Nanoparticle-mediated cytoplasmic delivery of proteins to target cellular machinery

Protein Nanotubes Assembled from Imidazole-Grafted Horseradish Peroxidase Nanogels

Protein assembly, a common phenomenon in nature, plays an important role in the evolution of life. Inspired by nature, assembling protein monomers into delicate nanostructures has emerged as an attractive research area. However, sophisticated protein assemblies usually need complicated designs or templates. In this work, we successfully fabricated protein nanotubes in a facile way by coordination interactions between imidazole-grafted horseradish peroxidase (HRP) nanogels (iHNs) and Cu2+. The iHNs were synthesized by polymerization on the surface of HRP by employing vinyl imidazole as a comonomer. By direct addition of Cu2+ into iHN solution, protein tubes were therefore formed. The size of the protein tubes could be adjusted by changing the added Cu2+ amount, and the mechanism behind the formation of protein nanotubes was elucidated. Furthermore, a highly sensitive H2O2 detection system was established based on the protein tubes. This work provides a facile method to construct diverse sophisticated functional protein nanomaterials.

Exosome-mediated delivery of superoxide dismutase for anti-aging studies in Caenorhabditis elegans

Aging is a dynamic and progressive process mediated by reactive oxygen species (ROS), and the antioxidant enzyme superoxide dismutase (SOD) can effectively scavenge ROS to extend longevity. However, the instability and impermeability of native enzyme limit its in vivo biomedical application. Currently, exosome as protein carriers attracts considerable attention in the disease treatment owing to low immunogenicity and high stability. Herein, SOD was encapsulated into exosomes via mechanical extrusion with saponin permeabilization to obtain SOD-loaded EXO (SOD@EXO). SOD@EXO with a hydrodynamic diameter of 101.7 ± 5.6 nm could scavenge excessive ROS and protect the cells from oxidative damage induced by 1-methyl-4-phenylpyridine. Compared with native SOD, SOD@EXO significantly extended the lifespan of N2 wild-type Caenorhabditis elegans under normal conditions. Moreover, SOD@EXO improved the resistance against heat and oxidative stress, leading to notable survival ratio under these hostile conditions. Overall, the exosome-mediated delivery of SOD could reduce ROS level and delay aging in C. elegans model, thereby providing potential strategies to treat ROS-related diseases in future.

Protein delivery to living cells by thermal stimulation for biophysical investigation

Studying biomolecules in their native environment represents the ideal sample condition for structural biology investigations. Here we present a novel protocol which allows to delivery proteins into eukaryotic cells through a mild thermal stimulation. The data presented herein show the efficacy of this approach for delivering proteins in the intracellular environment of mammalian cells reaching a concentration range suitable for successfully applying biophysical methods, such as double electron electron resonance (DEER) measurements for characterising protein conformations.

Endocytosis-Independent and Cancer-Selective Cytosolic Protein Delivery via Reversible Tagging with LAT1 substrate

Protein drugs targeting intracellular machineries have shown profound therapeutic potentials, but their clinical utilities are greatly hampered by the lack of efficient cytosolic delivery techniques. Existing strategies mainly rely on nanocarriers or conjugated cell-penetrating peptides (CPPs), which often have drawbacks such as materials complexity/toxicity, lack of cell specificity, and endolysosomal entrapment. Herein, a unique carrier-free approach is reported for mediating cancer-selective and endocytosis-free cytosolic protein delivery. Proteins are sequentially modified with 4-nitrophenyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzyl carbonate as the H₂ O₂ -responsive domain and 3,4-dihydroxy-l-phenylalanine as the substrate of l-type amino acid transporter 1 (LAT1). Thus, the pro-protein can be directly transported into tumor cells by overexpressed LAT1 on cell membranes, bypassing endocytosis and endolysosomal entrapment. In the cytosol, overproduced H₂ O₂ restores the protein structure and activity. Using this technique, versatile proteins are delivered into tumor cells with robust efficiency, including toxins, enzymes, CRISPR-Cas9 ribonucleoprotein, and antibodies. Furthermore, intravenously injected pro-protein of saporin shows potent anticancer efficacy in 4T1-tumor-bearing mice, without provoking systemic toxicity. Such a facile and versatile pro-protein platform may benefit the development of protein pharmaceuticals.

Magnetic Nanobubble Mechanical Stress Induces the Piezo1-Ca2+ -BMP2/Smad Pathway to Modulate Neural Stem Cell Fate and MRI/Ultrasound Dual Imaging Surveillance for Ischemic Stroke

Neural stem cells (NSCs) are used to treat various nervous system diseases because of their self-renewal ability and multidirectional differentiation potential. However, an insufficient ability to track their migration in vivo and poor control over their survival and differentiation efficiency are two major critical challenges for clinical application. Here, it is shown that when magnetic nanobubbles (MNBs), which are assembled from magnetic nanoparticles, are internalized by NSCs, intramembrane volumetric oscillation of the MNBs induces an increase in intracellular hydrostatic pressure and cytoskeleton force, resulting in the activation of the Piezo1-Ca²⁺ mechanosensory channel. This subsequently triggers the BMP2/Smad biochemical signaling pathway, leading to differentiation of NSCs into the neuronal phenotype. Signaling through the Piezo1-Ca²⁺ -BMP2/Smad pathway can be further accelerated by application of an external shear stress force using low-intensity pulsed ultrasound. More importantly, magnetic resonance imaging and ultrasound imaging surveillance of NSCs based on MNB labeling can be leveraged to provide NSC therapeutic outcomes. Both the in vitro and in vivo findings demonstrate that a bubble nanostructure-induced physical force can modulate and control the mechanical signaling pathway regulating stem cell development.

