Rational design of diblock copolymer enables efficient cytosolic protein delivery

Polymer-mediated cytosolic protein delivery demonstrates a promising strategy for the development of protein therapeutics. Here, we propose a new designed diblock copolymer which realizes efficient cytosolic protein delivery both in vitro and in vivo. The polymer contains one protein-binding block composed of phenylboronic acid (PBA) and N-(3-dimethylaminopropyl) (DMAP) pendant units for protein binding and endosomal escape, respectively, followed by the response to ATP enriched in the cytosol which triggers the protein release. The other block is PEG designed to improve particle size control and circulation in vivo. By optimizing the block composition, sequence and length of the copolymer, the optimal one (BP20) was identified with the binding block containing 20 units of both PBA and DMAP, randomly distributed along the chain. When mixed with proteins, the BP20 forms stable nanoparticles and mediates efficient cytosolic delivery of a wide range of proteins including enzymes, toxic proteins and CRISPR/Cas9 ribonucleoproteins (RNP), to various cell lines. The PEG block, especially when further modified with folic acid (FA), enables tumor-targeted delivery of Saporin in vivo, which significantly suppresses the tumor growth. Our results shall inspire the design of novel polymeric vehicles with robust capability for cytosolic protein delivery, which holds great potential for both biological research and therapeutic applications.

Lung-specific supramolecular nanoparticles for efficient delivery of therapeutic proteins and genome editing nucleases

Protein therapeutics play a critical role in treating a large variety of diseases, ranging from infections to genetic disorders. However, their delivery to target tissues beyond the liver, such as the lungs, remains a great challenge. Here, we report a universally applicable strategy for lung-targeted protein delivery by engineering Lung-Specific Supramolecular Nanoparticles (LSNPs). These nanoparticles are designed through the hierarchical self-assembly of metal-organic polyhedra (MOP), featuring a customized surface chemistry that enables protein encapsulation and specific lung affinity after intravenous administration. Our design of LSNPs not only addresses the hurdles of cell membrane impermeability of protein and nonspecific tissue distribution of protein delivery, but also shows exceptional versatility in delivering various proteins, including those vital for anti-inflammatory and CRISPR-based genome editing to the lung, and across multiple animal species, including mice, rabbits, and dogs. Notably, the delivery of antimicrobial proteins using LSNPs effectively alleviates acute bacterial pneumonia, demonstrating a significant therapeutic potential. Our strategy not only surmounts the obstacles of tissue-specific protein delivery but also paves the way for targeted treatments in genetic disorders and combating antibiotic resistance, offering a versatile solution for precision protein therapy.

Simultaneously Modulating HIF-1α and HIF-2α and Optimizing Macrophage Polarization through the Biomimetic Gene Vector toward the Treatment of Osteoarthritis

In osteoarthritis (OA), articular cartilage is continuously submerged in a hypoxic environment throughout life, and hypoxia-inducible factors (HIFs) play a crucial role in OA progression. Among the various HIF phenotypes, HIF-1α positively contributes to maintaining the stability of the articular cartilage matrix. In contrast, HIF-2α has a detrimental effect, leading to chondrocyte apoptosis and exacerbating inflammation. Notably, there is currently no simultaneous regulation of HIF-1α and HIF-2α for OA treatment. Thus, the biomimetic gene vector (MENP) was developed for co-delivery of siHIF-2α and Mg2+ to the inflamed regions in OA joints, comprising an inner core consisting of siHIF-2α and Mg2+ and an outer M2 macrophage membrane. In vitro and in vivo studies demonstrate that MENP effectively targets inflamed areas, efficiently silences HIF-2α, and facilitates HIF-1α-mediated cartilage restoration through Mg2+. Furthermore, it indirectly promotes the polarization of macrophages toward an anti-inflammatory M2 phenotype through its action on inflamed synoviocytes. Overall, MENP is an efficient biomimetic vehicle for alleviating inflammation and promoting cartilage repair, representing an appealing approach for OA treatment.

Boronic Acid-Rich Lanthanide Metal-Organic Frameworks Enable Deep Proteomics with Ultratrace Biological Samples

Label-free proteomics is widely used to identify disease mechanism and potential therapeutic targets. However, deep proteomics with ultratrace clinical specimen remains a major technical challenge due to extensive contact loss during complex sample pretreatment. Here, a hybrid of four boronic acid-rich lanthanide metal-organic frameworks (MOFs) with high protein affinity is introduced to capture proteins in ultratrace samples jointly by nitrogen-boronate complexation, cation-π and ionic interactions. A MOFs Aided Sample Preparation (MASP) workflow that shrinks sample volume and integrates lysis, protein capture, protein digestion and peptide collection steps into a single PCR tube to minimize sample loss caused by non-specific absorption, is proposed further. MASP is validated to quantify ≈1800 proteins in 10 HEK-293T cells. MASP is applied to profile cerebrospinal fluid (CSF) proteome from cerebral stroke and brain damaged patients, and identified ≈3700 proteins in 1 µL CSF. MASP is further demonstrated to detect ≈9600 proteins in as few as 50 µg mouse brain tissues. MASP thus enables deep, scalable, and reproducible proteome on precious clinical samples with low abundant proteins.

Reversible Assembly of Proteins and Phenolic Polymers for Intracellular Protein Delivery with Serum Stability

The design of intracellular delivery systems for protein drugs remains a challenge due to limited delivery efficacy and serum stability. Herein, we propose a reversible assembly strategy to assemble cargo proteins and phenolic polymers into stable nanoparticles for this purpose using a heterobifunctional adaptor (2-formylbenzeneboronic acid). The adaptor is easily decorated on cargo proteins via iminoboronate chemistry and further conjugates with catechol-bearing polymers to form nanoparticles via boronate diester linkages. The nanoparticles exhibit excellent serum stability in culture media but rapidly release the cargo proteins triggered by lysosomal acidity and GSH after endocytosis. In a proof-of-concept animal model, the strategy successfully transports superoxide dismutase to retina via intravitreal injection and efficiently ameliorates the oxidative stress and cellular damage in the retina induced by ischemia-reperfusion (I/R) with minimal adverse effects. The reversible assembly strategy represents a robust and efficient method to develop serum-stable systems for the intracellular delivery of biomacromolecules.

