Anisotropic Gold Nanoprobes And Their Applications In Therapy And Biosensing

After several decades of progress and unquestionable development,nanotechnology has been applied in a myriad of applications in the biomedical field.The translation of nanoparticles to the clinic,as well as any other type of therapy,is filled with lights and shadows that can derive in both vibrant opportunities and challenging threats.The hectic pace in terms of increasing number of scientific publications is just a small symptom of the true potential of nanotherapies,which nonetheless could make us overestimate our understanding of the implications of these new technologies.Gold nanoparticles represent a big fraction of the different applications of nanotechnology,and have a noteworthy role in nanomedicine.This comes from the simplicity and versatility of their synthesis,which can give rise of nanomaterials of many different types,shapes and sizes.All of this is combined with the low toxicity and a high resilience of gold,as well as with the ease of introducing surface modifications.But what makes gold nanoparticles unique are their optical properties,known as plasmons,and more specifically surface plasmons,absent in the bulk material,and which make these versatile nanoparticles useful for all kinds of applications from changes of color for sensing,Raman signal amplification,optoacoustic imaging,controlled release of drugs,production of reactive oxygen species,or calorific capacities,among others.In this particular case,we will focus in anisotropic gold nanoparticles,which,in addition to all that has been previously said,are capable of absorbing light in wavelengths of the infrared region of the electromagnetic spectrum,region where living organisms and organic compounds have a minimum absorptivity.This allows anisotropic gold nanoparticles to be excellent candidates for their use in therapy and sensors,as they join a remarkable heating efficiency with an excellent contrast due to the minimized interference of biological structures in the vicinity of the nanoparticle.The present thesis focuses in the use of triangular nanoprisms and nanorods,which thank to their geometry possess a good absorptivity in the near infrared.The main aim of this thesis is to determine in which aspects one type of nanoparticle is superior to the other.More specifically,these nanoparticles are exploited for the development of a thermal biosensor in a test strip format,for an in vitro differential study of fotothermal therapy,and for an in vivo study of the biodistribution/elimination from an animal model.See general conclusions in Chapter 6.