Comparison of passive targeted delivery of inorganic and organic nanocarriers among different types of tumors.

In this study, we have considered four types of nanoparticles (NPs): polylactic acid (PLA), gold (Au), calcium carbonate (CaCO3), and silica (SiO2) with similar sizes (TEM: 50-110 nm and DLS: 110-140 nm) to examine their passive accumulation in three different tumors: colon (CT26), melanoma (B16-F10), and breast (4T1) cancers. Our results demonstrate that each tumor model showed a different accumulation of NPs, in the following order: CT26 > B16-F10 > 4T1. The Au and PLA NPs were evidently characterized by a higher delivery efficiency in case of CT26 tumors compared to CaCO3 and SiO2 NPs. The Au NPs demonstrated the highest accumulation in B16-F10 cells compared to other NPs. These results were verified using SPECT, ex vivo fluorescence bioimaging, direct radiometry and histological analysis. Thus, this work contributes to new knowledge in passive tumor targeting of NPs and can be used for the development of new strategies for delivery of bioactive compounds.

Encapsulation of a small-molecule drug based on substituted 2-aminothiophenes in calcium carbonate carriers for therapy of melanoma.

Although small molecule drugs are widely used in chemotherapy, their low bioavailability, low-concentrated dose in the tumor zone, systemic toxicity, and chemoresistance can significantly limit the therapeutic outcome. These drawbacks can be overcome by two main strategies: (i) development of novel therapeutic molecules with more significant antitumor activity than currently available drugs and (ii) loading chemotherapeutic agents into drug delivery systems. In this study, we aimed to encapsulate a highly prospective small molecule drug based on substituted 2-aminothiophene (2-AT) into calcium carbonate (CaCO3) microparticles (MPs) for the treatment of melanoma tumors. In particular, we have optimized the encapsulation of 2-AT into MPs (2-AT@MPs), studied drug release efficiency, investigated cellular uptake, and evaluated in vivo biodistribution and tumor inhibition efficiency. In vitro results revealed that 2-AT@MPs were able to penetrate into tumor spheroids, leading to prolonged release of 2-AT. By performing intratumoral injection of 2-AT@MPs we observed significant melanoma suppressions in murine models: ∼0.084 cm3 for 2-AT@MPs at a dose of 0.4 g kg-1versus ∼1.370 cm3 for untreated mice. In addition, the 2-AT@MPs showed negligible in vivo toxicity towards major organs such as heart, lung, liver, kidney, and spleen. Thus, this work provided an efficient strategy for the improved chemotherapy of solid tumors by using an encapsulated form of small molecule drugs.

Controllable synthesis of barium carbonate nano- and microparticles for SPECT and CT imaging.

The design and synthesis of nano- and microcarriers for preclinical and clinical imaging are highly attractive due to their unique features, for example, multimodal properties. However, broad translation of these carriers into clinical practice is postponed due to the unknown biological reactivity of the new components used for their synthesis. Here, we have developed microcarriers (∼2-3 µm) and  nanocarriers (<200 nm) made of barium carbonate (BaCO3) for multiple imaging applications in vivo. In general, barium in the developed carriers can be used for X-ray computed tomography, and the introduction of a diagnostic isotope (99mTc) into the BaCO3 structure enables in vivo visualization using single-photon emission computed tomography. The bioimaging has shown that the radiolabeled BaCO3 nano- and microcarriers had different biodistribution profiles and tumor accumulation efficiencies after intratumoral and intravenous injections. In particular, in the case of intratumoral injection, all the types of used carriers mostly remained in the tumors (>97%). For intravenous injection, BaCO3 microcarriers were mainly localized in the lung tissues. However, BaCO3 NPs were mainly accumulated in the liver. These results were supported by ex vivo fluorescence imaging, direct radiometry, and histological analysis. The BaCO3-based micro- and nanocarriers showed negligible in vivo toxicity towards major organs such as the heart, lungs, liver, kidneys, and spleen. This study provides a simple strategy for the design and fabrication of the BaCO3-based carriers for the development of dual bioimaging.

Multifunctional Inorganic-Organic Composite Carriers for Synergistic Dual Therapy of Melanoma.

