Advanced engineered nanoparticulate platforms to address key biological barriers for delivering chemotherapeutic agents to target sites

Gold nanorods/tetrahedral DNA composites for chemo-photothermal therapy

Combination therapy is extensively developed for cancer treatment in recent years due to its high efficiency. Herein, we constructed a nanocomposite based on gold nanorods (GNRs) and drug-loaded tetrahedral DNA nanostructures (TDN) for chemo-photothermal combinational therapy. Anti-tumor drug doxorubicin (DOX) was loaded via the insertion within GC base pairs of TDN. The aptamer AS1411 was attached to the apex of TDN (ATDN) to target tumor cells. The DOX-loaded DNA tetrahedron (ATDN-DOX) was compressed by the GNRs coated with PEI (GNRs@ATDN-DOX) to realize the photothermal function and lysosome escape. GNRs under the illumination of 808 nm infrared laser showed high photothermal conversion and stability due to the protection of PEI layer. The drug-loading capacity of ATDN-DOX was as high as 314 DOX molecules in per ATDN. The positive charge of PEI in GNRs@ATDN-DOX nanocomposites was utilized to achieve excellent cell penetration and induce proton sponge effect for lysosomal escape. The nanocomposites presented HeLa and 4T1 cells targeting and resulted in efficient anticancer activity.

A mitochondria-targeting lipid-small molecule hybrid nanoparticle for imaging and therapy in an orthotopic glioma model

Hybrid lipid‒nanoparticle complexes have shown attractive characteristics as drug carriers due to their integrated advantages from liposomes and nanoparticles. Here we developed a kind of lipid-small molecule hybrid nanoparticles (LPHNPs) for imaging and treatment in an orthotopic glioma model. LPHNPs were prepared by engineering the co-assembly of lipids and an amphiphilic pheophorbide a‒quinolinium conjugate (PQC), a mitochondria-targeting small molecule. Compared with the pure nanofiber self-assembled by PQC, LPHNPs not only preserve the comparable antiproliferative potency, but also possess a spherical nanostructure that allows the PQC molecules to be administrated through intravenous injection. Also, this co-assembly remarkably improved the drug-loading capacity and formulation stability against the physical encapsulation using conventional liposomes. By integrating the advantages from liposome and PQC molecule, LPHNPs have minimal system toxicity, enhanced potency of photodynamic therapy (PDT) and visualization capacities of drug biodistribution and tumor imaging. The hybrid nanoparticle demonstrates excellent curative effects to significantly prolong the survival of mice with the orthotopic glioma. The unique co-assembly of lipid and small molecule provides new potential for constructing new liposome-derived nanoformulations and improving cancer treatment.

Combinatorial therapeutic strategies for enhanced delivery of therapeutics to brain cancer cells through nanocarriers: current trends and future perspectives

Brain cancer is the most aggressive one among various cancers. It has a drastic impact on people's lives because of the failure in treatment efficacy of the currently employed strategies. Various strategies used to relieve pain in brain cancer patients and to prolong survival time include radiotherapy, chemotherapy, and surgery. Nevertheless, several inevitable limitations are accompanied by such treatments due to unsatisfactory curative effects. Generally, the treatment of cancers is very challenging due to many reasons including drugs’ intrinsic factors and physiological barriers. Blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB) are the two additional hurdles in the way of therapeutic agents to brain tumors delivery. Combinatorial and targeted therapies specifically in cancer show a very promising role where nanocarriers’ based formulations are designed primarily to achieve tumor-specific drug release. A dual-targeting strategy is a versatile way of chemotherapeutics delivery to brain tumors that gets the aid of combined ligands and mediators that cross the BBB and reaches the target site efficiently. In contrast to single targeting where one receptor or mediator is targeted, the dual-targeting strategy is expected to produce a multiple-fold increase in therapeutic efficacy for cancer therapy, especially in brain tumors. In a nutshell, a dual-targeting strategy for brain tumors enhances the delivery efficiency of chemotherapeutic agents via penetration across the blood-brain barrier and enhances the targeting of tumor cells. This review article highlights the ongoing status of the brain tumor therapy enhanced by nanoparticle based delivery with the aid of dual-targeting strategies. The future perspectives in this regard have also been highlighted.

Versatile polyphenolic platforms in regulating cell biology

Polyphenolic materials are a class of fascinating and versatile bioinspired materials for biointerfacial engineering. In particular, due to the presence of active chemical groups, a series of unique physicochemical properties become accessible and tunable of the as-prepared polyphenolic platforms, which could delicately regulate the cell activities via cell-material contact-dependent interactions. More interestingly, polyphenols could also affect the cell behaviors via cell-material contact-independent manner, which arise due to their intrinsically functional characteristics (e.g., antioxidant and photothermal behaviors). As such, a comprehensive understanding on the relationship between material properties and desired biomedical applications, as well as the underlying mechanism at the cellular and molecular level would provide material design principles and accelerate the lab-to-clinic translation of polyphenolic platforms. In this review, we firstly give a brief overview of cell hallmarks governed by surrounding cues, followed by the introduction of polyphenolic material engineering strategies. Subsequently, a detailed discussion on cell-polyphenols contact-dependent interfacial interaction and contact-independent interaction was also carefully provided. Lastly, their biomedical applications were elaborated. We believe that this review could provide guidances for the rational material design of multifunctional polyphenols and extend their application window.

Antibiotic-loaded reactive oxygen species-responsive nanomedicine for effective management of chronic bacterial prostatitis

Chronic bacterial prostatitis (CBP) occurs frequently in the male population and significantly influences quality of life. Antibiotics are the main strategy for managing chronic bacterial prostatitis; however, most antibiotics have low efficacy due to their poor penetration of prostate tissues. To overcome this challenge, we fabricated cefpodoxime proxetil (CPD)-loaded reactive oxygen species (ROS)-responsive nanoparticles (NPs) for targeted treatment of CBP. These NPs were modified with folic acid (FA) and could be effectively internalized by bacteria-infected macrophages and prostatic epithelial cells because of the high expression of folate receptors (FRs) in these cells. In vitro cellular assays demonstrated that the CPD-loaded nanomedicine can obviously reduce proinflammatory cytokine expression in cells since the nanomedicine can efficiently eradicate cellular bacteria. In vivo imaging results verified that FA-modified nanomedicines can penetrate the prostatic epithelium and accumulate in the glandular lumen because FRs overexpression was also observed in the prostate tissues of CBP mice. Animal experiments demonstrated that FA-modified nanomedicine can remarkably relieve pelvic pain in CBP mice and dramatically decrease proinflammatory cytokine expression in prostate tissues via eradication of bacteria and scavenging of ROS. Our results provide a new strategy to deliver antibiotics for targeted therapy of CBP. STATEMENT OF SIGNIFICANCE: To overcome poor penetration of antibiotics in prostatic tissues, we developed an antibiotics-loaded ROS-responsive NPs for targeted treatment of CBP. We demonstrated that both bacteria-infected macrophages and prostatic epithelial cells have FRs overexpression, thus FA-modified NPs can be efficiently internalized by these cells. FA-modified NPs can penetrate the prostatic epithelium and accumulate in the glandular lumen via FRs-mediated endocytosis, and the accumulated NPs can smartly release their payload under high ROS microenvironment. A distinguished therapy outcome was obtained in murine CBP model since CPD-loaded NPs can efficiently eradicate the resident bacteria in prostate tissues and downregulate proinflammatory cytokine expression. Our work provides a practicable strategy to expand the application of antibiotics for management of CBP.

