Facile Synthesis of Multifunctional Bioreducible Polymers for mRNA Delivery

Bioreducible polymeric mRNA carriers are an emerging family of vectors for gene delivery and vaccine development. A few bioreducible systems have been generated through aqueous-phase ring-opening polymerization of lipoic acid derivatives, however this methodology limits hydrophobic group incorporation and functionality into resulting polymers. Herein, a poly(active ester)disulfide polymer is synthesized that can undergo facile aminolysis with amine-containing substrates under stoichiometric control and mild reaction conditions to yield a library of multifunctional polydisulfide polymers. Functionalized polydisulfide polymer species form stable mRNA-polymer nanoparticles for intracellular delivery of mRNAs in vitro. Alkyl-functionalized polydisulfide-RNA nanoparticles demonstrate rapid cellular uptake and excellent biodegradability when delivering EGFP and OVA mRNAs to cells in vitro. This streamlined polydisulfide synthesis provides a new facile methodology for accessing multifunctional bioreducible polymers as biomaterials for RNA delivery and other applications.

Electrochemical Single-Cell Protein Therapeutics Using a Double-Barrel Nanopipette

Single-cell protein therapeutics is expected to promote our in-depth understanding of how a specific protein with a therapeutic dosage treats the cell without population averaging. However, it has not yet been tackled by current single-cell nanotools. We address this challenge by the use of a double-barrel nanopipette, in which one lumen was used for electroosmotic cytosolic protein delivery and the other was customized for ionic evaluation of the consequence. Upon injection of protein DJ-1 through the delivery lumen, upregulation of the antioxidant protein could protect neural PC-12 cells against oxidative stress from phorbol myristate acetate exposure, as deduced by targeting of the cytosolic hydrogen peroxide by the detecting lumen. The nanotool developed in this study for single-cell protein therapeutics provides a perspective for future single-cell therapeutics involving different therapeutic modalities, such as peptides, enzymes and nucleic acids.

Nanocarriers for intracellular co-delivery of proteins and small-molecule drugs for cancer therapy

In the past few decades, the combination of proteins and small-molecule drugs has made tremendous progress in cancer treatment, but it is still not satisfactory. Because there are great differences in molecular weight, water solubility, stability, pharmacokinetics, biodistribution, and the ways of release and action between macromolecular proteins and small-molecule drugs. To improve the efficacy and safety of tumor treatment, people are committed to developing protein and drug co-delivery systems. Currently, intracellular co-delivery systems have been developed that integrate proteins and small-molecule drugs into one nanocarrier via various loading strategies. These systems significantly improve the blood stability, half-life, and biodistribution of proteins and small-molecule drugs, thus increasing their concentration in tumors. Furthermore, proteins and small-molecule drugs within these systems can be specifically targeted to tumor cells, and are released to perform functions after entering tumor cells simultaneously, resulting in improved effectiveness and safety of tumor treatment. This review summarizes the latest progress in protein and small-molecule drug intracellular co-delivery systems, with emphasis on the composition of nanocarriers, as well as on the loading methods of proteins and small-molecule drugs that play a role in cells into the systems, which have not been summarized by others so far.

Tetraphenylethylene-Featured Fluorescent Supramolecular Nanoparticles for Intracellular Trafficking of Protein Delivery and Neuroprotection

The delivery of protein into mammalian cells enables the dissection and manipulation of biological processes; however, this potency is challenged by the lack of an efficient protein delivery tool and a means to monitor its intracellular trafficking. Herein, we report that the hierarchical self-assembly of tetraphenylethylene (TPE)-featured metal-organic cages (MOCs) and β-cyclodextrin-conjugated polyethylenimine can generate fluorescent supramolecular nanoparticles (FSNPs) to deliver protein into neural cells, a cell line that is hard to transfect using conventional strategy. Further, the aggregation-induced emission (AIE) of TPE enabled the fluorescent monitoring of cytosolic protein release. It is found that FSNPs can deliver and release protein into cytosol for subcellular targeting as fast as 18 h post-delivery. Moreover, the delivery of molecular chaperone DJ-1 using FSNPs activates MAPK/ERK signaling of neural cells to protect cells from oxidative stress.

