Infrared-Emitting Multimodal Nanostructures for Controlled In Vivo Magnetic Hyperthermia

E.X. and R.M. contributed equally to this work. Work partially supported by the Ministerio de Ciencia, Innovacion y Universidades (PID2019-106301RB-I00 and PID2019-105195RA-I00), by the Spanish Ministry of Economy and Competitiveness (MAT2017-85617-R, SEV-2016-0686), by the Comunidad de Madrid (RENIM-CM, B2017/BMD-3867, co-financed by the European Structural and Investment Fund; NANOMAGCOST-CM P2018/NMT-4321), by the European COST Actions CA17115 (MyWave) and CA17140 (Nano2Clinic), by the Spanish Scientific Network HiperNano (RED2018-102626-T) and by the European Commission Horizon 2020 project NanoTBTech (Grant Number: 801305). D.G.-C. acknowledges CAM for funding PEJ-2018-AI/IND-11245. A.B. acknowledges funding from Comunidad de Madrid through TALENTO grant ref. 2019-T1/IND-14014. E.X. is grateful for a Juan de la Cierva Formacion scholarship (FJC2018-036734-I). R.M. acknowledges the support of the European Commission through the European Union's Horizon 2020 research and innovation program under the Marie Skodowska-Curie Grant agreement N 797945 (LANTERNS). A. E. acknowledges the support from Comunidad de Madrid (Talento project 2018-T1/IND-1005) and from AECC (Ideas Semilla 2019 project). P.R.S. is grateful for a Juan de la Cierva Incorporacion scholarship (IJC2019-041915-I). Procedures involving animal experiments were approved by the regional authority for animal experimentation of the Comunidad de Madrid and were conducted in agreement with the Universidad Autonoma de Madrid Ethics Committee, in compliance with the European Union directives 63/2010UE and Spanish regulation RD 53/2013.Deliberate and local increase of the temperature within solid tumors represents an effective therapeutic approach. Thermal therapies embrace this concept leveraging the capability of some species to convert the absorbed energy into heat. To that end, magnetic hyperthermia (MHT) uses magnetic nanoparticles (MNPs) that can effectively dissipate the energy absorbed under alternating magnetic fields. However, MNPs fail to provide real-time thermal feedback with the risk of unwanted overheating and impeding on-the-fly adjustment of the therapeutic parameters. Localization of MNPs within a tissue in an accurate, rapid, and cost-effective way represents another challenge for increasing the efficacy of MHT. In this work, MNPs are combined with state-of-the-art infrared luminescent nanothermometers (LNTh; Ag2S nanoparticles) in a nanocapsule that simultaneously overcomes these limitations. The novel optomagnetic nanocapsule acts as multimodal contrast agents for different imaging techniques (magnetic resonance, photoacoustic and near-infrared fluorescence imaging, optical and X-ray computed tomography). Most crucially, these nanocapsules provide accurate (0.2 degrees C resolution) and real-time subcutaneous thermal feedback during in vivo MHT, also enabling the attainment of thermal maps of the area of interest. These findings are a milestone on the road toward controlled magnetothermal therapies with minimal side effects.Ministerio de Ciencia, Innovacion y Universidades PID2019-106301RB-I00 PID2019-105195RA-I00Spanish Ministry of Economy and Competitiveness MAT2017-85617-R SEV-2016-0686Comunidad de Madrid (RENIM-CM - European Structural and Investment Fund) B2017/BMD-3867 NANOMAGCOST-CM P2018/NMT-4321Spanish Scientific Network HiperNano RED2018-102626-TEuropean Commission Horizon 2020 project NanoTBTech 801305CAM PEJ-2018-AI/IND-11245Comunidad de Madrid 2019-T1/IND-14014Juan de la Cierva Formacion scholarship FJC2018-036734-IEuropean Commission through the European Union's Horizon 2020 research and innovation program under the Marie Skodowska-Curie Grant 797945Juan de la Cierva Incorporacion scholarship IJC2019-041915-IComunidad de Madrid 2018-T1/IND-1005AECC (Ideas Semilla 2019 project)European COST Action (MyWave) CA17115European COST Action (Nano2Clinic) CA1714

Multifunctional nanoparticles for hyperthermia, thermometry and fluorescenceimaging in the biological windows