Poly(beta-amino ester)-Based Nanoparticles Enable Nonviral Delivery of Base Editors for Targeted Tumor Gene Editing

Base editing is an emerging genome editing technology with the advantages of precise base corrections, no double-strand DNA breaks, and no need for templates, which provides an alternative treatment option for tumors with point mutations. However, effective nonviral delivery systems for base editors (BEs) are still limited. Herein, a series of poly(beta-amino esters) (PBAEs) with varying backbones, side chains, and end caps were synthesized to deliver plasmids of BEs and sgRNA. Efficient transfection and base editing were achieved in HEK-293T-sEGFP and U87-MG-sEGFP reporter cell lines by using lead PBAEs, which were superior to PEI and lipo3k. A single intratumor injection of PBAE/pDNA nanoparticles induced the robust conversion of stopped-EGFP into EGFP in mice bearing xenograft glioma tumors, indicating successful gene editing by ABEmax-NG. Overall, these results demonstrated that PBAEs can efficiently deliver BEs for tumor gene editing both in vitro and in vivo.

White Blood Cell Membrane-Coated Nanoparticles: Recent Development and Medical Applications

White blood cells (WBCs) are immune cells that play essential roles in critical diseases including cancers, infections, and inflammatory disorders. Their dynamic and diverse functions have inspired the development of WBC membrane-coated nanoparticles (denoted "WBC-NPs"), which are formed by fusing the plasma membranes of WBCs, such as macrophages, neutrophils, T cells, and natural killer cells, onto synthetic nanoparticle cores. Inheriting the entire source cell antigens, WBC-NPs act as source cell decoys and simulate their broad biointerfacing properties with intriguing therapeutic potentials. Herein, the recent development and medical applications of WBC-NPs focusing on four areas, including WBC-NPs as carriers for drug delivery, as countermeasures for biological neutralization, as nanovaccines for immune modulation, and as tools for the isolation of circulating tumor cells and fundamental research is reviewed. Overall, the recent development and studies of WBC-NPs have established the platform as versatile nanotherapeutics and tools with broad medical application potentials.

Intelligent Nanoplatform with Multi Therapeutic Modalities for Synergistic Cancer Therapy

Chemodynamic therapy (CDT) has attracted increasing attention in tumor treatment but is limited by insufficient endogenous H₂O₂. Moreover, it is challenging for monotherapy to achieve a satisfactory outcome due to tumor complexity. Herein, we developed an intelligent nanoplatform that could respond to a tumor microenvironment to induce efficient CDT without complete dependence on H₂O₂ and concomitantly generate chemotherapy and oncosis therapy (OT). The nanoplatform was constructed by a calcium- and iron-doped mesoporous silica nanoparticle (CFMSN) loaded with dihydroartemisinin (DHA). After entering into cancer cells, the nanoplatform could directly convert the intracellular H₂O₂ into toxic •OH due to the Fenton-like activity of CFMSN. Meanwhile, the acidic microenvironment and endogenous chelating molecules triggered Ca²⁺ and Fe³⁺ release from the nanoplatform, causing particle collapse with accompanying DHA release for chemotherapy. Simultaneously, the released Ca²⁺ induced intracellular Ca²⁺-overloading for OT, which was further enhanced by DHA, while the released Fe³⁺ was reduced to reactive Fe²⁺ by intracellular glutathione, guaranteeing efficient Fenton reaction-mediated CDT. Moreover, Fe²⁺ cleaved the peroxy bonds of DHA to generate C-centered radicals to further amplify CDT. Both in vitro and in vivo results confirmed that the nanoplatform exhibited excellent anticancer efficacy via the synergistic effect of multi therapeutic modalities, which is extremely promising for high-efficient cancer therapy.

A bone-targeting drug delivery vehicle of a metal-organic framework conjugate with zoledronate combined with photothermal therapy for tumor inhibition in cancer bone metastasis

Chemotherapy is a conventional treatment method for metastatic bone cancer, but it has limitations, such as lower drug-targeting of bone tissues and serious side effects. Bone metastasis almost always occurs in advanced cancer, and most patients in this period have strong drug resistance, which further worsens the curative effect. To address the above-mentioned difficulties, a drug delivery platform is proposed in this paper that accomplishes the bone-targeting of drugs to efficiently inhibit tumors. First, the anti-cancer drugs 5-fluorouracil (5-Fu) and indocyanine green (ICG) were loaded into a zeolitic imidazolate framework (ZIF-90) to form 5-Fu/ICG@ZIF-90. Polyethylene glycol with zoledronic acid (ZOL) was encapsulated using 5-Fu/ICG@ZIF-90 to synthesize 5-Fu/ICG@ZIF-90-PEG-ZOL nanoparticles, which showed dimensional stability, good thermal stability, and bone-targeting ability. Second, the in vitro anti-cancer activity of the designed platform was investigated using cytotoxicity, apoptosis, live-dead staining, cell cycle, and cell ultrathin section analysis. The results indicated that the nanoparticles inhibited MCF-7 cell activity when chemotherapy was combined with PTT. Finally, H&E staining and TUNEL detection were performed in mouse organs and tumors. The nanoparticles combined with photothermal therapy (PTT) and triggered by near-infrared irradiation induce apoptosis of tumor cells in vivo, displaying a better efficacy of combined chemotherapy and photothermal therapy. Experiments conducted on the 5-Fu/ICG@ZIF-90-PEG-ZOL nanoparticles demonstrated their promising performance for cancer bone metastasis inhibition.

