Polymer-Mediated Penetration-Independent Cancer Therapy

Recent development and future application of biodegradable ureteral stents

Ureteral stenting is a common clinical procedure for the treatment of upper urinary tract disorders, including conditions such as urinary tract infections, tumors, stones, and inflammation. Maintaining normal renal function by preventing and treating ureteral obstruction is the primary goal of this procedure. However, the use of ureteral stents is associated with adverse effects, including surface crusting, bacterial adhesion, and lower urinary tract symptoms (LUTS) after implantation. Recognizing the need to reduce the complications associated with permanent ureteral stent placement, there is a growing interest among both physicians and patients in the use of biodegradable ureteral stents (BUS). The evolution of stent materials and the exploration of different stent coatings have given these devices different roles tailored to different clinical needs, including anticolithic, antibacterial, antitumor, antinociceptive, and others. This review examines recent advances in BUS within the last 5 years, providing an in-depth analysis of their characteristics and performance. In addition, we present prospective insights into the future applications of BUS in clinical settings.

Metal-Organic Framework-Based Artificial Organelle Corrects Microenvironment Interference for Accurate Intratumoral Glucose Analysis

Enzymatic catalysis with high efficiency allows them a great prospect in metabolite monitoring in living cells. However, complex tumor microenvironments, such as acidity, H2 O2 , and hypoxia, are bound to disturb catalytic reactions for misleading results. Here, we report a spatially compartmentalized artificial organelle to correct intratumoral glucose analysis, where the zeolitic imidazolate framework-8 immobilized glucose oxidase-horseradish peroxidase cascade core and catalase-directed shell act as signal transduction and guarding rooms respectively. The acid-digested core and stable shell provide appropriate spaces to boost biocatalytic efficiency with good tolerability. Notably, the endogenous H2 O2 is in situ decomposed to O2 by catalase, which not only overcomes the interference in signal output but also alleviates the hypoxic states to maximize glucose oxidation. The marked protective effect and biocompatibility render artificial organelles to correct the signal transduction for dynamic monitoring glucose in vitro and in vivo, achieving our goal of accurate intratumoral metabolite analysis.

mRNA-activated DNAzyme nanoprobe for tumor cell precise imaging and gene therapy

A novel Au-nucleic acid nanoprobe, catalyzed by mRNA, has been developed for live cell imaging and precise treatment of tumor cells. This nanoprobe exhibits the remarkable ability to differentiate between tumor cells and normal cells through live cell mRNA imaging, while selectively inducing apoptosis in tumor cells.

Polymeric nanoparticle-based nanovaccines for cancer immunotherapy

Therapeutic cancer vaccines, which are designed to amplify tumor-specific T cell responses, have been envisioned as one of the most powerful tools for effective cancer immunotherapy. However, increasing the potency, quality and durability of the vaccine response remains a big challenge. In recent years, materials-based delivery systems focusing on the co-delivery of antigens and adjuvants to enhance cancer vaccination therapy have attracted increasing interest. Among various materials, polymeric nanoparticles (NPs) with different physicochemical properties which can incorporate multiple immunological cues are of great interest. In this review, the recent progress in the design and construction of both ex vivo subunit and in situ cancer vaccines using polymeric NPs is summarized. Especially, we will focus on how these NPs improve the adjuvanticity of vaccines. The design principles of polymeric NPs for ex vivo subunit cancer vaccines and in situ cancer vaccination are also discussed. Finally, we want to briefly discuss molecular chaperones in cancer immunity and the applications of our unique self-assembly mixed shell polymeric micelle-based nanochaperones for cancer vaccines.

A convergent fabrication of pH and redox dual-responsive hybrids of mesoporous silica nanoparticles for the treatment of breast cancer

