Hydroxyethyl starch based smart nanomedicine

Combined Hydroxyethyl Starch Luteolin Nanocrystals for Effective Anti-Hyperuricemia Effect in Mice Model

Introduction

Although flavonoid compounds exhibit various pharmacological activities, their clinical applications are restricted by low oral bioavailability owing to their poor solubility. Nanocrystals (NCs) represent an excellent strategy for enhancing the oral bioavailability of flavonoids. Hydroxyethyl starch (HES), a biomaterial compound used as a plasma expander, could be an ideal stabilizer material for preparing flavonoid NCs.

Methods

HES was used to stabilize flavonoid nanocrystals (NCs), using luteolin (LUT) as a model drug. After full characterization, the freeze-drying and storage stability, solubility, intestinal absorption, pharmacokinetics, and in vivo anti-hyperuricemic effect of the optimized HES-stabilized LUT NCs (LUT-HES NCs) were investigated.

Results

Uniformed LUT-HES NCs were prepared with mean particle size of 191.1±16.8 nm, zeta potential of about -23 mV, drug encapsulation efficiency of 98.52 ± 1.01%, and drug loading of 49.26 ± 0.50%. The freeze-dried LUT-HES NCs powder showed good re-dispersibility and storage stability for 9 months. Notably, compared with the coarse drug, LUT-HES NCs exhibited improved saturation solubility (7.49 times), increased drug dissolution rate, enhanced Caco-2 cellular uptake (2.78 times) and oral bioavailability (Fr=355.7%). Pharmacodynamic studies showed that LUT-HES NCs remarkably lowered serum uric acid levels by 69.93% and ameliorated renal damage in hyperuricemic mice.

Conclusion

HES is a potential stabilizer for poorly soluble flavonoid NCs and provides a promising strategy for the clinical application of these compounds. LUT-HES NCs may be an alternative or complementary strategy for hyperuricemia treatment.

Co-delivery of fucoxanthin and Twist siRNA using hydroxyethyl starch-cholesterol self-assembled polymer nanoparticles for triple-negative breast cancer synergistic therapy

INTRODUCTION

Triple-negative breast cancer (TNBC) represents the most aggressive subtype of breast cancer with an extremely dismal prognosis and few treatment options. As a desmoplastic tumor, TNBC tumor cells are girdled by stroma composed of cancer-associated fibroblasts (CAFs) and their secreted stromal components. The rapidly proliferating tumor cells, together with the tumor stroma, exert additional solid tissue pressure on tumor vasculature and surrounding tissues, severely obstructing therapeutic agent from deep intratumoral penetration, and resulting in tumor metastasis and treatment resistance.

OBJECTIVES

Fucoxanthin (FX), a xanthophyll carotenoid abundant in marine algae, has attracted widespread attention as a promising alternative candidate for tumor prevention and treatment. Twist is a pivotal regulator of epithelial to mesenchymal transition, and its depletion has proven to sensitize antitumor drugs, inhibit metastasis, reduce CAFs activation and the following interstitial deposition, and increase tumor perfusion. The nanodrug delivery system co-encapsulating FX and nucleic acid drug Twist siRNA (siTwist) was expected to form a potent anti-TNBC therapeutic cyclical feedback loop.

METHODS AND RESULTS

Herein, our studies constituted a novel self-assembled polymer nanomedicine (siTwist/FX@HES-CH) based on the amino-modified hydroxyethyl starch (HES-NH2) grafted with hydrophobic segment cholesterol (CH). The MTT assay, flow cytometry apoptosis analysis, transwell assay, western blot, and 3D multicellular tumor spheroids growth inhibition assay all showed that siTwist/FX@HES-CH could kill tumor cells and inhibit their metastasis in a synergistic manner. The in vivo anti-TNBC efficacy was demonstrated that siTwist/FX@HES-CH remodeled tumor microenvironment, facilitated interstitial barrier crossing, killed tumor cells synergistically, drastically reduced TNBC orthotopic tumor burden and inhibited lung metastasis.

