Improved controlled release of protein from expanded-pore mesoporous silica nanoparticles modified with co-functionalized poly(n-isopropylacrylamide) and poly(ethylene glycol) (PNIPAM-PEG)

Metal-Organic Framework as a New Type of Magnetothermally-Triggered On-Demand Release Carrier

The development of external stimuli-controlled payload systems has been sought after with increasing interest toward magnetothermally-triggered drug release (MTDR) carriers due to their non-invasive features. However, current MTDR carriers present several limitations, such as poor heating efficiency caused by the aggregation of iron oxide nanoparticles (IONPs) or the presence of antiferromagnetic phases which affect their efficiency. Herein, a novel MTDR carrier is developed using a controlled encapsulation method that fully fixes and confines IONPs of various sizes within the metal-organic frameworks (MOFs). This novel carrier preserves the MOF's morphology, porosity, and IONP segregation, while enhances heating efficiency through the oxidation of antiferromagnetic phases in IONPs during encapsulation. It also features a magnetothermally-responsive nanobrush that is stimulated by an alternating magnetic field to enable on-demand drug release. The novel carrier shows improved heating, which has potential applications as contrast agents and for combined chemo and magnetic hyperthermia therapy. It holds a great promise for magneto-thermally modulated drug dosing at tumor sites, making it an exciting avenue for cancer treatment.

Mesoporous silica nanoparticles: An emerging approach in overcoming the challenges with oral delivery of proteins and peptides

Proteins and peptides (PPs), as therapeutics are widely explored in the past few decades, by virtue of their inherent advantages like high specificity and biocompatibility with minimal side effects. However, owing to their macromolecular size, poor membrane permeability, and high enzymatic susceptibility, the effective delivery of PPs is often challenging. Moreover, their subjection to varying environmental conditions, when administered orally, results in PPs denaturation and structural conformation, thereby lowering their bioavailability. Hence, for effective delivery with enhanced bioavailability, protection of PPs using nanoparticle-based delivery system has gained a growing interest. Mesoporous silica nanoparticles (MSNs), with their tailored morphology and pore size, high surface area, easy surface modification, versatile loading capacity, excellent thermal stability, and good biocompatibility, are eligible candidates for the effective delivery of macromolecules to the target site. This review highlights the different barriers hindering the oral absorption of PPs and the various strategies available to overcome them. In addition, the potential benefits of MSNs, along with their diversifying role in controlling the loading of PPs and their release under the influence of specific stimuli, are also discussed in length. Further, the tuning of MSNs for enhanced gene transfection efficacy is also highlighted. Since extensive research is ongoing in this area, this review is concluded with an emphasis on the potential risks of MSNs that need to be addressed prior to their clinical translation.

Virus-Bionic Mesoporous Silica Nanoplatform for Malignant Tumor Inhibition via Effective Cellular Uptake and Precise Drug Delivery

Over the past few decades, sophisticated nanomaterials have been used as carries for the targeted delivery of therapeutics to solid tumors. However, the low efficiency of intracellular internalization of nanocarriers in current use restricts their biomedical application. In this work, we demonstrate that novel virus-bionic mesoporous-silica-based nanocarriers can be successfully prepared for programmed precise drug delivery. These unique viral mimic nanovesicles not only present virus bionic counterparts and nanostructures, but also have infectious virus-like properties toward tumor cells and tumor tissues. Encouragingly, their large surface area (322.1 m2 /g) endows them with high loading capacity for therapeutic agents, especially, they have more effective gene transfection properties than the commercially available LipoGeneTM transfection reagent. Thanks to their virus-inspired morphology, they exhibit outstanding cellular uptake efficiency with living tumor cells and the ability to invade cells in large quantities with incubation times as short as 5 min, which is much faster than traditional mesoporous silica nanoparticles (mSN) with smooth appearance. Importantly, after doxorubicin (DOX) loading and surface modification of tumor recognition motifs, RGD (Arg-Gly-Asp, vMN@DOX-RGD), the bionic drug-loaded viral mimics elicit potent tumor cell elimination both in vitro and in vivo, greatly exceeding the mSN-based group. Our work paves the way toward virus bionic nanocarrier design for malignant tumor suppression in the clinic.