Mesoporous silica nanoparticle (MSN), sodium hyaluronate (SH), silk fibroin (SS), and oxidized sodium carboxymethyl cellulose (O-CMC) hybrids were used to develop an intelligent drug delivery platform that may be employed for pH and redox-responsive bi-drug administration. The first drug, cytarabine (Cyt), was loaded with amino-functionalized mesoporous silica (MSN-NH₂) encased by the hydrogel of cystamine (Cys) and SH cross-linked by amide bonds. Hydrophobic doxorubicin (DOX) was co-loaded with Cyt/MSN-NH₂/SA in the hydrogel of SS and O-CMC in the Cyt- loaded hydrogel. Dual-responsive drug delivery may be achieved by encapsulating SS and O-CMC in a hydrogel, including Cyt/MSN-NH₂/SA/DOX/SS/O-CMC, which has acyl hydrazone bonds (-HC = N) and disulfide bond (-S-S-) exchange reaction with glutathione (GSH). Compared to hydrogels encapsulating only one drug (Cyt or DOX), cell survival analysis revealed that the newly fabricated hydrogels have significantly greater chemotherapeutic efficacy. The cell proliferation of the fabricated nanoparticles was examined in MCF-7 and MDA-MB-231 cells, which indicates that the nanoparticles effectively kill the cancer cells without affecting non-cancerous cells. Further, we effectively investigated the morphological changes, and various biochemical staining methods examined nuclear fragmentation/condensation. Furthermore, the biosafety of the nanoparticles was investigated by the in vivo animal model, which reveals that they remarkably enhanced the safety profile in various organs. These outcomes demonstrated that this nanoparticle platform was a promising beneficial agent for improving breast cancer treatment.

Assessing the In Vivo Biocompatibility of Molecularly Imprinted Polymer Nanoparticles

Molecularly imprinted polymer nanoparticles (nanoMIPs) are high affinity synthetic receptors which show promise as imaging and therapeutic agents. Comprehensive analysis of the in vivo behaviour of nanoMIPs must be performed before they can be considered for clinical applications. This work reports the solid-phase synthesis of nanoMIPs and an investigation of their biodistribution, clearance and cytotoxicity in a rat model following both intravenous and oral administration. These nanoMIPs were found in each harvested tissue type, including brain tissue, implying their ability to cross the blood-brain barrier. The nanoMIPs were cleared from the body via both faeces and urine. Furthermore, we describe an immunogenicity study in mice, demonstrating that nanoMIPs specific for a cell surface protein showed moderate adjuvant properties, whilst those imprinted for a scrambled peptide showed no such behaviour. Given their ability to access all tissue types and their relatively low cytotoxicity, these results pave the way for in vivo applications of nanoMIPs.

The protein corona reduces the anticancer effect of graphene oxide in HER-2-positive cancer cells

In the last decade, graphene oxide (GO)-based nanomaterials have attracted much attention for their potential anti-cancer properties against various cancer cell types. However, while in vitro studies are promising, following in vivo investigations fail to show any relevant efficacy. Recent research has clarified that the wide gap between benchtop discoveries and clinical practice is due to our limited knowledge about the physical-chemical transformation of nanomaterials in vivo. In physiological environments, nanomaterials are quickly coated by a complex dress of biological molecules referred to as the protein corona. Mediating the interaction between the pristine material and the biological system the protein corona controls the mechanisms of action of nanomaterials up to the sub-cellular level. Here we investigate the anticancer ability of GO in SK-BR-3 human breast cancer cells over-expressing the human epidermal growth factor receptor 2 (HER-2), which is functionally implicated in the cell growth and proliferation through the activation of downstream pathways, including the PI3K/AKT/mTOR and MAPK/ERK signaling cascades. Western blot analysis demonstrated that GO treatment resulted in a marked decrease in total HER-2, associated with a down-regulation of the expression and activation of protein kinase B (AKT) and extracellular signal-regulated kinase (ERK) thus indicating that GO may act as a potent HER-2 inhibitor. On the other side, the protein corona reverted the effects of GO on HER-2 expression and molecular downstream events to the control level. Our findings may suggest a mechanistic explanation of the reduced anticancer properties of GO-based nanomaterials in vivo. These results may also represent a good prediction strategy for the anticancer activity of nanomaterials designed for biomedical purposes, reaffirming the necessity of exploring their effectiveness under physiologically relevant conditions before moving on to the next in vivo studies.