Selective strategies for antibacterial regulation of nanomaterials

Recalcitrant bacterial infection, as a worldwide challenge, causes large problems for human health and is attracting great attention. The excessive antibiotic-dependent treatment of infections is prone to induce antibiotic resistance. A variety of unique nanomaterials provide an excellent toolkit for killing bacteria and preventing drug resistance. It is of great importance to summarize the design rules of nanomaterials for inhibiting the growth of pathogenic bacteria. We completed a review involving the strategies for regulating antibacterial nanomaterials. First, we discuss the antibacterial manipulation of nanomaterials, including the interaction between the nanomaterial and the bacteria, the damage of the bacterial structure, and the inactivation of biomolecules. Next, we identify six main factors for controlling the antibacterial activity of nanomaterials, including their element composition, size dimensions, surface charge, surface topography, shape selection and modification density. Every factor possesses a preferable standard for maximizing antibacterial activity, providing universal rules for antibacterial regulation of nanomaterials. We hope this comprehensive review will help researchers to precisely design and synthesize nanomaterials, developing intelligent antibacterial agents to address bacterial infections.

This review builds universal design rules for the antibacterial regulation of nanomaterials.

Targeting the Inside of Cells with Biologicals: Chemicals as a Delivery Strategy

Delivering macromolecules into the cytosol or nucleus is possible in vitro for DNA, RNA and proteins, but translation for clinical use has been limited. Therapeutic delivery of macromolecules into cells requires overcoming substantially higher barriers compared to the use of small molecule drugs or proteins in the extracellular space. Breakthroughs like DNA delivery for approved gene therapies and RNA delivery for silencing of genes (patisiran, ONPATTRO^®, Alnylam Pharmaceuticals, Cambridge, MA, USA) or for vaccination such as the RNA-based coronavirus disease 2019 (COVID-19) vaccines demonstrated the feasibility of using macromolecules inside cells for therapy. Chemical carriers are part of the reason why these novel RNA-based therapeutics possess sufficient efficacy for their clinical application. A clear advantage of synthetic chemicals as carriers for macromolecule delivery is their favourable properties with respect to production and storage compared to more bioinspired vehicles like viral vectors or more complex drugs like cellular therapies. If biologicals can be applied to intracellular targets, the druggable space is substantially broadened by circumventing the limited utility of small molecules for blocking protein–protein interactions and the limitation of protein-based drugs to the extracellular space. An in depth understanding of the macromolecular cargo types, carrier types and the cell biology of delivery is crucial for optimal application and further development of biologicals inside cells. Basic mechanistic principles of the molecular and cell biological aspects of cytosolic/nuclear delivery of macromolecules, with particular consideration of protein delivery, are reviewed here. The efficiency of macromolecule delivery and applications in research and therapy are highlighted.

Synergistic Interplay of Covalent and Non-Covalent Interactions in Reactive Polymer Nanoassembly Facilitates Intracellular Delivery of Antibodies

The primary impediments in developing large antibodies as drugs against intracellular targets involve their low transfection efficiency and suitable reversible encapsulation strategies for intracellular delivery with retention of biological activity. To address this, we outline an electrostatics-enhanced covalent self-assembly strategy to generate polymer-protein/antibody nanoassemblies. Through structure-activity studies, we down-select the best performing self-immolative pentafluorophenyl containing activated carbonate polymer for bioconjugation. With the help of an electrostatics-aided covalent self-assembly approach, we demonstrate efficient encapsulation of medium to large proteins (HRP, 44 kDa and β-gal, 465 kDa) and antibodies (ca. 150 kDa). The designed polymeric nanoassemblies are shown to successfully traffic functional antibodies (anti-NPC and anti-pAkt) to cytosol to elicit their bioactivity towards binding intracellular protein epitopes and inducing apoptosis.

Nanomaterials for Protein Delivery in Anticancer Applications

Nanotechnology platforms, such as nanoparticles, liposomes, dendrimers, and micelles have been studied extensively for various drug deliveries, to treat or prevent diseases by modulating physiological or pathological processes. The delivery drug molecules range from traditional small molecules to recently developed biologics, such as proteins, peptides, and nucleic acids. Among them, proteins have shown a series of advantages and potential in various therapeutic applications, such as introducing therapeutic proteins due to genetic defects, or used as nanocarriers for anticancer agents to decelerate tumor growth or control metastasis. This review discusses the existing nanoparticle delivery systems, introducing design strategies, advantages of using each system, and possible limitations. Moreover, we will examine the intracellular delivery of different protein therapeutics, such as antibodies, antigens, and gene editing proteins into the host cells to achieve anticancer effects and cancer vaccines. Finally, we explore the current applications of protein delivery in anticancer treatments.

