Engineering Poly(ethylene glycol) Nanoparticles for Accelerated Blood Clearance Inhibition and Targeted Drug Delivery

Engineering unactivated platelets for targeted drug delivery

As a vital component of blood, platelets play crucial roles in hemostasis and maintaining vascular integrity, and actively participate in inflammation and immune regulation. The unique biological properties of natural platelets have enabled their utilization as drug delivery vehicles. The advancement and integration of various techniques, including biological, chemical, and physicochemical methods, have enabled the preparation of engineered platelets. Platelets can serve as drug delivery platforms combined with immunotherapy and chemokine therapy to enhance their therapeutic impact. This review focuses on the recent advancements in the application of unactivated platelets for drug delivery. The construction strategies of engineered platelets are comprehensively summarized, encompassing internal loading, surface modification, and genetic engineering techniques. Engineered platelets hold vast potential for treating cardiovascular diseases, cancers, and infectious diseases. Furthermore, the challenges and potential considerations in creating engineered platelets with natural activity are discussed.

Rational Design of Coordination Polymers Composited Hollow Multishelled Structures for Drug Delivery

Multifunctional drug delivery systems (DDS) are in high demand for effectively targeting specific cells, necessitating excellent biocompatibility, precise release mechanisms, and sustained release capabilities. The hollow multishelled structure (HoMS) presents a promising solution, integrating structural and compositional design for efficient DDS development amidst complex cellular environments. Herein, starting from a Fe-based metal-organic framework (MOF), amorphous coordination polymers (CP) composited HoMS with controlled shell numbers are fabricated by balancing the rate of MOF decomposition and shell formation. Fe-CP HoMS loaded with DOX is utilized for synergistic chemotherapy and chemodynamic therapy, offering excellent responsive drug release capability (excellent pH-triggered drug release 82% within 72 h at pH 5.0 solution with doxorubicin (DOX) loading capacity of 284 mg g-1). In addition to its potent chemotherapy attributes, Fe-CP-HoMS possesses chemodynamic therapy potential by continuously catalyzing H2O2 to generate ·OH species within cancer cells, thus effectively inhibiting cancer cell proliferation. DOX@3S-Fe-CP-HoMS, at a concentration of 12.5 µg mL-1, demonstrates significant inhibitory effects on cancer cells while maintaining minimal cytotoxicity toward normal cells. It is envisioned that CP-HoMS could serve as an effective and biocompatible platform for the advancement of intelligent drug delivery systems in the realm of cancer therapy.

Beyond the promise: Exploring the complex interactions of nanoparticles within biological systems

The exploration of nanoparticle applications is filled with promise, but their impact on the environment and human health raises growing concerns. These tiny environmental particles can enter the human body through various routes, such as the respiratory system, digestive tract, skin absorption, intravenous injection, and implantation. Once inside, they can travel to distant organs via the bloodstream and lymphatic system. This journey often results in nanoparticles adhering to cell surfaces and being internalized. Upon entering cells, nanoparticles can provoke significant structural and functional changes. They can potentially disrupt critical cellular processes, including damaging cell membranes and cytoskeletons, impairing mitochondrial function, altering nuclear structures, and inhibiting ion channels. These disruptions can lead to widespread alterations by interfering with complex cellular signaling pathways, potentially causing cellular, organ, and systemic impairments. This article delves into the factors influencing how nanoparticles behave in biological systems. These factors include the nanoparticles' size, shape, charge, and chemical composition, as well as the characteristics of the cells and their surrounding environment. It also provides an overview of the impact of nanoparticles on cells, organs, and physiological systems and discusses possible mechanisms behind these adverse effects. Understanding the toxic effects of nanoparticles on physiological systems is crucial for developing safer, more effective nanoparticle-based technologies.

Targeted and Self-Adjuvated Nanoglycovaccine Candidate for Cancer Immunotherapy

Advanced-stage solid primary tumors and metastases often express mucin 16 (MUC16), carrying immature glycans such as the Tn antigen, resulting in specific glycoproteoforms not found in healthy human tissues. This presents a valuable approach for designing targeted therapeutics, including cancer glycovaccines, which could potentially promote antigen recognition and foster the immune response to control disease spread and prevent relapse. In this study, we describe an adjuvant-free poly(lactic-co-glycolic acid) (PLGA)-based nanoglycoantigen delivery approach that outperforms conventional methods by eliminating the need for protein carriers while exhibiting targeted and adjuvant properties. To achieve this, we synthesized a library of MUC16-Tn glycoepitopes through single-pot enzymatic glycosylation, which were then stably engrafted onto the surface of PLGA nanoparticles, generating multivalent constructs that better represent cancer molecular heterogeneity. These glycoconstructs demonstrated affinity for Macrophage Galactose-type Lectin (MGL) receptor, known to be highly expressed by immature antigen-presenting cells, enabling precise targeting of immune cells. Moreover, the glycopeptide-grafted nanovaccine candidate displayed minimal cytotoxicity and induced the activation of dendritic cells in vitro, even in the absence of an adjuvant. In vivo, the formulated nanovaccine candidate was also nontoxic and elicited the production of IgG specifically targeting MUC16 and MUC16-Tn glycoproteoforms in cancer cells and tumors, offering potential for precise cancer targeting, including targeted immunotherapies.

