An immuno-potentiating vehicle made of mesoporous silica-zinc oxide micro-rosettes with enhanced doxorubicin loading for combined chemoimmunotherapy

Two Different Responsive Organosilica Nanocarriers to Combine Chemo- and Immunotherapy against Cancer

The combination of chemo- and immunotherapy was recently demonstrated to improve a patient's response to therapy, giving rise to an emerging cancer treatment known as chemoimmunotherapy (CIT). Despite the promising benefits of CIT, the most important challenges are (i) the simultaneous or time-controlled delivery of two drugs and (ii) the selective uptake into different cells for each of the drugs: cancer cells for the chemotherapeutic and macrophages for the immunostimulation actives. Herein, a delivery strategy based on morphologically different stimuli-responsive breakable organosilica nanocarriers is exploited to transport two distinct drugs in the different cells using different times of delivery. We employ stimulus-sensitive, PEGylated organosilica nanocages to encapsulate the chemotherapeutic agent doxorubicin, which is preferentially taken up by tumor cells vs macrophages. On the other hand, similar size mesoporous organosilica nanoparticles, preferentially internalized by macrophages, are filled with the immunostimulator resiquimod. The administration in a sequential manner of the two different nanocarriers allowed us to assess the integrated effect of the combined therapy versus treatment with a single drug. In vitro work clearly shows an important reduction of tumor cell viability when both chemo- and immunotherapeutic agents are delivered.

Slow degrading Mg-based materials induce tumor cell dormancy on an osteosarcoma-fibroblast coculture model

Osteosarcoma is one of the most common cancers in young adults and is commonly treated using surgery and chemotherapy. During the past years, these therapy approaches improved but failed to ameliorate the outcomes. Therefore, novel, targeted therapeutic approaches should be established to enhance treatment success while preserving patient's quality of life. Recent studies suggest the application of degradable magnesium (Mg) alloys as orthopedic implants bearing a potential antitumor activity. Here, we examined the influence of Mg-based materials on an osteosarcoma-fibroblast coculture. Both, Mg and Mg-6Ag did not lead to tumor cell apoptosis at low degradation rates. Instead, the Mg-based materials induced cellular dormancy in the cancer cells indicated by a lower number of Ki-67 positive cancer cells and a higher p38 expression. This dormancy-like state could be reversed by reseeding on non-degrading glass slides but could not be provoked by inhibition of the protein kinase R-like endoplasmic reticulum kinase. By investigating the influence of the disjunct surface-near effects of the Mg degradation on cell proliferation, an increased pH was found to be a main initiator of Mg degradation-dependent tumor cell proliferation inhibition.

Biosafety of mesoporous silica nanoparticles: a combined experimental and literature study

Mesoporous silica (MS) particles have been explored for various healthcare applications, but universal data about their safety and/or toxicity are yet to be well-established for clinical purposes. Information about general toxicity of hollow MS (HMS) particles and about immunotoxicity of MS particles are significantly lacked. Therefore, acute toxicity and immunotoxicity of HMS particles were experimentally evaluated. A systematic and objective literature study was parallelly performed to analyze the published in vivo toxicity of MS particles. Lethal acute toxicity of MS particles is likely to arise from their physical action after intravenous and intraperitoneal administrations, and only rarely observed after subcutaneous administration. No clear relationship was identified between physicochemical properties of MS particles and lethality as well as maximum tolerated dose with some exceptions. At sub-lethal doses, MS particles tend to accumulate mainly in lung, liver, and spleen. The HMS particles showed lower inflammation-inducing ability than polyinosinic-polycytidylic acid and almost the same allergy-inducing ability as Alum. Finally, the universal lowest observed adverse effect levels were determined as 0.45, 0.81, and 4.1 mg/kg (human equivalent dose) for intravenous, intraperitoneal, and subcutaneous administration of MS particles, respectively. These results could be helpful for determining an appropriate MS particle dose in clinical study.