Many methods for cancer treatment have been developed. Among them photothermal therapy (PTT) has drawn the most significant attention due to its noninvasiveness, remote control activation, and low side effects. However, a limited depth of light penetration of PTT is the main drawback. To improve the therapeutic efficiency, the development of combined PTT with other therapeutic agents is highly desirable. In this work, we have designed multifunctional composite carriers based on polylactic acid (PLA) particles decorated with gold nanorods (Au NRs) as nanoheaters and selenium nanoparticles (Se NPs) for reactive oxygen species (ROS) production in order to perform a combined PTT against B16-F10 melanoma. To do this, we have optimized the synthesis of PLA particles modified with Se NPs and Au NRs (PLA-Se:Au), studied the cellular interactions of PLA particles with B16-F10 cells, and analyzed in vivo biodistribution and tumor inhibition efficiency. The results of in vitro and in vivo experiments demonstrated the synergistic effect from ROS induced by Se NPs and the heating from Au NRs. In melanoma tumor-bearing mice, intratumoral injection of PLA-Se:Au followed by laser irradiation leads to almost complete elimination of tumor tissues. Thus, the optimal photothermal properties and ROS-generating capacity allow us to recommend PLA-Se:Au as a promising candidate for the development of the combined PTT against melanoma.

Synthesis of thieno[3,2-e]pyrrolo[1,2-a]pyrimidine derivatives and their precursors containing 2-aminothiophenes fragments as anticancer agents for therapy of pulmonary metastatic melanoma.

The design and synthesis of new promising compounds based on thienopyrimidine scaffold containing 2-aminothiophene fragments with good safety and favorable drug-like properties are highly relevant for chemotherapy. In this study, a series of 14 variants of thieno[3,2-e]pyrrolo[1,2-a]pyrimidine derivatives (11aa-oa) and their precursors (31 compounds) containing 2-aminothiophenes fragments (9aa-mb, 10aa-oa) were synthesized and screened for their cytotoxicity against B16-F10 melanoma cells. The selectivity of the developed compounds was assessed by determining the cytotoxicity using normal mouse embryonic fibroblasts (MEF NF2 cells). The lead compounds 9cb, 10ic and 11jc with the most significant antitumor activity and minimum cytotoxicity on normal non-cancerous cells were chosen for further in vivo experiments. Additional in vitro experiments with compounds 9cb, 10ic and 11jc showed that apoptosis was the predominant mechanism of death in B16-F10 melanoma cells. With support from in vivo studies, compounds 9cb, 10ic and 11jc demonstrated the biosafety to healthy mice and significant inhibition of the metastatic nodules in pulmonary metastatic melanoma mouse model. Histological analysis detected no abnormal changes in the main organs (the liver, spleen, kidneys, and heart) after the therapy. Thus, the developed compounds 9cb, 10ic and 11jc demonstrate high efficiency in the treatment of pulmonary metastatic melanoma and can be recommended for further preclinical investigation of the melanoma treatment.

Development of Nanocarrier-Based Radionuclide and Photothermal Therapy in Combination with Chemotherapy in Melanoma Cancer Treatment.

Conventional cancer therapy methods have serious drawbacks that are related to the nonspecific action of anticancer drugs that leads to high toxicity on normal cells and increases the risk of cancer recurrence. The therapeutic effect can be significantly enhanced when various treatment modalities are implemented. Here, we demonstrate that the radio- and photothermal therapy (PTT) delivered through nanocarriers (gold nanorods, Au NRs) in combination with chemotherapy in a melanoma cancer results in complete tumor inhibition compared to the single therapy. The synthesized nanocarriers can be effectively labeled with 188Re therapeutic radionuclide with a high radiolabeling efficiency (94-98%) and radiochemical stability (>95%) that are appropriate for radionuclide therapy. Further, 188Re-Au NRs, mediating the conversion of laser radiation into heat, were intratumorally injected and PTT was applied. Upon the irradiation of a near-infrared laser, dual photothermal and radionuclide therapy was achieved. Additionally, the combination of 188Re-labeled Au NRs with paclitaxel (PTX) has significantly improved the treatment efficiency (188Re-labeled Au NRs, laser irradiation, and PTX) compared to therapy in monoregime. Thus, this local triple-combination therapy can be a step toward the clinical translation of Au NRs for use in cancer treatment.