Tesis Doctoral inédita cotutelada por la Universidade Federal de Alagoas de Brasil y la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de Materiales. Fecha de lectura: 17-12-2018In this thesis, the use of core/shell engineering for the synthesis of fluorescent nanoparticles (NPs) capable of operating as nanothermometers, nanoheaters and/or contrast agents for fluorescence imaging in small animal models is explored. The materials here studied – rare-earth (Nd3+, Yb3+, Tm3+ and/or Er3+) doped NPs and PbS/CdS/ZnS quantum dots (QDs) – presented emission and/or excitation bands in the so-called biological windows, where light penetration into tissues is maximal, allowing for ex vivo and in vivo applications. It was demonstrated that the spatial separation between the rare-earth ions, achieved by the core/shell nano-engineering, resulted not only in a considerable improvement on the values of thermo-optical parameters such as the light-heat conversion efficiency and the relative thermal sensitivity, but also on a multi-functionality of the nanosystems. As a consequence, innovative applications in nanothermometry were successfully accomplished when developing this thesis. Among those applications, one can mention: the study in real time of the thermal dynamics of an in vivo tissue, the detection and monitoring of cardiovascular diseases and the recording of in vivo thermal images and videos at a subcutaneous level by means of a ratiometric approach. The results here presented open up avenues for new diagnosis and control techniques that can revolutionize the current methods found in biomedicin

New opportunities for light-based tumor treatment with an “iron fist”

The efficacy of photodynamic treatments of tumors can be significantly improved by using a new generation of nanoparticles that take advantage of the unique properties of the tumor microenvironmen

Quo vadis, nanoparticle-enabled in vivo fluorescence imaging?

The exciting advancements that we are currently witnessing in terms of novel materials and synthesis approaches are leading to the development of colloidal nanoparticles (NPs) with increasingly greater tunable properties. We have now reached a point where it is possible to synthesize colloidal NPs with functionalities tailored to specific societal demands. The impact of this new wave of colloidal NPs has been especially important in the field of biomedicine. In that vein, luminescent NPs with improved brightness and near-infrared working capabilities have turned out to be optimal optical probes that are capable of fast and high-resolution in vivo imaging. However, luminescent NPs have thus far only reached a limited portion of their potential. Although we believe that the best is yet to come, the future might not be as bright as some of us think (and have hoped!). In particular, translation of NP-based fluorescence imaging from preclinical studies to clinics is not straightforward. In this Perspective, we provide a critical assessment and highlight promising research avenues based on the latest advances in the fields of luminescent NPs and imaging technologies. The disillusioned outlook we proffer herein might sound pessimistic at first, but we consider it necessary to avoid pursuing "pipe dreams"and redirect the efforts toward achievable - yet ambitious - goalsThis work has been cofinanced by European Structural and Investment Fund and by the European Union’s Horizon 2020 FET Open program under grant agreement no. 801305 (NanoTBTech). E.X. is grateful for a Juan de la Cierva Formacion scholarship (FJC2018-036734-I). A.B. acknowl- ́ edges funding from Comunidad de Madrid through TALENTO grant ref. 2019-T1/IND-14014. D.

Less is more: dimensionality reduction as a general strategy for more precise luminescence thermometry

Thermal resolution (also referred to as temperature uncertainty) establishes the minimum discernible temperature change sensed by luminescent thermometers and is a key figure of merit to rank them. Much has been done to minimize its value via probe optimization and correction of readout artifacts, but little effort was put into a better exploitation of calibration datasets. In this context, this work aims at providing a new perspective on the definition of luminescence-based thermometric parameters using dimensionality reduction techniques that emerged in the last years. The application of linear (Principal Component Analysis) and non-linear (t-distributed Stochastic Neighbor Embedding) transformations to the calibration datasets obtained from rare-earth nanoparticles and semiconductor nanocrystals resulted in an improvement in thermal resolution compared to the more classical intensity-based and ratiometric approaches. This, in turn, enabled precise monitoring of temperature changes smaller than 0.1 °C. The methods here presented allow choosing superior thermometric parameters compared to the more classical ones, pushing the performance of luminescent thermometers close to the experimentally achievable limits.publishe