CONCLUSION

Systematic studies revealed that this dual-functional nanomedicine that targets both tumor cells and tumor microenvironment significantly alleviates TNBC orthotopic tumor burden and inhibits lung metastasis, establishing a new paradigm for TNBC therapy.

Hyperbaric Oxygen Boosts Antitumor Efficacy of Copper-Diethyldithiocarbamate Nanoparticles against Pancreatic Ductal Adenocarcinoma by Regulating Cancer Stem Cell Metabolism

Cuproptosis-based cancer nanomedicine has received widespread attention recently. However, cuproptosis nanomedicine against pancreatic ductal adenocarcinoma (PDAC) is severely limited by cancer stem cells (CSCs), which reside in the hypoxic stroma and adopt glycolysis metabolism accordingly to resist cuproptosis-induced mitochondria damage. Here, we leverage hyperbaric oxygen (HBO) to regulate CSC metabolism by overcoming tumor hypoxia and to augment CSC elimination efficacy of polydopamine and hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanoparticles (CuET@PH NPs). Mechanistically, while HBO and CuET@PH NPs inhibit glycolysis and oxidative phosphorylation, respectively, the combination of HBO and CuET@PH NPs potently suppresses energy metabolism of CSCs, thereby achieving robust tumor inhibition of PDAC and elongating mice survival importantly. This study reveals novel insights into the effects of cuproptosis nanomedicine on PDAC CSC metabolism and suggests that the combination of HBO with cuproptosis nanomedicine holds significant clinical translation potential for PDAC patients.

Hetastarch-stabilized polypyrrole with hyperthermia-enhanced release and catalytic activity for synergistic antitumor therapy

Fenton catalytic medicine that catalyzes the production of ·OH without external energy input or oxygen as a substrate has reshaped the landscape of conventional cancer therapy in recent decades, yet potential biosafety concerns caused by non-safety-approved components restrict their clinical translation from the bench to the bedside. Herein, to overcome this dilemma, we elaborately utilizate safety-approved hetastarch, which has been extensively employed in the clinic as a plasma substitute, as a stabilizer participating in the copper chloride-initiated polymerization of pyrrole monomer before loading it with DOX. The constructed DOX-loaded hetastarch-doped Cu-based polypyrrole (HES@CuP-D) catalyzes the excess H2O2 in tumor cells to ·OH through a Cu+-mediated Fenton-like reaction, which not only causes oxidative damage to tumor cells but also leads to the structural collapse and DOX release. Additionally, HES@CuP-D together with laser irradiation reinforces tumor killing efficiency by hyperthermia-enhanced catalytic activity and -accelerated drug release. As a result, the developed HES@CuP-D provides a promising strategy for Fenton catalytic therapy with negligible toxicity to the body.

Oral Nanomedicine: Challenges and Opportunities

Compared to injection administration, oral administration is free of discomfort, wound infection, and complications and has a higher compliance rate for patients with diverse diseases. However, oral administration reduces the bioavailability of medicines, especially biologics (e.g., peptides, proteins, and antibodies), due to harsh gastrointestinal biological barriers. In this context, the development and prosperity of nanotechnology have helped improve the bioactivity and oral availability of oral medicines. On this basis, first, the biological barriers to oral administration are discussed, and then oral nanomedicine based on organic and inorganic nanomaterials and their biomedical applications in diverse diseases are reviewed. Finally, the challenges and potential opportunities in the future development of oral nanomedicine, which may provide a vital reference for the eventual clinical transformation and standardized production of oral nanomedicine, are put forward.