Construction of Fe3O4-Loaded Mesoporous Carbon Systems for Controlled Drug Delivery

Magnetite (Fe₃O₄) nanoparticles as drug carriers can achieve precise drug target due to their magnetic property. However, they are easy to aggregate in the physiological environment, which obviously limits their application in drug delivery. The development of the Fe-MIL-88B-derived method to construct the Fe₃O₄-loaded mesoporous carbon (Fe₃O₄/carbon) system is a feasible strategy to solve the issue. First, iron atoms evenly distribute in the organic links through coordination bonds in Fe-MIL-88B. After the carbonization of Fe-MIL-88B, mesoporous carbon acts as a barrier to prevent the aggregation of Fe₃O₄ nanoparticles. Herein, Fe-MIL-88B particles were fabricated by the hydrothermal method and then pyrolyzed to construct Fe₃O₄/carbon systems. Results showed that Fe₃O₄ nanoparticles uniformly in situ grew on mesoporous carbon generated by the carbonization of organic components. More encouragingly, the Fe₃O₄/carbon system loaded with DOX demonstrated pH-responsive DOX release, efficient delivery of DOX into cancer cells, and significant cancer cell killing ability. Therefore, the Fe₃O₄/carbon systems prepared by the Fe-MIL-88B-derived method might open up a way for targeted and controlled drug delivery.

Nanoparticle-mediated synergistic chemoimmunotherapy for tailoring cancer therapy: recent advances and perspectives

Nowadays, a potent challenge in cancer treatment is considered the lack of efficacious strategy, which has not been able to significantly reduce mortality. Chemoimmunotherapy (CIT) as a promising approach in both for the first-line and relapsed therapy demonstrated particular benefit from two key gating strategies, including chemotherapy and immunotherapy to cancer therapy; therefore, the discernment of their participation and role of potential synergies in CIT approach is determinant. In this study, in addition to balancing the pros and cons of CIT with the challenges of each of two main strategies, the recent advances in the cancer CIT have been discussed. Additionally, immunotherapeutic strategies and the immunomodulation effect induced by chemotherapy, which boosts CIT have been brought up. Finally, harnessing and development of the nanoparticles, which mediated CIT have expatiated in detail.

3D Printed Zn-doped Mesoporous Silica-incorporated Poly-L-lactic Acid Scaffolds for Bone Repair

Poly-L-lactic acid (PLLA) lacks osteogenic activity, which limits its application in bone repair. Zinc (Zn) is widely applied to strengthen the biological properties of polymers due to its excellent osteogenic activity. In the present study, Zn-doped mesoporous silica (Zn-MS) particles were synthesized by one-pot hydrothermal method. Then, the particles were induced into PLLA scaffolds prepared by selective laser sintering technique, aiming to improve their osteogenic activity. Our results showed that the synthesized particles possessed rosette-like morphology and uniform mesoporous structure, and the composite scaffold displayed the sustained release of Zn ion in a low concentration range, which was attributed to the shield effect of the PLLA matrix and the strong bonding interaction of Si-O-Zn. The scaffold could evidently promote osteogenesis differentiation of mouse bone marrow mesenchymal stem cells by upregulating their osteogenesis-related gene expression. Besides, Zn-MS particles could significantly increase the compressive strength of the PLLA scaffold because of their rosette-like morphology and mesoporous structure, which can form micromechanical interlocking with the PLLA matrix. The Zn-MS particles possess great potential to improve various polymer scaffold properties due to their advantageous morphology and physicochemical properties.

Advances in engineering local drug delivery systems for cancer immunotherapy

Cancer immunotherapy aims to leverage the immune system to suppress the growth of tumors and to inhibit metastasis. The recent promising clinical outcomes associated with cancer immunotherapy have prompted research and development efforts towards enhancing the efficacy of immune checkpoint blockade, cancer vaccines, cytokine therapy, and adoptive T cell therapy. Advancements in biomaterials, nanomedicine, and micro-/nano-technology have facilitated the development of enhanced local delivery systems for cancer immunotherapy, which can enhance treatment efficacy while minimizing toxicity. Furthermore, locally administered cancer therapies that combine immunotherapy with chemotherapy, radiotherapy, or phototherapy have the potential to achieve synergistic antitumor effects. Herein, the latest studies on local delivery systems for cancer immunotherapy are surveyed, with an emphasis on the therapeutic benefits associated with the design of biomaterials and nanomedicines. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease.

Quantum-Sized Zinc Oxide Nanoparticles Synthesised within Mesoporous Silica (SBA-11) by Humid Thermal Decomposition of Zinc Acetate

A modified facile method is presented to synthesise quantum-sized zinc oxide nanoparticles within the pores of a mesoporous silica host (SBA-11). This method eliminates the 3 h alcohol reflux and the basic solution reaction steps of zinc acetate. The mesoporous structure and the ZnO nanoparticles were analysed by X-ray diffractometry, transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, nitrogen sorption analysis and UV–VIS spectroscopy. These tests confirm the synthesis of ~1 nm sized ZnO within the pores of SBA-11 and that the porous structure remained intact after ZnO synthesis.