Glutathione-Responsive and Hydrogen Sulfide Self-Generating Nanocages Based on Self-Weaving Technology To Optimize Cancer Immunotherapy

As an ideal drug carrier, it should possess high drug loading and encapsulation efficiency and precise drug targeting release. Herein, we utilized a template-guided self-weaving technology of phase-separated silk fibroin (SF) in reverse microemulsion (RME) to fabricate a kind of hyaluronic acid (HA) coated SF nanocage (HA-gNCs) for drug delivery of cancer immunotherapy. Due to the hollow structure, HA-gNCs were capable of simultaneous encapsulation of the anti-inflammatory drug betamethasone phosphate (BetP) and the immune checkpoint blockade (ICB) agent PD-L1 antibody (αPD-L1) efficiently. Another point worth noting was that the thiocarbonate cross-linkers used to strengthen the SF shell of HA-gNCs could be quickly broken by overexpressed glutathione (GSH) to reach responsive drug release inside tumor tissues accompanied by hydrogen sulfide (H2S) production in one step. The synergistic effect of released BetP and generated H2S guaranteed chronological modulation of the immunosuppressive tumor microenvironment (ITME) to amplify the therapeutic effect of αPD-L1 for the growth, metastasis, and recurrence of tumors. This study highlighted the exceptional prospect of HA-gNCs as a self-assistance platform for cancer drug delivery.

Engineered nanomicelles inhibit the tumour progression via abrogating the prostaglandin-mediated immunosuppression

Cancer treatment is challenged due to immunosuppressive inflammatory tumour microenvironment (TME) caused by infiltration of tumour-promoting and inhibition of tumour-inhibiting immune cells. Here, we report the engineering of chimeric nanomicelles (NMs) targeting the cell proliferation using docetaxel (DTX) and inflammation using dexamethasone (DEX) that alters the immunosuppressive TME. We show that a combination of phospholipid-DTX conjugate and PEGylated-lipid-DEX conjugate can self-assemble to form sub-100 nm chimeric NMs (DTX-DEX NMs). Anti-cancer activities against syngeneic and xenograft mouse models showed that the DTX-DEX NMs are more effective in tumour regression, enhance the survival of mice over other treatment modes, and alter the tumour stroma. DTX-DEX NMs cause a significant reduction in myeloid-derived suppressor cells, alter the polarization of macrophages, and enhance the accumulation of cytotoxic CD4+ and CD8+ T cells in tumour tissues, along with alterations in cytokine expression. We further demonstrated that these DTX-DEX NMs inhibit the synthesis of prostaglandins, especially PGE2, by targeting the cyclooxygenase 2 that is partly responsible for immunosuppressive TME. Therefore, this study presents, for the first time, the engineering of lithocholic acid-derived chimeric NMs that affect the prostaglandin pathway, alter the TME, and mitigate tumour progression with enhanced mice survival.

Engineering poly(ethylene glycol) particles for targeted drug delivery

Poly(ethylene glycol) (PEG) is considered to be the "gold standard" among the stealth polymers employed for drug delivery. Using PEG to modify or engineer particles has thus gained increasing interest because of the ability to prolong blood circulation time and reduce nonspecific biodistribution of particles in vivo, owing to the low fouling and stealth properties of PEG. In addition, endowing PEG-based particles with targeting and drug-loading properties is essential to achieve enhanced drug accumulation at target sites in vivo. In this feature article, we focus on recent work on the synthesis of PEG particles, in which PEG is the main component in the particles. We highlight different synthesis methods used to generate PEG particles, the influence of the physiochemical properties of PEG particles on their stealth and targeting properties, and the application of PEG particles in targeted drug delivery.

