Role of non-covalent and covalent interactions in cargo loading capacity and stability of polymeric micelles

mPEG-PCL modified Caffeic acid eye drops for endotoxin-induced uveitis treatment

The modulation of inflammatory mediators has emerged as a critical therapeutic strategy in uveitis management. Current nonsteroidal anti-inflammatory therapies face limitations due to systemic side effects. Caffeic acid (CA), a natural polyphenol with anti-inflammatory properties, holds therapeutic potential but suffers from poor solubility and ocular irritation. This study aimed to develop mPEG-PCL-modified CA-loaded nanoparticles (NanoCA) as a non-invasive eye drop formulation to enhance CA's solubility, bioavailability, and efficacy in treating endotoxin-induced uveitis (EIU). NanoCA was synthesized via the thin-film hydration method, characterized for size, zeta potential, drug loading, and release profile. Cytotoxicity was assessed in human corneal epithelial and RAW264.7 cells. Ocular tolerance was tested via slit-lamp and histopathological examinations. In vivo efficacy was evaluated in an EIU rat model using clinical scoring, histopathology, and immunofluorescence. NanoCA formed uniform nanospheres (42.40 ± 0.22 nm, -0.97 mV) with high encapsulation efficiency (99.17%). It exhibited sustained release over 12 h and reduced cytotoxicity compared to free CA. In EIU rats, NanoCA significantly suppressed inflammation, downregulated CD68 expression, and preserved aqueous barrier integrity. Histopathology confirmed minimal inflammatory infiltrates in NanoCA-treated eyes. The formulation demonstrated excellent ocular biocompatibility without corneal damage. NanoCA eye drops offer a safe, non-invasive therapeutic strategy for EIU, combining enhanced anti-inflammatory efficacy with high ocular tolerance. This nanoformulation presents a promising alternative to conventional CA delivery methods.

Tailoring carrier-free nanoparticles based on natural small molecule assembly for synergistic anti-tumor efficacy

Interfacial modular assemblies of versatile polyphenols have attracted widespread interest in surface and materials engineering. In this study, natural polyphenol (tannic acid, TA) and nobiletin (NOB) can directly form binary carrier-free spherical nanoparticles (NT NPs) through synergistically driven by a variety of interactions (such as hydrogen bonding, oxidative reactions, etc.). The synthesis involves polyphenolic deposition on hydrophobic NOB nanoaggregates, followed by in situ oxidative self-polymerization. Interestingly, the assembled NT NPs exhibit controllable and dynamic changes in particle size during the initial stage. Ultimately, uniform and spherical NT NPs appear stable, with high loading capability, enabling incorporated NOB to preserve their function. Furthermore, in vitro evaluations demonstrate that the rational combination of polyphenol module and NOB can induce apoptosis and inhibit tumor metastasis for both lung cancer H1299 and human fibrosarcoma HT1080 cell lines. Notably, the optimized NT48 NPs were then verified in vivo experiments to achieve a promising synergistic anti-tumor efficacy. These findings not only provide new opportunities for the streamlined and sensible engineering of future polyphenol-based biomaterials, but also open up new prospects for the design of small-molecule nature phytochemicals.

Emerging phospholipid-targeted affinity materials for extracellular vesicle isolation and molecular profiling

Extracellular vesicles (EVs) carrying lipids, proteins, nucleic acids and small molecular metabolites have emerged as an attractive paradigm for understanding and interfering physiological and pathological processes. To this end, selective and efficient separation approaches are highly demanded to obtain target EVs from complicated biosamples. With increasing knowledges on EV lipids, recent years have witnessed rapid advances of phospholipid-targeted affinity materials and platforms for high-performance isolation and analysis of EVs. In view of this, this review is contributed to introduce recent progresses in lipid membrane-targeted affinity strategies for EV isolation and molecular detection in biofluids. Affinity ligands including lipids, peptides, small molecules and aptamers and their molecular interactions with lipids are discussed in focus. The design, construction and mechanism of actions of affinity interfaces are summarized. The EV separation performances in complex biosamples and downstream proteomic, lipidomic and metabolic profiling are introduced. Finally, the perspectives and challenges for the development of next-generation phospholipid-targeted EV separation platforms are discussed.