Versatile Polymer-Initiating Biomineralization for Tumor Blockade Therapy

Tumor blockade therapy is a promising penetration-independent antitumor modality, which effectively inhibits the exchange of nutrients, oxygen, and information between the tumor and surrounding microenvironments. However, the current blockade therapy strategies have limited antitumor efficacy due to defects of inadequate tumor obstruction, possible side effects, and short duration. For these reasons, a facilely synthesized versatile polymer 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-poly(ethylene glycol)-alendronate (DSPE-PEG-ALN, DPA) is developed to initiate the formation of biomineral shell around osteosarcoma as a potent physical barrier. The DSPE moiety shares a similar chemical structure with the cytomembrane, allowing the membrane insertion of DPA. The bisphosphonic acid groups in ALN attract ions to realize biomineralization around cells. After injection in the invasive osteosarcoma tissue, DPA inserts into the cytomembrane, induces continuous mineral deposition, and ultimately builds a physical barrier around the tumor. Meanwhile, ALN in DPA alleviates bone destruction by suppressing the activity of osteoclasts. Through hindering the exchange of necessary substances, the biomineralization coating inhibits the growth of primary osteosarcoma and pulmonary metastasis simultaneously. Therefore, the multifunctional polymer-initiating blockade therapy provides a promising modality for tumor inhibition in clinics with high efficacy and negligible side effects.

Effect of Cationic Charge Density on Transcytosis of Polyethylenimine

The adsorption-mediated transcytosis (AMT) induced by the electrostatic interaction between the positively charged surface of carriers and negatively charged cell membrane is a new paradigm enabling nanomedicine's tumor extravasation and infiltration. However, little is known about the correlation between the carrier's charge density and its AMT-induced tumor infiltration efficiency. Herein, we investigate the effect of the cationic polymer's charge on the AMT-induced tumor penetration ability using in vitro multilayer tumor spheroids (MTSs). A cationic polymer, polyethylenimine (PEI), is amidized with acetic anhydride to obtain acetylated PEIs (AcPEIs) with different cationic charge densities. As the amidization ratio increases, the AcPEIs' cytotoxicity, zeta potential, and cell-binding affinity significantly decrease. Notably, not only does the weak cell binding (AcPEIs with high acetylation degrees) lead to slow endocytosis and inefficient transcytosis, so does the strong cell-binding PEI. The PEI with 24% acetylation (AcPEI_24%) is found to have the highest transcytosis efficiency because its balanced cell-binding affinity triggers fast adsorption-mediated endocytosis. The subsequent Golgi apparatus/endoplasmic reticulum-mediated exocytosis via extracellular vesicles leads to highly effective transcellular delivery and tumor penetration in MTSs. Therefore, the drug carrier's surface cationic charge density critically influences its AMT-induced tumor penetration efficiency. This study provides mechanistic insights into the design of drug-delivery systems with active transcytosis for improved tumor penetration and enhanced therapeutic efficiency.

Binding-Induced Fibrillogenesis Peptides Recognize and Block Intracellular Vimentin Skeletonization against Breast Cancer

Life is recognized as a sophisticated self-assembling material system. Cancer involves the overexpression and improper self-assembly of proteins, such as cytoskeleton protein vimentin, an emerging target related to tumor metastasis. Herein, we design a binding-induced fibrillogenesis (BIF) peptide that in situ forms fibrous networks, blocking the improper self-assembly of vimentin against cancer. The BIF peptide can bind to vimentin and subsequently perform fibrillogenesis to form fibers on vimentin. The resultant peptide fibrous network blocks vimentin skeletonization and inhibits the migration and invasion of tumor cells. In mouse models of tumor metastasis, the volume of tumor and the number of lung metastases are markedly decreased. Moreover, the efficacy of BIF peptide (5 mg/kg) is much higher than small molecular antimetastasis drug withaferin A (5 mg/kg) as a standard, indicating that the BIF peptide shows advantages over small molecular inhibitors in blocking the intracellular protein self-assembly.

In situ self-assembled peptide nanofibers for cancer theranostics

Self-assembled nanofibers hold tremendous promise for cancer theranostics owing to their in situ assembly, spatiotemporal responsiveness, and diverse bioactivity. Herein, this review summarizes the recent advances of self-assembled peptide nanofibers and their applications in biological systems, focusing on the dynamic process of capturing cancer cells from the outside-in. (1) In situ self-assembly in response to pathological or physiological changes. (2) Diverse functions at different locations of tumors, such as forming thrombus in tumor vasculature, constructing a barrier on the cancer cell membrane, and disrupting the cancer organelles. Of note, with the assembly/aggregation induced residence (AIR) effect, the nanofibers could form a drug depot in situ for sustained release of chemotherapeutic drugs to increase their local concentration and prolong the residence time. Finally, perspectives toward future directions and challenges are presented to further understand and expand this exciting field.

