Paclitaxel-Loaded Lipid-Coated Magnetic Nanoparticles for Dual Chemo-Magnetic Hyperthermia Therapy of Melanoma.

Melanoma is the most aggressive and metastasis-prone form of skin cancer. Conventional therapies include chemotherapeutic agents, either as small molecules or carried by FDA-approved nanostructures. However, systemic toxicity and side effects still remain as major drawbacks. With the advancement of nanomedicine, new delivery strategies emerge at a regular pace, aiming to overcome these challenges. Stimulus-responsive drug delivery systems might considerably reduce systemic toxicity and side-effects by limiting drug release to the affected area. Herein, we report the development of paclitaxel-loaded lipid-coated manganese ferrite magnetic nanoparticles (PTX-LMNP) as magnetosomes synthetic analogs, envisaging the combined chemo-magnetic hyperthermia treatment of melanoma. PTX-LMNP physicochemical properties were verified, including their shape, size, crystallinity, FTIR spectrum, magnetization profile, and temperature profile under magnetic hyperthermia (MHT). Their diffusion in porcine ear skin (a model for human skin) was investigated after intradermal administration via fluorescence microscopy. Cumulative PTX release kinetics under different temperatures, either preceded or not by MHT, were assessed. Intrinsic cytotoxicity against B16F10 cells was determined via neutral red uptake assay after 48 h of incubation (long-term assay), as well as B16F10 cells viability after 1 h of incubation (short-term assay), followed by MHT. PTX-LMNP-mediated MHT triggers PTX release, allowing its thermal-modulated local delivery to diseased sites, within short timeframes. Moreover, half-maximal PTX inhibitory concentration (IC50) could be significantly reduced relatively to free PTX (142,500×) and Taxol® (340×). Therefore, the dual chemo-MHT therapy mediated by intratumorally injected PTX-LMNP stands out as a promising alternative to efficiently deliver PTX to melanoma cells, consequently reducing systemic side effects commonly associated with conventional chemotherapies.

Folate-Targeted PEGylated Magnetoliposomes for Hyperthermia-Mediated Controlled Release of Doxorubicin.

Doxorubicin (DOX) is a chemotherapeutic agent commonly used for the treatment of solid tumors. However, the cardiotoxicity associated with its prolonged use prevents further adherence and therapeutic efficacy. By encapsulating DOX within a PEGylated liposome, Doxil® considerably decreased DOX cardiotoxicity. By using thermally sensitive lysolipids in its bilayer composition, ThermoDox® implemented a heat-induced controlled release of DOX. However, both ThermoDox® and Doxil® rely on their passive retention in tumors, depending on their half-lives in blood. Moreover, ThermoDox® ordinarily depend on invasive radiofrequency-generating metallic probes for local heating. In this study, we prepare, characterize, and evaluate the antitumoral capabilities of DOX-loaded folate-targeted PEGylated magnetoliposomes (DFPML). Unlike ThermoDox®, DOX delivery via DFPML is mediated by the heat released through dynamic hysteresis losses from magnetothermal converting systems composed by MnFe2O4 nanoparticles (NPs) under AC magnetic field excitation-a non-invasive technique designated magnetic hyperthermia (MHT). Moreover, DFPML dismisses the use of thermally sensitive lysolipids, allowing the use of simpler and cheaper alternative lipids. MnFe2O4 NPs and DFPML are fully characterized in terms of their size, morphology, polydispersion, magnetic, and magnetothermal properties. About 50% of the DOX load is released from DFPML after 30 min under MHT conditions. Being folate-targeted, in vitro DFPML antitumoral activity is higher (IC50 ≈ 1 µg/ml) for folate receptor-overexpressing B16F10 murine melanoma cells, compared to MCF7 human breast adenocarcinoma cells (IC50 ≈ 4 µg/ml). Taken together, our results indicate that DFPML are strong candidates for folate-targeted anticancer therapies based on DOX controlled release.

Predictive Model for Delivery Efficiency: Erythrocyte Membrane-Camouflaged Magnetofluorescent Nanocarriers Study.

Delivery efficiencies of theranostic nanoparticles (NPs) based on passive tumor targeting strongly depend either on their blood circulation time or on appropriate modulations of the tumor microenvironment. Therefore, predicting the NP delivery efficiency before and after a tumor microenvironment modulation is highly desirable. Here, we present a new erythrocyte membrane-camouflaged magnetofluorescent nanocarrier (MMFn) with long blood circulation time (92 h) and high delivery efficiency (10% ID for Ehrlich murine tumor model). MMFns owe their magnetic and fluorescent properties to the incorporation of manganese ferrite nanoparticles (MnFe2O4 NPs) and IR-780 (a lipophilic indocyanine fluorescent dye), respectively, to their erythrocyte membrane-derived camouflage. MMFn composition, morphology, and size, as well as optical absorption, zeta potential, and fluorescent, magnetic, and magnetothermal properties, are thoroughly examined in vitro. We then present an analytical pharmacokinetic (PK) model capable of predicting the delivery efficiency (DE) and the time of peak tumor uptake (tmax), as well as changes in DE and tmax due to modulations of the tumor microenvironment, for potentially any nanocarrier. Experimental PK data sets (blood and tumor amounts of MMFns) are simultaneously fit to the model equations using the PK modeling software Monolix. We then validate our model analytical solutions with the numerical solutions provided by Monolix. We also demonstrate how our a priori nonmechanistic model for passive targeting relates to a previously reported mechanistic model for active targeting. All in vivo PK studies, as well as in vivo and ex vivo biodistribution studies, were conducted using two noninvasive techniques, namely, fluorescence molecular tomography (FMT) and alternating current biosusceptometry (ACB). Finally, histopathology corroborates our PK and biodistribution results.