Overcoming the blood-brain barrier for the therapy of malignant brain tumor: current status and prospects of drug delivery approaches.

Besides the broad development of nanotechnological approaches for cancer diagnosis and therapy, currently, there is no significant progress in the treatment of different types of brain tumors. Therapeutic molecules crossing the blood-brain barrier (BBB) and reaching an appropriate targeting ability remain the key challenges. Many invasive and non-invasive methods, and various types of nanocarriers and their hybrids have been widely explored for brain tumor treatment. However, unfortunately, no crucial clinical translations were observed to date. In particular, chemotherapy and surgery remain the main methods for the therapy of brain tumors. Exploring the mechanisms of the BBB penetration in detail and investigating advanced drug delivery platforms are the key factors that could bring us closer to understanding the development of effective therapy against brain tumors. In this review, we discuss the most relevant aspects of the BBB penetration mechanisms, observing both invasive and non-invasive methods of drug delivery. We also review the recent progress in the development of functional drug delivery platforms, from viruses to cell-based vehicles, for brain tumor therapy. The destructive potential of chemotherapeutic drugs delivered to the brain tumor is also considered. This review then summarizes the existing challenges and future prospects in the use of drug delivery platforms for the treatment of brain tumors.

Calcium carbonate carriers for combined chemo- and radionuclide therapy of metastatic lung cancer.

Considering the clinical limitations of individual approaches against metastatic lung cancer, the use of combined therapy can potentially improve the therapeutic effect of treatment. However, determination of the appropriate strategy of combined treatment can be challenging. In this study, combined chemo- and radionuclide therapy has been realized using radionuclide carriers (177Lu-labeled core-shell particles, 177Lu-MPs) and chemotherapeutic drug (cisplatin, CDDP) for treatment of lung metastatic cancer. The developed core-shell particles can be effectively loaded with 177Lu therapeutic radionuclide and exhibit good radiochemical stability for a prolonged period of time. In vivo biodistribution experiments have demonstrated the accumulation of the developed carriers predominantly in lungs. Direct radiometry analysis did not reveal an increased absorbance of radiation by healthy organs. It has been shown that the radionuclide therapy with 177Lu-MPs in mono-regime is able to inhibit the number of metastatic nodules (untreated mice = 120 ± 12 versus177Lu-MPs = 50 ± 7). The combination of chemo- and radionuclide therapy when using 177Lu-MPs and CDDP further enhanced the therapeutic efficiency of tumor treatment compared to the single therapy (177Lu-MPs = 50 ± 7 and CDDP = 65 ± 10 versus177Lu-MPs + CDDP = 37 ± 5). Thus, this work is a systematic research on the applicability of the combination of chemo- and radionuclide therapy to treat metastatic lung cancer.

An investigation of calcium carbonate core-shell particles for incorporation of 225Ac and sequester of daughter radionuclides: in vitro and in vivo studies.

Alpha therapy provides an outstanding prospect in the treatment of recalcitrant and micrometastatic cancers. However, side effects on the normal tissues and organs (especially, kidneys) due to the release of daughter isotopes from α-emitters remain a bottleneck. In this work, calcium carbonate core-shell particles of different sizes were considered as isotope carriers for encapsulation of 225Ac (highly powerful alpha-emitter that generates 4 net alpha particle isotopes in a short decay chain) in order to achieve in vitro and in vivo retention of 225Ac and its daughter isotopes. According to the in vitro studies, the developed calcium carbonate core-shell particles were able to retain 225Ac and its daughter isotopes (221Fr and 213Bi) exhibited good stability in biological media and dose-dependent biocompatibility (over 30 d). The SPECT imaging demonstrated the size-dependent distribution of 225Ac-doped core-shell particles. Further, in vivo studies confirmed the high retention efficiency of calcium carbonate core-shell particles, which was demonstrated in normal Wistar rats (up to 10 d). Interestingly, the radioactivity accumulation in kidney and urine was significantly less for encapsulated 225Ac than in case of non-encapsulated form of 225Ac (225Ac conjugated with albumin), indicating the absence of radioisotope leakage from the developed particles. Thus, our study validates the application of 225Ac-doped core-shell particles to sequester α-emitter (225Ac) and its decay products in order to reduce their systemic toxicity during alpha therapy.