Synthesis of hydroxyethyl starch 200/0.5-loaded albumin nanoparticles: biocompatibility and interaction mechanism

We aimed to synthesize hydroxyethyl starch (HES) 200/0.5-loaded bovine serum albumin nanoparticles (HBNs) and investigate the compatibility and binding mechanism in simulated physiological environments. Here, to elucidate the morphology, biocompatibility, and formation mechanism of HBNs, techniques such as scanning electron microscopy, haemolysis test, fluorescence, and circular dichroism spectroscopy were applied. The thermodynamic parameters at body temperature (ΔS° = -26.7 J·mol-1 ·K-1 , ΔH° = -3.20 × 104  J·mol-1 , and ΔG = -2.35 × 104  J·mol-1 ) showed a 1:1 binding stoichiometry, which was formed by hydrogen bonds and van der Waals interactions. In addition, the conformational analysis showed that the microenvironment of fluorophores was altered with the adaptational protein secondary structural changes. Energy transfer occurred from the fluorophores to HES with a high possibility. All these results provided accurate and complete primary data for demonstrating the interaction mechanisms of HES with BSA, which helps to understand its pharmaceutical effects in blood.

Gel Based on Hydroxyethyl Starch with Immobilized Amikacin for Coating of Bone Matrices in Experimental Osteomyelitis Treatment

A polysaccharide gel containing covalently bound amikacin, a broad-spectrum antibiotic, was produced by using epichlorohydrin-activated hydroxyethyl starch (HES). The structure of the polymers was analyzed by 13C and 1H nuclear magnetic resonance (13C NMR and 1H NMR) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. The sites of covalent attachment of amikacin to the epoxypropyl substituent and the HES backbone were determined. The antibacterial activity of the polymer was evaluated in vitro using the agar well diffusion method with the Staphylococcus aureus P209 strain. It was demonstrated that the polymer retained activity in the presence of bacterial amylase, which is released upon bacterial attack. The gel was applied for coating pores and surfaces of a biocomposite material based on a xenogenic bovine bone matrix. In vivo experiments showed the effectiveness of utilizing amikacin-containing biocomposite bone-substitute materials in the treatment of experimental osteomyelitis in rats using objective histological control and X-ray tomography.

Hemorrhagic Activity of Cationic Starch Conjugates with Sterically Hindered Phenol after Intravenous Administration to Guinea Pigs

Intravenous injection of cationic starch conjugated with sterically hindered phenol (terpenophenol) to guinea pigs did not increase hemorrhagic activity (in doses of 2 and 4 mg/kg) and plasma clotting time in activated partial thromboplastin time and prothrombin time tests (in a dose of 4 mg/kg) in comparison with administration of physiological saline. Intravenous injection of the cationic starch conjugate with the highest content of terpenophenol fragments (4.1%wt) in a dose of 2 mg/kg to guinea pigs leads to a decrease in hemorrhagic activity by 4 times in comparison with the control.

The modulation of local and systemic anti-tumor immune response induced by methotrexate nanoconjugate in murine MC38 colon carcinoma and B16 F0 melanoma tumor models

Methotrexate (MTX) which is one of the longest-used cytostatics, belongs to the group of antimetabolites and is used for treatment in different types of cancer as well as during autoimmune diseases. MTX can act as a modulator enable to create the optimal environment to generate the specific anti-tumor immune response. A novel system for MTX delivery is its conjugation with high-molecular-weight carriers such as hydroxyethyl starch (HES), a modified amylopectin-based polymer applied in medicine as a colloidal plasma volume expander. Such modification prolongs the plasma half-life of the HES-MTX nanoconjugate and improves the distribution of the drug in the body. In the current study, we focused on evaluating the dose-dependent therapeutic efficacy of chemotherapy with HES-MTX nanoconjugate compared to the free form of MTX, and examining the time-dependent changes in the local and systemic anti-tumor immune response induced by this therapy. To confirm the higher effectiveness of HES-MTX in comparison to MTX, we analyzed its action using murine MC38 colon carcinoma and B16 F0 melanoma tumor models. It was noted that HES-MTX at a dose of 20 mg/kg b.w. was more effective in tumor growth inhibition than MTX in both tumor models. One of the main differences between the two analyzed tumor models concerned the kinetics of the appearance of the immunomodulation. In MC38 tumors, the beneficial change in the tumor microenvironment (TME) landscape, manifested by the depletion of pro-tumor immune cells, and increased influx of cells with strong anti-tumor activity was noted already 3 days after HES-MTX administration, while in B16 F0 model, these changes occurred 10 days after the start of therapy. Thus, the immunomodulatory potential of the HES-MTX nanoconjugate may be closely related to the specific immune cell composition of the TME, which combined with additional treatment such as immunotherapies, would enhance the therapeutic potential of the nanoconjugate.

