Calcium carbonate nanoparticles tumor delivery for combined chemo-photodynamic therapy: Comparison of local and systemic administration.

The use of nanoparticles (NPs) as delivery vehicles for multiple drugs is an intensively developing area. However, the success of NPs' accumulation in the tumor area for efficient tumor treatment has been recently questioned. Distribution of NPs in a laboratory animal is mainly related to the administration route of NPs and their physicochemical parameters, which significantly affect the delivery efficiency. In this work, we aim to compare the therapeutic efficiency and side effects of the delivery of multiple therapeutic agents with NPs by both intravenous and intratumoral injections. For this, we systematically developed universal nanosized carriers based on calcium carbonate (CaCO3) NPs (< 100 nm) that were co-loaded with a photosensitizer (Chlorin e6, Ce6) and chemotherapeutic agent (doxorubicin, Dox) for combined chemo- and photodynamic therapy (PDT) of B16-F10 melanoma tumors. By performing intratumoral or intravenous injections of NPs, we observed different biodistribution profiles and tumor accumulation efficiencies. In particular, after intratumoral administration of NPs, they mostly remained in the tumors (> 97%); while for intravenous injection, the tumor accumulation of NPs was determined to be 8.67-12.4 ID/g%. Although the delivery efficiency of NPs (presented in ID/g%) in the tumor differs, we have developed an effective strategy for tumor inhibition based on combined chemo- and PDT by both intratumoral and intravenous injections of NPs. Notably, after the combined chemo- and PDT treatment with Ce6/Dox@CaCO3 NPs, all B16-F10 melanoma tumors in mice shrank substantially, by approximately 94% for intratumoral injection and 71% for intravenous injection, which are higher values compared to mono-therapy. In addition, the CaCO3 NPs showed negligible in vivo toxicity towards major organs such as the heart, lungs, liver, kidneys, and spleen. Thus, this work demonstrates a successful approach for the enhancement of NPs' efficiency in combined anti-tumor therapy.

Theoretical simulation and experimental design of selenium and gold incorporated polymer-based microcarriers for ROS-mediated combined photothermal therapy.

Recently, multi-modal combined photothermal therapy (PTT) with the use of photo-active materials has attracted significant attention for cancer treatment. However, drug carriers enabling efficient heating at the tumor site are yet to be designed: this is a fundamental requirement for broad implementation of PTT in clinics. In this work, we design and develop hybrid carriers based on multilayer capsules integrated with selenium nanoparticles (Se NPs) and gold nanorods (Au NRs) to realize reactive oxygen species (ROS)-mediated combined PTT. We show theoretically and experimentally that cooperative interaction of Se NPs with Au NRs improves the heat release efficiency of the developed capsules. In addition, after uptake by tumor cells, intracellular ROS level amplified by Se NPs inhibits the tumor growth. As a consequence, the synergy between Se NPs and Au NRs exhibits the advantages of hybrid carriers such as (i) improved photothermal conversion efficiency and (ii) dual-therapeutic effect. The results of in vitro and in vivo experiments demonstrate that the combination of ROS-mediated therapy and PTT has a higher tumor inhibition efficiency compared to the single-agent treatment (using only Se-loaded or Au-loaded capsules). Furthermore, the developed hybrid carriers show negligible in vivo toxicity towards major organs such as the heart, lungs, liver, kidneys and spleen. This study not only provides a potential strategy for the design of multifunctional "all-in-one" carriers, but also contributes to the development of combined PTT in clinical practice.

Luminescent Erbium-Doped Silicon Thin Films for Advanced Anti-Counterfeit Labels.

The never-ending struggle against counterfeit demands the constant development of security labels and their fabrication methods. This study demonstrates a novel type of security label based on downconversion photoluminescence from erbium-doped silicon. For fabrication of these labels, a femtosecond laser is applied to selectively irradiate a double-layered Er/Si thin film, which is accomplished by Er incorporation into a silicon matrix and silicon-layer crystallization. The study of laser-induced heating demonstrates that it creates optically active erbium centers in silicon, providing stable and enhanced photoluminescence at 1530 nm. Such a technique is utilized to create two types of anti-counterfeiting labels. The first type is realized by the single-step direct laser writing of luminescent areas and detected by optical microscopy as holes in the film forming the desired image. The second type, with a higher degree of security, is realized by adding other fabrication steps, including the chemical etching of the Er layer and laser writing of additional non-luminescent holes over an initially recorded image. During laser excitation at 525 nm of luminescent holes of the labels, a photoluminescent picture repeating desired data can be seen. The proposed labels are easily scalable and perspective for labeling of goods, securities, and luxury items.