Delivery of nanoparticle antigens to antigen-presenting cells: from extracellular specific targeting to intracellular responsive presentation

An appropriate delivery system can improve the immune effects of antigens against various infections or tumors. Antigen-presenting cells (APCs) are specialized to capture and process antigens in vivo, which link the innate and adaptive immune responses. Functionalization of vaccine delivery systems with targeting moieties to APCs is a promising strategy for provoking potent immune responses. Additionally, the internalization and intracellular distribution of antigens are closely related to the initiation of downstream immune responses. With a deeper understanding of the intracellular microenvironment and the mechanisms of antigen presentation, vehicles designed to respond to endogenous and external stimuli can modulate antigen processing and presentation pathways, which are critical to the types of immune response. Here, an overview of extracellular targeting delivery of antigens to APCs and intracellular stimulus-responsiveness strategies is provided, which might be helpful for the rational design of vaccine delivery systems.

Molecular Targeted Agent and Immune Checkpoint Inhibitor Co-Loaded Thermosensitive Hydrogel for Synergistic Therapy of Rectal Cancer

Molecular targeted therapy has been proved effective in treatment of rectal cancer. Up-regulated expression of programmed death ligand-1 (PD-L1) was observed after the management of molecular targeted therapy, which made the therapeutic effect discounted. Tumors with higher PD-L1 expression were more sensitive and responsive to treatment of PD-L1 inhibitor. Therefore, the combination of molecular targeted therapy and immune checkpoint blockade makes sense. In this study, the copolymers of poly (ethylene glycol)-block-poly (_L-leucine) (PEG-PLLeu) were synthesized as a thermosensitive hydrogel composite for consecutive release of regorafenib (REG) and BMS202. The mechanical properties of PEG-PLLeu were investigated, confirming that PEG-PLLeu (5 wt.%) was suitable for in situ injection as drug-delivery composite at low temperature and stable after sol-gel transition at body temperature. Importantly, the double drug loaded hydrogel showed superior antitumour activity over single drugs in an orthotopic rectal cancer model (CT26-Luc). Further analysis of the tumor tissues suggested that REG upregulated the expression of PD-L1 in tumor tissues. In addition, the immunosuppressive tumor microenvironment of CT26-Luc tumor was distinctly relieved under the effect of BMS202, as characterized by increased infiltration of CD8⁺ T cells in tumors and enhanced secretion of antitumour cytokines (IFN-γ and TNF-α). Moreover, the drug-loaded composite showed no obvious toxicity in histological analysis. Taken together, the administration of REG and BMS202 in the PEG-PLLeu composite could induce a synergistic effect in in situ treatment of rectal cancer without obvious toxicity, and thus represented a potential strategy for enhanced in situ therapeutic modality.

The Availability of the α7-Nicotinic Acetylcholine Receptor in Early Identification of Vulnerable Atherosclerotic Plaques: A Study Using a Novel 18F-Label Radioligand PET

Background: It has been confirmed that the α7-nicotinic acetylcholine receptor (α7nAChR) is an important target for identifying vulnerable atherosclerotic plaques. Previously, we successfully designed and synthesized a series of ¹⁸F-labeled PET molecular probes targeting α7nAChR, which are mainly used in the diagnosis of Alzheimer's disease. Based on the characteristics of α7nAChR in blood vessels, we have firstly screened for a suitable novel ¹⁸F-labeled PET molecular probe ([¹⁸F]YLF-DW), with high selectivity for α7nAChR over α4β2nAChR and a good effect for the imaging of atherosclerotic animal models, to effectively identify vulnerable atherosclerotic plaques at an early stage. Meanwhile, we compared it with the “gold standard” pathological examination of atherosclerosis, to verify the reliability of [¹⁸F]YLF-DW in early diagnosis of atherosclerosis.