Amphiphilic Block Copolymer Nanostructures as a Tunable Delivery Platform: Perspective and Framework for the Future Drug Product Development

Nanoformulation of active payloads or pharmaceutical ingredients (APIs) has always been an area of interest to achieve targeted, sustained, and efficacious delivery. Various delivery platforms have been explored, but loading and delivery of APIs have been challenging because of the chemical and structural properties of these molecules. Polymersomes made from amphiphilic block copolymers (ABCPs) have shown enormous promise as a tunable API delivery platform and confer multifold advantages over lipid-based systems. For example, a COVID booster vaccine comprising polymersomes encapsulating spike protein (ACM-001) has recently completed a Phase I clinical trial and provides a case for developing safe drug products based on ABCP delivery platforms. However, several limitations need to be resolved before they can reach their full potential. In this Perspective, we would like to highlight such aspects requiring further development for translating an ABCP-based delivery platform from a proof of concept to a viable commercial product.

Tumor-targeted delivery of SNHG15 siRNA using a ZIF-8 nanoplatform: Towards a more effective prostate cancer therapy

Small interfering RNAs (siRNAs) can be used as a powerful tool in gene therapy to downregulate the expression of specific disease related genes. Some properties however, such as instability, and low penetration into cells can limit their efficacy, and thus reduce their therapeutic potential. Metal-organic frameworks (MOFs) such as zeolitic imidazolate framework-8 (ZIF-8), which consist of organic bridging ligands and metal cations (Zn), have a very high binding affinity with nucleic acids including siRNAs. In this study, we designed a PEGylated ZIF-8 platform that was equipped with epithelial cell adhesion molecule (EpCAM) aptamer for the targeted delivery of siRNA molecules, in order to knockdown SNHG15 in both a prostate cancer (PC) cell line, and a human PC xenograft mouse model. SNHG15 is a long noncoding RNA, with oncogenic roles in different cancers including PC. The results indicated that the depletion of SNHG15 by Apt-PEG-siRNA@ZIF-8 nanoplatfrom inhibited cell proliferation and colony formation, and increased apoptosis in PC cells. This nanoparticle facilitated the release of siRNAs into the tumor environment in vivo, and subsequently reduced the tumor growth, with no side effects observed in vital organs. We have therefore developed a novel siRNA nano-delivery system for targeted prostate cancer treatment; however further studies are required before it can be tested in clinical trials.

On the origin of the low immunogenicity and biosafety of a neutral α-helical polypeptide as an alternative to polyethylene glycol

Poly(ethylene glycol) (PEG) is a prominent synthetic polymer widely used in biomedicine. Despite its notable success, recent clinical evidence highlights concerns regarding the immunogenicity and adverse effects associated with PEG in PEGylated proteins and lipid nanoparticles. Previous studies have found a neutral helical polypeptide poly(γ-(2-(2-(2-methoxyethoxy)ethoxy)ethyl l-glutamate), namely L-P(EG3Glu), as a potential alternative to PEG, displaying lower immunogenicity. To comprehensively assess the immunogenicity, distribution, degradation, and biosafety of L-P(EG3Glu), herein, we employ assays including enzyme-linked immunosorbent assay, positron emission tomography-computed tomography, and fluorescent resonance energy transfer. Our investigations involve in vivo immune responses, biodistribution, and macrophage activation of interferon (IFN) conjugates tethered with helical L-P(EG3Glu) (L20k-IFN), random-coiled DL-P(EG3Glu) (DL20k-IFN), and PEG (PEG20k-IFN). Key findings encompass: minimal anti-IFN and anti-polymer antibodies elicited by L20k-IFN; length-dependent affinity of PEG to anti-PEG antibodies; accelerated clearance of DL20k-IFN and PEG20k-IFN linked to anti-IFN and anti-polymer IgG; complement activation for DL20k-IFN and PEG20k-IFN but not L20k-IFN; differential clearance with L20k-IFN kidney-based, and DL20k-IFN/PEG20k-IFN accumulation mainly in liver/spleen; enhanced macrophage activation by DL20k-IFN and PEG20k-IFN; L-P(EG3Glu) resistance to proteolysis; and safer repeated administrations of L-P(EG3Glu) in rats. Overall, this study offers comprehensive insights into the lower immunogenicity of L-P(EG3Glu) compared to DL-P(EG3Glu) and PEG, supporting its potential clinical use in protein conjugation and nanomedicines.