Advancement in Nanotheranostics for Effective Skin Cancer Therapy: State of the Art

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The skin cancer has become a leading concern worldwide as a result of high mortality rate. The treatment modality involves radiation therapy, chemotherapy or surgery. More often combination therapy of chemotherapeutic agents gives better solution over single chemotherapeutic agent. The Globocon report suggested that high incidence and mortality rate in skin cancer is growing day-to-day. This type of cancer is more prevalent in that area where a person is highly exposed to sunlight. The nanotechnology-based therapy is nowadays drawing attention and becoming a more important issue to be discussed. The nanotherapy of skin cancer is dealt with various approaches and strategies. The strategic based approaches imply nanoparticles targeting carcinoma cells, functionalized nanoparticles for specific targeting to cancer cells, receptor-mediated active targeting as nanoshells, nanostrutured lipid carriers, liposome, ethosome, bilosome, polymeric nanoparticle, nanosphere, dendrimers, carbon nanotubes, quantum dots, solid lipid nanoparticles and fullerenes which are highly efficient in specific killing of cancer cells. The passive targeting of chemotherapeutic agents is also helpful in dealing with carcinoma due to enhanced permeability and retention effect (EPR).

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The article outlines nano-based therapy currently focused globally, and the outcomes of the therapy as well.

Surface Modification of Mobile Composition of Matter (MCM)-41 Type Silica Nanoparticles for Potential Oral Mucosa Vaccine Delivery

Development of mobile composition of matter (MCM)-41 silica nanoparticles faces challenges, e.g. surface charge properties, antigen loading efficiency, protecting from enzymes and harsh GIT environment and effective release at target mucosal site. We report the production and characterization of polymer and amine modified MCM-41 type silica nanoparticles for oral antigen delivery using ovalbumin (OVA) as model antigen. Nanoparticles were characterized by dynamic light scattering (DLS), differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, circular dichroism (CD), sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), mucin binding, stability in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) and in vitro OVA release in SGF and SIF. Unmodified nanoparticles size of 146 nm increased to 175-321 nm after modification while modified particles remained intact for more than 3 h in SGF and 96 h in SIF (DLS and SEM). Mucin binding proved polyethylene glycol (PEG) and chitosan modified nanoparticles as potential candidates for oral mucosa delivery. Both showed highest OVA encapsulation at 67% and 73%, and sustained OVA release in SIF (96 h) at 65% and 64% respectively. BET results showed that nanopores were not blocked during surface modification. CD and SDS-PAGE showed that OVA conformational structure did not change after release from the nanoparticles.

Biomimetic Nanotechnology toward Personalized Vaccines

While traditional approaches for disease management in the era of modern medicine have saved countless lives and enhanced patient well-being, it is clear that there is significant room to improve upon the current status quo. For infectious diseases, the steady rise of antibiotic resistance has resulted in super pathogens that do not respond to most approved drugs. In the field of cancer treatment, the idea of a cure-all silver bullet has long been abandoned. As a result of the challenges facing current treatment and prevention paradigms in the clinic, there is an increasing push for personalized therapeutics, where plans for medical care are established on a patient-by-patient basis. Along these lines, vaccines, both against bacteria and tumors, are a clinical modality that could benefit significantly from personalization. Effective vaccination strategies could help to address many challenging disease conditions, but current vaccines are limited by factors such as a lack of potency and antigenic breadth. Recently, researchers have turned toward the use of biomimetic nanotechnology as a means of addressing these hurdles. Recent progress in the development of biomimetic nanovaccines for antibacterial and anticancer applications is discussed, with an emphasis on their potential for personalized medicine.

Boronic acid-engineered gold nanoparticles for cytosolic protein delivery

Boronic acid-engineered gold nanoparticles for effective cytosolic protein delivery with the help of hypertonicity.

Transient Photoinactivation of Cell Membrane Protein Activity without Genetic Modification by Molecular Hyperthermia

Precise manipulation of protein activity in living systems has broad applications in biomedical sciences. However, it is challenging to use light to manipulate protein activity in living systems without genetic modification. Here, we report a technique to optically switch off protein activity in living cells with high spatiotemporal resolution, referred to as molecular hyperthermia (MH). MH is based on the nanoscale-confined heating of plasmonic gold nanoparticles by short laser pulses to unfold and photoinactivate targeted proteins of interest. First, we show that protease-activated receptor 2 (PAR2), a G-protein-coupled receptor and an important pathway that leads to pain sensitization, can be photoinactivated in situ by MH without compromising cell proliferation. PAR2 activity can be switched off in laser-targeted cells without affecting surrounding cells. Furthermore, we demonstrate the molecular specificity of MH by inactivating PAR2 while leaving other receptors intact. Second, we demonstrate that the photoinactivation of a tight junction protein in brain endothelial monolayers leads to a reversible blood-brain barrier opening in vitro. Lastly, the protein inactivation by MH is below the nanobubble generation threshold and thus is predominantly due to the nanoscale heating. MH is distinct from traditional hyperthermia (that induces global tissue heating) in both its time and length scales: nanoseconds versus seconds, nanometers versus millimeters. Our results demonstrate that MH enables selective and remote manipulation of protein activity and cellular behavior without genetic modification.