Methods: The vulnerable atherosclerotic plaques model of ApoE-/-mice were successfully established. Then based on the methods of 3D-QSAR and molecular docking, we designed oxazolo[4,5-b] pyridines and fluorenone compounds, which are targeted at α7nAChR. Through further screening, a novel alpha7 nicotinic acetylcholine receptor radioligand ([¹⁸F]YLF-DW) was synthesized and automatically ¹⁸F-labeled using a Stynthra RNplus module. Subsequently, we employed [¹⁸F]YLF-DW for the targeting of α7nAChR in atherosclerotic plaques and control group, using a micro-PET/CT respectively. After imaging, the mice were sacrificed by air embolism and the carotid arteries taken out for making circular sections. The paraffin embedded specimens were sectioned with 5 μm thickness and stained with oil red. After staining, immunohistochemistry experiment was carried out to verify the effect of micro-PET/CT imaging.

Results: The micro-PET/CT imaging successfully identified the vulnerable atherosclerotic plaques in the carotid arteries of ApoE-/-mice; whereas, no signal was observed in normal control mice. In addition, compared with the traditional imaging agent [¹⁸F]FDG, [¹⁸F]YLF-DW had a significant effect on the early plaques imaging of carotid atherosclerosis. The results of oil red staining and immunohistochemistry also showed early formations of carotid plaques in ApoE-/-mice and provided pathological bases for the evaluation of imaging effect.

Conclusion: We innovated to apply the novel molecular probe ([¹⁸F]YLF-DW) to the identification of vulnerable atherosclerotic plaques in carotid arteries, to detect atherosclerosis early inflammatory response and provide powerful input for the early diagnosis of atherosclerotic lesions, which may play an early warning role in cardiovascular acute events.

Regulation of tumor microenvironment for pancreatic cancer therapy

Pancreatic cancer (PC) is one kind of the most lethal malignancies worldwide, owing to its insidious symptoms, early metastases, and negative responses to current therapies. With an increasing understanding of pathology, the tumor microenvironment (TME) plays a significant role in ineffective treatment and poor prognosis of PC. Thus, a growing number of studies have focused on whether components of the TME could be effective targets for PC therapy. Biomaterials have been widely applied in cancer therapy, and numerous organic or inorganic biomaterials for TME regulation have been developed to inhibit the growth and metastasis of PC, as well as reverse therapeutic resistance. In this review, we discuss various biomaterials utilized to treat PC based on different components of the TME, including, but not limited to, extracellular matrix (ECM), abnormal tumor vascularization, and tumor-associated immune cells, as well as other unconventional therapeutic strategies. Besides, the perspectives on the underlying future of theranostic nanomedicines for PC therapy are also presented.

A PEGylated alternating copolymeric prodrug of sulfur dioxide with glutathione responsiveness for Irinotecan delivery

An enhanced anticancer strategy combining the chemotherapy from Irinotecan with the oxidative damage from a sulfur dioxide polymer prodrug is presented.

Design and Application in Delivery System of Intranasal Antidepressants

One of the major reasons why depressed patients fail their treatment course is the existence of the blood-brain barrier (BBB), which prevents drugs from being delivered to the central nervous system (CNS). In recent years, nasal drug delivery has achieved better systemic bioavailability and activity in low doses in antidepressant treatment. In this review, we focused on the latest strategies for delivery carriers (or formation) of intranasal antidepressants. We began this review with an overview of the nasal drug delivery systems, including nasal drug delivery route, absorption mechanism, advantages, and limitations in the nasal drug delivery route. Next, we introduced the development of nasal drug delivery devices, such as powder devices, liquid-based devices, and so on. Finally, intranasal delivery carriers of antidepressants in clinical studies, including nanogels, nanostructured lipid, liposomes nanoparticles, nanoemulsions/microemulsion, were summarized. Moreover, challenges and future perspectives on recent progress of intranasal delivery carriers in antidepressant treatments were discussed.

Implantable and Injectable Biomaterial Scaffolds for Cancer Immunotherapy

Cancer immunotherapy has become an emerging strategy recently producing durable immune responses in patients with varieties of malignant tumors. However, the main limitation for the broad application of immunotherapies still to reduce side effects by controlling and regulating the immune system. In order to improve both efficacy and safety, biomaterials have been applied to immunotherapies for the specific modulation of immune cells and the immunosuppressive tumor microenvironment. Recently, researchers have constantly developed biomaterials with new structures, properties and functions. This review provides the most recent advances in the delivery strategies of immunotherapies based on localized biomaterials, focusing on the implantable and injectable biomaterial scaffolds. Finally, the challenges and prospects of applying implantable and injectable biomaterial scaffolds in the development of future cancer immunotherapies are discussed.