Design and Application of Hybrid Polymer-Protein Systems in Cancer Therapy

Polymer-protein systems have excellent characteristics, such as non-toxic, non-irritating, good water solubility and biocompatibility, which makes them very appealing as cancer therapeutics agents. Inspiringly, they can achieve sustained release and targeted delivery of drugs, greatly improving the effect of cancer therapy and reducing side effects. However, many challenges, such as reducing the toxicity of materials, protecting the activities of proteins and controlling the release of proteins, still need to be overcome. In this review, the design of hybrid polymer-protein systems, including the selection of polymers and the bonding forms of polymer-protein systems, is presented. Meanwhile, vital considerations, including reaction conditions and the release of proteins in the design process, are addressed. Then, hybrid polymer-protein systems developed in the past decades for cancer therapy, including targeted therapy, gene therapy, phototherapy, immunotherapy and vaccine therapy, are summarized. Furthermore, challenges for the hybrid polymer-protein systems in cancer therapy are exemplified, and the perspectives of the field are covered.

Dimethylglycine Can Enhance the Cryopreservation of Red Blood Cells by Reducing Ice Formation and Oxidative Damage

The cryopreservation of red blood cells (RBCs) holds great potential for ensuring timely blood transfusions and maintaining an adequate RBC inventory. The conventional cryoprotectants (CPAs) have a lot of limitations, and there is an obvious need for novel, efficient, and biocompatible CPAs. Here, it is shown for the first time that the addition of dimethylglycine (DMG) improved the thawed RBC recovery from 11.55 ± 1.40% to 72.15 ± 1.22%. We found that DMG could reduce the mechanical damage by inhibiting ice formation and recrystallization during cryopreservation. DMG can also scavenge reactive oxygen species (ROS) and maintain endogenous antioxidant enzyme activities to decrease oxidative damage during cryopreservation. Furthermore, the properties of thawed RBCs were found to be similar to the fresh RBCs in the control. Finally, the technique for order performance by similarity to ideal solution (TOPSIS) was used to compare the performance of glycerol (Gly), hydroxyethyl starch (HES), and DMG in cryopreservation, and DMG exhibited the best efficiency. This work confirms the use of DMG as a novel CPA for cryopreservation of RBCs and may promote clinical transfusion therapy.

Hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanocrystals for cancer therapy

Cancer stem cells (CSCs) have been recognized as the culprit for tumor progression, treatment resistance, metastasis, and recurrence while redox homeostasis represents the Achilles' Heel of CSCs. However, few drugs or formulations that are capable of elevating oxidative stress have achieved clinical success for eliminating CSCs. Here, we report hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanoparticles (CuET@HES NPs), which conspicuously suppress CSCs not only in vitro but also in numerous tumor models in vivo. Furthermore, CuET@HES NPs effectively inhibit CSCs in fresh tumor tissues surgically excised from hepatocellular carcinoma patients. Mechanistically, we uncover that hydroxyethyl starch stabilized copper-diethyldithiocarbamate nanocrystals via copper‑oxygen coordination interactions, thereby promoting copper-diethyldithiocarbamate colloidal stability, cellular uptake, intracellular reactive oxygen species production, and CSCs apoptosis. As all components are widely used in clinics, CuET@HES NPs represent promising treatments for CSCs-rich solid malignancies and hold great clinical translational potentials. This study has critical implications for design of CSCs targeting nanomedicines.