A review on the latest developments of mesoporous silica nanoparticles as a promising platform for diagnosis and treatment of cancer

Cancer is the second cause of human mortality after cardiovascular disease around the globe. Conventional cancer therapies are chemotherapy, radiation, and surgery. In fact, due to the lack of absolute specificity and high drug concentrations, early recognition and treatment of cancer with conventional approaches have become challenging issues in the world. To mitigate against the limitations of conventional cancer chemotherapy, nanomaterials have been developed. Nanomaterials exhibit particular properties that can overcome the drawbacks of conventional therapies such as lack of specificity, high drug concentrations, and adverse drug reactions. Among nanocarriers, mesoporous silica nanoparticles (MSNs) have gained increasing attention due to their well-defined pore size and structure, high surface area, good biocompatibility and biodegradability, ease of surface modification, and stable aqueous dispersions. This review highlights the current progress with the use of MSNs for the delivery of chemotherapeutic agents for the diagnosis and treatment of cancer. Various stimuli-responsive gatekeepers, which endow the MSNs with on-demand drug delivery, surface modification strategies for targeting purposes, and multifunctional MSNs utilized in drug delivery systems (DDSs) are also addressed. Also, the capability of MSNs as flexible imaging platforms is considered. In addition, physicochemical attributes of MSNs and their effects on cancer therapy with a particular focus on recent studies is emphasized. Moreover, major challenges to the use of MSNs for cancer therapy, biosafety and cytotoxicity aspects of MSNs are discussed.

Functionalization of Nanoparticulate Drug Delivery Systems and Its Influence in Cancer Therapy

Research into the application of nanocarriers in the delivery of cancer-fighting drugs has been a promising research area for decades. On the other hand, their cytotoxic effects on cells, low uptake efficiency, and therapeutic resistance have limited their therapeutic use. However, the urgency of pressing healthcare needs has resulted in the functionalization of nanoparticles' (NPs) physicochemical properties to improve clinical outcomes of new, old, and repurposed drugs. This article reviews recent research on methods for targeting functionalized nanoparticles to the tumor microenvironment (TME). Additionally, the use of relevant engineering techniques for surface functionalization of nanocarriers (liposomes, dendrimers, and mesoporous silica) and their critical roles in overcoming the current limitations in cancer therapy-targeting ligands used for targeted delivery, stimuli strategies, and multifunctional nanoparticles-were all reviewed. The limitations and future perspectives of functionalized nanoparticles were also finally discussed. Using relevant keywords, published scientific literature from all credible sources was retrieved. A quick search of the literature yielded almost 400 publications. The subject matter of this review was addressed adequately using an inclusion/exclusion criterion. The content of this review provides a reasonable basis for further studies to fully exploit the potential of these nanoparticles in cancer therapy.

Recent Advances in Mesoporous Silica Nanoparticles for Targeted Drug Delivery applications

Nanotechnology provides the means to design and fabricate delivery vehicles capable of overcoming physiologically imposed obstacles and undesirable side effects of systemic drug delivery. This protocol allows maximal targeting effectiveness and therefore enhances therapeutic efficiency. In recent years, mesoporous silica nanoparticles (MSNPs) have sparked interest in the nanomedicine research community, particularly for their promising applications in cancer treatment. The intrinsic physio-chemical stability, facile functionalization, high surface area, low toxicity, and great loading capacity for a wide range of chemotherapeutic agents make MSNPs very appealing candidates for controllable drug delivery systems. Importantly, the peculiar nanostructures of MSNPs enabled them to serve as an effective drug, gene, protein, and antigen delivery vehicle for a variety of therapeutic regimens. For these reasons, in this review article, we underscore the recent progress in the design and synthesis of MSNPs and the parameters influencing their characteristic features and activities. In addition, the process of absorption, dissemination, and secretion by injection or oral management of MSNPs are also discussed, as they are key directions for the potential utilization of MSNPs. Factors influencing the in vivo fate of MSNPs will also be highlighted, with the main focus on particle size, morphology, porosity, surface functionality, and oxidation. Given that combining other functional materials with MSNPs may increase their biological compatibility, monitor drug discharge, or improve absorption by tumor cells coated MSNPs; these aspects are also covered and discussed herein.