Improving the Efficacy of Common Cancer Treatments via Targeted Therapeutics towards the Tumour and Its Microenvironment

Cancer is defined as the uncontrolled proliferation of heterogeneous cell cultures in the body that develop abnormalities and mutations, leading to their resistance to many forms of treatment. Left untreated, these abnormal cell growths can lead to detrimental and even fatal complications for patients. Radiation therapy is involved in around 50% of cancer treatment workflows; however, it presents significant recurrence rates and normal tissue toxicity, given the inevitable deposition of the dose to the surrounding healthy tissue. Chemotherapy is another treatment modality with excessive normal tissue toxicity that significantly affects patients' quality of life. To improve the therapeutic efficacy of radiotherapy and chemotherapy, multiple conjunctive modalities have been proposed, which include the targeting of components of the tumour microenvironment inhibiting tumour spread and anti-therapeutic pathways, increasing the oxygen content within the tumour to revert the hypoxic nature of the malignancy, improving the local dose deposition with metal nanoparticles, and the restriction of the cell cycle within radiosensitive phases. The tumour microenvironment is largely responsible for inhibiting nanoparticle capture within the tumour itself and improving resistance to various forms of cancer therapy. In this review, we discuss the current literature surrounding the administration of molecular and nanoparticle therapeutics, their pharmacokinetics, and contrasting mechanisms of action. The review aims to demonstrate the advancements in the field of conjugated nanomaterials and radiotherapeutics targeting, inhibiting, or bypassing the tumour microenvironment to promote further research that can improve treatment outcomes and toxicity rates.

Amplified Targeted Drug Delivery Independent of Target Number through Alternative Administration of Two Matched Nanoparticles

Targeting nanoparticles (NPs) based on the specific binding of ligands with molecular targets provides a promising tool for tissue-selective drug delivery. However, the number of molecular targets on the cell surface is limited, hindering the number of NPs that can bind and, thus, limiting the therapeutic outcome. Although several strategies have been developed to enhance drug delivery, such as enhancing drug loading and circulation time or increasing the enhanced permeability and retention effect of nanocarriers, none have resolved this issue. Herein, we designed a simple method for amplified and targeted drug delivery using two matched NPs. One NP was aptamer-functionalized to specifically bind to target cells, while the other was aptamer-complementary DNA-functionalized to specifically bind to aptamer-NPs. Alternate administration of the two matched NPs enables their continuous accumulation in the disease site despite their limited molecular targets. As a proof of concept, the method was tested in a breast cancer model and significantly enhanced chemotherapy of tumor cells in vitro and in vivo. The potential applications of this method in a brain injury model were also demonstrated. Overall, the study describes a method for amplified targeted drug delivery independent of the target number.

Pegloticase co-administered with high MW polyethylene glycol effectively reduces PEG-immunogenicity and restores prolonged circulation in mouse

The interactions between polymers and the immune system remains poorly controlled. In some instances, the immune system can produce antibodies specific to polymer constituents. Indeed, roughly half of pegloticase patients without immunomodulation develop high titers of anti-PEG antibodies (APA) to the PEG polymers on pegloticase, which then quickly clear the drug from circulation and render the gout treatment ineffective. Here, using pegloticase as a model drug, we show that addition of high molecular weight (MW) free (unconjugated) PEG to pegloticase allows us to control the immunogenicity and mitigates APA induction in mice. Compared to pegloticase mixed with saline, mice repeatedly dosed with pegloticase containing different MW or amount of free PEG possessed 4- to 12- fold lower anti-PEG IgG, and 6- to 10- fold lower anti-PEG IgM, after 3 rounds of pegloticase dosed every 2 weeks. The markedly reduced APA levels, together with competitive inhibition by free PEG, restored the prolonged circulation of pegloticase to levels observed in APA-naïve animals. In contrast, mice with pegloticase-induced APA eliminated nearly all pegloticase from the circulation within just four hours post-injection. These results support the growing literature demonstrating free PEG may effectively suppress drug-induced APA, which in turn may offer sustained therapeutic benefits without requiring broad immunomodulation. We also showed free PEG effectively blocked the PEGylated protein from binding with cells expressing PEG-specific B cell receptors. It provides a template of how we may be able to tune the interactions and immunogenicity of other polymer-modified therapeutics. STATEMENT OF SIGNIFICANCE: A major challenge with engineering materials for drug delivery is their interactions with the immune system. For instance, our body can produce high levels of anti-PEG antibodies (APA). Unfortunately, the field currently lack tools to limit immunostimulation or overcome pre-existing anti-PEG antibodies, without using broad immunosuppression. Here, we showed that simply introducing free PEG into a clinical formulation of PEG-uricase can effectively limit induction of anti-PEG antibodies, and restore their prolonged circulation upon repeated dosing. Our work offers a readily translatable method to safely and effectively restore the use PEG-drugs in patients with PEG-immunity, and provides a template to use unconjugated polymers with low immunogenicity to regulate interactions with the immune system for other polymer-modified therapeutics.