In Vivo Spectral Distortions of Infrared Luminescent Nanothermometers Compromise Their Reliability

“This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Nano, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see: https://pubs.acs.org/doi/full/10.1021/acsnano.9b08824Luminescence nanothermometry has emerged over the past decade as an exciting field of research due to its potential applications where conventional methods have demonstrated to be ineffective. Preclinical research has been one of the areas that have benefited the most from the innovations proposed in the field. Nevertheless, certain questions concerning the reliability of the technique under in vivo conditions have been continuously overlooked by most of the scientific community. In this proof-of-concept, hyperspectral in vivo imaging is used to explain how unverified assumptions about the thermal dependence of the optical transmittance of biological tissues in the so-called biological windows can lead to erroneous measurements of temperature. Furthermore, the natural steps that should be taken in the future for a reliable in vivo luminescence nanothermometry are discussed together with a perspective view of the field after the findings here reportedThis work was supported by the Spanish Ministry of Economy and Competitiveness under projects MAT2016-75362-C3-1-R, MAT2017-83111R, and MAT2017-85617-R, by the Instituto de Salud Carlos III (PI16/00812), and by the Comunidad Autónoma de Madrid (B2017/BMD-3867RENIMCM) and cofinanced by the European Structural and investment fund. Additional funding was provided by the European Union’s Horizon 2020 FET Open programme (grant agreement No 801305), the Fundación para la Investigación Biomédica del Hospital Universitario Ramón y Cajal project IMP18_38 (2018/0265), and also COST action CA17140. Y. Shen acknowledges a scholarship from the China Scholarship Council (No. 201806870023

The role of tissue fluorescence in in vivo optical bioimaging

The following article appeared in Journal of Applied Physics 128.17 (2020): 171101 and may be found at https://doi.org/10.1063/5.0021854The technological advancements made in optics and semiconductors (e.g., cameras and laser diodes) working with infrared have brought interest in optical bioimaging back to the forefront of research investigating in vivo medical imaging techniques. The definition of the near-infrared transparency windows has turned optical imaging into more than just a method for topical imaging applications. Moreover, this has focused attention back to tissue fluorescence, emissions by tissues and organs that occur when excited by external illumination sources. Most endogenous fluorophores emit in the blue to green range of the electromagnetic spectrum and the resulting tissue fluorescence can be employed in studies from cells to tissue metabolism or avoided by shifting to the red if seen as unwanted autofluorescence. With the more recent move to infrared, it was discovered that autofluorescence is not limited to the visible but also strongly affects in vivo imaging in the infrared. In this Tutorial, we give an overview on tissue fluorescence and tissue interactions with excitation light as well as their effect on in vivo imaging. Furthermore, potential sources of tissue fluorescence in the near-infrared are identified and we describe approaches for successful biomedical imaging in the biological windows, taking into consideration infrared autofluorescence and summarizing techniques for avoiding it in in vivo imaging experimentsThis work was supported by the Spanish Ministry of Economy and Competitiveness under Project No. MAT2016-75362-C3-1-R, the Spanish Ministry of Sciences, Innovation and Universities under Project No. PID2019-106211RB-I00 (NANONERV), by the Instituto de Salud Carlos III (Nos. PI16/00812 and PI19/00565), and through the Comunidad Autónoma de Madrid (No. B2017/ BMD-3867RENIMCM), and co-financed by the European Structural and investment fund. Additional funding was provided by the European Union’s Horizon 2020 FET Open project NanoTBTech (Grant Agreement No. 801305), the Fundación para la Investigación Biomédica del Hospital Universitario Ramón y Cajal under Project No. IMP18_38(2018/0265), and also COST action CA17140. Y.S. acknowledges a scholarship from the China Scholarship Council (No.201806870023), E.X. is grateful for a Juan de la Cierva Formación scholarship (No. FJC2018-036734-I), and D.H.O. is thankful to the Instituto de Salud Carlos III for a Sara Borrell Fellowship (No. CD17/00210). The authors thank Dr. Blanca del Rosal for the helpful discussion and input on the manuscrip