Engineering Matrix-Free Drug Protein Nanoparticles with Promising Penetration through Biobarriers for Treating Corneal Neovascularization

Protein drugs have been widely used in treating various clinical diseases because of their high specificity, fewer side effects, and favorable therapeutic effect, but they greatly suffer from their weak permeability through tissue barriers, high sensitivity to microenvironments, degradation by proteases, and rapid clearance by the immune system. Herein, we disrupted the standard protocol where protein drugs must be delivered as the cargo via a delivery system and innovatively developed a free entrapping matrix strategy by simply mixing bevacizumab (Beva) with zinc ions to generate Beva-NPs (Beva-Zn2+), where Beva is coordinatively cross-linked by zinc ions with a loading efficiency as high as 99.2% ± 0.41%. This strategy was universal to generating various protein NPs, with different metal ions (Cu2+, Fe3+, Mg2+, Sr2+). The synthetic conditions of Beva-NPs were optimized, and the generated mechanism was investigated in detail. The entrapment, releasing profile, and the bioactivities of released Beva were thoroughly studied. By using in situ doping of the fourth-generation polyamindoamine dendrimer (G4), the Beva-G4-NPs exhibited extended ocular retention and penetration through biobarriers in the anterior segment through transcellular and paracellular pathways, effectively inhibiting corneal neovascularization (CNV) from 91.6 ± 2.03% to 13.5 ± 1.87% in a rat model of CNV. This study contributes to engineering of protein NPs by using a facile strategy for overcoming the weaknesses of protein drugs and protein NPs, such as weak tissue barrier permeability, low encapsulation efficiency, poor loading capacity, and susceptibility to inactivation.

E3MPH16: An efficient endosomolytic peptide for intracellular protein delivery

To facilitate the introduction of proteins, such as antibodies, into cells, a variety of delivery peptides have been engineered. These peptides are typically highly cationic and somewhat hydrophobic, enabling cytosolic protein delivery at the cost of causing cell damage by rupturing membranes. This balance between delivery effectiveness and cytotoxicity presents obstacles for their real-world use. To tackle this problem, we designed a new endosome-disruptive cytosolic delivery peptide, E3MPH16, inspired by mastoparan X (MP). E3MPH16 was engineered to incorporate three Glu (E3) and 16 His (H16) residues at the N- and C-termini of MP, respectively. The negative charges of E3 substantially mitigate the cell-surface damage induced by MP. The H16 segment is known to enhance cell-surface adsorption and endocytic uptake of the associated molecules. With these modifications, E3MPH16 was successfully trapped within endosomes. The acidification of endosomes is expected to protonate the side chains of E3 and H16, enabling E3MPH16 to rupture endosomal membranes. As a result, nearly 100% of cells achieved cytosolic delivery of a model biomacromolecule, Alexa Fluor 488-labeled dextran (10 kDa), via endosomal escape by co-incubation with E3MPH16. The delivery process also suggested the involvement of macropinocytosis and caveolae-mediated endocytosis. With the assistance of E3MPH16, Cre recombinase and anti-Ras-IgG delivered into HEK293 cells and HT1080 cells enabled gene recombination and inhibited cell proliferation, respectively. The potential for in vivo application of this intracellular delivery method was further validated by topically injecting the green fluorescent protein fused with a nuclear localization signal (NLS-GFP) along with E3MPH16 into Colon-26 tumor xenografts in mice.

Filamentous-Actin-Mimicking Nanoplatform for Enhanced Cytosolic Protein Delivery

Despite the potential of protein therapeutics, the cytosolic delivery of proteins with high efficiency and bioactivity remains a significant challenge owing to exocytosis and lysosomal degradation after endocytosis. Therefore, it is important to develop a safe and efficient strategy to bypass endocytosis. Inspired by the extraordinary capability of filamentous-actin (F-actin) to promote cell membrane fusion, a cyanine dye assembly-containing nanoplatform mimicking the structure of natural F-actin is developed. The nanoplatform exhibits fast membrane fusion to cell membrane mimics and thus enters live cells through membrane fusion and bypasses endocytosis. Moreover, it is found to efficiently deliver protein cargos into live cells and quickly release them into the cytosol, leading to high protein cargo transfection efficiency and bioactivity. The nanoplatform also results in the superior inhibition of tumor cells when loaded with anti-tumor proteins. These results demonstrate that this fusogenic nanoplatform can be valuable for cytosolic protein delivery and tumor treatment.

Intracellular Protein Delivery: Approaches, Challenges, and Clinical Applications

Protein biologics are powerful therapeutic agents with diverse inhibitory and enzymatic functions. However, their clinical use has been limited to extracellular applications due to their inability to cross plasma membranes. Overcoming this physiological barrier would unlock the potential of protein drugs for the treatment of many intractable diseases. In this review, we highlight progress made toward achieving cytosolic delivery of recombinant proteins. We start by first considering intracellular protein delivery as a drug modality compared to existing Food and Drug Administration-approved drug modalities. Then, we summarize strategies that have been reported to achieve protein internalization. These techniques can be broadly classified into 3 categories: physical methods, direct protein engineering, and nanocarrier-mediated delivery. Finally, we highlight existing challenges for cytosolic protein delivery and offer an outlook for future advances.

Bioactive Phosphorus Dendrimers as a Universal Protein Delivery System for Enhanced Anti-inflammation Therapy

Nanocarrier-based cytoplasmic protein delivery offers opportunities to develop protein therapeutics; however, many delivery systems are positively charged, causing severe toxic effects. For enhanced therapeutics, it is also of great importance to design nanocarriers with intrinsic bioactivity that can be integrated with protein drugs due to the limited bioactivity of proteins alone for disease treatment. We report here a protein delivery system based on anionic phosphite-terminated phosphorus dendrimers with intrinsic anti-inflammatory activity. A phosphorus dendrimer termed AK-137 with optimized anti-inflammatory activity was selected to complex proteins through various physical interactions. Model proteins such as bovine serum albumin, ribonuclease A, ovalbumin, and fibronectin (FN) can be transfected into cells to exert their respective functions, including cancer cell apoptosis, dendritic cell maturation, or macrophage immunomodulation. Particularly, the constructed AK-137@FN nanocomplexes display powerful therapeutic effects in acute lung injury and acute gout arthritis models by integrating the anti-inflammatory activity of both the carrier and protein. The developed anionic phosphite-terminated phosphorus dendrimers may be employed as a universal carrier for protein delivery and particularly utilized to deliver proteins and fight different inflammatory diseases with enhanced therapeutic efficacy.