Synergistic Disruption of Metabolic Homeostasis through Hyperbranched Poly(ethylene glycol) Conjugates as Nanotherapeutics to Constrain Cancer Growth

Combination therapy is a promising approach for effective treatment of tumors through synergistically regulating pathways. However, the synergistic effect is limited, likely by uncontrolled co-delivery of different therapeutic payloads in a single nanoparticle. Herein, a combination nanotherapeutic is developed by using two amphiphilic conjugates, hyperbranched poly(ethylene glycol)-pyropheophorbide-a (Ppa) (HP-P) and hyperbranched poly(ethylene glycol)-doxorubicin (DOX) (HP-D) to construct co-assembly nanoparticles (HP-PD NPs) for controllably co-loading and co-delivering Ppa and DOX. In vitro and in vivo antitumor studies confirm the synergistic effect of photodynamic therapy and chemotherapy from HP-PD NPs. Metabolic variations reveal that tumor suppression is associated with disruption of metabolic homeostasis, leading to reduced protein translation. This study uncovers the manipulation of metabolic changes in tumor cells through disruption of cellular homeostasis using HP-PD NPs and provides a new insight into the rational design of synergistic nanotherapeutics for combination therapy.

Macrophage-Mimic Hollow Mesoporous Fe-Based Nanocatalysts for Self-Amplified Chemodynamic Therapy and Metastasis Inhibition via Tumor Microenvironment Remodeling

Fe-based nanomaterials with Fenton reaction activity are promising for tumor-specific chemodynamic therapy (CDT). However, most of the nanomaterials suffer from low catalytic efficiency due to its insufficient active site exposure and the relatively high tumor intracellular pH, which greatly impede its clinical application. Herein, macrophage membrane-camouflaged carbonic anhydrase IX inhibitor (CAI)-loaded hollow mesoporous ferric oxide (HMFe) nanocatalysts are designed to remodel the tumor microenvironment with decreased intracellular pH for self-amplified CDT. The HMFe not only serves as a Fenton agent with high active-atom exposure to enhance CDT but also provides hollow cavity for CAI loading. Meanwhile, the macrophage membrane-camouflaging endows the nanocatalysts with immune evading capability and improves tumoritropic accumulation by recognizing tumor endothelium and cancer cells through α4/VCAM-1 interaction. Once internalized by tumor cells, the CAI could be specifically released, which can not only inhibit CA IX to induce intracellular H⁺ accumulation for accelerating the Fenton reaction but also could prevent tumor metastasis because of the insufficient H⁺ formation outside cells for tumor extracellular matrix degradation. In addition, the HMFe can be employed to highly efficient magnetic resonance imaging to real-time monitor the agents' bio-distribution and treatment progress. Both in vitro and in vivo results well demonstrated that the nanocatalysts could realize self-amplified CDT and breast cancer metastasis inhibition via tumor microenvironment remodeling, which also provides a promising paradigm for improving CDT and antimetastatic treatment.

Carrier-free nanodrugs with efficient drug delivery and release for cancer therapy: From intrinsic physicochemical properties to external modification

The considerable development of carrier-free nanodrugs has been achieved due to their high drug-loading capability, simple preparation method, and offering "all-in-one" functional platform features. However, the native defects of carrier-free nanodrugs limit their delivery and release behavior throughout the in vivo journey, which significantly compromise the therapeutic efficacy and hinder their further development in cancer treatment. In this review, we summarized and discussed the recent strategies to enhance drug delivery and release of carrier-free nanodrugs for improved cancer therapy, including optimizing the intrinsic physicochemical properties and external modification. Finally, the corresponding challenges that carrier-free nanodrugs faced are discussed and the future perspectives for its application are presented. We hope this review will provide constructive information for the rational design of more effective carrier-free nanodrugs to advance therapeutic treatment.

Doxorubicin nanoformulations on therapy against cancer: An overview from the last 10 years

Doxorubicin (DOX) is a natural antibiotic with antineoplastic activity. It has been used for over 40 years and remains one of the most used drugs in chemotherapy for a variety of cancers. However, cardiotoxicity limits its use for long periods. To overcome this limitation, encapsulation in smart drug delivery systems (DDS) brings advantages in comparison with free drug administration (i.e., conventional anticancer drug therapy). In this review, we present the most relevant nanostructures used for DOX encapsulation over the last 10 years, such as liposomes, micelles and polymeric vesicles (i.e., polymersomes), micro/nanoemulsions, different types of polymeric nanoparticles and hydrogel nanoparticles, as well as novel approaches for DOX encapsulation. The studies highlighted here show these nanoformulations achieved higher solubility, improved tumor cytotoxicity, prolonged DOX release, as well as reduced side effects, among other interesting advantages.

pH-Responsive size-shrinkable mesoporous silica-based nanocarriers for improving tumor penetration and therapeutic efficacy

Poor tumor penetration is a major obstacle to nanomedicine for achieving effective anticancer therapy. Tumor microenvironment-induced nanomedicine size shrinkage is a promising strategy to overcome the drug penetration barrier across the dense tumor matrix. Herein, we design a size-shrinkable nanocarrier that uses acid as a means of triggering a change in particle size for co-achievement of efficient tumor accumulation followed by deep tumor penetration and rapid clearance from the body. This nanocarrier is constructed from a pH-sensitive lipid layer shell and an ultrasmall amino-functionalized mesoporous silica nanoparticle core capable of loading drugs. After intravenous injection into mice bearing the 4T1 tumor, the nanocarrier with an initial hydrodynamic size of about 33 nm could effectively accumulate at the tumor site through the enhanced permeability and retention effect. Subsequently, in the acidic tumor microenvironment, the lipid layer comprising 9 alkyl-spiropyran (SP-C9) undergoes a volume shrinkage due to the conversion of hydrophobic SP-C9 to amphiphilic 9 alkyl-merocyanine (MC-C9), thus leading to a significant decrease in the entire particle size (hydrodynamic size ∼17 nm) for enhanced intratumoral penetration. Moreover, we find that this size-shrinkable nanocarrier could be rapidly excreted out of the body based on the ICP analysis, significantly reducing biosafety issues. Benefiting from the effective tumor accumulation and penetration of the nanocarrier, the released doxorubicin shows potent antitumor efficacy. This demonstrates the high potential of the designed nanocarrier in solid tumor treatment.

Spatial configuration of charge and hydrophobicity tune particle transport through mucus

Mucus is a selectively permeable hydrogel that protects wet epithelia from pathogen invasion and poses a barrier to drug delivery. Determining the parameters of a particle that promote or prevent passage through mucus is critical, as it will enable predictions about the mucosal passage of pathogens and inform the design of therapeutics. The effect of particle net charge and size on mucosal transport has been characterized using simple model particles; however, predictions of mucosal passage remain challenging. Here, we utilize rationally designed peptides to examine the integrated contributions of charge, hydrophobicity, and spatial configuration on mucosal transport. We find that net charge does not entirely predict transport. Specifically, for cationic peptides, the inclusion of hydrophobic residues and the position of charged and hydrophobic residues within the peptide impact mucosal transport. We have developed a simple model of mucosal transport that predicts how previously unexplored amino acid sequences achieve slow versus fast passage through mucus. This model may be used as a basis to predict transport behavior of natural peptide-based particles, such as antimicrobial peptides or viruses, and assist in the engineering of synthetic sequences with desired transport properties.