DNAzyme-Catalyzed Cellular Oxidative Stress Amplification for Pro-protein Activation in Living Cells

The conditional control of protein function in response to the physiological change of cells is of great interest for studying protein function in biological settings and developing protein therapeutics. We report herein that catalase (CAT) DNAzyme can potentiate the generation of reactive oxygen species (ROS) in living cells by knocking down catalase expression, which could further activate a reactive oxygen species (ROS)-responsive pro-protein, RNase A-NBC, in situ. Using an optimized lipid nanoparticle delivery system to simultaneously introduce CAT DNAzyme and RNase A-NBC into cells, we show that the pro-protein, RNase A-NBC, could be activated in a significantly enhanced manner to prohibit tumor cell growth in different types of cancer cells. We believe the methodology of regulating pro-protein activity using DNAzyme biocatalysis to differentiate intracellular environment could further be extended to other functional proteins, and even fundamental investigations in living systems to develop pro-protein therapeutics.

Magnetically Navigated Protein Transduction In Vivo using Iron Oxide-Nanogel Chaperone Hybrid

Systems for "protein transduction," intracellular delivery of functional proteins, are needed to address deliverability challenges of protein therapeutics. However, in vivo protein transduction remains challenging because of instability in serum, extracellular protease digestion and rapid excretion from the bloodstream. Here, a magnetically guided in vivo protein transduction using magnetic nanogel chaperone (MC) composed of iron oxide nanoparticles and a polysaccharide nanogel, a protein carrier inspired by "catch and release" mechanisms of molecular chaperones is demonstrated. The MC system enables efficient delivery of anti-cancer proteins, saporin and RNaseA, into cultured tumor lines and inhibits cell proliferation, mainly via apoptosis. Magnetic in vivo protein transduction via intravenous whole body administration is demonstrated in a fibrosarcoma model. By in vivo optical imaging, MC accumulated in tumor tissues under magnetic field three times more than without irradiation. With subcutaneous injection, saporin is delivered by MC to the cytoplasm in magnetically targeted tissues. In an oral cancer model, MC-delivered magnetically targeted saporin decreased tumor volume without significant body weight changes and no regrowth of tumor at 3 months after complete regression. Protein transduction with MC shows promise for cancer therapeutics and, potentially, for regenerative medicine and other biomedical applications.

Hierarchical Self-assembly of Discrete Metal-Organic Cages into Supramolecular Nanoparticles for Intracellular Protein Delivery

Hierarchical self-assembly (HAS) is a powerful approach to create supramolecular nanostructures for biomedical applications. This potency, however, is generally challenged by the difficulty of controlling the HAS of biomacromolecules and the functionality of resulted HAS nanostructures. Herein, we report a modular approach for controlling the HAS of discrete metal-organic cages (MOC) into supramolecular nanoparticles, and its potential for intracellular protein delivery and cell-fate specification. The hierarchical coordination-driven self-assembly of adamantane-functionalized M12 L24 MOC (Ada-MOC) and the host-guest interaction of Ada-MOC with β-cyclodextrin-conjugated polyethylenimine (PEI-βCD) afford supramolecular nanoparticles in a controllable manner. HAS maintains high efficiency and orthogonality in the presence of protein, enabling the encapsulation of protein into the nanoparticles for intracellular protein delivery for therapeutic application and CRISPR/Cas9 genome editing.

Exosome vesicle as a nano-therapeutic carrier for breast cancer

Breast cancer (BC) is one of the most common lethal diseases found in women; in which shortcomings of currently used treatment procedures and efficiency to target disease contribute to the increment in mortality. Despite other factors, exosomes, a major class of EVs (extracellular vesicles) also play a regulatory role in normal physiological processes and have a major function in proliferation, metastases, and resistance in BC. Interestingly, despite their role in the progression of BC, exosomes also showed their importance as a drug carrier in the targeted drug delivery. The present review aims to shed light on the role of exosomes as a potential nano-therapeutic vehicle in the targeted drug delivery for BC. Information for this review was searched from PubMed and Google Scholar mostly during the year 2019-2020 by using appropriate keywords. The exosomes have been efficiently used in cancer therapeutics where these nano vehicles having specific markers help in efficient targeted delivery of therapeutics including proteins, nucleic acid, and anti-cancer drugs to BC cells. The properties of exosomes as an efficient delivery system can be explored in the future and holds the potential to be used in other forms of cancer as well.

