Nanoparticles to mediate X‐ray‐induced photodynamic therapy and Cherenkov radiation photodynamic therapy

Abstract

Photodynamic therapy (PDT) has emerged as an attractive option for cancer treatment. However, conventional PDT is activated by light that has poor tissue penetration depths, limiting its applicability in the clinic. Recently the idea of using X-ray sources to activate PDT and overcome the shallow penetration issue has garnered significant interest. This can be achieved by external beam irradiation and using a nanoparticle scintillator as transducer. Alternatively, research on exploiting Cherenkov radiation from radioisotopes to activate PDT has also begun to flourish. In either approach, the most auspicious success is achieved using nanoparticles as either a scintillator or a photosensitizer to mediate energy transfer and radical production. Both X-ray induced PDT (X-PDT) and Cherenkov radiation PDT (CR-PDT) contain a significant radiation therapy (RT) component and are essentially PDT and RT combination. Unlike the conventional combination, however, in X-PDT and CR-PDT, one energy source simultaneously activates both processes, making the combination always in synchronism and the synergy potential maximized. While still in early stage of development, X-PDT and CR-PDT address important issues in the clinic and hold great potential in translation. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Radionuclide‐Activated Nanomaterials and Their Biomedical Applications

“…[72] Additionally,s ince many radioactive compounds can selectively reach tumor tissues after intravenous administration, CR-PDT can potentially be achieved in multiple tumor loci with high selectivity. [7] It is well-known that the efficiency of PDT depends on the intracellular concentration of ROS. ROSc oncentration depends,i nt urn, on the local photon intensity generated by the interaction between alight source and photosensitizers.…”

“…[6] Besides imaging, CR can also be exploited to activate nanoparticle systems in at herapeutic approach that is referred to as Cherenkov radiation induced therapy (CRIT), often utilizing photosensitizers to generate reactive oxygen species to cause cellular damage or an ischemic environment. [7] Thec ombination of radionuclides and nanomaterials broadens the possibilities of in vivo CR-based applications. Herein, we will review the types of interactions between nanomaterials and radionuclides,i ncluding CRET,g amma and beta scintillation, X-ray production, as well as possible therapeutic outcomes.W ew ill also provide ac omprehensive review on the main design and interaction mechanisms of radionuclide-activatable nanomaterials,s uch as quantum dots,g old nanoparticles,r are-earth fluorides,a nd metal oxide nanoparticles.C erenkov radiation-based medical applications,s uch as CLI, CRET imaging,g amma-induced and X-ray imaging,p hotodynamic therapy (PDT), and radionuclide-induced chemotherapy will also be covered in this Review.…”

Radionuklidaktivierte Nanomaterialien und ihre biomedizinische Anwendung

“…Wie bei der Bildgebung muss eine Colokalisierung beider Agentien für die Umsetzung therapeutischer Zwecke erzielt werden. Es sind bereits verschiedene Kombinationen aus Radionuklid und Photosensibilisator für eine Behandlung in Krebszellen oder ganzen Tumoren in Tiermodellen untersucht worden . In diesem Abschnitt werden wir einen Überblick über diese therapeutischen Anwendungen geben, darunter photodynamische Therapie und aktivierte Chemotherapie, erreicht durch die Interaktion von CR und Photosensibilisator, Nanomaterial und Chemotherapeutika.…”

“…Schließlich kann die Mehrheit der klinisch verwendeten Isotope die Tscherenkow‐Barriere überwinden, was ubiquitäre Anwendungen ermöglicht . Zusätzlich könnte eine hochselektive CR‐PDT an multiplen Tumorloci möglich sein, da viele radioaktive Verbindungen nach der intravenösen Verabreichung Tumorgewebe selektiv erreichen können.…”

“…Zusätzlich kann die Interaktion von Nukliden mit schweratomhaltigen Nanomaterialien zur Emission charakteristischer Röntgenstrahlen führen, die sich in der Multiplex‐SPECT‐Bildgebung nutzen lassen . Außer zur Bildgebung kann CR auch zur Aktivierung von Nanopartikeln in therapeutischen Ansätzen angewendet werden, die auch als Tscherenkow‐strahlungsinduzierte Therapie (CRIT) bekannt ist und sich oft bestimmter Photosensibilisatoren bedient, um reaktive Sauerstoffspezies zu generieren, die wiederum zelluläre Schäden oder ischämische Umgebungen verursachen …”