Cancer-Associated Fibroblast Mimetic AIE Probe for Precision Imaging-Guided Full-Cycle Management of Ovarian Cancer Surgery

Fluorescence imaging can improve surgical accuracy in ovarian cancer, but a high signal-to-noise ratio is crucial for tiny metastatic cancers. Meanwhile, intraoperative fluorescent surgical navigation modalities alone are still insufficient to completely remove ovarian cancer lesions, and the recurrence rate remains high. Here, we constructed a cancer-associated fibroblasts (CAFs)-mimetic aggregation-induced emission (AIE) probe to enable full-cycle management of surgery that eliminates recurrence. AIE molecules (P3-PPh3) were packed in hollow mesoporous silica nanoparticles (HMSNs) to form HMSN-probe and then coated with a CAFs membrane to prepare CAF-probe. First, due to the negative potential of the CAF-probe, the circulation time in vivo is elevated, which facilitates passive tumor targeting. Second, the CAF-probe avoids its clearance by the immune system and improves the bioavailability. Finally, the fibronectin on the CAF-probe specifically binds to integrin α-5 (ITGA5), which is highly expressed in ovarian cancer cells, enabling fluorescence imaging with a contrast of up to 8.6. CAF-probe-based fluorescence imaging is used to evaluate the size and location of ovarian cancer before surgery (preoperative evaluation), to guide tumor removal during surgery (intraoperative navigation), and to monitor tumor recurrence after surgery (postoperative monitoring), ultimately significantly improving the efficiency of surgery and completely eliminating tumor recurrence. In conclusion, we constructed a CAFs mimetic AIE probe and established a full-cycle surgical management model based on its precise imaging properties, which significantly reduced the recurrence of ovarian cancer.

Antifouling polymers for nanomedicine and surfaces: recent advances

Antifouling polymers are materials that can resist nonspecific interactions with cells, proteins, and other biomolecules. Typically, they are hydrophilic polymers with polar or charged moieties that are capable of strong nonbonding interactions with water molecules. This propensity to bind water generates a surface hydration layer that reduces nonspecific interactions with other molecules and is paramount to the antifouling behavior. This property is especially useful for nanoscale applications such as nanomedicine and surface modifications at the molecular level. In nanomedicine, antifouling polymers such as poly(ethylene glycol) and its alternatives play a key role in shielding drug molecules and therapeutic proteins/genes from the immune system within nanoassemblies, thereby enabling effective delivery to target tissues. For coatings, antifouling polymers help to prevent adhesion of cells and molecules to surfaces and are thus valued in marine and biomedical device applications. In this Review, we survey recent advances in antifouling polymers in the context of nanomedicine and coatings, while shining the spotlight on the major polymer classes such as PEG, polyzwitterions, poly(oxazoline)s, and other nonionic hydrophilic polymers.

Four Ounces Can Move a Thousand Pounds: The Enormous Value of Nanomaterials in Tumor Immunotherapy

The application of nanomaterials in healthcare has emerged as a promising strategy due to their unique structural diversity, surface properties, and compositional diversity. In particular, nanomaterials have found a significant role in improving drug delivery and inhibiting the growth and metastasis of tumor cells. Moreover, recent studies have highlighted their potential in modulating the tumor microenvironment (TME) and enhancing the activity of immune cells to improve tumor therapy efficacy. Various types of nanomaterials are currently utilized as drug carriers, immunosuppressants, immune activators, immunoassay reagents, and more for tumor immunotherapy. Necessarily, nanomaterials used for tumor immunotherapy can be grouped into two categories: organic and inorganic nanomaterials. Though both have shown the ability to achieve the purpose of tumor immunotherapy, their composition and structural properties result in differences in their mechanisms and modes of action. Organic nanomaterials can be further divided into organic polymers, cell membranes, nanoemulsion-modified, and hydrogel forms. At the same time, inorganic nanomaterials can be broadly classified as nonmetallic and metallic nanomaterials. The current work aims to explore the mechanisms of action of these different types of nanomaterials and their prospects for promoting tumor immunotherapy.