Protein and mRNA Delivery Enabled by Cholesteryl-Based Biodegradable Lipidoid Nanoparticles

Developing safe and efficient delivery systems for therapeutic biomacromolecules is a long-standing challenge. Herein, we report a newly developed combinatorial library of cholesteryl-based disulfide bond-containing biodegradable cationic lipidoid nanoparticles. We have identified a subset of this library which is effective for protein and mRNA delivery in vitro and in vivo. These lipidoids showed comparable transfection efficacies but much lower cytotoxicities compared to the Lpf2k in vitro. In vivo studies in adult mice demonstrated the successful delivery of genome engineering protein and mRNA molecules in the skeletal muscle (via intramuscular injection), lung and spleen (via intravenous injection), and brain (via lateral ventricle infusion).

Cationic Lipid-based Intracellular Delivery of Bacterial Effectors for Rewiring Malignant Cell Signaling

The abundance of bacterial effectors have inspired us to explore their potential in rewiring malignant cell signaling. Their incapability for entering cells, however, hinders such application. Herein we developed a cationic lipid-based high throughput library screening platform for effective intracellular delivery of bacterial effectors. As the misregulated MAPK signaling is a hallmark of many types of cancer, we turned to the Shigella effector OspF which irreversibly inactivates ERK, the terminal component of MAPK cascade. We created a function-based screening assay to obtain AMPA-O16B lipid nanoparticles for effective OspF intracellular delivery, which inhibited the malignant MAPK signaling and tumor growth in vitro and in vivo. Furthermore, the optimized lipid nanoparticle formulation can deliver OspF to modulate the immunosuppressive responses in macrophages. Our work is a general strategy to explore the therapeutic potentials of naturally evolved bacterial effectors.

Modular AND Gate-Controlled Delivery Platform for Tumor Microenvironment Specific Activation of Protein Activity

Protein therapeutics have inspired intensive research interest in a variety of realms. It is still urgently required to avoid premature or unexpected activation of therapeutic proteins to achieve great specificity for therapy. Herein, we reported a modular AND gate-controlled delivery platform for tumor microenvironment specific activation of therapeutic protein activity based on biomineralization of molecular glue-adhered protein enzyme. The AND gate integrates the specific microenvironment of tumor tissues (acidic pH and a certain concentration of ATP) as inputs and activates the therapeutic activity of protein only when both inputs are active. More importantly, the activity of therapeutic protein would not be activated either at acidic pH or in the presence of ATP, which could greatly avoid the deleterious effect on normal tissues. Besides, this AND gate can be modular design and suitable for a variety of therapeutic proteins and nucleic acids.

Ultrasound-Guided Cytosolic Protein Delivery via Transient Fluorous Masks

The inability to spatiotemporally guide proteins in tissues and efficiently deliver them into cells remains a key barrier to realizing their full potential in precision medicine. Here, we report ultrasound-sensitive fluoro-protein nanoemulsions which can be acoustically tracked, guided, and activated for on-demand cytosolic delivery of proteins, including antibodies, using clinically relevant diagnostic ultrasound. This advance is accessed through the discovery of a family of fluorous tags, or FTags, that transiently mask proteins to mediate their efficient dispersion into ultrasound-sensitive liquid perfluorocarbons, a phenomenon akin to dissolving an egg in liquid Teflon. We identify the biochemical basis for protein fluorous masking and confirm FTag coatings are shed during delivery, without disrupting the protein structure or function. Harnessing the ultrasound sensitivity of fluorous emulsions, real-time imaging is used to simultaneously monitor and activate FTag-protein complexes to enable controlled cytosolic antibody delivery in vitro and in vivo. These findings may advance the development of image-guided, protein-based biosensing and therapeutic modalities.