Development of Optimized Strategies for Growth Factor Incorporation onto Electrospun Fibrous Scaffolds To Promote Prolonged Release.

Growth factor incorporation in biomedical constructs for their local delivery enables specific pharmacological effects such as the induction of cell growth and differentiation. This has enabled a promising way to improve the tissue regeneration process. However, it remains challenging to identify an appropriate approach that provides effective growth factor loading into biomedical constructs with their following release kinetics in a prolonged manner. In the present work, we performed a systematic study, which explores the optimal strategy of growth factor incorporation into sub-micrometric-sized CaCO3 core-shell particles (CSPs) and hollow silica particles (SiPs). These carriers were immobilized onto the surface of the polymer scaffolds based on polyhydroxybutyrate (PHB) with and without reduced graphene oxide (rGO) in its structure to examine the functionality of incorporated growth factors. Bone morphogenetic protein-2 (BMP-2) and ErythroPOietin (EPO) as growth factor models were included into CSPs and SiPs using different entrapping strategies, namely, physical adsorption, coprecipitation technique, and freezing-induced loading method. It was shown that the loading efficiency, release characteristics, and bioactivity of incorporated growth factors strongly depend on the chosen strategy of their incorporation into delivery systems. Overall, we demonstrated that the combination of scaffolds with drug delivery systems containing growth factors has great potential in the field of tissue regeneration compared with individual scaffolds.

Biomimetic drug delivery platforms based on mesenchymal stem cells impregnated with light-responsive submicron sized carriers.

Synthetic organic and inorganic carriers often have limitations associated with problematic targeting ability or non-optimized pharmacokinetics, and, therefore, they have restricted therapeutic potential. Natural drug carriers (e.g. mesenchymal stem cells, MSCs) are able to migrate towards the tumor site and penetrate cancerous cells. These biomimetic features make MSCs an attractive delivery platform that allows achieving maximal therapeutic efficiency with minimal toxic side effects. A combination of MSCs exhibiting a homing effect on tumors with stimuli-responsive nanostructured carriers is foreseen to have a huge impact in the field of personalized oncology. Here we develop for the first time a light-sensitive biomimetic delivery platform based on MSCs impregnated with submicron sized composite capsules containing an antitumor drug. This cell-based delivery system triggers the release of the drug upon near-infrared (NIR) laser irradiation due to gold nanorods (Au NRs) incorporated into the capsule wall. The NIR-triggered release of the antitumor drug such as vincristine leads to the effective mortality of tumor spheroids made of primary melanoma cells. Encapsulated vincristine delivered by MSCs into the tumor spheroids and deployed over the whole spheroid upon NIR exposure represents a promising therapy for the improved treatment of malignant neoplasms.

Safe and Effective Delivery of Antitumor Drug Using Mesenchymal Stem Cells Impregnated with Submicron Carriers.

An important area in modern malignant tumor therapy is the optimization of antitumor drugs pharmacokinetics. The use of some antitumor drugs is limited in clinical practice due to their high toxicity. Therefore, the strategy for optimizing the drug pharmacokinetics focuses on the generation of high local concentrations of these drugs in the tumor area with minimal systemic and tissue-specific toxicity. This can be achieved by encapsulation of highly toxic antitumor drug (vincristine (VCR) that is 20-50 times more toxic than widely used the antitumor drug doxorubicin) into nano- and microcarriers with their further association into therapeutically relevant cells that possess the ability to migrate to sites of tumor. Here, we fundamentally examine the effect of drug carrier size on the behavior of human mesenchymal stem cells (hMSCs), including internalization efficiency, cytotoxicity, cell movement, to optimize the conditions for the development of carrier-hMSCs drug delivery platform. Using the malignant tumors derived from patients, we evaluated the capability of hMSCs associated with VCR-loaded carriers to target tumors using a three-dimensional spheroid model in collagen gel. Compared to free VCR, the developed hMSC-based drug delivery platform showed enhanced antitumor activity regarding those tumors that express CXCL12 (stromal cell-derived factor-1 (SDF-1)) gene, inducing directed migration of hMSCs via CXCL12 (SDF-1)/CXCR4 pathway. These results show that the combination of encapsulated antitumor drugs and hMSCs, which possess the properties of active migration into tumors, is therapeutically beneficial and demonstrated high efficiency and low systematic toxicity, revealing novel strategies for chemotherapy in the future.