Luminescence based temperature bio-imaging: Status, challenges, and perspectives

The only way to get thermal images of living organisms without perturbing them is to use luminescent probes with temperature-dependent spectral properties. The acquisition of such thermal images becomes essential to distinguish various states of cells, to monitor thermogenesis, to study cellular activity, and to control hyperthermia therapy. Current efforts are focused on the development and optimization of luminescent reporters such as small molecules, proteins, quantum dots, and lanthanide-doped nanoparticles. However, much less attention is devoted to the methods and technologies that are required to image temperature distribution at both in vitro or in vivo levels. Indeed, rare examples can be found in the scientific literature showing technologies and materials capable of providing reliable 2D thermal images of living organisms. In this review article, examples of 2D luminescence thermometry are presented alongside new possibilities and directions that should be followed to achieve the required level of simplicity and reliability that ensure their future implementation at the clinical level. This review will inspire specialists in chemistry, physics, biology, medicine, and engineering to collaborate with materials scientists to jointly develop novel more accurate temperature probes and enable mapping of temperature with simplified technical mean

Luminescence thermometry for brain activity monitoring: A perspective

Minimally invasive monitoring of brain activity is essential not only to gain understanding on the working principles of the brain, but also for the development of new diagnostic tools. In this perspective we describe how brain thermometry could be an alternative to conventional methods (e.g., magnetic resonance or nuclear medicine) for the acquisition of thermal images of the brain with enough spatial and temperature resolution to track brain activity in minimally perturbed animals. We focus on the latest advances in transcranial luminescence thermometry introducing a critical discussion on its advantages and shortcomings. We also anticipate the main challenges that the application of luminescent nanoparticles for brain thermometry will face in next years. With this work we aim to promote the development of near infrared luminescence for brain activity monitoring, which could also benefit other research areas dealing with the brain and its illnessesThis work was financed by the Spanish Ministerio de Innovación y Ciencias under project NANONERV PID 2019-106211RB-I00. BD acknowledges support from the Australian Research Council (DE200100985), RMIT University (Vice-Chancellor’s Fellowship Programme) and the Australian Academy of Sciences (JG Russell Award). PR-S is grateful for a Juan de la Cierva—Incorporación scholarship (IJC2019-041915-I). AB acknowledges funding from Comunidad de Madrid through TALENTO grant ref. 2019-T1/IND-14014. EX is grateful for a Juan de la Cierva - Incorporación scholarship (IJC2020-045229-I

A brighter era for silver chalcogenide semiconductor nanocrystals

Silver chalcogenide semiconductor nanocrystals (Ag2E SNCs) have become a household name in the biomedical field, where they are used as contrast agents in bioimaging, photothermal therapy agents, and luminescent nanothermometers. The prominent position they have come to occupy in this field stems from a unique combination of features, above all near-infrared excitation and emission alongside low cytotoxicity. However, the first reports on Ag2E SNCs showed that a great limitation of these luminescent nanomaterials resided in their low photoluminescence quantum yield, which results in reduced brightness: a crippling feature in bioimaging and biosensing. In this article, we provide an overview of the strategies developed to overcome this hurdle. These strategies aim to remedy the presence of defects in the SNC core and/or surface, the presence of metallic silver, and off-stoichiometric composition. These features stem from the high mobility and redox potential of Ag+ ions, alongside the difficulty in controlling the nucleation and growth rate of Ag2E SNCs. The effectiveness of each approach is discussed. Lastly, a perspective on future research efforts to make Ag2E SNCs even brighter – and thus more effective in biomedical applications – is provided, with the hope of inspiring further investigation on these nanomaterials with a rich, complex set of physicochemical and spectroscopic propertiesThis work was financed by the Spanish Ministerio de Ciencia e Innovacion under project NANONERV PID2019-106211RB-I00, NANOGRANZ PID2021-123318OB-I00, PID2021-122806OB-I00 and TED2021-132317-I00B, by the Instituto de Salud Carlos III (PI19/ 00565), by the Comunidad Autonoma de Madrid (P2022/BMD-7403 RENIM-CM) and co-financed by the European structural and investment fund. R.M. is grateful to the Spanish Ministerio de Ciencia e Innovación for support to research through a Ramón y Cajal Fellowship (RYC2021- 032913-I). I.Z.-G. thanks UCM-Santander for a predoctoral contract (CT63/19-CT64/19). L.M. acknowledges a scholarship from the China Scholarship Council (No. 202108350018