Rational Design of Nanocarriers for Intracellular Protein Delivery

Protein/antibody therapeutics have exhibited the advantages of high specificity and activity even at an extremely low concentration compared to small molecule drugs. However, they are accompanied by unfavorable physicochemical properties such as fragile tertiary structure, large molecular size, and poor penetration of the membrane, and thus the clinical use of protein drugs is hindered by inefficient delivery of proteins into the host cells. To overcome the challenges associated with protein therapeutics and enhance their biopharmaceutical applications, various protein-loaded nanocarriers with desired functions, such as lipid nanocapsules, polymeric nanoparticles, inorganic nanoparticles, and peptides, are developed. In this review, the different strategies for intracellular delivery of proteins are comprehensively summarized. Their designed routes, mechanisms of action, and potential therapeutics in live cells or in vivo are discussed in detail. Furthermore, the perspective on the new generation of delivery systems toward the emerging area of protein-based therapeutics is presented as well.

Sensitive and sustained imaging of intracellular microRNA in living cells by a high biocompatible liposomal vehicle introduced isothermal symmetric exponential amplification reaction

A high biocompatible liposomal vehicle was used to deliver enzymes and oligonucleotide substances of the isothermal symmetric exponential amplification reaction into living cells, allowing sensitive and sustained imaging of microRNA in living cells for more than 24 h without apoptosis.

Precision medicine by designer interference peptides: applications in oncology and molecular therapeutics

In molecular cancer therapeutics only 10% of known cancer gene products are targetable with current pharmacological agents. Major oncogenic drivers, such as MYC and KRAS proteins are frequently highly overexpressed or mutated in multiple human malignancies. However, despite their key role in oncogenesis, these proteins are hard to target with traditional small molecule drugs due to their large, featureless protein interfaces and lack of deep pockets. In addition, they are inaccessible to large biologicals, which are unable to cross cell membranes. Designer interference peptides (iPeps) represent emerging pharmacological agents created to block selective interactions between protein partners that are difficult to target with conventional small molecule chemicals or with large biologicals. iPeps have demonstrated successful inhibition of multiple oncogenic drivers with some now entering clinical settings. However, the clinical translation of iPeps has been hampered by certain intrinsic limitations including intracellular localization, targeting tissue specificity and pharmacological potency. Herein, we outline recent advances for the selective inhibition of major cancer oncoproteins via iPep approaches and discuss the development of multimodal peptides to overcome limitations of the first generations of iPeps. Since many protein–protein interfaces are cell-type specific, this approach opens the door to novel programmable, precision medicine tools in cancer research and treatment for selective manipulation and reprogramming of the cancer cell oncoproteome.

Endosomal escape by photo-activated fusion of liposomes containing a malachite green derivative: a novel class of photoresponsive liposomes for drug delivery vehicles

We conducted photo-activated delivery of drugs based on the fusion of liposomes with endocytic membranes, thus allowing the direct release of encapsulated drugs inside the cytoplasm. As described in our earlier works, liposomes can be photoresponsive and fusogenic following the incorporation of a malachite green derivative carrying a long alkyl chain (MGL) into the lipid membrane. We prepared MGL liposomes using 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylcholine and encapsulated doxorubicin (DOX). Though the shape of MGL liposomes became elliptical after encapsulating DOX, UV irradiation did not enhance DOX leakage from MGL liposomes. We demonstrated the cellular uptake of MGL liposomes into murine cells derived from colon cancer (Colon 26 cells) using flow cytometry, and we found that the uptake was governed by a clathrin-dependent endocytosis pathway. Confocal fluorescence microscopic observations of Colon 26 cells treated with MGL liposomes encapsulating DOX revealed that DOX was localized in endosomes under dark conditions, while DOX was observed in the cytosol and nucleus after UV irradiation. The viability of Colon 26 cells treated with MGL liposomes encapsulating DOX was reduced by UV irradiation, indicating photo-induced enhancement of anti-cancer efficacy.

Protein Delivery into the Cell Cytosol using Non-Viral Nanocarriers

Protein delivery into cells is a potentially transformative tool for treating "undruggable" targets in diseases associated with protein deficiencies or mutations. The vast majority of these targets are accessed via the cytosol, a challenging prospect for proteins with therapeutic and diagnostic relevance. In this review we will present promising non-viral approaches for intracellular and ultimately cytosolic delivery of proteins using nanocarriers. We will also discuss the mechanistic properties that govern the efficacy of nanocarrier-mediated protein delivery, applications of nanomaterials, and key challenges and opportunities in the use of nanocarriers for intracellular protein delivery.