Designing Peptide-Based Nanoinhibitors of Programmed Cell Death Ligand 1 (PD-L1) for Enhanced Chemo-immunotherapy

The combination of immune checkpoint blockade (ICB) and chemotherapy has shown significant potential in the clinical treatment of various cancers. However, circulating regeneration of PD-L1 within tumor cells greatly limits the efficiency of chemo-immunotherapy and consequent patient response rates. Herein, we report the synthesis of a nanoparticle-based PD-L1 inhibitor (FRS) with a rational design for effective endogenous PD-L1 suppression. The nanoinhibitor is achieved through self-assembly of fluoroalkylated competitive peptides that target PD-L1 palmitoylation. The FRS nanoparticles provide efficient protection and delivery of functional peptides to the cytoplasm of tumors, showing greater inhibition of PD-L1 than nonfluorinated peptidic inhibitors. Moreover, we demonstrate that FRS synergizes with chemotherapeutic doxorubicin (DOX) to boost the antitumor activities via simultaneous reduction of PD-L1 abundance and induction of immunogenic cell death in murine colon tumor models. The nano strategy of PD-L1 regulation present in this study is expected to advance the development of ICB inhibitors and overcome the limitations of conventional ICB-assisted chemo-immunotherapy.

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.

Fluoropolymer Nanoparticles Synthesized via Reversible-Deactivation Radical Polymerizations and Their Applications

Fluorinated polymeric nanoparticles (FPNPs) combine unique properties of fluorocarbon and polymeric nanoparticles, which has stimulated massive interest for decades. However, fluoropolymers are not readily available from nature, resulting in synthetic developments to obtain FPNPs via free radical polymerizations. Recently, while increasing cutting-edge directions demand tailored FPNPs, such materials have been difficult to access via conventional approaches. Reversible-deactivation radical polymerizations (RDRPs) are powerful methods to afford well-defined polymers. Researchers have applied RDRPs to the fabrication of FPNPs, enabling the construction of particles with improved complexity in terms of structure, composition, morphology, and functionality. Related examples can be classified into three categories. First, well-defined fluoropolymers synthesized via RDRPs have been utilized as precursors to form FPNPs through self-folding and solution self-assembly. Second, thermally and photoinitiated RDRPs have been explored to realize in situ preparations of FPNPs with varied morphologies via polymerization-induced self-assembly and cross-linking copolymerization. Third, grafting from inorganic nanoparticles has been investigated based on RDRPs. Importantly, those advancements have promoted studies toward promising applications, including magnetic resonance imaging, biomedical delivery, energy storage, adsorption of perfluorinated alkyl substances, photosensitizers, and so on. This Review should present useful knowledge to researchers in polymer science and nanomaterials and inspire innovative ideas for the synthesis and applications of FPNPs.

Engineering Nucleotidoproteins for Base-Pairing-Assisted Cytosolic Delivery and Genome Editing

Protein therapeutics targeting intracellular machineries hold profound potential for disease treatment, and hence robust cytosolic protein delivery technologies are imperatively demanded. Inspired by the super-negatively charged, nucleotide-enriched structure of nucleic acids, adenylated pro-proteins (A-proteins) with dramatically enhanced negative surface charges have been engineered for the first time via facile green synthesis. Then, thymidine-modified polyethyleneimine is developed, which exhibits strong electrostatic attraction, complementary base pairing, and hydrophobic interaction with A-proteins to form salt-resistant nanocomplexes with robust cytosolic delivery efficiencies. The acidic endolysosomal environment enables traceless restoration of the A-proteins and consequently promotes the intracellular release of the native proteins. This strategy shows high efficiency and universality for a variety of proteins with different molecular weights and isoelectric points in mammalian cells. Moreover, it enables highly efficient delivery of CRISPR-Cas9 ribonucleoproteins targeting fusion oncogene EWSR1-FLI1, leading to pronounced anti-tumor efficacy against Ewing sarcoma. This study provides a potent and versatile platform for cytosolic protein delivery and gene editing, and may benefit the development of protein pharmaceuticals.

Engineered therapeutic proteins for sustained-release drug delivery systems

Proteins play a vital role in diverse biological processes in the human body, and protein therapeutics have been applied to treat different diseases such as cancers, genetic disorders, autoimmunity, and inflammation. Protein therapeutics have demonstrated their advantages, such as specific pharmaceutical effects, low toxicity, and strong solubility. However, several disadvantages arise in clinical applications, including short half-life, immunogenicity, and low permeation, leading to reduced drug effectiveness. The structure of protein therapeutics can be modified to increase molecular size, leading to prolonged stability and increased plasma half-life. Notably, the controlled-release delivery systems for the sustained release of protein drugs and preserving the stability of cargo proteins are envisioned as a potential approach to overcome these challenges. In this review, we summarize recent research progress related to structural modifications (PEGylation, glycosylation, poly amino acid modification, and molecular biology-based strategies) and promising long-term delivery systems, such as polymer-based systems (injectable gel/implants, microparticles, nanoparticles, micro/nanogels, functional polymers), lipid-based systems (liposomes, solid lipid nanoparticles, nanostructured lipid carriers), and inorganic nanoparticles exploited for protein therapeutics. STATEMENT OF SIGNIFICANCE: In this review, we highlight recent advances concerning modifying proteins directly to enhance their stability and functionality and discuss state-of-the-art methods for the delivery and controlled long-term release of active protein therapeutics to their target site. In terms of drug modifications, four widely used strategies, including PEGylation, poly amino acid modification, glycosylation, and genetic, are discussed. As for drug delivery systems, we emphasize recent progress relating to polymer-based systems, lipid-based systems developed, and inorganic nanoparticles for protein sustained-release delivery. This review points out the areas requiring focused research attention before the full potential of protein therapeutics for human health and disease can be realized.

Fluorous Tagged Peptides for Intracellular Delivery and Biomedical Imaging

Fluorous tagged peptides have shown promising features for biomedical applications such as drug delivery and multimodal imaging. The bioconjugation of fluoroalkyl ligands onto cargo peptides greatly enhances their proteolytic stability and membrane penetration via a proposed "fluorine effect". The tagged peptides also efficiently deliver other biomolecules such as DNA and siRNA into cells via a co-assembly strategy. The fluoroalkyl chains on peptides with antifouling properties enable efficient gene delivery in the presence of serum proteins. Besides intracellular biomolecule delivery, the amphiphilic peptides can be used to stabilized perfluorocarbon-filled microbubbles for ultrasound imaging. The fluorine nucleus on fluoroalkyls provides intrinsic probes for background-free magnetic resonance imaging. Labeling of fluorous tags with radionuclide 18 F also allows tracing the biodistribution of peptides via positron emission tomography imaging. This mini-review will discuss properties and mechanism of the fluorous tagged peptides in these applications.