Review of the Mechanism of Nanocarriers and Technological Developments in the Field of Nanoparticles for Applications in Cancer Theragnostics

Cancer cannot be controlled by the usage of drugs alone, and thus, nanotechnology is an important technique that can provide the drug with an impetus to act more effectively. There is adequate availability of anticancer drugs that are classified as alkylating agents, hormones, or antimetabolites. Nanoparticle (NP) carriers increase the residence time of the drug, thereby enhancing the survival rate of the drug, which otherwise gets washed off owing to the small size of the drug particles by the excretory system. For example, for enhancing the circulation, a coating of nonfouling polymers like PEG and dextran is done. Famous drugs such as doxorubicin (DOX) are commonly encapsulated inside the nanocomposite. The various classes of nanoparticles are used to enhance drug delivery by aiding it to fight against the tumor. Targeted therapy aims to attack the cells with features common to the cancer cells while minimizing damage to the normal cell, and these therapies work in one in four ways. Some block the cancer cells from reproducing newer cells, others release toxic substances to kill the cancer cells, some stimulate the immune system to destroy the cancer cells, and some block the growth of more blood vessels around cancer cells, which starve the cells of the nutrients, which is needed for their growth. This review aims to testify the advancements nanotechnology has brought in cancer therapy, and its statements are supported with recent research findings and clinical trial results.

Cooling-Triggered Release from Mesoporous Poly(N-isopropylacrylamide) Microgels at Physiological Conditions

Poly(N-isopropylacrylamide) (pNIPAM) hydrogels have broad potential applications as drug delivery vehicles because of their thermoresponsive behavior. pNIPAM loading/release performances are directly affected by the gel network structure. Therefore, there is a need with the approaches for accurate design of 3D pNIPAM assemblies with the structure ordered at the nanoscale. This study demonstrates size-selective spontaneous loading of macromolecules (dextrans 10-500 kDa) into pNIPAM microgels by microgel heating from 22 to 35 °C (microgels collapse and trap dextrans) followed by the dextran release upon further cooling down to 22 °C (microgels swell back) . This temperature-mediated behavior is fully reversible. The structure of pNIPAM microgels was tailored via hard templating and cross-linking of the hydrogel using sacrificial mesoporous cores of vaterite CaCO3 microcrystals. In addition, the fabrication of hollow thermoresponsive pNIPAM microshells has been demonstrated, utilizing vaterite microcrystals that had narrower pores. The proposed approach for heating-triggered encapsulation and cooling-triggered release into/from pNIPAM microgels may pave the ways for applications of pNIPAM hydrogels for skin and transdermal cooling-responsive drug delivery in the future.

Magnetic properties of γ-Fe2O3 nanoparticles in a porous SiO2 shell for drug delivery

A method is presented for synthesizing core-shell nanoparticles with a magnetic core and a porous shell suitable for drug delivery and other medical applications. The core contains multiple γ-Fe2O3 nanoparticles (∼15 nm) enclosed in a SiO2 (∼100-200 nm) matrix using either methyl (denoted TMOS-γ-Fe2O3) or ethyl (TEOS-γ-Fe2O3) template groups. Low-temperature Mössbauer spectroscopy showed that the magnetic nanoparticles have the maghemite structure, γ-Fe2O3, with all the vacancies in the octahedral sites. Saturation magnetization measurements revealed that the density of γ-Fe2O3 was greater in the TMOS-γ-Fe2O3 nanoparticles than TEOS-γ-Fe2O3 nanoparticles, presumably because of the smaller methyl group. Magnetization measurements showed that the blocking temperature is around room temperature for the TMOS-γ-Fe2O3 and around 250 K for the TEOS-γ-Fe2O3. Three dimensional topography analysis shows clearly that the magnetic nanoparticles are not only at the surface but have penetrated deep in the silica to form the core-shell structure.

A glimpse of biodegradable polymers and their biomedical applications

Over the past two decades, biodegradable polymers (BPs) have been widely used in biomedical applications such as drug carrier, gene delivery, tissue engineering, diagnosis, medical devices, and antibacterial/antifouling biomaterials. This can be attributed to numerous factors such as chemical, mechanical and physiochemical properties of BPs, their improved processibility, functionality and sensitivity towards stimuli. The present review intended to highlight main results of research on advances and improvements in terms of synthesis, physical properties, stimuli response, and/or applicability of biodegradable plastics (BPs) during last two decades, and its biomedical applications. Recent literature relevant to this study has been cited and their developing trends and challenges of BPs have also been discussed.