Shear Speed-Regulated Properties of Long-Acting Docetaxel Control Release Poly (Lactic-Co-Glycolic Acid) Microspheres

Advanced drug carriers for the controlled release of chemotherapeutics in the treatment of malignant tumors have drawn significant notice in recent years. In the current study, microspheres (MPs) loaded with docetaxel (DTX) were prepared using polylactic-co-glycolic acid copolymer (PLGA). The double emulsion solvent evaporation method is simple to perform, and results in high encapsulation efficiency. Electron micrographs of the MPs showed that controlling the shear rate can effectively control the size of the MPs. At present, most DTX sustained-release carriers cannot maintain stable and long-term local drug release. The 1.68 μm DTX-loaded microspheres (MP/DTX) with elastase was completely degraded in 14 d. This controlled degradation period is similar to a course of treatment for most cancers. The drug release profile of all kinds of MP/DTX demonstrated an initial rapid release, then slower and stable release to the end. The current study demonstrates that it is possible to create drug-loaded MPs with specific degradation times and drug release curves, which may be useful in achieving optimal treatment times and drug release rates for different diseases, and different drug delivery routes. The initial burst release reaches the effective concentration of the drug at the beginning of release, and then the drug concentration is maintained by stable release to reduce the number of injections and improve patient compliance.

A pH-responsive polymer linked with immunomodulatory drugs: synthesis, characteristics and in vitro biocompatibility

Cancer immunotherapy is a promising method for cancer therapy. Imiquimod (R837) is a molecule that could activate immune systems for cancer immunotherapy, but an easily manufactured biocompatible carrier to deliver R837 may be needed to overcome the disadvantages of R837. Micelles formed by biocompatible copolymers have been widely used to deliver chemotherapeutic drugs but not immunotherapeutic drugs. In this study, R837 was linked to an amphiphilic biodegradable copolymer mPEG-b-PLA via acid-sensitive Schiff bases. The molecular structures were investigated by ¹ H nuclear magnetic resonance, gel permeation chromatography and Fourier transform infrared spectroscopy. The product could be self-assembled into micelles with R837 content as high as 22.4%. Owing to acid-cleavable Schiff bases, the release of R837 from micelles was markedly accelerated under acidic media. Consequently, the micelles linked with R837 stimulated the expression of major histocompatibility complex II-stimulating molecules on the surface of RAW 264.7 macrophages at pH 6.5 but not pH 7.4. By using human umbilical vein endothelial cells as the in vitro model, it was shown that the polymer carriers and R837-linked micelles were minimally cytotoxic and did not induce the activation of endothelial cells under physiological pH, which suggested the relatively high biocompatibility. In conclusion, this study successfully developed pH-responsive immunotherapeutic drug-loaded micelles that could activate macrophages at acidic pH in vitro. The high biocompatibility of the micelles to endothelial cells also indicated the potential uses under in vivo conditions.

Locally Controlled Release of Methotrexate and Alendronate by Thermo-Sensitive Hydrogels for Synergistic Inhibition of Osteosarcoma Progression

Osteosarcoma (OS) is a serious primary bone malignant tumor that can easily affect children and adolescents. Chemotherapy is one of the important and feasible clinical treatment strategies for the treatment of OS at present, which is severely limited due to insufficient retention time, poor penetration ability, and serious side effects of current anti-tumor drug preparations. In this work, a novel injectable thermo-sensitive hydrogel (mPEG₄₅-PLV₁₉) loaded with methotrexate and alendronate, and the sustained release at the tumor site synergistically inhibited the progression of OS. The mPEG₄₅-PLV₁₉ shows excellent physical and chemical properties. Compared with other treatment groups, the in vivo treatment of gel+ methotrexate + alendronate effectively inhibited the growth of tumor. More importantly, it significantly reduced bone destruction and lung metastasis caused by OS. Therefore, this injectable thermo-sensitive hydrogel drug delivery system has broad prospects for OS chemotherapy.