Iron-Gallic Acid Peptide Nanoparticles as a Versatile Platform for Cellular Delivery with Synergistic ROS Enhancement Effect

Cytosolic delivery of peptides is of great interest owing to their biological functions, which could be utilized for therapeutic applications. However, their susceptibility to enzymatic degradation and multiple cellular barriers generally hinders their clinical application. Integration into nanoparticles, which can enhance the stability and membrane permeability of bioactive peptides, is a promising strategy to overcome extracellular and intracellular obstacles. Herein, we present a versatile platform for the cellular delivery of various cargo peptides by integration into metallo-peptidic coordination nanoparticles. Both termini of cargo peptides were conjugated with gallic acid (GA) to assemble GA-modified peptides into nanostructures upon coordination of Fe(III). Initial pre-complexation of Fe(III) by poly-(vinylpolypyrrolidon) (PVP) as a template favored the formation of nanoparticles, which are able to deliver the peptides into cells efficiently. Iron-gallic acid peptide nanoparticles (IGPNs) are stable in water and are supposed to generate reactive oxygen species (ROS) from endogenous H₂O₂ in cells via the Fenton reaction. The strategy was successfully applied to an exemplary set of peptide sequences varying in length (1-7 amino acids) and charge (negative, neutral, positive). To confirm the capability of transporting bioactive cargos into cells, pro-apoptotic peptides were integrated into IGPNs, which demonstrated potent killing of human cervix carcinoma HeLa and murine neuroblastoma N2a cells at a 10 µM peptide concentration via the complementary mechanisms of peptide-triggered apoptosis and Fe(III)-mediated ROS generation. This study demonstrates the establishment of IGPNs as a novel and versatile platform for the assembly of peptides into nanoparticles, which can be used for cellular delivery of bioactive peptides combined with intrinsic ROS generation.

Mussel-Inspired Polydopamine Composite Mesoporous Bioactive Glass Nanoparticles: An Exploration of Potential Metal-Ion Loading Platform and In Vitro Bioactivity

Exploring new approaches to realize the possibility of incorporating biologically active elements into mesoporous silicate bioactive glass nanoparticles (MBG NPs) and guaranteeing their meso- structural integrity and dimensional stability has become an attractive and interesting challenge in biomaterials science. We present a postgrafting strategy for introducing different metal elements into MBG NPs. This strategy is mediated by polydopamine (PDA) coating, achieving uniform loading of copper or copper-cobalt on the particles efficiently and ensuring the stability of MBG NPs in terms of particle size, mesoporous structure, and chemical structure. However, the PDA coating reduced the ion-binding free energy of the MBG NPs for calcium and phosphate ions, resulting in the deposition of minimal CaP clusters on the PDA@MBG NP surface when immersed for 7 days in simulated body fluid, indicating the absence of hydroxyapatite mineralization.

Recent Progress of Rational Modified Nanocarriers for Cytosolic Protein Delivery

Therapeutic proteins garnered significant attention in the field of disease treatment. In comparison to small molecule drugs, protein therapies offer distinct advantages, including high potency, specificity, low toxicity, and reduced carcinogenicity, even at minimal concentrations. However, the full potential of protein therapy is limited by inherent challenges such as large molecular size, delicate tertiary structure, and poor membrane penetration, resulting in inefficient intracellular delivery into target cells. To address these challenges and enhance the clinical applications of protein therapies, various protein-loaded nanocarriers with tailored modifications were developed, including liposomes, exosomes, polymeric nanoparticles, and nanomotors. Despite these advancements, many of these strategies encounter significant issues such as entrapment within endosomes, leading to low therapeutic efficiency. In this review, we extensively discussed diverse strategies for the rational design of nanocarriers, aiming to overcome these limitations. Additionally, we presented a forward-looking viewpoint on the innovative generation of delivery systems specifically tailored for protein-based therapies. Our intention was to offer theoretical and technical support for the development and enhancement of nanocarriers capable of facilitating cytosolic protein delivery.

Zwitterionic Targeting Doxorubicin -Loaded Micelles Assembled by Amphiphilic Dendrimers with Enhanced Antitumor Performance

Chemotherapy is the main method of treating malignant tumors in clinical treatment. However, the commonly used chemotherapeutic drugs have the disadvantages of high biological toxicity, poor water solubility, low targeting ability, and high side effects. Zwitterionic micelles assembled by amphiphilic dendrimers modified with zwitterionic groups and targeting ligand should largely overcome these shortcomings. Herein, the zwitterionic group and targeting peptide c(RGDfC) were modified on the surface of generation 2 poly(propylene imine) dendrimers (G2 PPI), which was conjugated with hydrophobic N-(2-mercaptoethyl) oleamide to form amphiphilic dendrimers (PPIMYRC). PPIMYRC self-assembled into micelles with doxorubicin (DOX) loaded in the interior of micelles to prepare DOX-loaded micelles (PPIMYRC-DOX micelles). The PPIMYRC-DOX micelles had great stability in fibrinogen and pH-responsive drug release. Furthermore, PPIMYRC-DOX micelles had higher cellular uptake rates than free DOX, resulting in higher cytotoxicity of PPIMYRC-DOX micelles than that of free DOX. More importantly, PPIMYRC-DOX micelles inhibited tumors much better than free DOX. The tumor inhibition rate of PPIMYRC-DOX micelles was as high as 93%. Taken together, PPIMYRC-DOX micelles were assembled by amphiphilic dendrimers with the zwitterionic and targeting groups, which enhanced the therapeutic effect of DOX and reduced its side effects. The prepared targeting nanodrug has great potential for further application in antitumor therapy.

Recent progress in nanomedicine-mediated cytosolic delivery

Cytosolic delivery of bioactive agents has exhibited great potential to cure undruggable targets and diseases. Because biological cell membranes are a natural barrier for living cells, efficient delivery methods are required to transfer bioactive and therapeutic agents into the cytosol. Various strategies that do not require cell invasive and harmful processes, such as endosomal escape, cell-penetrating peptides, stimuli-sensitive delivery, and fusogenic liposomes, have been developed for cytosolic delivery. Nanoparticles can easily display functionalization ligands on their surfaces, enabling many bio-applications for cytosolic delivery of various cargo, including genes, proteins, and small-molecule drugs. Cytosolic delivery uses nanoparticle-based delivery systems to avoid degradation of proteins and keep the functionality of other bioactive molecules, and functionalization of nanoparticle-based delivery vehicles imparts a specific targeting ability. With these advantages, nanomedicines have been used for organelle-specific tagging, vaccine delivery for enhanced immunotherapy, and intracellular delivery of proteins and genes. Optimization of the size, surface charges, specific targeting ability, and composition of nanoparticles is needed for various cargos and target cells. Toxicity issues with the nanoparticle material must be managed to enable clinical use.