Preparation of pH-Sensitive Polysaccharide-Small Molecule Nanoparticles and Their Applications for Tumor Chemo- and Immunotherapy

Hydrophobic chemotherapy drugs face significant challenges in cancer treatment, including low bioavailability, unavoidable toxic side effects, and the development of drug resistance. To address these issues, a multifunctional nanoplatform was developed for cancer therapy, aimed at achieving effective drug delivery and enhancing antitumor efficacy. Poria cocos polysaccharide (PCP), a natural polymer known for its immunomodulatory properties, was utilized as an immunoreactive vector for drug delivery after being cross-linked with 1,4-phenylenebisboronic acid (BDBA). Subsequently, a small-molecule chemotherapy drug, esculetin (EL), was confirmed through density functional theory (DFT) simulations to be encapsulated within the PCP-BDBA nanoparticles via weak interactions. The results demonstrated that the synthesized nanoparticles were spherical, with an average particle size of 162.0 nm. In addition to exhibiting excellent stability, the nanoparticles also displayed pH-responsive drug release properties. In vivo experiments indicated that EL@PCP-BDBA NPs exhibited antitumor effects. Furthermore, EL@PCP-BDBA NPs showed superior in vitro antitumor activity compared to EL at the cellular level. Additionally, EL@PCP-BDBA NPs were found to increase intracellular reactive oxygen species (ROS) levels, induce cell apoptosis, and suppress cell migration to combat cancer. Meanwhile, EL@PCP-BDBA NPs enhanced immune function in vivo. In summary, this study developed a nano-pharmaceutical that combined chemotherapy and immunotherapy functions, which was considered a promising tool for cancer therapy.

The Application and Pharmaceutical Development of Etomidate: Challenges and Strategies

Etomidate is a synthetic imidazole anesthetic that exerts hypnotic effects by potentiating the action of the inhibitory neurotransmitter γ-aminobutyric acid (GABA) or directly activating the anionic GABA (GABAA) receptor. It stands out among many anesthetics because of its multiple advantages, such as good hemodynamic stability and minimal inhibition of spontaneous respiration. However, its low water solubility and side effects, such as adrenal cortex inhibition and myoclonus, have limited the clinical application of this drug. To address these issues, extensive research has been conducted on the drug delivery of etomidate in recent decades, which has led to the emergence of different etomidate preparations. Despite so many etomidate preparations, so far some of the toxic side effects have not yet been effectively addressed. Herein we discuss the pharmaceutical design of etomidate that may resolve the above problem. We also propose targeted strategies for future research on etomidate preparations and discuss the feasibility of different administration routes and dosage forms to expand the application of this drug. Through this review, we hope to draw more attention to the potential of etomidate and its application challenges and provide valuable insights into the development of new etomidate preparations.

Encapsulation of astaxanthin in OSA-starch based amorphous solid dispersions with HPMCAS-HF/Soluplus® as effective recrystallization inhibitor

In this study, the interaction among multifunctional excipients, including polysaccharides, cellulose derivatives, and surfactants, was particularly investigated, together with its impact on the physicochemical properties of astaxanthin amorphous solid dispersions (ASTX ASDs). It was indicated that Span 20 could rapidly form hemimicelles or aggregates in the presence of hypromellose acetate succinate HF (HPMCAS-HF, HF) or Soluplus®, while octenyl succinic anhydride modified starch (OSA-starch) efficiently assisted in the coalescence inhibition of drug-excipients aggregates, which was jointly beneficial to the recrystallization inhibition of amorphous ASTX. ASTX ASDs were further prepared with OSA-starch, HPMCAS-HF/Soluplus®, and Span 20 as the wall materials. DSC, SEM, and XRD confirmed that crystalline ASTX had transformed to amorphous state in the ASDs, while FT-IR spectra provided evidence suggesting the existence of hydrogen bonds and hydrophobic interaction between ASTX and the excipients. The dissolution of ASTX ASDs in different media revealed significant promotion, while the pharmacokinetic results further demonstrated the oral bioavailability of ASTX ASDs enhanced remarkably, exhibiting 2.75-fold (SD1) and 1.87-fold (SD2) increase, respectively, compared to ASTX bulk powder. In summary, the cellulose derivatives-surfactant interaction had great impact on the physicochemical properties of ASTX ASDs, and their combinations exhibited great potential for delivering the hydrophobic bioactive compounds efficiently.