Mesoporous Silica Nanoparticles for Protein Protection and Delivery

Therapeutic proteins are widely used in clinic for numerous therapies such as cancer therapy, immune therapy, diabetes management and infectious diseases control. The low stability and large size of proteins generally compromise their therapeutic effects. Thus, it is a big challenge to deliver active forms of proteins into targeted place in a controlled manner. Nanoparticle based delivery systems offer a promising method to address the challenges. In particular, mesoporous silica nanoparticles (MSNs) are of special interest for protein delivery due to their excellent biocompatibility, high stability, rigid framework, well-defined pore structure, easily controllable morphology and tuneable surface chemistry. Therefore, enhanced stability, improved activity, responsive release, and intracellular delivery of proteins have been achieved using MSNs as delivery vehicles. Here, we systematically review the effects of various structural parameters of MSNs on protein loading, protection, and delivery performance. We also highlight the status of the most recent progress using MSNs for intracellular delivery, extracellular delivery, antibacterial proteins delivery, enzyme mobilization, and catalysis.

Antibody Delivery for Intracellular Targets: Emergent Therapeutic Potential

Proteins have sparked fast growing interest as biological therapeutic agents for several diseases. Antibodies, in particular, carry an enormous potential as drugs owing to their remarkable target specificity and low immunogenicity. Although the market has numerous antibodies directed toward extracellular targets, their use in targeting therapeutically important intracellular targets is limited by their inability to cross cellular membrane. Realizing the potential for antibody therapy in disease treatment, progress has been made in the development of methods to deliver antibodies intracellularly. In this review, we address various platforms for delivery of antibodies and their merits and drawbacks.

Biomimetic Nanoparticle Vaccines for Cancer Therapy

It is currently understood that, in order for a tumor to successfully grow, it must evolve means of evading immune surveillance. In the past several decades, researchers have leveraged increases in our knowledge of tumor immunology to develop therapies capable of augmenting endogenous immunity and eliciting strong antitumor responses. In particular, the goal of anticancer vaccination is to train the immune system to properly utilize its own resources in the fight against cancer. Although attractive in principle, there are currently only limited examples of anticancer vaccines that have been successfully translated to the clinic. Recently, there has been a significant push towards the use of nanotechnology for designing vaccine candidates that exhibit enhanced potency and specificity. In this progress report, we discuss recent developments in the field of anticancer nanovaccines. By taking advantage of the flexibility offered by nanomedicine to purposefully program immune responses, this new generation of vaccines has the potential to address many of the hurdles facing traditional platforms. A specific emphasis is placed on the emergence of cell membrane-coated nanoparticles, a novel biomimetic platform that can be used to generate personalized nanovaccines that elicit strong, multi-antigenic antitumor responses.

Protein delivery into cells using inorganic nanoparticle-protein supramolecular assemblies

The delivery of proteins into cells is a potential game changer for a wide array of therapeutic purposes, including cancer therapy, immunomodulation and treatment of inherited diseases. In this review, we present recently developed nanoassemblies for protein delivery that utilize strategies that range from direct assembly, encapsulation and composite formation. We will discuss factors that affect the efficacy of nanoassemblies for delivery from the perspective of both nanoparticles and proteins. Challenges in the field, particularly achieving effective cytosolar protein delivery through endosomal escape or evasion are discussed.

A Concentration-Dependent Insulin Immobilization Behavior of Alkyl-Modified Silica Vesicles: The Impact of Alkyl Chain Length

The insulin immobilization behaviors of silica vesicles (SV) before and after modification with hydrophobic alkyl -C₈ and -C₁₈ groups have been studied and correlated to the grafted alkyl chain length. In order to minimize the influence from the other structural parameters, monolayered -C₈ or -C₁₈ groups are grafted onto SV with controlled density. The insulin immobilization capacity of SV is dependent on the initial insulin concentrations (IIC). At high IIC (2.6-3.0 mg/mL), the trend of insulin immobilization capacity of SV is SV-OH > SV-C₈ > SV-C₁₈, which is determined mainly by the surface area of SV. At medium IIC (0.6-1.9 mg/mL), the trend changes to SV-C₈ ≥ SV-C₁₈ > SV-OH as both the surface area and alkyl chain length contribute to the insulin immobilization. At an extremely low IIC, the hydrophobic-hydrophobic interaction between the alkyl group and insulin molecules plays the most significant role. Consequently, SV-C₁₈ with longer alkyl groups and the highest hydrophobicity show the best insulin enrichment performance compared to SV-C₈ and SV-OH, as evidenced by an insulin detection limit of 0.001 ng/mL in phosphate buffered saline (PBS) and 0.05 ng/mL in artficial urine determined by mass spectrometry (MS).

Design of Pyrene-Fatty Acid Conjugates for Real-Time Monitoring of Drug Delivery and Controllability of Drug Release

Fluorescence probes are usually employed to analyze pharmacokinetics of drug carriers; however, this method using usual probes is not suitable to monitor drug carriers in detail because fluorescence spectra do not change by the disruption of drug carriers. In this study, pyrene-fatty acid conjugates were investigated as probes to monitor the state of drug carriers in real time. 1-Pyrenemethanol was conjugated with fatty acids, such as lauric acid, stearic acid, and behenic acid, and the conjugates were stirred in ethanol, resulting in the formation of submicron particles; these particles exhibited excimer emission. When J774.1 and Colon 26 cells were treated with these particles, the associated fluorescence spectra shifted from excimer emission to monomer emission. Moreover, the degree of change was controlled by the type of fatty acid. These results support the design of drug carriers that can be used to monitor pharmacokinetics in real time and to control the disruption time.