Characteristic Synthesis of a Covalent Organic Framework and Its Application in Multifunctional Tumor Therapy

For decades, covalent organic frameworks (COFs) have attracted wide biomedical interest due to their unique properties including ease of synthesis, porosity, and adjustable biocompatibility. Versatile COFs can easily encapsulate various therapeutic drugs due to their extremely high payload and porosity. COFs with abundant functional groups can be surface-modified to achieve active targeting and enhance biocompatibility. In this paper, the latest developments of COFs in the biomedical field are summarized. First, the classification and synthesis of COFs are discussed. Cancer diagnosis and treatment based on COFs are studied, and the advantages and limitations of each method are discussed. Second, the specific preparation methods to obtain specific therapeutic properties are summarized. Finally, based on the combination and modification of COFs with various components, this review system summarizes different combination therapies. In addition, the main challenges faced in COF research and prospects for applying COFs to cancer diagnosis and treatment are evaluated. This review provides enlightening insights into the interdisciplinary research on COFs and applications in biomedicine, which highlight the great expectations for their further clinical transformation.

Development of targeted micelles and polymersomes prepared from degradable RAFT-based diblock copolymers and their potential role as nanocarriers for chemotherapeutics

Modern polymerisation techniques allow synthesis of functional block copolymers that can self-assemble into degradable nanoparticles (NPs) of different sizes and conformations.

Supramolecular Nanostructures for Vaccines

Although this is an era of pandemics and many devastating diseases, this is also a time when bionanotechnology flourishes, illuminating a multidisciplinary field where vaccines are quickly becoming a balsam and a prevention against insidious plagues. In this work, we tried to gain and also give a deeper understanding on nanovaccines and their way of acting to prevent or cure cancer, infectious diseases, and diseases caused by parasites. Major nanoadjuvants and nanovaccines are temptatively exemplified trying to contextualize our own work and its relative importance to the field. The main properties for novel adjuvants seem to be the nanosize, the cationic character, and the biocompatibility, even if it is achieved in a low dose-dependent manner.

ssDNA nanotubes for selective targeting of glioblastoma and delivery of doxorubicin for enhanced survival

Effective treatment of glioblastoma remains a daunting challenge. One of the major hurdles in the development of therapeutics is their inability to cross the blood-brain tumor barrier (BBTB). Local delivery is an alternative approach that can still suffer from toxicity in the absence of target selectivity. Here, we show that nanotubes formed from self-assembly of ssDNA-amphiphiles are stable in serum and nucleases. After bilateral brain injections, nanotubes show preferential retention by tumors compared to normal brain and are taken up by glioblastoma cells through scavenger receptor binding and macropinocytosis. After intravenous injection, they cross the BBTB and internalize in glioblastoma cells. In a minimal residual disease model, local delivery of doxorubicin showed signs of toxicity in the spleen and liver. In contrast, delivery of doxorubicin by the nanotubes resulted in no systemic toxicity and enhanced mouse survival. Our results demonstrate that ssDNA nanotubes are a promising drug delivery vehicle to glioblastoma.

Advanced biomedical hydrogels: molecular architecture and its impact on medical applications

Hydrogels are cross-linked polymeric networks swollen in water, physiological aqueous solutions or biological fluids. They are synthesized by a wide range of polymerization methods that allow for the introduction of linear and branched units with specific molecular characteristics. In addition, they can be tuned to exhibit desirable chemical characteristics including hydrophilicity or hydrophobicity. The synthesized hydrogels can be anionic, cationic, or amphiphilic and can contain multifunctional cross-links, junctions or tie points. Beyond these characteristics, hydrogels exhibit compatibility with biological systems, and can be synthesized to render systems that swell or collapse in response to external stimuli. This versatility and compatibility have led to better understanding of how the hydrogel's molecular architecture will affect their physicochemical, mechanical and biological properties. We present a critical summary of the main methods to synthesize hydrogels, which define their architecture, and advanced structural characteristics for macromolecular/biological applications.

An Efficient Carbon-Based Drug Delivery System for Cancer Therapy through the Nucleus Targeting and Mitochondria Mediated Apoptotic Pathway

The emergence of nanocarriers solves the problems of antitumor drugs such as non-targeting, huge side effects, etc., and has been widely used in tumor therapy. Some kinds of antitumor drugs such as doxorubicin (DOX) mainly act on the nucleic acid causing DNA damage, interfering with transcription, and thereby disrupting or blocking the process of cancer cell replication. Herein, a new nanodrug delivery system, the carbon-based nanomaterials (CBNs)-Pluronic F127-DOX (CPD), is designed by using CBNs as a nanocarrier for DOX. As a result, the tumor growth inhibition rate of CPD group is as high as 79.42 ± 2.83%, and greatly reduces the side effects. The targeting rate of the CPD group of DOX in the tumor nucleus is 36.78%, and the %ID/g in tumor tissue is 30.09%. The CPD regulates the expression levels of Caspase-3, p53, and Bcl-2 genes by increasing intracellular reactive oxygen species (ROS) levels and reducing mitochondrial membrane potential, which indicates that mitochondrial-mediated pathways are involved in apoptosis. The CPD nanodrug delivery system increases the effective accumulation of DOX in tumor cell nuclei and tumor tissues, and generates massive ROS, thereby inhibiting tumor growth in vivo, representing a promising agent for anticancer applications.

Mitochondrial Targeting and pH-Responsive Nanogels for Co-Delivery of Lonidamine and Paclitaxel to Conquer Drug Resistance

Multidrug resistance (MDR) is one of the leading causes of the failure of cancer chemotherapy and mainly attributed to the overexpression of drug efflux transporters in cancer cells, which is dependent on adenosine triphosphate (ATP). To overcome this phenomenon, herein, a mitochondrial-directed pH-sensitive polyvinyl alcohol (PVA) nanogel incorporating the hexokinase inhibitor lonidamine (LND) and the chemotherapeutic drug paclitaxel (PTX) was developed to restore the activity of PTX and synergistically treat drug-resistant tumors. The introduction of 2-dimethylaminoethanethiol (DMA) moiety into the nanogels not only promoted the drug loading capacity but also enabled the lysosomal escape of the nanogels. The subsequent mitochondrial targeting facilitated the accumulation and acid-triggered payload release in the mitochondria. The released LND can destroy the mitochondria by exhausting the mitochondrial membrane potential (MMP), generating reactive oxygen species (ROS) and restraining the energy supply, resulting in apoptosis and susceptibility of the MCF-7/MDR cells to PTX. Hence, the nanogel-enabled combination regimen of LND and PTX showed a boosted anti-tumor efficacy in MCF-7/MDR cells. These mitochondrial-directed pH-sensitive PVA nanogels incorporating both PTX and LND represent a new nanoplatform for MDR reversal and enhanced therapeutic efficacy.

