers13236114 www.mdpi.com/journal/cancers Article Biosynthesized Silver Nanoparticles for Cancer Therapy and In Vivo Bioimaging Shagufta Haque 1,2,† , Caroline Celine Norbert 1 , Rajarshi Acharyya 1 , Sudip Mukherjee 1,2 , Muralidharan Kathirvel 1,2 and Chitta Ranjan Patra 1,2, * 1 Department of Applied Biology, CSIR-Indian Institute of Chemical Technology, Uppal Road, Tarnaka, Hyderabad 500007, India; shagufta.220@csiriict.in (S.H.); carolinenorb@gmail.com (C.C.N.); acharyyarajarshi@gmail.com (R.A.); sudip.mukherjee1988@gmail.com (S.M.); muralidharan@csiriict.in (M.K.) 2 Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, Uttar Pradesh, India * Correspondence: crpatra@iict.res.in or patra.chitta@gmail.com; Tel.: +91-40-27191855 † Contributed equally. Simple Summary: Chemotherapy, a conventional treatment strategy, is associated with several lim- itations. Alternatively, cancer nanotechnology offers new strategies for remedy from drug delivery and extending to therapeutics using nanoformulation. Recently, silver nanoparticles are utilized for different cancer theranostics. In this context, the current manuscript demonstrates the design and development of biologically synthesized silver nanoparticles (AgZE) and their applications for can- cer theranostics. The synthesized AgZE is optimized and thoroughly characterized. The AgZE ex- hibits biocompatibility and selective anticancer activity towards the cancer cell lines established through various assays. The fluorescence properties of AgZE are observed in the NIR region (exci- tation: 710nm, emission: 820nm) in the normal and tumor bearing C57BL6/J mice. The silver of AgZE is found to be biodistributed in different vital organs as analyzed by ICPOES. Thereafter, these re- sults highlight that AgZE could be an efficient cancer therapeutic and NIR based non-invasive im- aging agent in the upcoming times. Abstract: In the current communication, a simple, environmentally compatible, non-toxic green chemistry process is used for the development of silver nanoparticles (AgZE) by the reaction be- tween silver nitrate (AgNO3) and the ethanolic leaf extract of Zinnia elegans (ZE). The optimization of AgZE is carried out using a series of experiments. Various physico-chemical techniques are uti- lized to characterize the nanomaterials. The cell viability assay of AgZE in normal cells (CHO, HEK- 293T, EA.hy926, and H9c2) shows their biocompatible nature, which is supported by hemolytic as- say using mouse RBC. Interestingly, the nanoparticles exhibited cytotoxicity towards different can- cer cell lines (U-87, MCF-7, HeLa, PANC-1 and B16F10). The detailed anticancer activity of AgZE on human glioblastoma cell line (U-87) is exhibited through various in vitro assays. In vivo the AgZE illustrates anticancer activity by inhibiting blood vessel formation through CAM assay. Fur- thermore, the AgZE nanoparticles when intraperitoneally injected in C57BL6/J mice (with and with- out tumor) exhibit fluorescence properties in the NIR region (excitation: 710nm, emission: 820nm) evidenced by bioimaging studies. The AgZE biodistribution through ICPOES analysis illustrates the presence of silver in different vital organs. Considering all the results, AgZE could be useful as a potential cancer therapeutic agent, as well as an NIR based non-invasive imaging tool in near future. Keywords: silver nanoparticles; green chemistry approach; Zinnia elegans; cancer therapeutic; NIR bioimaging; nanomedicine 1. Introduction Citation: Haque, S.; Norbert, C.C.; Acharyya, R.; Mukherjee, S.; Kathirvel, M.; Patra, C.R. Biosynthe- sized Silver Nanoparticles for Can- cer Therapy and In Vivo Bioimag- ing. Cancers 2021, 13, 6114. https://doi.org/10.3390/can- cers13236114 Academic Editor: Morteza Mahmoudi Received: 28 October 2021 Accepted: 2 December 2021 Published: 4 December 2021 Publisher’s Note: MDPI stays neu- tral with regard to jurisdictional claims in published maps and insti- tutional affiliations. Copyright: © 2021 by the authors. Li- censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con- ditions of the Creative Commons At- tribution (CC BY) license (https://cre- ativecommons.org/licenses/by/4.0/).