Cancer stem cells (CSCs), cervical CSCs and targeted therapies

Accumulating evidence has shown that cancer stem cells (CSCs) have a tumour-initiating capacity and play crucial roles in tumour metastasis, relapse and chemo/radio-resistance. As tumour propagation initiators, CSCs are considered to be promising targets for obtaining a better therapeutic outcome. Cervical carcinoma is the most common gynaecological malignancy and has a high cancer mortality rate among females. As a result, the investigation of cervical cancer stem cells (CCSCs) is of great value. However, the numbers of cancer cells and corresponding CSCs in malignancy are dynamically balanced, and CSCs may reside in the CSC niche, about which little is known to date. Therefore, due to their complicated molecular phenotypes and biological behaviours, it remains challenging to obtain “purified” CSCs and continuously culture CSCs for further in vitro studies without the cells losing their stem properties. At present, CSC-related markers and functional assays are used to purify, identify and therapeutically target CSCs both in vitro and in vivo. Nevertheless, CSC-related markers are not universal to all tumour types, although some markers may be valid in multiple tumour types. Additionally, functional identifications based on CSC-specific properties are usually limited in in vivo studies. Furthermore, an optimal method for identifying potential CCSCs in CCSC studies has not been previously published, and these techniques are currently of great importance. This article updates our knowledge on CSCs and CCSCs, reviews potential stem cell markers and functional assays for identifying CCSCs, and describes the potential of targeting CCSCs in the treatment of cervical carcinoma.

A Distinct Endocytic Mechanism of Functionalized-Silica Nanoparticles in Breast Cancer Stem Cells

Nanoparticles provide new fields for life medical science application, including targeted-drug delivery and cancer treatment. To maximize the delivery efficiency of nanoparticle, one must understand the uptake mechanism of nanoparticle in cells, which may determine their ultimate fate and localization in cells. Recently, the proposed-cancer stem cell (CSC) theory has been attracted great attention and regarded as new targets for the new nanodrug developmet and cancer therapies. The interaction between nanoparticles and cancer cells has been extensively studied, but the uptake mechanism of nanoparticles in CSCs has received little attention. Here, we use the pharmacological inhibitors of major endocytic pathways to study the silica nanoparticle (SiNP) uptake mechanisms in the human breast adenocarcinoma cell line (MCF-7) and MCF-7-derived breast cancer stem cells (BCSCs). The results demonstrate that the uptake of SiNPs, particularly amino-functionalized SiNPs, in MCF-7 cells is strongly affected by the actin depolymerization, whereas BCSCs more strongly inhibit the amino-functionalized SiNP uptake after the scavenger receptor disruption. These findings indicate a distinct endocytic mechanism of functionalized SiNPs in BCSCs, which is significant for designing ideal nanosized drug delivery systems and improving the selectivity for CSC-targeted therapy.

Understanding the Effect of Surface Chemistry of Mesoporous Silica Nanorods on Their Vaccine Adjuvant Potency

Mesoporous silica nanoparticles are reported as adjuvants in nanovaccines in generating robust antigen-specific immunity. However, the effect of surface chemistry in initiating and modulating the immune response remains largely unexplored. In this study, mesoporous silica nanorods (MSNRs) are modified with NH₂ and C₁₈ groups to investigate the influence of surface functional groups (OH, NH₂ , and C₁₈ ) on their adjuvant efficacy. It is found that compared to OH and NH₂ groups, the hydrophobic C₁₈ modification significantly enhances antigen uptake by antigen presenting cells and endosomal-lysosomal escape in vitro, dendritic cells, and macrophages maturation ex vivo, and elicits secretion of interferon-γ level and antibody response in immunized mice. Moreover, bare MSNR and MSNRNH₂ exhibit T-helper 2 biased immune response, while MSNRC₁₈ shows a T-helper 1 biased immune response. These findings suggest that the surface chemistry of nanostructured adjuvants has profound impact on the immune response, which provides useful guidance for the design of effective nanomaterial based vaccines.

Functional insights into the cellular response triggered by a bile-acid platinum compound conjugated to biocompatible ferric nanoparticles using quantitative proteomic approaches

At present, bioferrofluids are employed as powerful multifunctional tools for biomedical applications such as drug delivery, among others. The present study explores the cellular response evoked when bile-acid platinum derivatives are conjugated with bioferrofluids by testing the biological activity in osteosarcoma (MG-63) and T-cell leukemia (Jurkat) cells. The aim of this work is to evaluate the biocompatibility of a bile-acid platinum derivative conjugated with multi-functional polymer coated bioferrofluids by observing the effects on the protein expression profiles and in intracellular pathways of nanoparticle-stimulated cells. To this end, a mass spectrometry-based approach termed SILAC has been applied to determine in a high-throughput manner the key proteins involved in the cellular response process (including specific quantitatively identified proteins related to the vesicular transport, cellular structure, cell cycle, biosynthetic process, apoptosis and regulation of the cell cycle). Finally, biocompatibility was evaluated and validated by conventional strategies also (such as flow cytometry, MTT, etc.).