Hierarchical bioresponsive nanocarriers for codelivery of curcumin and doxorubicin

Hierarchical responsive nanocarriers have received much attention for targeted delivery of chemotherapeutics. In this study, we designed pH and redox dual-stage responsive nanocarriers in the different delivery stages for co-delivery phosphorylated curcumin (p-Cur) with doxorubicin (Dox). The MSNs nanocarriers were functionalized via specific cleavable PEGylation and hydrogel coating crosslinked by disulfide bonds: MSNs as core load Dox; p-Cur encapsulated in hydrogel coating. In blood circulation, PEGylation endow the nanocarriers with long time during blood circulation; while in tumor tissue, PEG shells could be cleaved due to the pH-sensitive bond and expose the cationic hydrogel coating to improve cell uptake; while inside tumor cells, hydrogel coating could be cleaved due to the GSH and release the drugs. The results showed that the dual-responsive shells endowed the nanocarriers with tumor extracellular pH-triggered cell uptake and specific cancer cell target release. The synergistic effects of the p-Cur and Dox enhanced cellular apoptosis in Hela cells.

Smart Mesoporous Silica Nanoparticles for Protein Delivery

Mesoporous silica nanoparticles (MSN) have attracted a lot of attention during the past decade which is attributable to their versatile and high loading capacity, easy surface functionalization, excellent biocompatibility, and great physicochemical and thermal stability. In this review, we discuss the factors affecting the loading of protein into MSN and general strategies for targeted delivery and controlled release of proteins with MSN. Additionally, we also give an outlook for the remaining challenges in the clinical translation of protein-loaded MSNs.

Functionalized mesoporous silica nanoparticles and biomedical applications

Since the first report in early 1990s, mesoporous silica nanoparticles (MSNs) have progressively attracted the attention of scientists due to their potential applications in physic, energy storage, imaging, and especially in biomedical engineering. Owning the unique physiochemical properties, such as highly porosity, large surface area and pore volume, functionalizable, tunable pore and particle sizes and biocompatibility, and high loading cavity, MSNs offer efficient encapsulation and then controlled release, and in some cases, intracellular delivery of bioactive molecules for biomedical applications. During the last decade, functionalized MSNs that show respond upon the surrounding stimulus changes, such as temperature, pH, redox, light, ultrasound, magnetic or electric fields, enzyme, redox, ROS, glucose, and ATP, or their combinations, have continuously revolutionized their potential applications in biomedical engineering. Therefore, this review focuses on discussion the recent fabrication of functionalized MSNs and their potential applications in drug delivery, therapeutic treatments, diagnostic imaging, and biocatalyst. In addition, some potential clinical applications and challenges will also be discussed.

Macrophage entrapped silica coated superparamagnetic iron oxide particles for controlled drug release in a 3D cancer model

Targeted delivery of drugs is a major challenge in treatment of diverse diseases. Systemically administered drugs demand high doses and are accompanied by poor selectivity and side effects on non-target cells. Here, we introduce a new principle for targeted drug delivery. It is based on macrophages as transporters for nanoparticle-coupled drugs as well as controlled release of drugs by hyperthermia mediated disruption of the cargo cells and simultaneous deliberation of nanoparticle-linked drugs. Hyperthermia is induced by an alternating electromagnetic field (AMF) that induces heat from silica-coated superparamagnetic iron oxide nanoparticles (SPIONs). We show proof-of-principle of controlled release by the simultaneous disruption of the cargo cells and the controlled, AMF induced release of a toxin, which was covalently linked to silica-coated SPIONs via a thermo-sensitive linker. Cells that had not been loaded with SPIONs remain unaffected. Moreover, in a 3D co-culture model we demonstrate specific killing of associated tumour cells when employing a ratio as low as 1:40 (SPION-loaded macrophage: tumour cells). Overall, our results demonstrate that AMF induced drug release from macrophage-entrapped nanoparticles is tightly controlled and may be an attractive novel strategy for targeted drug release.

Mesoporous silica nanoparticles for therapeutic/diagnostic applications

Based on unique intrinsic properties of mesoporous silica nanoparticles (MSNs) such as high surface area, large pore size, good biocompatibility and biodegradability, stable aqueous dispersion, they have received much attention in the recent decades for their applications as a promising platform in the biomedicine field. These porous structures possess a pore size ranging from 2 to 50 nm which make them excellent candidates for various biomedical applications. Herein, at first we described the common approaches of cargo loading and release processes from MSNs. Then, the intracellular uptake, safety and cytotoxicity aspects of MSNs are discussed as well. This review also highlights the most recent advances in the biomedical applications of MSNs, including 1) MSNs-based carriers, 2) MSNs as bioimaging agents, 3) MSNs-based biosensors, 4) MSNs as therapeutic agents (photodynamic therapy), 5) MSN based quantum dots, 6) MSNs as platforms for upconverting nanoparticles, and 6) MSNs in tissue engineering.