Piperazine-modified dendrimer achieves efficient intracellular protein delivery via caveolar endocytosis bypassing the endo-lysosomal pathway

Intracellular protein delivery has been a major challenge due to various physiological barriers including low proteolytic stability and poor membrane permeability of the biologics. Nanoparticles were widely proposed to deliver cargo proteins into cells by endocytosis, however, the materials and complexes with proteins are often entrapped in endosomes and subject to lysosome degradation. In this study, we report a piperazine modified dendrimer for stabilizing the complexes via a combination of electrostatic interaction and hydrophobic interactions. The complexes show rapid cell internalization and the loaded proteins are released into the cytosols as early as half an hour post incubation. Mechanism study suggests that the complexes are endocytosed into cells via caveolae-based pathways, which could be inhibited by inhibitors such as genistein, filipin III, brefeldin A and nystatin. The phenylpiperazine-modified polymer enables the delivery of cargo proteins with reserved bioactivity and show high permeability in three-dimensional cell spheroids. The results prove the beneficial roles of phenylpiperazine ligands in polymer-mediated cytosolic protein delivery systems. STATEMENT OF SIGNIFICANCE: We synthesized a list of piperazine and derivatives modified dendrimers as cytosolic protein delivery vectors via facile reactions. Phenylpiperazine modification enables the efficient protein binding through the combination of electrostatic, hydrogen bonding and hydrophobic interactions. Phenylpiperazine modified dendrimers were internalized into the cells via a caveolae-based endo/lysosome-independent path and could release the cargo proteins into the cytosols as early as half an hour post incubation. Phenylpiperazine modified dendrimers delivered cargo proteins with reserved bioactivity and showed high permeability in three-dimensional cell spheroids.

Efficient intracellular and in vivo delivery of toxin proteins by a ROS-responsive polymer for cancer therapy

Rational design of efficient cytosolic protein delivery carriers holds enormous promise for biotherapeutics development. Several delivery systems have been developed during the past decades, while tailoring the balance between extracellular protein binding and intracellular cargo release is still challenging. In this study, we synthesized a series of oxygen-sensitive reactive polymers, rich in boron, by radical polymerization and post-modification for cytosolic protein delivery in vitro and in vivo. The introduction of boronate building blocks into the polymer scaffold significantly enhanced its protein binding affinity, and the polymer/protein complexes with high stability were obtained by tailoring the molecular ratios between the boronate ligands and the amine groups. The lead material screened from the polymer library exhibited efficient protein delivery efficacy that can release cargo proteins in cytosol in a reactive oxygen species responsive manner, which enables intracellular delivery of proteins with maintained bioactivity. In addition, the polymer-based nanoformulations efficiently delivered saporin, a toxin protein, into osteosarcoma cells and tumor tissues, and exhibited high therapeutic efficacy in an osteosarcoma mouse model. The synthesized polymer in this study can be developed as a promising nanocarrier for cytosolic delivery of protein therapeutics to treat a variety of diseases.

Histidine-based coordinative polymers for efficient intracellular protein delivery via enhanced protein binding, cellular uptake, and endosomal escape

Polymers are one of the most promising protein delivery carriers; however, their applications are hindered by low delivery efficacy owing to their undesirable performance in protein binding, cellular uptake and endosomal escape. Here, we designed a series of histidine-based coordinative polymers for efficient intracellular protein delivery. Coordination of metal ions such as Ni²⁺, Zn²⁺, and Cu²⁺ with histidine residues on a polymer greatly improved its performance in protein binding, complex stability, cellular uptake and endosomal escape, therefore achieving highly improved protein delivery efficacy. Among the coordinative polymers, the Zn²⁺-coordinated one exhibited the highest cellular uptake, while the Cu²⁺-coordinated one exhibited the highest endosomal escape. The Ni²⁺-coordinated polymer formed large-sized aggregates with cargo proteins and showed insufficient protein release after endocytosis. The results obtained in this study provided new insight into the development of coordinative polymer-based protein delivery systems.

Functionalized PAMAM constructed nanosystems for biomacromolecule delivery

Polyamidoamines (PAMAMs) are a class of dendrimer with monodispersity and controlled topology, which can deliver biologically active macromolecules (e.g., genes and proteins) to specific regions with high efficiency and minimum side effects. In detail, PAMAMs can be functionalized easily by core modification or surface amendment to encapsulate a wide range of biomacromolecules. Besides, self-assembled, cross-linked and hybrid PAMAMs with customized therapeutic purposes are developed as delivery vehicles, which makes PAMAMs promising for biomacromolecule therapy. In this review, we comprehensively summarize the application of PAMAMs in biomacromolecule delivery from the synthesis of functionalized PAMAM carriers to the development of PAMAM-based drug delivery systems. The underlying strategies for PAMAM functionalization and assembly are first systematically discussed, and then the current applications of PAMAMs for biomacromolecule delivery are reviewed. Finally, a brief perspective on the further applications of PAMAMs concludes, aiming to provide insights into developing PAMAM-based biomacromolecule delivery systems.

A light-activated polymer with excellent serum tolerance for intracellular protein delivery

The design of efficient materials for intracellular protein delivery has attracted great interest in recent years; however, most current materials for this purpose are limited by poor serum stability due to the early release of cargoes triggered by abundant serum proteins. Here, we propose a light-activated crosslinking (LAC) strategy to prepare efficient polymers with excellent serum tolerance for intracellular protein delivery. A cationic dendrimer engineered with photoactivatable O-nitrobenzene moieties co-assembles with cargo proteins via ionic interactions, followed by light activation to yield aldehyde groups on the dendrimer and the formation of imine bonds with cargo proteins. The light-activated complexes show high stability in buffer and serum solutions, but dis-assemble under low pH conditions. As a result, the polymer successfully delivers cargo proteins green fluorescent protein and β-galactosidase into cells with maintained bioactivity even in the presence of 50% serum. The LAC strategy proposed in this study provides a new insight to improve the serum stability of polymers for intracellular protein delivery.

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.