Advanced Gene Manipulation Methods for Stem Cell Theranostics

In the field of tissue engineering, autologous cell sources are ideal to prevent adverse immune responses; however, stable and reliable cell sources are limited. To acquire more reliable cell sources, the harvesting and differentiation of stem cells from patients is becoming more and more common. To this end, the need to control the fate of these stem cells before transplantation for therapeutic purposes is urgent. Since transcription factors orchestrate all of the gene activities inside of a cell, researchers have developed engineered and synthetic transcription factors to precisely control the fate of stem cells allowing for safer and more effective cell sources. Engineered transcription factors, mutant fusion proteins of naturally occurring proteins, comprise the three main domains of natural transcription factors including DNA binding domains, transcriptional activation domains, and a linker domain. Several key advancements of engineered zinc finger proteins, transcriptional activator-like effectors, and deficient cas9 proteins have revolutionized the field of engineered transcription factors allowing for precise control of gene regulation. Synthetic transcription factors are chemically made transcription factor mimics that use small molecule based moieties to replicate the main functions of natural transcription factors. These include hairpin polyamides, triple helix forming oligonucleotides, and nanoparticle-based methods. Synthetic transcription factors allow for non-viral delivery and greater spatiotemporal control of gene expression. The developments in engineered and synthetic transcription factors have lowered the risk of tumorigenicity and improved differentiation capability of stem cells, as well as facilitated many key discoveries in the fields of cancer and stem cell biology, thus providing a stepping stone to advance regenerative medicine in the clinic for cell replacement therapies.

Nanodiamonds Mediate Oral Delivery of Proteins for Stem Cell Activation and Intestinal Remodeling in Drosophila

Introduction of exogenous biomacromolecules into living systems is of great interest in genome editing, cancer immunotherapy, and stem cell reprogramming. Whereas current strategies generally depend on nucleic acids transfection, direct delivery of functional proteins that provides enhanced specificity, increased safety, and fast and temporal regulation is highly desirable. Nevertheless, intracellular delivery of intact and bioactive proteins, especially in vivo, remains poorly explored. In this study, we developed a nanodiamonds (NDs)-based protein delivery system in cultured cells and in Drosophila that showed high adsorption, high efficiency, and effective cytosolic release of fully functional proteins. Through live-cell imaging, we observed a novel phenomenon wherein a substantial amount of internalized NDs-protein complex rejected fusion with the early endosome, thereby evading protein degradation in the lysosome. More significantly, we demonstrated that dietary NDs-RNase induced apoptosis in enterocytes, stimulating regenerative divisions in intestinal stem cells and increasing the number of stem cells and precursor cells in Drosophila intestine. As stem cells are poorly accessible by exogenous agents in vivo, NDs-mediated oral delivery of proteins provides a new approach to modulate the stem cell microenvironment for intestinal remodeling, which has important implications for colorectal cancer therapy and regenerative medicine.

Self-assembled protein nanocarrier for intracellular delivery of antibody

Despite the great potential of antibodies as intracellular therapeutics, there is a significant, unmet challenge in delivering sufficient amounts of folded antibodies inside cells. We describe an all-protein self-assembled nanocarrier capable of delivering functional antibodies to the cytosol. By combining an α-helical peptide that self-assembles into a hexameric coiled-coil bundle and an Fc-binding Protein A fragment, we generated the Hex nanocarrier that is efficiently internalized by cells without cytotoxicity. Localization of multiple Fc-binding domains on the hexameric core allowed the Hex nanocarrier to tightly bind antibody with sub-nanomolar affinity regardless of pH and the antibody's originating species. The size of the Hex nanocarrier ranges from 25 to 35nm depending on the antibody loading ratio. We demonstrated the capacity of the Hex nanocarrier to deliver functional antibodies to the cytosol by employing anti-β-tubulin or anti-nuclear pore complex antibody as cargo. The design of the Hex nanocarrier is modular, which enables functionalization beyond Fc-binding. We exploited this feature to improve the cytosolic delivery efficiency of the Hex nanocarrier by addition of an endosomolytic motif to the core. The modified Hex nanocarrier exhibited similar antibody-binding behavior, but delivered more antibodies to their cytosolic targets at a faster rate. This work demonstrates an efficient intracellular antibody delivery platform with significant advantages over existing approaches as it does not require modification of the antibody, is biodegradable, and has an antibody to carrier mass ratio of 13, which is greater than other reported antibody carriers.

Silica-based nanoparticles for therapeutic protein delivery

This review focuses on recent advances in silica-based nanoparticles (SiNPs) as therapeutic protein carriers for disease and cancer treatment.

Evaluating the toxicity of silicon dioxide nanoparticles on neural stem cells using RNA-Seq

Neural stem cells are characterized by self-renewal and multipotency, and a capacity to regenerate in response to brain injury or neurodegenerative disease.