Protein@Inorganic Nanodumpling System for High-Loading Protein Delivery with Activatable Fluorescence and Magnetic Resonance Bimodal Imaging Capabilities

Efficient protein delivery into the target cell is highly desirable for protein therapeutics. Current approaches for protein delivery commonly suffer from low-loading protein capacity, poor specificity for target cells, and invisible protein release. Herein, we report a protein@inorganic nanodumpling (ND) system as an intracellular protein delivery platform. Similar to a traditional Chinese food, the dumpling, ND consists of a protein complex "filling" formed by metal-ion-directed self-assembly of protein cargos fused to histidine-rich green fluorescent proteins (H₃₉GFPs), which are further encapsulated by an external surface "wrapper" of manganese dioxide (MnO₂) via in situ biomineralization. This ND structure allows for a high loading capacity (>63 wt %) for protein cargos with enhanced stability. NDs can be targeted and internalized into cancer cells specifically through folic acid receptors by surface-tailored folic acid. The protein cargo release is in a bistimuli-responsive manner, triggered by an either reductive or acidic intracellular microenvironment. Moreover, the MnO₂ nanowrapper is an efficient fluorescence quencher for inner fused GFPs and also a "switch-on" magnetic resonance imaging (MRI) agent via triggered release of Mn²⁺ ions, which enables activatable fluorescence/MRI bimodal imaging of protein release. Finally, the ND is highly potent and specific to deliver functional protein ribonuclease A (RNase A) into cultured target cells and the tumor site in a xenografted mouse model, eliminating the tumor cells with high therapeutic efficacy. Our approach provides a promising alternative to advance protein-based cancer therapeutics.

Targeted co-delivery of protein and drug to a tumor in vivo by sophisticated RGD-modified lipid-calcium carbonate nanoparticles

Synchronized bio-distribution of combination therapies has several merits such as synergistic effects and reduced side-effects. Co-delivery of a protein and small molecule drug using a single nanocarrier is challenging because they possess totally different characteristics. Herein, we report the development of sophisticated nanoparticles composed of lipids, calcium carbonate and RGD peptide ligands for the co-delivery of a protein and small molecule drug combination via a simple preparation method. A 'one-step' ethanol injection method was employed to prepare the highly organized nanoparticles. The nanoparticles exhibited a spherical shape with ca. 130 nm diameter, and clearly had an integrated lipid layer covering the periphery. As a ligand, an RGD-modified lipid was post-inserted into the nanoparticles, which was important to overcome the 'PEG dilemma'. The pH-sensitivity of the targeted nanoparticles contributed to the efficient intracellular co-delivery of a protein and drug combination in Colon26 tumor cells, and noticeably improved their accumulation in the tumor region of xenograft mice. Synchronized bio-distribution of the protein and drug was achieved, which was the foundation for the synergistic effects of the combination. The targeting capability of the nanoparticles along with their pH-sensitive drug release and the synchronized bio-distribution of their cargos led to the significant antitumor activity of the SOD and paclitaxel combination in mice. This study provides novel information for the design and preparation of functionalized nanoparticles for the delivery of a protein/drug combination in vivo.

Protein-Engineered Biomaterials for Cancer Theranostics

Proteins are an important class of biomaterials promising a variety of applications such as drug delivery, and imaging or therapy, owing to their biodegradability, biocompatibility, as well as inherent biological activities acting as enzymes, recognizing molecules, or therapeutics by themselves. Over the few past decades, different types of proteins with desired properties have been widely explored for biomedical applications. Many therapeutic proteins have now entered clinical use. This review therefore summarizes various strategies in the engineering of biomaterials for delivery of therapeutic proteins, as well as the recent development of protein-based biomaterials for cancer theranostics.

Bioinspired Diselenide-Bridged Mesoporous Silica Nanoparticles for Dual-Responsive Protein Delivery

Controlled delivery of protein therapeutics remains a challenge. Here, the inclusion of diselenide-bond-containing organosilica moieties into the framework of silica to fabricate biodegradable mesoporous silica nanoparticles (MSNs) with oxidative and redox dual-responsiveness is reported. These diselenide-bridged MSNs can encapsulate cytotoxic RNase A into the 8-10 nm internal pores via electrostatic interaction and release the payload via a matrix-degradation controlled mechanism upon exposure to oxidative or redox conditions. After surface cloaking with cancer-cell-derived membrane fragments, these bioinspired RNase A-loaded MSNs exhibit homologous targeting and immune-invasion characteristics inherited from the source cancer cells. The efficient in vitro and in vivo anti-cancer performance, which includes increased blood circulation time and enhanced tumor accumulation along with low toxicity, suggests that these cell-membrane-coated, dual-responsive degradable MSNs represent a promising platform for the delivery of bio-macromolecules such as protein and nucleic acid therapeutics.