Hierarchically Structured and Highly Dispersible MOF Nanozymes Combining Self-Assembly and Biomineralization for Sensitive and Persistent Chemiluminescence Immunoassay

Metal-organic frameworks (MOF) are promising candidates for the construction of artificial nanozymes and have found applications in many fields. However, the preparation of nanosized MOF materials with high performance and good dispersibility is still a big challenge and is in great demand as signal labels for immunoassays. In this work, hierarchically structured and highly dispersible MOF nanoparticles were facilely prepared in a one-pot method. Self-assembled micelles from PEGylated hematin were used as structured templates to mediate the formation of zeolitic imidazole framework-8 (ZIF-8) nanoparticles in aqueous solution. The encapsulation of micelles in ZIF-8 frameworks produces well-dispersed nanoparticles and generates dual-confinement effects for catalytic hematin. Owing to the hierarchical structures, the formed MOF nanozymes show enhanced peroxidase-like activity and enable persistent chemiluminescence behaviors for the luminol system. Sandwich-type chemiluminescence immunoassays for carcinoembryonic antigen (CEA) were proposed using MOF nanozymes as signal labels, and good analytical performances were achieved. The combination of self-assembly and biomineralization may open new avenues for the development of MOF nanomaterials.

Advancement of regulating cellular signaling pathways in NSCLC target therapy via nanodrug

Lung cancer (LC) is one of the leading causes of high cancer-associated mortality worldwide. Non-small cell lung cancer (NSCLC) is the most common type of LC. The mechanisms of NSCLC evolution involve the alterations of multiple complex signaling pathways. Even with advances in biological understanding, early diagnosis, therapy, and mechanisms of drug resistance, many dilemmas still need to face in NSCLC treatments. However, many efforts have been made to explore the pathological changes of tumor cells based on specific molecular signals for drug therapy and targeted delivery. Nano-delivery has great potential in the diagnosis and treatment of tumors. In recent years, many studies have focused on different combinations of drugs and nanoparticles (NPs) to constitute nano-based drug delivery systems (NDDS), which deliver drugs regulating specific molecular signaling pathways in tumor cells, and most of them have positive implications. This review summarized the recent advances of therapeutic targets discovered in signaling pathways in NSCLC as well as the related NDDS, and presented the future prospects and challenges.

Vaccination of TLR7/8 Agonist-Conjugated Antigen Nanoparticles for Cancer Immunotherapy

Nanovaccine-based immunotherapy can initiate strong immune responses and establish a long-term immune memory to prevent tumor invasion and recurrence. Herein, the assembly of redox-responsive antigen nanoparticles (NPs) conjugated with imidazoquinoline-based TLR7/8 agonists for lymph node-targeted immune activation is reported, which can potentiate tumor therapy and prevention. Antigen NPs are assembled via the templating of zeolitic imidazolate framework-8 NPs to cross-link ovalbumin with disulfide bonds, which enables the NPs with redox-responsiveness for improved antigen cross-presentation and dendritic cell activation. The formulated nanovaccines promote the lymphatic co-delivery of antigens and agonists, which can trigger immune responses of cytotoxic T lymphocytes and strong immunological memory. Notably, nanovaccines demonstrate their superiority for tumor prevention owing to the elicited robust antitumor immunity. The reported strategy provides a rational design of nanovaccines for enhanced cancer immunotherapy.

Site-specific nanoswitch circumventing immune resistance via activating TLR and inhibiting PD-L1/PD-1 axis

Immunotherapy has fundamentally altered cancer treatment; however, its effectiveness is clinically hampered by insufficient intratumoral T lymphocyte infiltration and failed T lymphocyte priming. Additionally, inducing cancer-specific immune responses while sparing normal cells remains challenging. Herein, we developed a redox-activatable polymeric nanoswitch (c-N@IM/JQ) that remained 'off' status in circulation but rapidly switched 'on' after entering the tumor. Toll-like receptor (TLR) 7/8 agonist (imidazoquinoline, IMQ) and bromodomain and extraterminal inhibitor (JQ1) are locked in c-N@IM/JQ with a redox-cleavable linker (switch off). Upon systemic administration, c-N@IM/JQ with c-RGD peptide modification preferentially accumulated at tumor sites and responded to the high glutathione levels to release native IMQ for fully mobilizing T lymphocyte army, and JQ1 for removing the programmed death ligand (PD-L)-1 protection on tumor cells (switch on). These strengthened T lymphocyte armies are easily accessible to these de-protected tumor cells, revitalizing the immune response against tumors.

Investigating the mechanism of action of DNA-loaded PEGylated lipid nanoparticles

PEGylated lipid nanoparticles (LNPs) are commonly used to deliver bioactive molecules, but the role of PEGylation in DNA-loaded LNP interactions at the cellular and subcellular levels remains poorly understood. In this study, we investigated the mechanism of action of DNA-loaded PEGylated LNPs using gene reporter technologies, dynamic light scattering (DLS), synchrotron small angle X-ray scattering (SAXS), and fluorescence confocal microscopy (FCS). We found that PEG has no significant impact on the size or nanostructure of DNA LNPs but reduces their zeta potential and interaction with anionic cell membranes. PEGylation increases the structural stability of LNPs and results in lower DNA unloading. FCS experiments revealed that PEGylated LNPs are internalized intact inside cells and largely shuttled to lysosomes, while unPEGylated LNPs undergo massive destabilization on the plasma membrane. These findings can inform the design, optimization, and validation of DNA-loaded LNPs for gene delivery and vaccine development.