Micelle-Induced Self-Assembling Protein Nanowires: Versatile Supramolecular Scaffolds for Designing the Light-Harvesting System

Organic nanoparticle induced self-assembly of proteins with periodic nanostructures is a promising and burgeoning strategy to develop functional biomimetic nanomaterials. Cricoid proteins afford monodispersed and well-defined hollow centers, and can be used to multivalently interact with geometrically symmetric nanoparticles to form one-dimensional protein nanoarrays. Herein, we report that core-cross-linked micelles can direct cricoid stable protein one (SP1) to self-assembling nanowires through multiple electrostatic interactions. One micelle can act as an organic nanoparticle to interact with two central concaves of SP1 in an opposite orientation to form a sandwich structure, further controlling the assembly direction to supramolecular protein nanowires. The reported versatile supramolecular scaffolds can be optionally manipulated to develop multifunctional integrated or synergistic biomimetic nanomaterials. Artificial light-harvesting nanowires are further developed to mimic the energy transfer process of photosynthetic bacteria for their structural similarity, by means of labeling donor and acceptor chromophores to SP1 rings and spherical micelles, respectively. The absorbing energy can be transferred within the adjacent donors around the ring and shuttling the collected energy to the nearby acceptor chromophore. The artificial light-harvesting nanowires are designed by mimicking the structural characteristic of natural LH-2 complex, which are meaningful in exploring the photosynthesis process in vitro.

Functional characterizations of interactive recombinant PTEN–silica nanoparticles for potential biomedical applications

Nanosystem mediated successful stabilization and delivery of functional recombinant PTEN.

Robust glucose oxidase with a Fe3O4@C-silica nanohybrid structure

An enzyme-material hybrid, biomineralization-based method has been developed for glucose oxidase immobilization with high thermal stability, operational stability and recyclability.

Understanding the contribution of surface roughness and hydrophobic modification of silica nanoparticles to enhanced therapeutic protein delivery

Intracellular protein delivery holds great promise for cancer therapy. In this work, the individual and combined contribution of the surface roughness and hydrophobic modification (octadecyl-group) of silica nanoparticles has been studied in a number of events for cellular delivery of therapeutic proteins, including loading capacity, release behaviour, cellular uptake and endo/lysosomal escape. Both surface roughening and hydrophobic modification enhance the protein adsorption capacity and sustained release, while the contribution from the surface roughness is higher for loading capacity and hydrophobic modification is more effective for sustained protein release. Both structural parameters improve the cellular uptake performance; however the difference in the contribution is cell type-dependent. Only the hydrophobic modification shows a contribution to endo/lysosomal escape, independent of the surface topography. Octadecyl-functionalized rough silica nanoparticles thus show the best performance in therapeutic protein (RNase A) delivery, causing significant cell viability inhibition in different cancer cells among all groups under study.

Core-Cone Structured Monodispersed Mesoporous Silica Nanoparticles with Ultra-large Cavity for Protein Delivery

A new type of monodispersed mesoporous silica nanoparticles with a core-cone structure (MSN-CC) has been synthesized. The large cone-shaped pores are formed by silica lamellae closely packed encircling a spherical core, showing a structure similar to the flower dahlia. MSN-CC has a large pore size of 45 nm and a high pore volume of 2.59 cm(3) g(-1). MSN-CC demonstrates a high loading capacity of large proteins and successfully delivers active β-galactosidase into cells, showing their potential as efficient nanocarriers for the cellular delivery of proteins with large molecular weights.

Shaping Nanoparticles with Hydrophilic Compositions and Hydrophobic Properties as Nanocarriers for Antibiotic Delivery

Inspired by the lotus effect in nature, surface roughness engineering has led to novel materials and applications in many fields. Despite the rapid progress in superhydrophobic and superoleophobic materials, this concept of Mother Nature's choice is yet to be applied in the design of advanced nanocarriers for drug delivery. Pioneering work has emerged in the development of nanoparticles with rough surfaces for gene delivery; however, the preparation of nanoparticles with hydrophilic compositions but with enhanced hydrophobic property at the nanoscale level employing surface topology engineering remains a challenge. Herein we report for the first time the unique properties of mesoporous hollow silica (MHS) nanospheres with controlled surface roughness. Compared to MHS with a smooth surface, rough mesoporous hollow silica (RMHS) nanoparticles with the same hydrophilic composition show unusual hydrophobicity, leading to higher adsorption of a range of hydrophobic molecules and controlled release of hydrophilic molecules. RMHS loaded with vancomycin exhibits an enhanced antibacterial effect. Our strategy provides a new pathway in the design of novel nanocarriers for diverse bioapplications.

Biphasic Synthesis of Large-Pore and Well-Dispersed Benzene Bridged Mesoporous Organosilica Nanoparticles for Intracellular Protein Delivery

Large pore (4.6-7.6 nm) and well-dispersed benzene bridged mesoporous organosilica nanoparticles with uniform particle size of ≈50 nm are prepared via a biphasic approach. They can be directly used as nanocarriers without surface modification for the intracellular delivery of therapeutic proteins.