Advances in Drug Delivery via Biodegradable Ureteral Stent for the Treatment of Upper Tract Urothelial Carcinoma

Drug eluting ureteral stent is an effective means for local drug delivery to the urinary tract. It can potentially solve a variety of upper urinary tract problems, such as stent-related urinary tract infections and discomfort, ureteral stricture, and neoplastic diseases. However, the release of drug elutes on the surface of biostable stents is unsustainable and uncontrollable. With the development of biomaterial science, the emergence of biodegradable ureteral stents (BUSs) provides a new approach for local drug delivery in the urinary tract. The drugs can be continuously released in a controlled manner from a drug-eluting BUS, when the stent degrades. Especially for the delivery of anti-tumor drugs, the stents can obviously improve the therapeutic effectiveness of the drugs by prolonging the contact duration of the drug and tumor cells. In addition, a secondary stent removal procedure can be avoided. The purpose of this review article is to provide an overview of anti-tumor drug-eluting BUSs and discuss the biomaterials and drug delivery systems of BUS that are currently being developed to deliver anti-tumor drugs for upper tract urothelial carcinoma.

Interactions of Alginate-Deferoxamine Conjugates With Blood Components and Their Antioxidation in the Hemoglobin Oxidation Model

While deferoxamine (DFO) has long been used as an FDA-approved iron chelator, its proangiogenesis ability attracts increasing number of research interests. To address its drawbacks such as short plasma half-life and toxicity, polymeric conjugated strategy has been proposed and shown superiority. Owing to intravenous injection and application in blood-related conditions, however, the blood interactions and antioxidation of the DFO-conjugates and the mechanisms underlying these outcomes remain to be elucidated. In this regard, incubating with three different molecular-weight (MW) alginate-DFO conjugates (ADs) red blood cells (RBCs), coagulation system, complement and platelet were investigated. To prove the antioxidant activity of ADs, we used hemoglobin oxidation model in vitro. ADs did not cause RBCs hemolysis while reversible aggregation and normal deformability ability were observed. However, the coagulation time, particularly APTT and TT, were significantly prolonged in a dose-dependent manner, and fibrinogen was dramatically decreased, suggesting ADs could dominantly inhibit the intrinsic pathways in the process of coagulation. The dose-dependent anticoagulation might be related with the functional groups along the alginate chains. The complements, C3a and C5a, were activated by ADs in a dose-dependent manner through alternative pathway. For platelet, ADs slightly suppressed the activation and aggregation at low concentration. Based on above results, the cross-talking among coagulation, complement and platelet induced by ADs was proposed. The antioxidation of ADs through iron chelation was proved and the antioxidant activity was shown in a MW-dependent manner.

Effective Targeting of Colon Cancer Cells with Piperine Natural Anticancer Prodrug Using Functionalized Clusters of Hydroxyapatite Nanoparticles

Targeted drug delivery offers great opportunities for treating cancer. Here, we developed a novel anticancer targeted delivery system for piperine (Pip), an alkaloid prodrug derived from black pepper that exhibits anticancer effects. The tailored delivery system comprises aggregated hydroxyapatite nanoparticles (HAPs) functionalized with phosphonate groups (HAP-Ps). Pip was loaded into HAPs and HAP-Ps at pH 7.2 and 9.3 to obtain nanoformulations. The nanoformulations were characterized using several techniques and the release kinetics and anticancer effects investigated in vitro. The Pip loading capacity was >20%. Prolonged release was observed with kinetics dependent on pH, surface modification, and coating. The nanoformulations fully inhibited monolayer HCT116 colon cancer cells compared to Caco2 colon cancer and MCF7 breast cancer cells after 72 h, whereas free Pip had a weaker effect. The nanoformulations inhibited ~60% in HCT116 spheroids compared to free Pip. The Pip-loaded nanoparticles were also coated with gum Arabic and functionalized with folic acid as a targeting ligand. These functionalized nanoformulations had the lowest cytotoxicity towards normal WI-38 fibroblast cells. These preliminary findings suggest that the targeted delivery system comprising HAP aggregates loaded with Pip, coated with gum Arabic, and functionalized with folic acid are a potentially efficient agent against colon cancer.

Recent progress of therapeutic peptide based nanomaterials: from synthesis and self-assembly to cancer treatment

This review has described the synthesis, self-assembly and the anti-cancer application of therapeutic peptides and their conjugates, particularly polymer–peptide conjugates (PPCs).