Adhesion, proliferation, and osteogenic differentiation of human mesenchymal stem cells on additively manufactured Ti6Al4V alloy scaffolds modified with calcium phosphate nanoparticles.

In the present study, biocomposites based on 3D porous additively manufactured Ti6Al4V (Ti64) scaffolds modified with biocompatible calcium phosphate nanoparticles (CaPNPs) were investigated. Ti64 scaffolds were manufactured via electron beam melting technology using an Arcam machine. Electrophoretic deposition was used to modify the scaffolds with CaPNPs, which were synthesized by precipitation in the presence of polyethyleneimine (PEI). Dynamic light scattering revealed that the CaP/PEI nanoparticles had an average size of 46 ± 18 nm and a zeta potential of +22 ± 9 mV. Scanning electron microscopy (SEM) revealed that the obtained spherical CaPNPs had an average diameter of approximately 90 nm. The titanium-based scaffolds coated with CaPNPs exhibited improved hydrophilic surface properties, with a water contact angle below 5°. Cultivation of human mesenchymal stem cells (hMSCs) on the CaPNPs-coated Ti64 scaffolds indicated that the improved hydrophilicity was beneficial for the attachment and growth of cells in vitro. The Ti6Al4V/CaPNPs scaffold supported an increase in the alkaline phosphatase (ALP) activity of cells. In addition to the favourable cell proliferation and differentiation, Ti6Al4V/CaPNPs scaffolds displayed increased mineralization compared to non-coated Ti6Al4V scaffolds. Thus, the developed composite 3D scaffolds of Ti6Al4V functionalized with CaPNPs are promising materials for different applications related to bone repair.

Multifunctional Scaffolds with Improved Antimicrobial Properties and Osteogenicity Based on Piezoelectric Electrospun Fibers Decorated with Bioactive Composite Microcapsules.

The incorporation of bioactive compounds onto polymer fibrous scaffolds with further control of drug release kinetics is essential to improve the functionality of scaffolds for personalized drug therapy and regenerative medicine. In this study, polymer and hybrid microcapsules were prepared and used as drug carriers, which are further deposited onto polymer microfiber scaffolds [polycaprolactone (PCL), poly(3-hydroxybutyrate) (PHB), and PHB doping with the conductive polyaniline (PANi) of 2 wt % (PHB-PANi)]. The number of immobilized microcapsules decreased with increase in their ζ-potential due to electrostatic repulsion with the negatively charged fiber surface, depending on the polymer used for the scaffold's fabrication. Additionally, the immobilization of the capsules in dynamic mechanical conditions at a frequency of 10 Hz resulted in an increase in the number of the capsules on the fibers with increase in the scaffold piezoelectric response in the order PCL < PHB < PHB-PANi, depending on the chemical composition of the capsules. The immobilization of microcapsules loaded with different bioactive molecules onto the scaffold surface enabled multimodal triggering by physical (ultrasound, laser radiation) and biological (enzymatic treatment) stimuli, providing controllable release of the cargo from scaffolds. Importantly, the microcapsules immobilized onto the surface of the scaffolds did not influence the cell growth, viability, and cell proliferation on the scaffolds. Moreover, the attachment of human mesenchymal stem cells (hMSCs) on the scaffolds revealed that the PHB and PHB-PANi scaffolds promoted adhesion of hMSCs compared to that of the PCL scaffolds. Two bioactive compounds, antibiotic ceftriaxone sodium (CS) and osteogenic factor dexamethasone (DEXA), were chosen to load the microcapsules and demonstrate the antimicrobial properties and osteogenesis of the scaffolds. The modified scaffolds had prolonged release of CS or DEXA, which provided an improved antimicrobial effect, as well as enhanced osteogenic differentiation and mineralization of the scaffolds modified with capsules compared to that of individual scaffolds soaked in CS solution or incubated in an osteogenic medium. Thus, the immobilization of microcapsules provides a simple, convenient way to incorporate bioactive compounds onto polymer scaffolds, which makes these multimodal materials suitable for personalized drug therapy and bone tissue engineering.