A perfect stimuli-responsive magnetic nanocomposite for intracellular delivery of doxorubicin

Iron oxide nanoparticles (IONs) have been extensively applied in cancer therapy and theranostics due to their admissible magnetic properties, excellent chemical stability and biocompatibility. Herein, a novel stimuli-responsive magnetic nanocomposite was synthesized for cancer therapy; thereby, the triblock copolymer of poly[(2-succinyloxyethylmethacrylate)-b-(N-isopropylacrylamide)-b-dimethylaminoethylmethacrylate) [poly(SEMA-b-NIPAM-b-DMAEMA)] was prepared by reversible addition of fragmentation chain transfer (RAFT) polymerization. This triblock copolymer with carboxylic groups of succinyloxyethylmethacrylate was adsorbed onto the surface of Fe₃O₄ nanoparticles. The morphology, nanocomposite properties and stimuli-responsive behaviours were investigated by field emission scanning electron microscopy, X-ray diffraction, dynamic light scattering, vibrating sample magnetometer (VSM) and thermogravimetric analysis. Doxorubicin (DOX) encapsulation efficacy was 94.3%. Release behaviours of DOX from the magnetic nanocomposite exhibited that the rate of DOX release could be efficiently controlled through temperature and pH. The cytotoxicity of the drug was investigated in vitro against breast cancer cell line (MCF7) using (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assays, 4',6-diamidino-2-phenylindole (DAPI) staining and cellular uptake. In conclusion, the synthesized DOX@nanocomposite can be applied in theranostic applications and anticancer drug delivery owing to admissible properties.

Design, Synthesis and Architectures of Hybrid Nanomaterials for Therapy and Diagnosis Applications

Hybrid nanomaterials based on inorganic nanoparticles and polymers are highly interesting structures since they combine synergistically the advantageous physical-chemical properties of both inorganic and polymeric components, providing superior functionality to the final material. These unique properties motivate the intensive study of these materials from a multidisciplinary view with the aim of finding novel applications in technological and biomedical fields. Choosing a specific synthetic methodology that allows for control over the surface composition and its architecture, enables not only the examination of the structure/property relationships, but, more importantly, the design of more efficient nanodevices for therapy and diagnosis in nanomedicine. The current review categorizes hybrid nanomaterials into three types of architectures: core-brush, hybrid nanogels, and core-shell. We focus on the analysis of the synthetic approaches that lead to the formation of each type of architecture. Furthermore, most recent advances in therapy and diagnosis applications and some inherent challenges of these materials are herein reviewed.

Thermoresponsive Polymer Grafted Porous Silicas as Smart Nanocarriers

Porous silica particles grafted with various stimuli-responsive polymers are investigated with great interest for their use as smart pharmaceutical nanocarriers in advanced drug delivery systems (DDS). In particular, porous silica particles grafted with thermoresponsive polymers that exhibit thermally triggered on/off gating mechanisms have shown improved performance as hybrid DDS capable of controlling the release of different drugs in various mediums which resemble complex biological environments. In addition, the tuning of the drug release profiles as per requirements has proved possible with modifications to the porous core and the grafted thermoresponsive polymers. This highlight presents a brief discussion of basic preparation techniques and some recent significant developments in the field of thermoresponsive polymer grafted porous silica particles as smart pharmaceutical nanocarriers.

Mesoporous Silica Nanoparticles

Integration of nanotechnology and biomedicine has offered great opportunities for the development of nanoscaled therapeutic platforms. Amongst various nanocarriers, mesoporous silica nanoparticles (MSNs) is one of the most developed and promising inorganic materials-based drug delivery system for clinical translations due to their simple composition and nanoporous structure. MSNs possess unique structural features, for example, well-defined morphology, large surface areas, uniform size, controllable structure, flexible pore volume, tunable pore sizes, extraordinarily high loading efficiency, and excellent biocompatibility. Progress in structure control and functionalization may endow MSNs with functionalities that enable medical applications of these integrated nanoparticles such as molecularly targeted drug delivery, multicomponent synergistic therapy, in vivo imaging and therapeutic capability, on-demand/stimuli-responsive drug release, etc. In this chapter, the authors overview MSNs' characteristics and the scientific efforts developed till date involving drug delivery and biomedical applications.