IR-780-Albumin-Based Nanocarriers Promote Tumor Regression Not Only from Phototherapy but Also by a Nonirradiation Mechanism.

IR-780 iodide is a fluorescent dye with optical properties in the near-infrared region that has applications in tumor detection and photothermal/photodynamic therapy. This multifunctional effect led to the development of theranostic nanoparticles with both IR-780 and chemotherapeutic drugs such as docetaxel, doxorubicin, and lonidamine. In this work, we developed two albumin-based nanoparticles containing near-infrared IR-780 iodide multifunctional dyes, one of them possessing a magnetic core. Molecular docking with AutoDock Vina studies showed that IR-780 binds to bovine serum albumin (BSA) with greater stability at a higher temperature, allowing the protein binding pocket to better fit this dye. The theoretical analysis corroborates the experimental protocols, where an enhancement of IR-780 was found coupled to BSA at 60 °C, even 30 days after preparation, in comparison to 30 °C. In vitro assays monitoring the viability of Ehrlich ascites carcinoma cells revealed the importance of the inorganic magnetic core on the nanocarrier photothermal-cytotoxic effect. Fluorescence molecular tomography measurements of Ehrlich tumor-bearing Swiss mice revealed the biodistribution of the nanocarriers, with marked accumulation in the tumor tissue (≈3% ID). The histopathological analysis demonstrated strong increase in tumoral necrosis areas after 24 and 72 h after treatment, indicating tumor regression. Tumor regression analysis of nonirradiated animals indicate a IR-780 dose-dependent antitumoral effect with survival rates higher than 70% (animals monitored up to 600 days). Furthermore, an in vivo photothermal therapy procedure was performed and tumor regression was also verified. These results show a novel insight for the biomedical application of IR-780-albumin-based nanocarriers, namely cancer therapy, not only by photoinduced therapy but also by a nonirradiation mechanism. Safety studies (acute oral toxicity, cardiovascular evaluation, and histopathological analysis) suggest potential for clinical translation.

Multichannel AC Biosusceptometry System to Map Biodistribution and Assess the Pharmacokinetic Profile of Magnetic Nanoparticles by Imaging.

In this paper, the application of a technique to evaluate in vivo biodistribution of magnetic nanoparticles (MNP) is addressed: the Multichannel AC Biosusceptometry System (MC-ACB). It allows real-time assessment of magnetic nanoparticles in both bloodstream clearance and liver accumulation, where a complex network of inter-related cells is responsible for MNP uptake. Based on the acquired MC-ACB images, we propose a mathematical model which helps to understand the distribution and accumulation pharmacokinetics of MNP. The MC-ACB showed a high time resolution to detect and monitor MNP, providing sequential images over the particle biodistribution. Utilizing the MC-ACB instrument, we assessed regions corresponding to the heart and liver, and we determined the MNP transfer rates between the bloodstream and the liver. The pharmacokinetic model resulted in having a strong correlation with the experimental data, suggesting that the MC-ACB is a valuable and accessible imaging device to assess in vivo and real-time pharmacokinetic features of MNP.

Clavanin A-bioconjugated Fe3O4/Silane core-shell nanoparticles for thermal ablation of bacterial biofilms.

The use of central venous catheters (CVC) is highly associated with nosocomial blood infections and its use largely requires a systematic assessment of benefits and risks. Bacterial contamination of these tubes is frequent and may result in development of microbial consortia also known as biofilm. The woven nature of biofilm provides a practical defense against antimicrobial agents, facilitating bacterial dissemination through the patient's body and development of antimicrobial resistance. In this work, the authors describe the modification of CVC tubing by immobilizing Fe3O4-aminosilane core-shell nanoparticles functionalized with antimicrobial peptide clavanin A (clavA) as an antimicrobial prophylactic towards Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae. Its anti-biofilm-attachment characteristic relies in clavA natural activity to disrupt the bacterial lipidic membrane. The aminosilane shell prevents iron leaching, which is an important nutrient for bacterial growth. Fe3O4-clavA-modified CVCs showed to decrease Gram-negative bacteria attachment up to 90% when compared to control clean CVC. Additionally, when hyperthermal treatment is triggered for 5 min at 80 °C in a tubing that already presents bacterial biofilm (CVC-BF), the viability of attached bacteria reduces up to 88%, providing an efficient solution to avoid changing catheter.