Semiconducting Polymer Nanoenzymes with Photothermic Activity for Enhanced Cancer Therapy

Regulation of enzyme activity is fundamentally challenging but practically meaningful for biology and medicine. However, noninvasive remote control of enzyme activity in living systems has been rarely demonstrated and exploited for therapy. Herein, we synthesize a semiconducting polymer nanoenzyme with photothermic activity for enhanced cancer therapy. Upon near-infrared (NIR) light irradiation, the activity of the nanoenzyme can be enhanced by 3.5-fold to efficiently digest collagen in the tumor extracellular matrix (ECM), leading to enhanced nanoparticle accumulation in tumors and consequently improved photothermal therapy (PTT). This study thus provides a promising strategy to remotely regulate enzyme activity for cancer therapy.

pH-Sensitive Coiled-Coil Peptide-Cross-Linked Hyaluronic Acid Nanogels: Synthesis and Targeted Intracellular Protein Delivery to CD44 Positive Cancer Cells

The clinical translation of protein drugs that act intracellularly is limited by the absence of safe and efficient intracellular protein delivery vehicles. Here, pH-sensitive coiled-coil peptide-cross-linked hyaluronic acid nanogels (HA-cNGs) were designed and investigated for targeted intracellular protein delivery to CD44 overexpressing MCF-7 breast cancer cells. HA-cNGs were obtained with a small size of 176 nm from an equivalent mixture of hyaluronic acid conjugates with GY(EIAALEK)₃GC (E3) and GY(KIAALKE)₃GC (K3) peptides, respectively, at pH 7.4 by nanoprecipitation. Circular dichroism (CD) proved the formation of coiled-coil structures between E3 and K3 peptides at pH 7.4 while fast uncoiling at pH 5.0. HA-cNGs showed facile loading of cytochrome C (CC) and greatly accelerated CC release under mild acidic conditions (18.4%, 76.8%, and 91.4% protein release in 24 h at pH 7.4, 6.0, and 5.0, respectively). Confocal microscopy and flow cytometry displayed efficient internalization of CC-loaded HA-cNGs and effective endosomal escape of CC in MCF-7 cancer cells. Remarkably, HA-cNGs loaded with saporin, a ribosome inactivating protein, exhibited significantly enhanced apoptotic activity to MCF-7 cells with a low IC₅₀ of 12.2 nM. These coiled-coil peptide-cross-linked hyaluronic acid nanogels have appeared as a simple and multifunctional platform for efficient intracellular protein delivery.

Development of a Dual-Functional Hydrogel Using RGD and Anti-VEGF Aptamer

Synthetic molecular libraries hold great potential to advance the biomaterial development. However, little effort is made to integrate molecules with molecular recognition abilities selected from different libraries into a single biomolecular material. The purpose of this work is to incorporate peptides and nucleic acid aptamers into a porous hydrogel to develop a dual-functional biomaterial. The data show that an anti-integrin peptide can promote the attachment and growth of endothelial cells in a 3D porous poly(ethylene glycol) hydrogel and an antivascular endothelial growth factor aptamer can sequester and release VEGF of high bioactivity. Importantly, the dual-functional porous hydrogel enhances the growth and survival of endothelial cells. This work demonstrates that molecules selected from different synthetic libraries can be integrated into one system for the development of novel biomaterials.

Construction of versatile multilayered composite nanoparticles from a customized nanogel template

We present a highly adaptable design platform for multi-responsive, multilayered composite nanoparticles (MC-NPs) with fine-tunable functional layers. A flexible disulfide-linked nanogel template is obtained by a controlled in-situ gelation method, enabling a high degree of control over each successive layer. From this template, we optimize “smart” biomaterials with biofunctional surfaces, tunable drug release kinetics, and magnetic or pH-responsive functionality, fabricated into MC-NPs for targeted drug release and periosteum-mimetic structures for controlled rhBMP-2 release towards bone tissue formation in-vivo. Such a versatile platform for the design of MC-NPs is a powerful tool that shows considerable therapeutic potential in clinical fields such as oncology and orthopedics.

