{"id":474,"date":"2019-09-10T05:23:24","date_gmt":"2019-09-10T05:23:24","guid":{"rendered":"https:\/\/materials.international\/?p=474"},"modified":"2019-09-17T19:04:09","modified_gmt":"2019-09-17T19:04:09","slug":"tailored-gold-nanoparticles-for-cancer-imaging-and-therapy","status":"publish","type":"post","link":"https:\/\/materials.international\/?p=474","title":{"rendered":"Tailored Gold Nanoparticles for Cancer Imaging and Therapy"},"content":{"rendered":"\n

Materials International, 2019, 1, 1, 0013-0024, https:\/\/doi.org\/10.33263\/Materials11.013024<\/a> <\/p>\n\n\n\n

M\u0103d\u0103lina Elena David1,*<\/sup>, Alexandru Mihai\nGrumezescu2<\/sup><\/strong><\/sup><\/a><\/strong><\/p>\n\n\n\n

  1. National Research & Development Institute\nfor Chemistry and Petrochemistry\u2013ICECHIM, 202 Splaiul Independentei, Sector 6,\nBucharest 060021, Romania<\/li>
  2. Department\nof Science and Engineering of Oxide Materials and Nanomaterials, Faculty of\nApplied Chemistry and Materials Science, Politehnica University of Bucharest,\n060042 Bucharest, Romania<\/li><\/ol>\n\n\n\n

    *<\/strong>  Correspondence: madalina.e.david@gmail.com<\/a><\/p>\n\n\n\n

    Download<\/a><\/div>\n\n\n\n
    \n\n\n\n

    Abstract: <\/strong>In recent years, nanomedicine focused on the development of\nfunctional AuNPs for biomedical imaging, attributed to the intriguing optical properties\nof these nanoparticles, which are discussed in this review. Moreover, are presented\nthe most important in vivo<\/em> diagnostic\ntechniques which have benefited from the development of engineered AuNPs, such\nas computed tomography and photothermal\/photoacoustic imaging. Another\nimportant advantage related to these nanoparticles refers to their excellent\nperformance in recent in vivo<\/em> studies\nand clinical trials. Also, side effects of conventional drugs have been\nminimized by conjugation of AuNPs.<\/p>\n\n\n\n

    Keywords: <\/strong>gold\nnanoparticles, biomedical imaging, biocompatible nanoparticles.<\/p>\n\n\n\n

    Abbreviations:<\/strong> DOX: doxorubicin, PVP: Polyvinyl\npyrrolidone, Hyd: Hydrazone, PEG: Polyethylene glycol, BLM: Bleomycin, CPP:\nCell penetrating peptides, MTX: Methotrexate, 3-MPA: 3-mercaptopropionic acid,\nTAM- tamoxifen, FA: Folic acid, BHC: Berberine hydrochloride, Gem: gemcitabine,\nC225: cetuximab, DOD: dodecylcysteine, LL2: Lewis lung carcinoma, EAC:\nEhrlich-Lettre ascites carcinoma.<\/p>\n\n\n\n
    \n \u00a9\n 2019 by the authors. This article is an open-access article distributed under\n the terms and conditions of the Creative Commons Attribution (CC BY) license\n (http:\/\/creativecommons.org\/licenses\/by\/4.0\/).\n <\/td><\/tr><\/tbody><\/table>\n\n\n\n

    1. Introduction<\/strong><\/p>\n\n\n\n

    Presently, numerous nanoparticles and nanomaterials synthesized either biologically or physiochemically have emerged from different bulk elements such as gold, silver, iron, copper, in order to be used in advanced nanotechnology and medical science [1, 2]. One of the main advantages of these nanoparticles is represented by the ability to control their properties (physical, chemical and biological), which offer many possibilities to explore these nanoparticles in applications like drug delivery, as image contrast agents and for diagnostic purposes [3]. In comparison with others nanoparticles, gold nanoparticles (AuNPs) offer unique optical and Surface Plasmon Resonance (SPR) properties, which make them suitable to be used in biological and pharmaceutical fields, such as imaging-based therapeutic techniques and ultrasensitive detection for the treatment of cancer [4, 5].<\/p>\n\n\n\n

    Cancer\nis caused by abnormal cell growth and is the second leading cause of death\nglobally, being responsible for an estimated 9.6 million deaths in 2018.\nAccording to the World Health Organization (WHO) about 1 in 6 deaths is due to\ncancer [6]. Presently, the treatment of cancer is based on chemotherapeutic\ndrugs, with the aim of killing the cancer cells. It has been demonstrated in\nseveral studies that these treatments often result in side effects due to the\ndamage caused to the surrounding healthy tissues [3]. <\/p>\n\n\n\n

    \nIn the last several years, AuNPs (bare\nor functionalized) have received important attention in nanotherapeutic cancer\ntreatment (Figure 1) due to their unique properties, which make them suitable\ncandidates for conjugation with targeting ligands, imaging labels, and\ntherapeutic drugs. Also, it has been demonstrated that functionalized AuNPs can\nbe used for targeted molecular imaging and localized surface plasmon resonance\n(LSPR) [7-9].\n\n<\/p>\n\n\n\n