Precise Delivery of Nanomedicines to M2 Macrophages by Combining "Eat Me/Don't Eat Me" Signals and Its Anticancer Application

Targeted delivery of nanomedicines to M2 tumor-associated macrophages (TAMs) has been proposed to reduce tumor promotion and enhance the efficacy of anticancer therapy. However, upregulated receptors on M2 TAMs are also expressed on M1 TAMs and other macrophages in normal tissues. Therefore, improving targeting specificity remains a key challenge. Here, we developed a precise M2 TAM-targeted delivery system using "eat-me" and "don't-eat-me" signals. A CD47-derived self-peptide ligand (don't-eat-me signal) and galactose ligand (eat-me signal) were introduced on liposomes. Cleavable phospholipid-polyethylene glycol was covered on the surface and could combine with the self-peptide to inhibit macrophage recognition even after immunoglobulin M adsorption and protect galactose from hepatic clearance to prolong the circulation time and promote the accumulation of liposomes in tumors. This detachable polymer can be removed by the redox microenvironment upon transcytosis through the tumor endothelium and re-expose the self-peptide and galactose. The self-peptide highly reduced M1 macrophage phagocytosis, and the galactose ligand enhanced the interaction between the liposomes and M2 macrophages. Thus, the modified liposomes enabled specific recognition of M1/M2 TAMs. In vitro evidence revealed reduced endocytosis of the liposomes by M1 macrophages. Moreover, in vivo studies demonstrated that doxorubicin-loaded liposomes efficiently eliminated M2 TAMs but did not affect M1 TAMs, enhancing the potency of the antitumor therapy. Collectively, our results demonstrate the potential of combining active escape and active targeting for precisely delivering a drug of interest to M2 macrophages and suggest its application in anticancer therapy.

Engineered strategies to enhance tumor penetration of drug-loaded nanoparticles

Nanocarriers have been widely employed in preclinical studies and clinical trials for the delivery of anticancer drugs. The most important causes of failure in clinical translation of nanocarriers is their inefficient accumulation and penetration which arises from special characteristics of tumor microenvironment such as insufficient blood supply, dense extracellular matrix, and elevated interstitial fluid pressure. Various strategies such as engineering extracellular matrix, optimizing the physicochemical properties of nanocarriers have been proposed to increase the depth of tumor penetration; however, these strategies have not been very successful so far. Novel strategies such as transformable nanocarriers, transcellular transport of peptide-modified nanocarriers, and bio-inspired carriers have recently been emerged as an advanced generation of drug carriers. In this study, the latest developments of nanocarrier-based drug delivery to solid tumor are presented with their possible limitations. Then, the prospects of advanced drug delivery systems are discussed in detail.

Synergistic Therapy of a Naturally Inspired Glycopolymer-Based Biomimetic Nanomedicine Harnessing Tumor Genomic Instability

Inspired by natural saccharide-protein complexes, a stimuli-responsive biodegradable and branched glycopolymer-pyropheophorbide-a (Ppa) conjugate (BSP) with saccharide units for cancer therapy is constructed. A linear glycopolymeric conjugate (LSP), a branched glycopolymeric conjugate (BShP) from Ppa with long carbon chains, and a branched conjugate (BHSP) based on poly[N-(2-hydroxypropyl) methacrylamide] (polyHPMA) without saccharide units are prepared as controls. Through structure-activity relationship studies, BSP with a 3D network structure forms stable nanostructures via weak intermolecular interactions, regulating the stacking state of Ppa to improve the singlet oxygen quantum yield and the corresponding photodynamic therapy (PDT) effect. BSP shows high loading of olaparib, and are further coated with tumor cell membranes, resulting in a biomimetic nanomedicine (CM-BSPO). CM-BSPO shows highly efficient tumor targeting and cellular internalization properties. The engulfment of CM-BSPO accompanied with laser irradiation results in a prominent antitumor effect, evidenced by disruption of cell cycles in tumor cells, increased apoptosis and DNA damage, and subsequent inhibition of repair for damaged DNA. The mechanism for the synergistic effect from PDT and olaparib is unveiled at the genetic and protein level through transcriptome analysis. Overall, this biodegradable and branched glycopolymer-drug conjugate could be effectively optimized as a biomimetic nanomedicine for cancer therapy.

Metronomic Anti-Cancer Therapy: A Multimodal Therapy Governed by the Tumor Microenvironment

Simple Summary

Metronomic chemotherapy with different mechanisms of action against cancer cells and their microenvironment represents an exceptional holistic cancer treatment. Each type of tumor has its own characteristics, including each individual tumor in each patient. Understanding the complexity of the dynamic interactions that take place between tumor and stromal cells and the microenvironment in tumor progression and metastases, as well as the response of the host and the tumor itself to anticancer therapy, will allow therapeutic actions with long-lasting effects to be implemented using metronomic regimens. This study aims to highlight the complexity of cellular interactions in the tumor microenvironment and summarize some of the preclinical and clinical results that explain the multimodality of metronomic therapy, which, together with its low toxicity, supports an inhibitory effect on the primary tumor and metastases. We also highlight the possible use of nano-therapeutic agents as good partners for metronomic chemotherapy.

Abstract

The concept of cancer as a systemic disease, and the therapeutic implications of this, has gained special relevance. This concept encompasses the interactions between tumor and stromal cells and their microenvironment in the complex setting of primary tumors and metastases. These factors determine cellular co-evolution in time and space, contribute to tumor progression, and could counteract therapeutic effects. Additionally, cancer therapies can induce cellular and molecular responses in the tumor and host that allow them to escape therapy and promote tumor progression. In this study, we describe the vascular network, tumor-infiltrated immune cells, and cancer-associated fibroblasts as sources of heterogeneity and plasticity in the tumor microenvironment, and their influence on cancer progression. We also discuss tumor and host responses to the chemotherapy regimen, at the maximum tolerated dose, mainly targeting cancer cells, and a multimodal metronomic chemotherapy approach targeting both cancer cells and their microenvironment. In a combination therapy context, metronomic chemotherapy exhibits antimetastatic efficacy with low toxicity but is not exempt from resistance mechanisms. As such, a better understanding of the interactions between the components of the tumor microenvironment could improve the selection of drug combinations and schedules, as well as the use of nano-therapeutic agents against certain malignancies.