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A highly adaptable design platform for multi-responsive, multilayered composite nanoparticles.

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A flexible disulfide-linked nanogel template is obtained by a controlled in-situ gelation method.

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Sequential assembly of multilayered NPs with a nanogel template, porous silica shell, pH-responsive PAA layer, and hydroxyapatite coating.

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The ability to finely tune the structure and function of each layer.

Intracellular delivery of proteins by nanocarriers

Intracellular delivery of proteins is potentially a game-changing approach for therapeutics. However, for most applications, the protein needs to access the cytosol to be effective. A wide variety of strategies have been developed for protein delivery, however access of delivered protein to the cytosol without acute cytotoxicity remains a critical issue. In this review we discuss recent trends in protein delivery using nanocarriers, focusing on the ability of these strategies to deliver protein into the cytosol.

Magnetically Guided Protein Transduction by Hybrid Nanogel Chaperones with Iron Oxide Nanoparticles

Protein pharmaceuticals show great therapeutic promise, but effective intracellular delivery remains challenging. To address the need for efficient protein transduction systems, we used a magnetic nanogel chaperone (MC): a hybrid of a polysaccharide nanogel, a protein carrier with molecular chaperone-like properties, and iron oxide nanoparticles, enabling magnetically guided delivery. The MC complexed with model proteins, such as BSA and insulin, and was not cytotoxic. Cargo proteins were delivered to the target HeLa cell cytosol using a magnetic field to promote movement of the protein complex toward the cells. Delivery was confirmed by fluorescence microscopy and flow cytometry. Delivered β-galactosidase, inactive within the MC complex, became enzymatically active within cells to convert a prodrug. Thus, cargo proteins were released from MC complexes through exchange interactions with cytosolic proteins. The MC is a promising tool for realizing the therapeutic potential of proteins.

Silencing TNFα with lipidoid nanoparticles downregulates both TNFα and MCP-1 in an in vitro co-culture model of diabetic foot ulcers

Diabetes is one of the most formidable diseases facing the world today, with the number of patients growing every year. Poor glycemic control yields a host of complications, such as impaired wound healing. This often results in the formation of diabetic foot ulcers, which carry a poor prognosis because they are notoriously difficult to treat. Current therapies do not address the increased number of infiltrating macrophages to the wound bed that overproduce tumor necrosis factor α (TNFα), which increases fibroblast apoptosis and collagen dismantling and decreases angiogenesis. In this study, we investigated the potential of RNA interference therapy to reduce the inappropriately high levels of TNFα in the wound bed. Although TNFα is a challenging gene silencing target, our lipidoid nanoparticles potently silence TNFα mRNA and protein expression at siRNA doses of 5-100nM without inducing vehicle-related gene silencing or cell death. We also describe the creation of an in vitro macrophage-fibroblast co-culture model, which reflects the TNFα and monocyte chemotactant protein-1 (MCP-1/CCL2) cross-talk that exists in diabetic wounds. Because TNFα induces fibroblasts to produce MCP-1, we show that silencing TNFα results in a downregulation of MCP-1, which should inhibit the recruitment of additional macrophages to the wound. In co-culture experiments, a single lipidoid nanoparticle dose of 100nM siTNFα downregulated TNFα and MCP-1 by 64% and 32%, respectively. These data underscore the potential of lipidoid nanoparticle RNAi treatment to inhibit a positive feedback cycle that fuels the pathogenesis of diabetic foot ulcers.

STATEMENT OF SIGNIFICANCE

Diabetic foot ulcers are a rapidly growing issue worldwide, with current ulcer treatments not as effective as desired. RNA interference therapy represents a largely untapped possible solution to impaired wound healing. We show that siRNA-loaded lipidoid nanoparticles silence the overexpression of tumor necrosis factor α (TNFα) in inflammatory macrophages which leads to a subsequent downregulation of fibroblast-produced macrophage chemotactant protein-1 (MCP-1). Both TNFα and MCP-1 are critical components of the inflammatory feedback loop that exists in chronic wounds. In contrast to the majority of wound drug delivery studies, our study utilizes macrophage/fibroblast co-culture experiments to recapitulate a multicellular wound environment in which cytokine signaling influences inflammation. Results underscore the therapeutic potential of siRNA nanoparticles directed against TNFα in inhibiting two key inflammatory targets in chronic wounds.