    There are two processes are involved in differentiating malignant and nonmalignant cells: passive targeting and active targeting. Passive targeting takes advantage of the enhanced permeability and retention (EPR) effect observed in tumors to increase the concentration of AuNPs. The second process involves the selective molecular recognition of antigens that are expressed on the surfaces of cancer cells to localize AuNPs to malignant cells or the exploitation of the membrane properties associated with malignancy [10, 11]. <\/p>\n\n\n\n

    \"\"
    Figure 1.<\/strong> Applications of AuNPs in cancer diagnosis and treatment. <\/figcaption><\/figure>\n\n\n\n

    Typically,\nAuNPs are defined as particles of 1\u2013100 nm in size, which is in the\nsub-wavelength regime of visible light [12, 13]. These nanoparticles with\ncontrolled size and shape are synthesized by various physical, chemical, and\nbiological ways [3].<\/p>\n\n\n\n

    Physical\nmethods refer to the energy transfer that occurs in a material when it is\nirradiated using ionizing or non-ionizing radiation, which may trigger the\nreduction reactions that lead to the nucleation of metallic particles. This\nmethod includes photochemical processes, ionizing radiation and microwave\nradiation [14-16]. Ngo V.K.T. and co-workers obtained AuNPs by a low cost technique,\nmicrowave heating in order to investigate the effect of different elements\n(precursor reagents, irradiation time, and microwave radiation power) on the\nmorphology of AuNPs. It was observed that the size of AuNPs decreased and the\nsize distribution became narrower with increasing the concentration of sodium\ncitrate. Also, it has been reported that a longer reaction time and higher\nmicrowave radiation power increased the NPs size, demonstrating that microwave\nheating had a strong effect on the yield of the AuNPs [17]. Zhou Y. and\nco-workers obtained shape-controlled AuNPs by a novel ultraviolet irradiation technique\nat room temperature. It was demonstrated that, not only the concentration of Au\ncations and the irradiation time influenced the morphology of AuNPs, but also\nthe concentration and the species of the polymer capping materials play an\nimportant role. The prolongation of irradiation time facilitated the formation\nof the AuNPs with more regular shape [18]. In another study, it was\ndemonstrated that the production of hexagonal AuNPs began within seconds of\nmicrowave irradiation and the size growth increased with the microwave power\nand time [19].<\/p>\n\n\n\n

    Chemical\nmethods utilize chemicals and solvents, like sodium borohydride (NaBH4),\nhydrazine and citrate to initiate the synthetic process and promote\nnanoparticle nucleation. It has been demonstrated that the most efficient\nreducing agents are NaBH4 and hydrazine, but these agents present the\ndisadvantage that are biologically and environmentally toxic [20-23]. Suchomel\nP. and co-workers prepared AuNPsby the reduction of tetrachloroauric acid using\nmaltose in the presence of nonionic surfactant Tween 80 at various\nconcentrations, in order to control the size of the resulting AuNPs. It was\nobserved that when the concentration of Tween 80 increased, a decrease in the\nsize of produced AuNPs was observed, which ment that the surfactant plays a key\nrole in the nanoparticles dimensions [24]. <\/p>\n\n\n\n

    Biological\nsynthesis (plants and microorganisms mediated) is a relatively new,\neco-friendly, and promising area of research. Presently, it has been\ndemonstrating that numerous medicinal plants have shown potential to produce\nstable AuNPs [25-27]. There are some advantages using this method for making\nAuNPs, such as nontoxic biocomponents, limiting the waste formation and cutting\ndown the need for extra purification steps. This method involves mixing the\ngold salt with extracts of plant under varied reaction conditions like pH,\nincubation time and temperature to obtain specific shapes and sizes of AuNPs [18].\nAmong various methods, chemical reduction of Au3+ ions is considered to be the\nbest method to synthesize AuNPs with controlled size and morphology [28, 29]. <\/p>\n\n\n\n

    In\nthe last several years, these various synthesis methods to obtain AuNPs have\nbecome an attractive and potential option to explore as a tool for photothermal\ntherapy (PTT), photodynamic therapy (PDT), photoimaging, targeted drug\ndelivery, and immunoassays. Presently, various types of AuNPs, such as gold\nnanorods, nanocages, nanostarsand nanospheres, have become effective tools in\nhuman cancer [7, 30, 31].<\/p>\n\n\n\n

    In this review, we focus on providing further new insights for exploring the AuNPs applications as a tool in cancer imaging and therapy.<\/p>\n\n\n\n

    2. Gold Nanoparticles in Cancer Imaging<\/strong><\/p>\n\n\n\n

    AuNPs\nreceived significant attention due to their high absorption coefficient,\npotential biocompatibility and relatively low toxicity. Also, it is very\nimportant for AuNPs to be synthesized under special conditions which can reduce\nconcerns regarding the potential toxicity induced by the reducing agents and\nreaction conditions [32].<\/p>\n\n\n\n

    The main advantages of AuNPs in imaging applications are related to the fact that: <\/p>\n\n\n\n