A cooperative nano-CRISPR scaffold potentiates immunotherapy via activation of tumour-intrinsic pyroptosis

Efficient cancer immunotherapy depends on selective targeting of high bioactivity therapeutic agents to the tumours. However, delivering exogenous medication might prove difficult in clinical practice. Here we report a cooperative Nano-CRISPR scaffold (Nano-CD) that utilizes a specific sgRNA, selected from a functional screen for triggering endogenous GDSME expression, while releasing cisplatin to initiate immunologic cell death. Mechanistically, cascade-amplification of the antitumor immune response is prompted by the adjuvantic properties of the lytic intracellular content and enhanced by the heightened GDSME expression, resulting in pyroptosis and the release of tumor associated antigens. Neither of the single components provide efficient tumour control, while tumor growth is efficiently inhibited in primary and recurrent melanomas due to the combinatorial effect of cisplatin and self-supplied GSDME. Moreover, Nano-CD in combination with checkpoint blockade creates durable immune memory and strong systemic anti-tumor immune response, leading to disease relapse prevention, lung metastasis inhibition and increased survival in mouse melanomas. Taken together, our therapeutic approach utilizes CRISPR-technology to enable cell-intrinsic protein expression for immunotherapy, using GDSME as prototypic immune modulator. This nanoplatform thus can be applied to modulate further immunological processes for therapeutic benefit.

Properties and Bioapplications of Amphiphilic Janus Dendrimers: A Review

Amphiphilic Janus dendrimers are arrangements containing both hydrophilic and hydrophobic units, capable of forming ordered aggregates by intermolecular noncovalent interactions between the dendrimer units. Compared to conventional dendrimers, these molecular self-assemblies possess particular and effective attributes i.e., the presence of different terminal groups, essential to design new elaborated materials. The present review will focus on the pharmaceutical and biomedical application of amphiphilic Janus dendrimers. Important information for the development of novel optimized pharmaceutical formulations, such as structural classification, synthetic pathways, properties and applications, will offer the complete characterization of this type of Janus dendrimers. This work will constitute an up-to-date background for dendrimer specialists involved in designing amphiphilic Janus dendrimer-based nanomaterials for future innovations in this promising field.

A Cu+ /Thiourea Dendrimer Achieves Excellent Cytosolic Protein Delivery via Enhanced Cell Uptake and Endosome Escape

Intracellular protein delivery has attracted considerable attention in the development of protein-based therapeutics, however, the design of highly efficient materials for robust delivery of native proteins remains challenging. This study proposes a Cu⁺ -based coordination polymer for cytosolic protein delivery with high efficacy and robustness. The phenylthiourea grafted dendrimer is coordinated with cuprous ions to prepare the polymeric carrier, which efficiently bind cargo proteins via a combination of coordination, ionic and hydrophobic interactions. The incorporation of Cu⁺ ions in the polymer greatly improves its cellular uptake and endosomal escape. The cuprous-based coordination polymer successfully delivered a variety of structurally diverse proteins into various cell lines with reserved bioactivities. This study provides a new type of coordination polymers for cytosolic delivery of biomacromolecules.

Robust Reversible Cross-Linking Strategy for Intracellular Protein Delivery with Excellent Serum Tolerance

Intracellular protein delivery has attracted increasing attentions in biomedical applications. However, current delivery systems usually have poor serum stability due to the competitive binding of serum proteins to the polymers during delivery. Here, we report a reversible cross-linking strategy to improve the serum stability of polymers for robust intracellular protein delivery. In the proposed delivery system, nanoparticles are assembled by cargo proteins and cationic polymers and further stabilized by a glutathione-cleavable and traceless cross-linker. The cross-linked nanoparticles show high stability and efficient cell internalization in serum containing medium and can release the cargo proteins in response to intracellular glutathione and acidic pH in a traceless manner. The generality and versatility of the proposed strategy were demonstrated on different types of cationic polymers, cargo proteins, as well as cell lines. The study provides a facile and efficient method for improving the serum tolerance of cationic polymers in intracellular protein delivery.

Fluorous-Tagged Peptide Nanoparticles Ameliorate Acute Lung Injury via Lysosomal Stabilization and Inflammation Inhibition in Pulmonary Macrophages

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common respiratory critical syndrome that currently has no effective therapeutic interventions. Pulmonary macrophages play a principal role in the initiation and progression of the overwhelming inflammation in ALI/ARDS. Here, a type of fluorous-tagged bioactive peptide nanoparticle termed CFF13F is developed, which can be efficiently internalized by macrophages and suppress the excessive expression of cytokines and the overproduction of reactive oxygen species (ROS) triggered by lipopolysaccharide (LPS). The cytoprotective effect of CFF13F may be attributed to the lysosomal-stabilization property and regulation of the antioxidative system. Moreover, intratracheal pretreatment with CFF13F can effectively reduce local and systematic inflammation, and ameliorate pulmonary damage in an LPS-induced ALI murine model. The therapeutic efficacy of CFF13F is affected by the administration routes, and the local intratracheal injection is found to be the optimal choice for ALI treatment, with preferred biodistribution profiles. The present study provides solid evidence of the potent immunomodulatory bioactivity of the fluorous-tagged peptide nanoparticles CFF13F in vitro and in vivo, and sheds light on the development of novel efficient nanodrugs for ALI/ARDS.

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.

Virus-Like Particles as Nanocarriers for Intracellular Delivery of Biomolecules and Compounds

Virus-like particles (VLPs) are nanostructures assemble from viral proteins. Besides widely used for vaccine development, VLPs have also been explored as nanocarriers for cargo delivery as they combine the key advantages of viral and non-viral vectors. While it protects cargo molecules from degradation, the VLP has good cell penetrating property to mediate cargo passing the cell membrane and released into cells, making the VLP an ideal tool for intracellular delivery of biomolecules and drugs. Great progresses have been achieved and multiple challenges are still on the way for broad applications of VLP as delivery vectors. Here we summarize current advances and applications in VLP as a delivery vector. Progresses on delivery of different types of biomolecules as well as drugs by VLPs are introduced, and the strategies for cargo packaging are highlighted which is one of the key steps for VLP mediated intracellular delivery. Production and applications of VLPs are also briefly reviewed, with a discussion on future challenges in this rapidly developing field.

Polycatechols with Robust Efficiency in Cytosolic Peptide Delivery via Catechol-Boronate Chemistry

Cytosolic delivery of peptides remains a challenging task because of the limited binding sites on peptides and the existence of multiple intracellular barriers. Here, we proposed the use of polycatechols with a high cell permeability to deliver peptides of different physicochemical properties using the catechol-boronate chemistry. Peptides were decorated with boronate moieties via three strategies, and the introduced boronate groups greatly increased the binding affinity of cargo peptides with polycatechols. The loading peptides could be released under the endolysosomal acidity. When the cargo peptide was modified with boronate moiety via a p-hydroxybenzylcarbamate self-immolative spacer, it could be loaded by polycatechols and released in a traceless manner triggered by reactive oxygen species. The proposed strategies greatly promote the cytosolic delivery efficiency of different peptides into various cell lines and restored their biofunctions after intracellular delivery and release. This study provides a general and robust platform for the intracellular delivery of membrane-impermeable peptides.