Breakable Hybrid Organosilica Nanocapsules for Protein Delivery

The direct delivery of specific proteins to live cells promises a tremendous impact for biological and medical applications, from therapeutics to genetic engineering. However, the process mostly involves tedious techniques and often requires extensive alteration of the protein itself. Herein we report a straightforward approach to encapsulate native proteins by using breakable organosilica matrices that disintegrate upon exposure to a chemical stimulus. The biomolecule-containing capsules were tested for the intracellular delivery of highly cytotoxic proteins into C6 glioma cells. We demonstrate that the shell is broken, the release of the active proteins occurs, and therefore our hybrid architecture is a promising strategy to deliver fragile biomacromolecules into living organisms.

Cell-penetrating peptides transport therapeutics into cells

Nearly 30years ago, certain small, relatively nontoxic peptides were discovered to be capable of traversing the cell membrane. These cell-penetrating peptides, as they are now called, have been shown to not only be capable of crossing the cell membrane themselves but can also carry many different therapeutic agents into cells, including small molecules, plasmid DNA, siRNA, therapeutic proteins, viruses, imaging agents, and other various nanoparticles. Many cell-penetrating peptides have been derived from natural proteins, but several other cell-penetrating peptides have been developed that are either chimeric or completely synthetic. How cell-penetrating peptides are internalized into cells has been a topic of debate, with some peptides seemingly entering cells through an endocytic mechanism and others by directly penetrating the cell membrane. Although the entry mechanism is still not entirely understood, it seems to be dependent on the peptide type, the peptide concentration, the cargo the peptide transports, and the cell type tested. With new intracellular disease targets being discovered, cell-penetrating peptides offer an exciting approach for delivering drugs to these intracellular targets. There are hundreds of cell-penetrating peptides being studied for drug delivery, and ongoing studies are demonstrating their success both in vitro and in vivo.

Microfluidic synthesis of rigid nanovesicles for hydrophilic reagents delivery

We present a hollow-structured rigid nanovesicle (RNV) fabricated by a multi-stage microfluidic chip in one step, to effectively entrap various hydrophilic reagents inside, without complicated synthesis, extensive use of emulsifiers and stabilizers, and laborious purification procedures. The RNV contains a hollow water core, a rigid poly (lactic-co-glycolic acid) (PLGA) shell, and an outermost lipid layer. The formation mechanism of the RNV is investigated by dissipative particle dynamics (DPD) simulations. The entrapment efficiency of hydrophilic reagents such as calcein, rhodamine B and siRNA inside the hollow water core of RNV is ≈90 %. In comparison with the combination of free Dox and siRNA, RNV that co-encapsulate siRNA and doxorubicin (Dox) reveals a significantly enhanced anti-tumor effect for a multi-drug resistant tumor model.

Fine-tuning vitamin E-containing telodendrimers for efficient delivery of gambogic acid in colon cancer treatment

Certain natural products such as gambogic acid (GA) exhibit potent antitumor effects. Unfortunately, administration of these natural products is limited by their poor solubility in conventional pharmaceutical solvents. In this study, a series of telodendrimers, composed of linear polyethylene glycol (PEG)-blocking-dendritic oligomer of cholic acid (CA) and vitamin E (VE), have been designed with architectures optimized for efficient delivery of GA and other natural anticancer compounds. Two of the telodendrimers with segregated CA and VE domains self-assembled into stable cylindrical and/or spherical nanoparticles (NPs) after being loaded with GA as observed under transmission electron microscopy (TEM), which correlated with the dynamic light scattering (DLS) analysis of sub-30 nm particle sizes. A very high GA loading capacity (3:10 drug/polymer w/w) and sustained drug release were achieved with the optimized telodendrimers. These novel nanoformulations of GA were found to exhibit similar in vitro cytotoxic activity against colon cancer cells as the free drug. Near-infrared fluorescence small animal imaging revealed preferential accumulation of GA-loaded NPs into tumor tissue. The optimized nanoformulation of GA achieved superior antitumor efficacy compared to GA-Cremophor EL formulation at equivalent doses in HT-29 human colon cancer xenograft mouse models. Given the mild adverse effects associated with this natural compound and the enhanced anticancer effects via tumor targeted telodendrimer delivery, the optimized GA nanoformulation is a promising alternative to the traditional chemotherapy in colon cancer treatment.