The Impact of Serum Protein Adsorption on PEGylated NT3-BDNF Nanoparticles-Distribution, Protein Release, and Cytotoxicity in a Human Retinal Pigmented Epithelial Cell Model

The adsorption of biomolecules on nanoparticles' surface ultimately depends on the intermolecular forces, which dictate the mutual interaction transforming their physical, chemical, and biological characteristics. Therefore, a better understanding of the adsorption of serum proteins and their impact on nanoparticle physicochemical properties is of utmost importance for developing nanoparticle-based therapies. We investigated the interactions between potentially therapeutic proteins, neurotrophin 3 (NT3), brain-derived neurotrophic factor (BDNF), and polyethylene glycol (PEG), in a cell-free system and a retinal pigmented epithelium cell line (ARPE-19). The variance in the physicochemical properties of PEGylated NT3-BDNF nanoparticles (NPs) in serum-abundant and serum-free systems was studied using transmission electron microscopy, atomic force microscopy, multi-angle dynamic, and electrophoretic light scattering. Next, we compared the cellular response of ARPE-19 cells after exposure to PEGylated NT3-BDNF NPs in either a serum-free or complex serum environment by investigating protein release and cell cytotoxicity using ultracentrifuge, fluorescence spectroscopy, and confocal microscopy. After serum exposure, the decrease in the aggregation of PEGylated NT3-BDNF NPs was accompanied by increased cell viability and BDNF/NT3 in vitro release. In contrast, in a serum-free environment, the appearance of positively charged NPs with hydrodynamic diameters up to 900 nm correlated with higher cytotoxicity and limited BDNF/NT3 release into the cell culture media. This work provides new insights into the role of protein corona when considering the PEGylated nano-bio interface with implications for cytotoxicity, NPs' distribution, and BDNF and NT3 release profiles in the in vitro setting.

Nature-inspired nanocarriers for improving drug therapy of atherosclerosis

Atherosclerosis (AS) has emerged as one of the prevalent arterial vascular diseases characterized by plaque and inflammation, primarily causing disability and mortality globally. Drug therapy remains the main treatment for AS. However, a series of obstacles hinder effective drug delivery. Nature, from natural micro-/nano-structural biological particles like natural cells and extracellular vesicles to the distinctions between the normal and pathological microenvironment, offers compelling solutions for efficient drug delivery. Nature-inspired nanocarriers of synthetic stimulus-responsive materials and natural components, such as lipids, proteins and membrane structures, have emerged as promising candidates for fulfilling drug delivery needs. These nanocarriers offer several advantages, including prolonged blood circulation, targeted plaque delivery, targeted specific cells delivery and controlled drug release at the action site. In this review, we discuss the nature-inspired nanocarriers which leverage the natural properties of cells or the microenvironment to improve atherosclerotic drug therapy. Finally, we provide an overview of the challenges and opportunities of applying these innovative nature-inspired nanocarriers.

Three-dimensional (3D) bioprinting of medium toughened dipeptide hydrogel scaffolds with Hofmeister effect

Short peptide self-assembled hydrogels as 3D bioprinting inks show excellent biocompatibility and diverse functional expansion, and have broad application prospects in cell culture and tissue engineering. However, the preparation of biological hydrogel inks with adjustable mechanical strength and controllable degradation for 3D bioprinting still faces big challenges. Herein, we develop dipeptide bio-inks that can be gelled in-situ based on Hofmeister sequence, and prepare hydrogel scaffold by using a layer-by-layer 3D printing strategy. Excitingly, after the introduction of Dulbecco's Modified Eagle's medium (DMEM), which is necessary for cell culture, the hydrogel scaffolds show an excellent toughening effect, which matches the needs of cell culture. It's notable that in the whole process of preparation and 3D printing of hydrogel scaffolds, no cross-linking agent, ultraviolet (UV), heating or other exogenous factors are involved, ensuring high biosafety and biocompatibility. After two weeks of 3D culture, millimeter-sized cell spheres are obtained. This work provides an opportunity for the development of short peptide hydrogel bioinks without exogenous factors in 3D printing, tissue engineering, tumor simulant reconstruction and other biomedical fields.