Recent advances in polymeric core-shell nanocarriers for targeted delivery of chemotherapeutic drugs

The treatment effect of chemotherapeutics is often impeded by nonspecific biodistribution and limited biocompatibility. Polymeric core-shell nanocarriers (PCS NCs) composed of a polymer core and at least one shell have been widely applied for cancer therapy and have shown great potential in selectively delivering chemotherapeutic drugs to tumor sites. These PCS NCs can effectively ameliorate the delivery efficiency and therapeutic index of anticarcinogens by prolonging drug residence in the bloodstream, enhancing tumor tissue drug penetration, facilitating cellular drug uptake, controlling the spatiotemporal release of payloads, or codelivering two or more bioactive agents. This review summarizes recently published literature on using PCS NCs to transport chemotherapeutic drugs with poor aqueous solubility and discusses their design principles, structural features, functional properties, and potential limitations.

Nanotechnologies for the delivery of biologicals: Historical perspective and current landscape

Biological macromolecule-based therapeutics irrupted in the pharmaceutical scene generating a great hope due to their outstanding specificity and potency. However, given their susceptibility to degradation and limited capacity to overcome biological barriers new delivery technologies had to be developed for them to reach their targets. This review aims at analyzing the historical seminal advances that shaped the development of the protein/peptide delivery field, along with the emerging technologies on the lead of the current landscape. Particularly, focus is made on technologies with a potential for transmucosal systemic delivery of protein/peptide drugs, followed by approaches for the delivery of antigens as new vaccination strategies, and formulations of biological drugs in oncology, with special emphasis on mAbs. Finally, a discussion of the key challenges the field is facing, along with an overview of prospective advances are provided.

Advances in Engineered Polymer Nanoparticle Tracking Platforms towards Cancer Immunotherapy-Current Status and Future Perspectives

Engineering polymeric nanoparticles for their shape, size, surface chemistry, and functionalization using various targeting molecules has shown improved biomedical applications for nanoparticles. Polymeric nanoparticles have created tremendous therapeutic platforms, particularly applications related to chemo- and immunotherapies in cancer. Recently advancements in immunotherapies have broadened this field in immunology and biomedical engineering, where "immunoengineering" creates solutions to target translational science. In this regard, the nanoengineering field has offered the various techniques necessary to manufacture and assemble multifunctional polymeric nanomaterial systems. These include nanoparticles functionalized using antibodies, small molecule ligands, targeted peptides, proteins, and other novel agents that trigger and encourage biological systems to accept the engineered materials as immune enhancers or as vaccines to elevate therapeutic functions. Strategies to engineer polymeric nanoparticles with therapeutic and targeting molecules can provide solutions for developing immune vaccines via maintaining the receptor storage in T- and B cells. Furthermore, cancer immunotherapy using polymeric nanomaterials can serve as a gold standard approach for treating primary and metastasized tumors. The current status of the limited availability of immuno-therapeutic drugs highlights the importance of polymeric nanomaterial platforms to improve the outcomes via delivering anticancer agents at localized sites, thereby enhancing the host immune response in cancer therapy. This review mainly focuses on the potential scientific enhancements and recent developments in cancer immunotherapies by explicitly discussing the role of polymeric nanocarriers as nano-vaccines. We also briefly discuss the role of multifunctional nanomaterials for their therapeutic impacts on translational clinical applications.

Black phosphorus assisted polyionic micelles with efficient PTX loading for remotely controlled release and synergistic treatment of drug-resistant tumors

Nanomedicines have been widely used in the effective delivery of chemotherapeutic drugs due to their advantages such as increasing the half-life of drugs, selectively targeting tumor tissues, and thus reducing systemic toxicity. However, the low drug entrapment rate and the difficulty of real-controlled release at tumor sites hinder their further clinical translations. Here we have developed biodegradable polyionic micelles (PD-M) to facilitate black phosphorus (BP) encapsulation (PD-M@BP) for improved drug loading. With the introduction of BP, PTX-loaded PD-M@BP (PD-M@BP/PTX) with sizes of 124-162 nm exhibited superior encapsulation efficiency over 94% and excellent colloidal stability. Meanwhile, PD-M well protected BP from fast degradation to show the good photothermal performance under near-infrared (NIR) irradiation, thus achieving the remotely controlled fast PTX release due to micelle core melting and dissociation, accompanied by the synergistic photothermal tumor therapy. The in vivo results demonstrated that the PD-M@BP/PTX nanosystem not only realized significant inhibition of multi-drug resistant (MDR) cervical tumors (HeLa/PTXR tumor) by remote NIR-regulation, but also reduced the potential damage of chemotherapeutic drugs to the whole body, rendering these hybrid nanosystems as great tools to treat MDR tumors synergistically.

Mitochondria-acting carrier-free nanoplatform self-assembled by α-tocopheryl succinate carrying cisplatin for combinational tumor therapy

Unsatisfactory drug loading capability, potential toxicity of the inert carrier and the limited therapeutic effect of a single chemotherapy drug are all vital inhibitory factors of carrier-assisted drug delivery systems for chemotherapy. To address the above obstacles, a series of carrier-free nanoplatforms self-assembled by dual-drug conjugates was constructed to reinforce chemotherapy against tumors by simultaneously disrupting intratumoral DNA activity and inhibiting mitochondria function. In this nanoplatform, the mitochondria-targeting small-molecular drug, α-tocopheryl succinate (TOS), firstly self-assembled into nanoparticles, which then were used as the carrier to conjugate cisplatin (CDDP). Systematic characterization results showed that this nanoplatform exhibited suitable particle size and a negative surface charge with good stability in physicochemical environments, as well as pH-sensitive drug release and efficient cellular uptake. Due to the combined effects of reactive oxygen species (ROS) generation by TOS and DNA damage by CDDP, the developed nanoplatform could induce mitochondrial dysfunction and elevated cell apoptosis, resulting in highly efficient anti-tumor outcomes in vitro. Collectively, the combined design principles adopted for carrier-free nanodrugs construction in this study aimed at targeting different intracellular organelles for facilitating ROS production and DNA disruption can be extended to other carrier-free nanodrugs-dependent therapeutic systems.

Advanced and Innovative Nano-Systems for Anticancer Targeted Drug Delivery

The encapsulation of therapeutic agents into nano-based drug delivery system for cancer treatment has received considerable attention in recent years. Advancements in nanotechnology provide an opportunity for efficient delivery of anticancer drugs. The unique properties of nanoparticles not only allow cancer-specific drug delivery by inherent passive targeting phenomena and adopting active targeting strategies, but also improve the pharmacokinetics and bioavailability of the loaded drugs, leading to enhanced therapeutic efficacy and safety compared to conventional treatment modalities. Small molecule drugs are the most widely used anticancer agents at present, while biological macromolecules, such as therapeutic antibodies, peptides and genes, have gained increasing attention. Therefore, this review focuses on the recent achievements of novel nano-encapsulation in targeted drug delivery. A comprehensive introduction of intelligent delivery strategies based on various nanocarriers to encapsulate small molecule chemotherapeutic drugs and biological macromolecule drugs in cancer treatment will also be highlighted.