Advances in Anticancer Protein Delivery Using Micro-/ Nanoparticles

Proteins exhibiting anticancer activities, especially those capable of discriminately killing cancer cells, have attracted increasing interest in developing protein-based anticancer therapeutics. This progress report surveys recent advances in delivering anticancer proteins directly to tumor tissue for inducing apoptosis/necrosis or indirectly to antigen presenting cells for provoking immune responses. Protein delivery carriers such as inorganic particles, lipid particles, polymeric particles, DNA/protein based biomacromolecular particles as well as cell based carriers are reviewed with comments on their advantages and limitations. Future challenges and opportunities are also discussed.

Reactive oxygen species-responsive protein modification and its intracellular delivery for targeted cancer therapy

Herein we report a convenient chemical approach to reversibly modulate protein (RNase A) function and develop a protein that is responsive to reactive oxygen species (ROS) for targeted cancer therapy. The conjugation of RNase A with 4-nitrophenyl 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl) benzyl carbonate (NBC) blocks protein lysine and temporarily deactivates the protein. However, the treatment of RNase A-NBC with hydrogen peroxide (one major intracellular ROS) efficiently cleaves the NBC conjugation and restores the RNase A activity. Thus, RNase A-NBC can be reactivated inside tumor cells by high levels of intracellular ROS, thereby restoring the cytotoxicity of RNase A for cancer therapy. Due to higher ROS levels inside tumor cells compared to healthy cells, and the resulting different levels of RNase A-NBC reactivation, RNase A-NBC shows a significant specific cytotoxicity against tumor cells.

Cationic vesicles based on amphiphilic pillar[5]arene capped with ferrocenium: a redox-responsive system for drug/siRNA co-delivery

A novel ferrocenium capped amphiphilic pillar[5]arene (FCAP) was synthesized and self-assembled to cationic vesicles in aqueous solution. The cationic vesicles, displaying low cytotoxicity and significant redox-responsive behavior due to the redox equilibrium between ferrocenium cations and ferrocenyl groups, allow building an ideal glutathione (GSH)-responsive drug/siRNA co-delivery system for rapid drug release and gene transfection in cancer cells in which higher GSH concentration exists. This is the first report of redox-responsive vesicles assembled from pillararenes for drug/siRNA co-delivery; besides enhancing the bioavailability of drugs for cancer cells and reducing the adverse side effects for normal cells, these systems can also overcome the drug resistance of cancer cells. This work presents a good example of rational design for an effective stimuli-responsive drug/siRNA co-delivery system.

Poly(2-ethyl-2-oxazoline)-PLA-g-PEI amphiphilic triblock micelles for co-delivery of minicircle DNA and chemotherapeutics

The design of nanocarriers for the delivery of drugs and nucleic-acids remains a very challenging goal due to their physicochemical differences. In addition, the reported accelerated clearance and immune response of pegylated nanomedicines highlight the necessity to develop carriers using new materials. Herein, we describe the synthesis of amphiphilic triblock poly(2-ethyl-2-oxazoline)-PLA-g-PEI (PEOz-PLA-g-PEI) micelles for the delivery of minicircle DNA (mcDNA) vectors. In this copolymer the generally used PEG moieties are replaced by the biocompatible PEOz polymer backbone that assembles the hydrophilic shell. The obtained results show that amphiphilic micelles have low critical micellar concentration, are hemocompatible and exhibit stability upon incubation in serum. The uptake in MCF-7 cells was efficient and the nanocarriers achieved 2.7 fold higher expression than control particles. Moreover, mcDNA-loaded micelleplexes penetrated into 3D multicellular spheroids and promoted widespread gene expression. Additionally, to prove the concept of co-delivery, mcDNA and doxorubicin (Dox) were simultaneously encapsulated in PEOz-PLA-g-PEI carriers, with high efficiency. Dox-mcDNA micelleplexes exhibited extensive cellular uptake and demonstrated anti-tumoral activity. These findings led us to conclude that this system has a potential not only for the delivery of novel mcDNA vectors, but also for the co-delivery of drug-mcDNA combinations without PEG functionalization.