Determination of 5-formyluracil via oxime-based nucleotide-metal coordination

In this article, a small chemical molecule was synthesized, and its ability to regulate activities of DNA polymerase was tested. In addition, we also used isothermal amplification technology to detect the content of 5-formyluracil sites in irradiated genomic DNA, which confirmed its capability for the detection of 5-formyluracil content in general samples. This study presents the first example of the determination of 5fU based on coordination chemistry.

Tetrahedral framework nucleic acids-based delivery promotes intracellular transfer of healing peptides and accelerates diabetic would healing

Objectives

Peptide‐based therapeutics are natural candidates to desirable wound healing. However, enzymatic surroundings largely limit its stability and bioavailability. Here, we developed a tetrahedral framework nucleic acids(tFNA)‐based peptide delivery system, that is, p@tFNAs, to address deficiencies of healing peptide stability and intracellular delivery in diabetic wound healing.

Materials and Methods

AGEs (advanced glycation end products) were used to treat endothelial cell to simulate cell injury in diabetic microenvironment. The effects and related mechanisms of p@tFNAs on endothelial cell proliferation, migration, angiogenesis and ROS (reactive oxygen species) production have been comprehensively studied. The wound healing model in diabetic mice was photographically and histologically investigated in vivo.

Results

Efficient delivery of healing peptide by the framework(tFNA) was verified. p@tFNAs helped overcome the angiogenic obstacles induced by AGEs via ERK1/2 phosphorylation. In the meantime, p@tFNA exhibited its antioxidative property to achieve ROS balance. As a result, p@tFNA improved angiogenesis and diabetic wound healing in vitro and in vivo.

Conclusions

Our findings demonstrate that p@tFNA could be a novel therapeutic strategy for diabetic wound healing. Moreover, a new method for intracellular delivery of peptides was also constructed.

Dendrimers as nanoscale vectors: Unlocking the bars of cancer therapy

Chemotherapy is the first choice in the treatment of cancer and is always preferred to other approaches such as radiation and surgery, but it has never met the need of patients for a safe and effective drug. Therefore, new advances in cancer treatment are now needed to reduce the side effects and burdens associated with chemotherapy for cancer patients. Targeted treatment using nanotechnology are now being actively explored as they could effectively deliver therapeutic agents to tumor cells without affecting normal cells. Dendrimers are promising nanocarriers with distinct physiochemical properties that have received considerable attention in cancer therapy studies, which is partly due to the numerous functional groups on their surface. In this review, we discuss the progress of different types of dendrimers as delivery systems in cancer therapy, focusing on the challenges, opportunities, and functionalities of the polymeric molecules. The paper also reviews the various role of dendrimers in their entry into cells via endocytosis, as well as the molecular and inflammatory pathways in cancer. In addition, various dendrimers-based drug delivery (e.g., pH-responsive, enzyme-responsive, redox-responsive, thermo-responsive, etc.) and lipid-, amino acid-, polymer- and nanoparticle-based modifications for gene delivery, as well as co-delivery of drugs and genes in cancer therapy with dendrimers, are presented. Finally, biosafety concerns and issues hindering the transition of dendrimers from research to the clinic are discussed to shed light on their clinical applications.

Cytosolic Protein Delivery Using Modular Biotin-Streptavidin Assembly of Nanocomposites

Current strategies for the delivery of proteins into cells face general challenges of endosomal entrapment and concomitant degradation of protein cargo. Efficient delivery directly to the cytosol overcomes this obstacle: we report here the use of biotin-streptavidin tethering to provide a modular approach to the generation of nanovectors capable of a cytosolic delivery of biotinylated proteins. This strategy uses streptavidin to organize biotinylated protein and biotinylated oligo(glutamate) peptide into modular complexes that are then electrostatically self-assembled with a cationic guanidinium-functionalized polymer. The resulting polymer-protein nanocomposites demonstrate efficient cytosolic delivery of six biotinylated protein cargos of varying size, charge, and quaternary structure. Retention of protein function was established through efficient cell killing via delivery of the chemotherapeutic enzyme granzyme A. This platform represents a versatile and modular approach to intracellular delivery through the noncovalent tethering of multiple components into a single delivery vector.

Fluorescent dendrimer-based probes for cell membrane imaging: Zebrafish epidermal labeling-based toxicity evaluation

Visualizing the plasma membrane of living mammalian cells both in vitro and in vivo is crucial for tracking their cellular activities. However, due to the complex and dynamic nature of the plasma membrane, most commercial dyes for membrane staining can only realize very limited imaging performance. Thus, precise and stable plasma membrane imaging remains technically challenging. Here, by taking advantage of the small, well-defined, and amine-rich dendrimers, we prepared poly(ethylene glycol)-cholesterol (PEG-Chol)-conjugated and cyanine dye (e.g., cyanine2, cyanine3, and cyanine5)-labeled dendrimer nanoprobes (termed DPC-Cy2, DPC-Cy3, and DPC-Cy5 NPs). It was revealed that these probes enabled universal, wash-free, long-term (at least 8 h), and multicolor (green, yellow, and red) plasma membrane labeling of a variety of live mammalian cells. Further, we confirmed that the nanoprobes (using DPC-Cy5 as a representative) could achieve high-quality, wash-free, and stable cell surface labeling of live zebrafish embryos. More importantly, we demonstrated that our probes could act as biosensors to visualize the toxicity of metal-organic frameworks (MOFs) toward the epidermal cells of zebrafish embryos, and thus they hold great potential for identifying the toxic effect of drugs/materials at the single-cell scale or in live animals. The present work highlights the advantages of utilizing dendrimers for constructing functional imaging materials, and it is also believed that the fluorescent dendrimer nanoprobes developed in this work may find wide applications like cell imaging, drug toxicity evaluation, and cellular state monitoring.