Red Blood Cell Membrane-coated Functionalized Au Nanocage as a Biomimetic Platform for Improved MicroRNA Delivery in Hepatocellular Carcinoma

Dysregulation of microRNAs (miRNAs) expression is closely related to cancers and managing miRNA expression holds great promise for cancer therapy. However, their wide clinical application has been hampered by their poor stability, short half-life and non-specific biodistribution in vivo. Herein, a novel biomimetic platform designated as RHAuNCs-miRNA for improved miRNA delivery was prepared through wrapping miRNA-loaded functionalized Au nanocages (AuNCs) with red blood cell (RBC) membrane. RHAuNCs-miRNA not only successfully loaded miRNAs but also effectively protected them from enzymatic degradation. With good stability, RHAuNCs-miRNA had the characteristics of photothermal conversion and sustained release. Cellular uptake of RHAuNCs-miRNA by SMMC-7721 cells was in a time-dependent manner via clathrin- and caveolin-mediated endocytosis. The uptake of RHAuNCs-miRNAs was affected by cell types and improved by mild near infrared (NIR) laser irradiation. More importantly, RHAuNCs-miRNA exhibited a prolonged circulation time without the occurrence of accelerated blood clearance (ABC) in vivo, resulting in efficient delivery to tumor tissues. This study may demonstrate the great potential of RHAuNCs-miRNA for improved miRNAs delivery.

A multi-functional nano-system combining PI3K-110α/β inhibitor overcomes P-glycoprotein mediated MDR and improves anti-cancer efficiency

P-glycoprotein (P-gp/ABCB1)-mediated multidrug resistance (MDR) in cancers severely limit chemotherapeutic efficacy. We recently reported that phosphatidylinositol-3-kinase (PI3K) 110α and 110β subunits can be novel targets for reversal of P-gp mediated MDR in cancers, and BAY-1082439 as an inhibitor specific for PI3K 110α and 110β subunits could reverse P-gp-mediated MDR by downregulating P-gp expression in cancer cells. However, BAY-1082439 has very low solubility, short half-life and high in-vivo clearance rate. Till now, nano-system with the functions to target PI3K P110α and P110β and reverse P-gp mediated MDR in cancers has not been reported. In our study, a tumor targeting drug delivery nano-system PBDF was established, which comprised doxorubicin (DOX) and BAY-1082439 respectively encapsulated by biodegradable PLGA-SH nanoparticles (NPs) that were grafted to gold nanorods (Au NRs) modified with FA-PEG-SH, to enhance the efficacy to reverse P-gp mediated MDR and to target tumor cells, further, to enhance the efficiency to inhibit MDR tumors overexpressing P-gp. In-vitro experiments indicated that PBDF NPs greatly enhanced uptake of DOX, improved the activity to reverse MDR, inhibited the cell proliferation, and induced S-phase arrest and apoptosis in KB-C2 cells, as compared with free DOX combining free BAY-1082439. In-vivo experiments further demonstrated that PBDF NPs improved the anti-tumor ability of DOX and inhibited development of KB-C2 tumors. Notably, the metastasis of KB-C2 cells in livers and lungs of nude mice were inhibited by treatment with PBDF NPs, which showed no obvious in-vitro or in-vivo toxicity.

Remodeling liver microenvironment by L-arginine loaded hollow polydopamine nanoparticles for liver cirrhosis treatment

Liver cirrhosis is a liver disease with a high mortality rate worldwide, and antifibrotic drugs are commonly used clinically to alleviate the symptoms, but there are still many challenges. Many studies have shown that excessive reactive oxygen species (ROS) in the microenvironment of liver lesions is an important factor leading to the development of liver cirrhosis. Herein, a nanomedicine-mediated antioxidant therapy was utilized to remodel liver microenvironment and hence reverse the process of cirrhosis from the root. Firstly, L-arginine (L-Arg) loaded and pPB peptide modified PEGylated hollow polydopamine (HPDA) nanoparticles (L-Arg@HPDA-PEG-pPB, L@HPp) were prepared successfully. The in vitro and in vivo experiment showed that L@HPp significantly inhibited oxidative stress and inflammatory reaction, reduced the activation of hepatic stellate cells (HSCs), inhibited the pro-fibrosis molecular pathway, and reduced the deposition of extracellular matrix (ECM), thereby effectively inhibiting liver fibrosis. The pPB peptide modification increased the targeting effect to HSCs. In addition, the oxidative microenvironment in liver cirrhosis promoted the transformation of the loaded L-Arg to nitric oxide (NO), and the latter one caused vascular dilation and further relieved portal hypertension, a typical complication of liver cirrhosis. Therefore, L@HPp had a good prospect of clinical application in the treatment of liver cirrhosis and its complications.