Seite - 122 - in Cancer Nanotheranostics - What Have We Learnd So Far?

PERSPECTIVE published:12August2015 doi: 10.3389/fchem.2015.00051 Frontiers inChemistry |www.frontiersin.org August2015 |Volume3 |Article51 Editedby: JoãoConde, Massachusetts Instituteof Technology,USA Reviewedby: Jwa-MinNam, SeoulNationalUniversity,SouthKorea JayNadeau, McGillUniversity,Canada *Correspondence: TuanVo-Dinh, DepartmentofBiomedicalEngineering, DukeUniversity,Durham, NC27708,USA tuan.vodinh@duke.edu Specialtysection: Thisarticlewassubmitted to Chemical Engineering, asectionof the journal Frontiers inChemistry Received:01April 2015 Accepted:30July2015 Published:12August2015 Citation: LiuY,YuanH,FalesAM,Register JK andVo-DinhT (2015)Multifunctional goldnanostars formolecular imaging andcancer therapy. Front.Chem.3:51. doi: 10.3389/fchem.2015.00051 Multifunctionalgoldnanostars for molecular imagingandcancer therapy YangLiu1,2,3, HsiangkuoYuan1,2, AndrewM.Fales1,2, JannaK.Register1,2 and TuanVo-Dinh1,2,3* 1Fitzpatrick Institute forPhotonics,DukeUniversity,Durham,NC,USA, 2DepartmentofBiomedical Engineering,Duke University,Durham,NC,USA, 3DepartmentofChemistry,DukeUniversity,Durham,NC,USA Plasmonics-active gold nanoparticles offer excellent potential inmolecular imaging and cancer therapy.Among them,goldnanostars (AuNS) exhibit cross-platformflexibility as multimodalcontrastagents formacroscopicX-raycomputer tomography (CT),magnetic resonanceimaging(MRI),positronemissiontomography(PET),aswellasnanoprobesfor photoacoustic tomography (PAT), two-photon photoluminescence (TPL), and surface- enhancedRaman spectroscopy (SERS). Their surfactant-free surface enables versatile functionalization to enhance cancer targeting, and allow triggered drug release. AuNS can also be used as an efficient platform for drug carrying, photothermal therapy, and photodynamic therapy (PDT). This reviewpaper presents the latest progress regarding AuNS as a promising nanoplatform for cancer nanotheranostics. Future research directionswithAuNS forbiomedical applicationswill alsobediscussed. Keywords:multifunctional,plasmonics,goldnanostars,cancer imaging,cancer therapy Introduction Nanotheranostics, combining diagnostic and therapeutic functions into one nanoparticle, has attracted great attention due to its promise as a powerful tool for personalized therapy to treat cancer,which contributes tomore than sevenmilliondeaths each year (Ferlay et al., 2010; Jemal et al., 2010;Wanget al., 2014).Theranosticnanoprobes canpotentially beused for image-guided cancer therapy with improved targeting specificity and therapeutic efficacy (Choi et al., 2012). Nanoparticles of sizes ranging from20 to 100nmaccumulate in tumors through thewell-known enhancedpermeabilityandretention(EPR)effect thatoriginates fromthe leakytumorvasculature (Maeda,2001;Maedaetal.,2001,2003;Sykesetal.,2014).Furthermore,targetingligands, including antibodies andpeptides, can be functionalized onnanoparticles for active cancer targeting (Kim et al., 2011b). Various nanoplatforms, including liposomes, iron oxide nanoparticles, and gold nanoparticleshavebeendevelopedforcancerimagingandtreatment(Ahmadetal.,2010;Xieetal., 2010;Leeetal., 2014;Wangetal., 2014). Inparticular,goldnanoparticleshavedemonstratedgreat biocompatibility, plasmonic properties, and convenience in versatile functionalization through stronggold-thiolinteractions(30–40kcal/mol),ascanbeexemplifiedbygoldnanorods,nanoshells, andnanocagesinpreclinicalandclinicalcancermanagement(Ramachandranetal.,2003;Looetal., 2004;Alekseeva et al., 2006;Choi et al., 2012;Huschka et al., 2012;Xia et al., 2012b;Ahmadi and Arami,2014;Leeetal., 2014;XiaandXia,2014).Thoseestablishedplasmonicgoldnanoplatforms (nanorods, nanoshells andnanocages) have beenwidely used inprevious studies for in vitro and in vivo investigations of cancer imaging with positron emission tomography (PET), magnetic 122|