TGF-β blockade-improved chemo-immunotherapy with pH/ROS cascade-responsive micelle via tumor microenvironment remodeling

Immunosuppressive tumor microenvironment and low delivery efficiency severely impede the tumor chemotherapy effect. To address this issue, we develop a pH/ROS cascade-responsive prodrug micelle to deliver siTGF-β with size-shrinkage and charge-reversal property, leading to synergistical tumor microenvironment remodeling. The nanosystem highly improved endocytosis efficiency and tumor penetration depth through charge reversal and size reduction upon exposure to weakly acidic tumor microenvironment. Moreover, the nanocarrier would rapidly escape from endo/lysosome, disassemble and release siTGF-β and hydroxycamptothecin in response to high intracellular ROS. Furthermore, the nanosystem significantly boosted antitumor immune response and reduced immune tolerance with remodeling tumor microenvironment, which significantly prolonged the survival time of tumor-bearing mice (75% survival rate upon 35 days). It is realized by the combined effects of chemotherapy-enhanced immunogenicity and recruitment of effector T cells, TGF-β-blockade immunotherapy-activated inhibition immunosuppressive tumor microenvironment and epithelial-to-mesenchymal transition (EMT), and regulation physical tumor microenvironment via reducing the dense tumor extracellular matrix and the high tumor interstitial pressure obstacles. To this end, the nanosystem not only overcame biobarriers and reinforced antitumor immune response, but also effectively inhibited tumor growth, metastasis and recurrence in vivo.

Nano-immunotherapy for each stage of cancer cellular immunity: which, why, and what?

Immunotherapy provides a new avenue for combating cancer. Current research in anticancer immunotherapy is primary based on T cell-mediated cellular immunity, which can be divided into seven steps and is named the cancer-immunity cycle. Unfortunately, clinical applications of cancer immunotherapies are restricted by inefficient drug delivery, low response rates, and unmanageable adverse reactions. In response to these challenges, the combination of nanotechnology and immunotherapy (nano-immunotherapy) has been extensively studied in recent years. Rational design of advanced nano-immunotherapies requires in-depth consideration of "which" immune step is targeted, "why" it needs to be further enhanced, and "what" nanotechnology can do for immunotherapy. However, the applications and effects of nanotechnology in the cancer-immunity cycle have not been well reviewed. Herein, we summarize the current developments in nano-immunotherapy for each stage of cancer cellular immunity, with special attention on the which, why and what. Furthermore, we summarize the advantages of nanotechnology for combination immunotherapy in two categories: enhanced efficacy and reduced toxicity. Finally, we discuss the challenges of nano-immunotherapy in detail and provide a perspective.

Cloning and expression of the ChGstα and ChGstκ genes in the gills of Crassostrea hongkongensis under nanoparticulate and ionic Zn stress

Nanoparticulate and ionic Zn have potential impacts on the detoxification systems of organisms, and Gst genes play key roles in the detoxification of xenobiotics. In this study, we cloned the ChGstα and ChGstκ genes of C. hongkongensis, and studied their expression in gills under nanoparticulate and ionic Zn stress. The results showed that the coding sequences of the ChGstα and ChGstκ genes were 684 and 675 bp, respectively, and had no signal peptide; ChGstα was cytoplasmic, while ChGstκ was mitochondrial. The two genes were expressed in all 8 tested samples, with the most abundant expression observed in hemocytes for ChGstα and digestive glands for ChGstκ. After ZnCl₂ or ZnoNP challenge, the expression of ChGstα decreased significantly in the ZnCl₂ groups, and its expression was higher in the ZnoNP groups than in the ZnCl₂ groups. The expression of ChGstκ was significantly decreased in the ZnCl₂ and ZnoNP groups, and its expression was higher in the ZnoNP groups than in the ZnCl₂ groups except at 3 h post metal Zn stress, which suggested that ChGstα and ChGstκ were more sensitive to ZnoNP than ZnCl₂.

There and back again: a dendrimer's tale

The development of molecular nanostructures with well-defined particle size and shape is of eminent interest in biomedicine. Among many studied nanostructures, dendrimers represent the group of those most thoroughly characterized ones. Due to their unique structure and properties, dendrimers are very attractive for medical and pharmaceutical applications. Owing to the controllable cavities inside the dendrimer, guest molecules may be encapsulated, and highly reactive terminal groups are susceptible to further modifications, e.g., to facilitate target delivery. To understand the potential of these nanoparticles and to predict and avoid any adverse cellular reactions, it is necessary to know the mechanisms responsible for an efficient dendrimer uptake and the destination of their intracellular journey. In this article, we summarize the results of studies describing the dendrimer uptake, traffic, and efflux mechanisms depending on features of specific nanoparticles and cell types. We also present mechanisms of dendrimers responsible for toxicity and alteration in signal transduction pathways at the cellular level.

Characterization of Liposomes Using Quantitative Phase Microscopy (QPM)

The rapid development of nanomedicine and drug delivery systems calls for new and effective characterization techniques that can accurately characterize both the properties and the behavior of nanosystems. Standard methods such as dynamic light scattering (DLS) and fluorescent-based assays present challenges in terms of system's instability, machine sensitivity, and loss of tracking ability, among others. In this study, we explore some of the downsides of batch-mode analyses and fluorescent labeling, while introducing quantitative phase microscopy (QPM) as a label-free complimentary characterization technique. Liposomes were used as a model nanocarrier for their therapeutic relevance and structural versatility. A successful immobilization of liposomes in a non-dried setup allowed for static imaging conditions in an off-axis phase microscope. Image reconstruction was then performed with a phase-shifting algorithm providing high spatial resolution. Our results show the potential of QPM to localize subdiffraction-limited liposomes, estimate their size, and track their integrity over time. Moreover, QPM full-field-of-view images enable the estimation of a single-particle-based size distribution, providing an alternative to the batch mode approach. QPM thus overcomes some of the drawbacks of the conventional methods, serving as a relevant complimentary technique in the characterization of nanosystems.