Advanced Skin Antisepsis: Application of UVA-Cleavable Hydroxyethyl Starch Nanocapsules for Improved Eradication of Hair Follicle-Associated Microorganisms

Hair follicles constitute important drug delivery targets for skin antisepsis since they contain ≈25% of the skin microbiome. Nanoparticles are known to penetrate deeply into hair follicles. By massaging the skin, the follicular penetration process is enhanced based on a ratchet effect. Subsequently, an intrafollicular drug release can be initiated by various trigger mechanisms. Here, we present novel ultraviolet A (UVA)-responsive nanocapsules (NCs) with a size between 400 and 600 nm containing hydroxyethyl starch (HES) functionalized by an o-nitrobenzyl linker. A phase transfer into phosphate-buffered saline (PBS) and ethanol was carried out, during which an aggregation of the particles was observed by means of dynamic light scattering (DLS). The highest stabilization for the target medium ethanol as well as UVA-dependent release of ethanol from the HES-NCs was achieved by adding 0.1% betaine monohydrate. Furthermore, sufficient cytocompatibility of the HES-NCs was demonstrated. On ex vivo porcine ear skin, a strong UVA-induced release of the model drug sulforhodamine 101 (SR101) could be demonstrated after application of the NCs in cyclohexane using laser scanning microscopy. In a final experiment, a microbial reduction comparable to that of an ethanol control was demonstrated on ex vivo porcine ear skin using a novel UVA-LED lamp for triggering the release of ethanol from HES-NCs. Our study provides first indications that an advanced skin antisepsis based on the eradication of intrafollicular microorganisms could be achieved by the topical application of UVA-responsive NCs.

Hydroxyethyl starch-folic acid conjugates stabilized theranostic nanoparticles for cancer therapy

Small molecular prodrug-based nanomedicines with high drug-loading efficiency and tumor selectivity have attracted great attention for cancer therapy against solid tumors, including triple negative breast cancers (TNBC). However, abnormal tumor mechanical microenvironment (TMME) severely restricts antitumor efficacy of prodrug nanomedicines by limiting drug delivery and fostering cancer stem cells (CSCs). Herein, we employed carbamate disulfide bridged doxorubicin dimeric prodrug as pharmaceutical ingredient, marketed IR780 iodide as photothermal agent, and biocompatible hydroxyethyl starch-folic acid conjugates as amphiphilic surfactant to prepare a theranostic nanomedicine (FDINs), which could actively target at TNBC 4T1 tumor tissues and achieve reduction-responsive drug release with high glutathione concentration in cancer cells and CSCs. Importantly, in addition to directly causing damage to cancer cells and sensitizing chemotherapy, FDINs-mediated photothermal effect regulates aberrant TMME via reducing cancer associated fibroblasts and depleting extracellular matrix proteins, thereby normalizing intratumor vessel structure and function to facilitate drug and oxygen delivery. Furthermore, FDINs potently eliminate CSCs by disrupting unique CSCs niche and consuming intracellular GSH in CSCs. As a result, FDINs significantly suppress tumor growth in both subcutaneous and orthotopic 4T1 tumors. This study provides novel insights on rational design of prodrug nanomedicines for superior therapeutic effect against stroma- and CSCs-rich solid malignancies.

Novel self-assembly nano OSA starch micelles controlled by protonation in aqueous media

A new micellization method was applied to produce the nano octenyl succinic anhydride (OSA) modified starch micelles with controllable size. The underlying mechanism was explored by using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), dynamic light scattering (DLS), zeta-potential, surface tension, fluorescence spectra and transmission electron microscope (TEM). Due to the new starch modification method, the electrostatic repulsion between the deprotonation carboxyl groups prevented the aggregation of starch chains. With the progress of protonation, the weaken electrostatic repulsion and enhanced hydrophobic interaction driven the self-assembly of micelles. The size of micelles increased gradually with the increase of the protonation degree (PD) and concentration of OSA starch. However, a V-shaped trends were observed in the size as the increase of substitution of degree (DS). Curcuma loading test indicated that micelles had good encapsulated capability and the maximum value was 52.2 μg/mg. The understanding of the self-assembly behavior of OSA starch micelles can facilitate and improve the starch-based carrier designs used to synthesis complex and smart micelle delivery system with good biocompatibility.