Engineered EGCG-Containing Biomimetic Nanoassemblies as Effective Delivery Platform for Enhanced Cancer Therapy

Nano-based immunotherapy of therapeutic biomolecules is attractive but tremendously hampered by the poor delivery efficiency. This study reports a novel delivery system of fluorinated-coordinative-epigallocatechin gallate (EGCG), referring as FEGCG/Zn, through the integration of fluorination and zinc ions (Zn²⁺ ) into EGCG. The robust therapeutics of FEGCG/Zn are measured in terms of the regulating effect on programmed cell death ligand 1 (PD-L1), the effective delivery of diverse biomolecules, and the hitchhiking ability using living cells. Taking small interfering RNA of PD-L1 (siPD-L1) and erythrocytes as an example, the fabricated biomimetic system achieves excellent siPD-L1 delivery and further improves siPD-L1 accumulation in tumors. Finally, the combination of FEGCG/Zn and siPD-L1 promotes antitumor immunotherapy through alleviation of T cells exhaustion by regulating PD-L1 expression in tumor cells. The results demonstrate that FEGCG/Zn substantially regulates PD-L1 expression and improves immune-biomolecule delivery by forming biomimetic nanoassemblies, offering a versatile platform for cancer immunotherapy.

Biomedical polymers: synthesis, properties, and applications

Biomedical polymers have been extensively developed for promising applications in a lot of biomedical fields, such as therapeutic medicine delivery, disease detection and diagnosis, biosensing, regenerative medicine, and disease treatment. In this review, we summarize the most recent advances in the synthesis and application of biomedical polymers, and discuss the comprehensive understanding of their property-function relationship for corresponding biomedical applications. In particular, a few burgeoning bioactive polymers, such as peptide/biomembrane/microorganism/cell-based biomedical polymers, are also introduced and highlighted as the emerging biomaterials for cancer precision therapy. Furthermore, the foreseeable challenges and outlook of the development of more efficient, healthier and safer biomedical polymers are discussed. We wish this systemic and comprehensive review on highlighting frontier progress of biomedical polymers could inspire and promote new breakthrough in fundamental research and clinical translation.

Arginine-Rich Polymers with Pore-Forming Capability Enable Efficient Intracellular Delivery via Direct Translocation Across Cell Membrane

Efficient delivery of biomacromolecules or drugs across the cell membrane via endocytosis usually encounters inevitable entrapment in endosomes and subsequent degradation in lyso-endosomes. To address this issue, a series of arginine-rich cell penetrating polymers is designed and synthesized, which internalize into cells by inducing the formation of pores on the cell membrane, thereby crossing the cell membrane via direct translocation that fundamentally avoids endo/lysosomal entrapment. The structure-activity relationship studies show that PTn-R2-C6, which is a type of polymer that has two arginine residues and a flexible hexanoic acid linker in each side chain, exhibits excellent pore-formation ability on the cell membrane. Further investigations indicate that PTn-R2-C6 rapidly transports plasmid DNAs into cytosol through a similar endocytosis-independent pathway, thereby achieving significantly higher transfection efficiency and lower cytotoxicity than the gold-standard transfection reagent PEI 25K. These results suggest the great potential of PTn-R2-C6 as a safe and efficient gene transfection reagent for wide applications including disease treatments, vaccine development, and biomedical research purposes.

Amomum tsao-ko essential oil, a Novel Anti-COVID-19 Omircon Spike Protein Natural Products: A Computational Study

Since the outbreak of COVID-19, this virus has been constantly mutating. The latest mutant Omicron has been identified as VOC by WHO. The main reason for its concern is the mutation of 46 amino acids in spike protein, which has brought the global epidemic prevention into another difficulty. Herbal aromatic plant Amomum tsao-ko was excavated from formula 1 and 2 for the treatment of COVID-19 in China, and its active components were extracted and identified. Molecular dynamics simulation and Fpocket were applied to find the key sites on RBD_Omicron, and molecular docking was also used to reveal the interaction between A. tsao-ko essential oil (AEO) and RBD_Omicron. The AEO components were analyzed and identified by GC/Q-TOF MS. There were 20 kinds of AEO with a relative area percentage of more than 1%, and they were related to the three active centres of RBD_Omicron. In this study, virtual screening was used to mine the essential oil components of medicinal plants, and it was found that the components could interact with the spike protein RBD in aerosol to block the interaction of RBD and hACE2, thus cutting off the transmission route and protecting the host. This study has certain guiding significance in the modernization of Traditional Chinese medicine and the prevention of COVID-19.

Crosslinked Protein Delivery Strategy with Precise Activity Regulation Properties for Cancer Therapy and Gene Editing

Protein drugs hold tremendous promise for therapeutic applications due to their direct and superior pharmacological effects. However, protein drugs can be degraded in blood stream and unable to cross many physical barriers to exert therapeutic effect. Degradable synthetic crosslinking is a versatile strategy to enhance the stability of the nanoparticle in a complex physiological medium and is helpful to get through physical barriers. Herein, crosslinked polypeptide (PABP) composed of poly-amino acids including cystine, tyrosine, lysine, ketal bridge, and polyethylene glycol (PEG) is modularly explored and synthesized for protein delivery. Notably, plasma membrane V-ATPase is the particular pathway which induces the macropinocytosis of the inner peptide analogous core (PAB/protein) after the outer PEG shell disassociation at tumor intercellular sites. In addition, PABP/protein achieves proteins' activity shielding in systemic circulation and recovery in tumor cytoplasm precisely. In application, PABP/RNase-A shows satisfying tumor accumulation and antineoplastic efficacy. More importantly, PABP/Cas9 + small guide RNA displays obvious gene editing efficiency. The crosslinked protein delivery strategy not only makes the accurate protein transport and activity regulation possible but also is promising in paving the way for clinical translation of protein drugs.

Amphipathic poly-β-peptides for intracellular protein delivery

A series of amphipathic poly-β-peptides are designed for intracellular protein delivery. The poly-β-peptides with higher molecular weight and hydrophobic contents exhibit higher protein loading and superior delivery efficiency. The lead material efficiently delivers proteins into cells with reserved bioactivity.

Carbamoylated Guanidine-Containing Polymers for Non-Covalent Functional Protein Delivery in Serum-Containing Media

Despite the high potential of controlling cellular processes and treating various diseases by intracellularly delivered proteins, current delivery systems exhibit poor efficiency due to poor serum stability, cellular entry, and cytosolic availability of proteins. Here, we report a novel functional group, phenyl carbamoylated guanidine (Ph-CG), that greatly enhances the delivery efficiency to various types of cells. Owing to the substantially lowered pK_a , the hydrophobic Ph-CG offers optimized inter-macromolecular interactions via enhanced hydrogen-bonding and hydrophobic interactions. The coplanarity of Ph-CG also leads to the better intracellular entry of protein complexes. Intracellularly delivered apoptosis-inducing enzymes and antibodies significantly induce cell viability inhibitions in a serum-containing medium. The newly developed Ph-CG can be introduced to various existing carriers, leading to the realization of future therapeutic protein delivery.