A robust optimization approach for the breast cancer targeted design of PEtOx-b-PLA polymersomes

The equipping of nanoparticles with the peptide moiety recognizing a particular receptor, enables cell or tissue-specific targeting, therefore the optimization of the targeted nanoparticles is a key factor in the formulation design process. In this paper, we report the optimization concept of Doxorubicin encapsulating PEtOx-b-PLA polymersome formulation equipped with Peptide18, which is a breast cancer recognizing tumor homing peptide, and the unveiling of the cell-specific delivery potential. The most dominant formulation parameters, which are the polymer to Doxorubicin mass ratio (w/w) and the aqueous to organic phase ratio (v/v), were optimized using Central Composite Design (CCD) based Response Surface Methodology. The characteristics of optimum polymersome formulation were determined as the hydrodynamic diameter of 146.35 nm, the PDI value of 0.136, and the encapsulation efficiency of 57.11% and TEM imaging, which are in agreement with the DLS data, showed the spherical morphology of the polymersomes. In order to demonstrate the breast cancer-specific delivery of targeted polymersomes, the flow cytometry and confocal microscopy analyses were carried out. The targeted polymersomes were accumulated 8 times higher in AU565 cells compared to MCF10A cells and the intracellular Doxorubicin was almost 10 times higher in AU565 cells. The CCD-mediated optimized targeted polymersomes proposed in this report holds the promise of targeted therapy for breast cancer and can be potentially used for the development of novel treatments.

Progress of gelatin-based microspheres (GMSs) as delivery vehicles of drug and cell

Gelatin has various attractive features as biomedical materials, for instance, biocompatibility, low immunogenicity, biodegradability, and ease of manipulation. In recent years, various gelatin-based microspheres (GMSs) have been fabricated with innovative technologies to serve as sustained delivery vehicles of drugs and genetic materials as well as beneficial bacteria. Moreover, GMSs have exhibited promising potentials to act as both cell carriers and 3D scaffold components in tissue engineering and regenerative medicine, which not only exhibit excellent injectability but also could be integrated into a macroscale construct with the laden cells. Herein, we aim to thoroughly summarize the recent progress in the preparations and biomedical applications of GMSs and then to point out the research direction in future. First, various methods for the fabrication of GMSs will be described. Second, the recent use of GMSs in tumor embolization and in the delivery of cells, drugs, and genetic material as well as bacteria will be presented. Finally, several key factors that may enhance the improvement of GMSs were suggested as delivery vehicles.

A combinational chemo-immune therapy using an enzyme-sensitive nanoplatform for dual-drug delivery to specific sites by cascade targeting

Nanoparticle-based drug delivery faces challenges from the imprecise targeted delivery and the low bioavailability of drugs due to complex biological barriers. Here, we designed cascade-targeting, dual drug–loaded, core-shell nanoparticles (DLTPT) consisting of CD44-targeting hyaluronic acid shells decorated with doxorubicin (HA-DOX) and mitochondria-targeting triphenylphosphonium derivative nanoparticle cores loaded with lonidamine (LND) dimers (LTPT). DLTPT displayed prolonged blood circulation time and efficiently accumulated at the tumor site due to the tumor-homing effect and negatively charged hyaluronic acid. Subsequently, the HA-DOX shell was degraded by extracellular hyaluronidase, resulting in decreased particle size and negative-to-positive charge reversal, which would increase tumor penetration and internalization. The degradation of HA-DOX further accelerated the release of DOX and exposed the positively charged LTPT core for rapid endosomal escape and mitochondria-targeted delivery of LND. Notably, when DLTPT was used in combination with anti–PD-L1, the tumor growth was inhibited, which induced immune response against tumor metastasis.

Peptide conjugation enhances the cellular co-localization, but not endosomal escape, of modular poly(acrylamide-co-methacrylic acid) nanogels

Nanoparticles must recognize, adhere to, and/or traverse multiple barriers in sequence to achieve cytosolic drug delivery. New nanoparticles often exhibit a unique ability to cross a single barrier (i.e. the vasculature, cell membrane, or endosomal compartment), but fail to deliver an adequate dose to intracellular sites of action because they cannot traverse other biological barriers for which they were not optimized. Here, we developed poly(acrylamide-co-methacrylic acid) nanogels that were modified in a modular manner with bioactive peptides. This nanogel does not recognize target cells or disrupt endosomal vesicles in its unmodified state, but can incorporate peptides with molecular recognition or environmentally responsive properties. Nanogels were modified with up to 15 wt% peptide without significantly altering their size, surface charge, or stability in aqueous buffer. Nanogels modified with a colon cancer-targeting oligopeptide exhibited up to a 324% enhancement in co-localization with SW-48 colon cancer cells in vitro, while influencing nanogel uptake by fibroblasts and macrophages to a lesser extent. Nanogels modified with an endosome disrupting peptide failed to retain its native endosomolytic activity, when coupled either individually or in combination with the targeting peptide. Our results offer a proof-of-concept for modifying synthetic nanogels with a combination of peptides that address barriers to cytosolic delivery individually and in tandem. Our data further motivate the need to identify endosome disrupting moieties which retain their activity within poly(acidic) networks.

Redox-responsive polyethyleneimine/tetrahedron DNA/doxorubicin nanocomplexes for deep cell/tissue penetration to overcome multidrug resistance

Deep penetration of nanomedicines to cancer cells and tissues is a main obstacle to conquering multidrug resistant (MDR) cancer. Here, we presented redox-responsive polyethyleneimine (disulfide cross-linked PEI, PSP)/tetrahedral DNA (TDNs)/doxorubicin (DOX) nanocomplexes (NCs), PSP/TDNs@DOX NCs, to accomplish tumor cell/tissue penetration for overcoming MDR. The NCs can respond to glutathione and DNase I to disassociate and release DOX. In vitro study revealed that the NCs (N/P = 30) with positive charge could be associated to cell membranes and "dig holes" on them, evoking the membrane-breaking for enhanced cellular internalization and bypassing endocytosis regardless of drug-resistant mechanism. Transwell and 3D tumor models study established that NCs can efficiently depart from cells through "holes leakage" and "infected" surrounding cells to penetrate into deep tumor tissues. In vivo study showed that the PSP/TDNs@DOX NCs exhibited superior tumor penetration and therapeutic efficiency in xenografted drug-resistant tumor mouse models including human breast (MCF-7/R) and ovarian (SKOV3/R) cancer, which represent MDR with characteristics of DOX efflux and impermeability, respectively.

Functional gadolinium-based nanoscale systems for cancer theranostics

Cancer theranostics is a new strategy for combating cancer that integrates cancer imaging and treatment through theranostic agents to provide an efficient and safe way to improve cancer prognosis. Design and synthesis of these cancer theranostic agents are crucial since these agents are required to be biocompatible, tumor-specific, imaging distinguishable and therapeutically efficacious. In this regard, several types of gadolinium (Gd)-based nanomaterials have been introduced to combine different therapeutic agents with Gd to enhance the efficacy of therapeutic agents. At the same time, the entire treatment procedure could be monitored via imaging tools due to incorporation of Gd ions, Gd chelates and Gd/other imaging probes in the theranostic agents. This review aims to overview recent advances in the Gd-based nanomaterials for cancer theranostics and perspectives for Gd nanomaterial-based cancer theranostics are provided.