Precise fibrin decomposition and tumor mechanics modulation with hydroxyethyl starch-based smart nanomedicine for enhanced antitumor efficacy

Chemotherapy is a conventional cancer treatment in clinical settings. Although numerous nano drug delivery systems have been developed, the chemotherapeutic effect is greatly limited by abnormal tumor mechanics in solid tumors. Tumor stiffening and accumulated solid stress compress blood vessels and inhibit drug delivery to tumor cells, becoming critical challenges for chemotherapy. By loading doxorubicin (DOX), tissue plasminogen activator (tPA), and fibrin targeting peptide CREKA (Cys-Arg-Glu-Lys-Ala) within pH responsive amphiphilic block polymers, pyridyldithio-hydroxyethyl starch-Schiff base-polylactic acid (PA-HES-pH-PLA), we report a smart nanomedicine, DOX@CREKA/tPA-HES-pH-PLA (DOX@CREKA/tPA-HP), which exhibits a potent antitumor efficacy. In triple-negative breast cancer (TNBC) 4T1 tumors, DOX@CREKA/tPA-HP precisely targeted and effectively decomposed fibrin matrix. By measuring Young's Modulus of tumor slices and quantifying tumor openings, we demonstrated that DOX@CREKA/tPA-HP remarkably reduced tumor stiffness and solid stress. Consequently, the alleviated tumor mechanics decompressed tumor blood vessels, promoted drug delivery, and led to amplified antitumor effect. Our work reveals that decomposing fibrin is a significant means for modulating tumor mechanics, and DOX@CREKA/tPA-HP is a promising smart nanomedicine for treating TNBC.

Fluorene methoxycarbonyl-PEG-deferoxamine conjugates "hitchhike" with albumin in situ for iron overload therapy

Although deferoxamine (DFO) has been approved for the treatment the iron overloaded diseases, its clinical application is impeded by very short circulation time and its relating toxicity. In this work, the fluorene methoxycarbonyl (FMOC) for "albumin hitchhiking" was used to prolong the plasma circulation time of DFO and reduce toxicity. The designed FMOC-PEG-DFO conjugates were found to reversible bind to albumin and gradually release DFO in vivo. Herein, the FMOC-PEG₁₀₀₀-DFO conjugates could increase 30 times the blood circulation time of DFO with the improvement of the iron elimination efficacy. Meanwhile, the conjugates markedly reduced the cytotoxicity of DFO. Taken together, the result demonstrated the FMOC-PEG₁₀₀₀-DFO conjugates could be a potential therapeutic choice for iron-overload-related diseases.

Hydroxyethyl starch-new indocyanine green conjugates for enhanced cancer photodynamic therapy

In the present work, hydroxyethyl starch-new indocyanine green (HES-IR-820) conjugates were developed for enhanced cancer photodynamic therapy. HES-IR-820 conjugates were prepared by the condensation reaction between IR-820 and amino groups modified HES. HES-IR-820 conjugates with IR-820 loading content of 2.0% (HES-IR-820_2.0) and 3.2% (HES-IR-820_3.2) were prepared and characterized by ¹H NMR, FT-IR, HPLC, and UV-Vis. HES-IR-820_2.0 and HES-IR-820_3.2 are monomolecular nanosized particles with hydrodynamic diameters of around 10 nm. HES-IR-820_2.0 and HES-IR-820_3.2 exhibit significantly enhanced stability in pH 7.4 PBS buffer and pH 7.4 PBS buffer containing 10% fetal bovine serum as compared to free IR-820. HES-IR-820_2.0 and HES-IR-820_3.2 show limited drug release in pH 7.4 and pH 5.0 PBS buffer. HES-IR-820_2.0 and HES-IR-820_3.2 exhibit enhanced singlet oxygen generation under 808 nm laser irradiation and reduced cellular uptake amount as compared to free IR-820. The cellular uptake pathway study reveals that the lipid raft-mediated endocytosis and macropinocytosis are involved in the cellular uptake of HES-IR-820_2.0 and HES-IR-820_3.2. Compared to free IR-820, HES-IR-820_2.0 and HES-IR-820_3.2 show reduced cytotoxicity, enhanced in vitro antitumor effect under 0.3 W/cm² 808 nm laser irradiation, and similar in vitro antitumor effect under 0.6 W/cm² 808 nm laser irradiation. HES-IR-820 conjugates show significant potential for cancer photodynamic therapy.

Transforming growth factor-β blockade modulates tumor mechanical microenvironments for enhanced antitumor efficacy of photodynamic therapy

Photodynamic therapy (PDT) is frequently used in cancer treatment in clinical settings. However, its applications in stroma-rich solid tumors, e.g., triple negative breast cancer, are limited by abnormal mechanical microenvironments. Solid stress accumulated in stroma-rich solid tumors compresses tumor blood vessels, hampers the delivery of photosensitizers (PSs) in tumor tissues, and poses a major challenge for potent PDT. Here, we report a novel combination strategy to augment PDT based cancer therapy by combining hydroxyethyl starch-chlorin e6 conjugate self-assembled nanoparticles (HES-Ce6 NPs) with the transforming growth factor-β (TGFβ) inhibitor LY2157299 (LY). HES-Ce6 conjugates, as synthesized by one step esterification reaction, could self-assemble into uniform HES-Ce6 NPs, which exhibited enhanced photostability and generated more reactive oxygen species (ROS) under 660 nm laser irradiation than free Ce6. Prior to PDT, intragastric administration of LY decreased collagen deposition, alleviated solid stress, and decompressed tumor blood vessels. As a result, the reconstructed tumor mechanical microenvironment promoted accumulation and penetration of HES-Ce6 NPs into tumor tissues, contributing to augmented antitumor efficacy of HES-Ce6 NP mediated PDT. Modulating tumor mechanical microenvironments using TGFβ blockade to enhance the delivery of PSs in tumors with excessive extracellular matrix represents an efficient strategy for treating stroma-rich solid tumors.

Synthesis and biological evaluation of biotin-conjugated Portulaca oleracea polysaccharides

Biotinylated Portulaca oleracea polysaccharide (Bio-POP) conjugates were successfully prepared by the esterification reaction. The biotinylated polysaccharide products were an off-white powder with an average degree of substitution of 42.5%. After grafting biotin onto POP, the thermal stability of Bio-POP conjugates was much higher than that of POP and the surface topography of Bio-POP was a loose and porous cross-linked structure. The cytotoxicity assay in vitro demonstrated that POP, biotin, and Bio-POP conjugates exhibited different cytotoxicity to HeLa, MCF-7, LO-2, and A549, in particular POP inhibited the growth of the A549 cell line more than other cell lines. The nuclear staining method demonstrated that Bio-POP conjugates can interfere with the apoptosis of A549 cells to some extent and the immunofluorescence staining photograph illustrated that Bio-POP conjugates induced A549 cells to exhibit immune activity. Therefore, the combination of biotin and Portulaca oleracea polysaccharides had immune synergistic therapeutic effects on A549 cells and can be applied in the field of anti-tumor conjugate drugs.

Biotin grafted onto Portulaca oleracea polysaccharides (Bio-POP) was successfully prepared by the esterification reaction. Bio-POP conjugates had an obvious effect on the proliferation of A549 cells and induced A549 cells to exhibit immune activity.