Nano- and Micro-Platforms in Therapeutic Proteins Delivery for Cancer Therapy: Materials and Strategies

Proteins have emerged as promising therapeutics in oncology due to their great specificity. Many treatment strategies are developed based on protein biologics, such as immunotherapy, starvation therapy, and pro-apoptosis therapy, while some protein biologics have entered the clinics. However, clinical translation is severely impeded by instability, short circulation time, poor transmembrane transportation, and immunogenicity. Micro- and nano-particles-based drug delivery platforms are designed to solve those problems and enhance protein therapeutic efficacy. This review first summarizes the different types of therapeutic proteins in clinical and research stages, highlighting their administration limitations. Next, various types of micro- and nano-particles are described to demonstrate how they can overcome those limitations. The potential of micro- and nano-particles are then explored to enhance the therapeutic efficacy of proteins by combinational therapies. Finally, the challenges and future directions of protein biologics carriers are discussed for optimized protein delivery.

Effect of non-covalent interactions on the stability and structural properties of 2,4-dioxo-4-phenylbutanoic complex: a computational analysis

CONTEXT

The 2,4-dioxo-4-phenylbutanoic acid (DPBA) is a subject of interest in pharmaceutical research, particularly in developing new drugs targeting viral and bacterial infections. Complexation with metal ions can improve the stability and solubility of organic compounds. The present study uses quantum chemical calculations to explore the structural and electronic results arising from the interaction between the metal cation (Fe2+) and the π-system of DPBA in different solvents. For this purpose, the analyses of atoms in molecules (AIM) and natural bond orbital (NBO) are employed to comprehend the interaction features and the charge delocalization during the process of complexation. The results demonstrate that the strongest/weakest interactions are evident when the complex is situated in non-polar/polar solvents, respectively. In addition, the investigated complex exhibits two intramolecular hydrogen bonds (IMHBs) characterized by the O-H···O motif. The results indicate that the HBs present in the complex fall within the category of weak to medium HBs. Moreover, the O-H···O HBs are influenced by cation-π interactions, which can increase/decrease their strength in polar/non-polar solvents. To enhance understanding of the interactions above, an examination is conducted on various physical properties including the energy gap, electronic chemical potential, chemical hardness, softness, and electrophilicity power.

METHOD

All calculations are conducted within the density functional theory (DFT) using the ωB97XD functional and 6-311 +  + G(d,p) basis set. The computations are performed using the quantum chemistry package GAMESS, and the obtained results are visualized by employing the GaussView program.

Adipocyte-targeted celastrol delivery via biguanide-modified micelles improves treatment of obesity in DIO mice

Obesity has emerged as a significant global health burden, exacerbated by serious side effects associated with existing anti-obesity medications. Celastrol (CLT) holds promise for weight loss but encounters challenges related to poor solubility and systemic toxicity. Here, we present chondroitin sulfate (CS)-derived micelles engineered for adipocyte-specific targeting, aiming to enhance the therapeutic potential of CLT while minimizing its systemic toxicity. To further enhance adipocyte affinity, we introduced a biguanide moiety into a micellar vehicle. CS is sequentially modified with hydrophilic metformin and hydrophobic 4-aminophenylboronic acid pinacol ester (PBE), resulting in the self-assembly of CLT-encapsulated micelles (MET-CS-PBE@CLT). This innovative design imparts amphiphilicity via the PBE moieties while ensuring the outward exposure of hydrophilic metformin moieties, facilitating active interactions with adipocytes. In vitro studies confirmed the enhanced uptake of MET-CS-PBE@CLT micelles by adipocytes, while in vivo studies demonstrated increased distribution within adipose tissues. In a diet-induced obese mouse model, MET-CS-PBE@CLT exhibited remarkable efficacy in weight loss without affecting food intake. This pioneering strategy offers a promising, low-risk, and highly effective solution to address the global obesity epidemic.

Improved biodistribution and enhanced immune response of subunit vaccine using a nanostructure formed by self-assembly of ascorbyl palmitate

New adjuvant strategies are needed to improve protein-based subunit vaccine immunogenicity. We examined the potential to use nanostructure of 6-O-ascorbyl palmitate to formulate ovalbumin (OVA) protein and an oligodeoxynucleotide (CpG-ODN) (OCC). In mice immunized with a single dose, OCC elicited an OVA-specific immune response superior to OVA/CpG-ODN solution (OC). Rheological studies demonstrated OCC's self-assembling viscoelastic properties. Biodistribution studies indicated that OCC prolonged OVA and CpG-ODN retention at injection site and lymph nodes, reducing systemic spread. Flow-cytometry assays demonstrated that OCC promoted OVA and CpG-ODN co-uptake by Ly6ChiCD11bhiCD11c+ monocytes. OCC and OC induced early IFN-γ in lymph nodes, but OCC led to higher concentration. Conversely, mice immunized with OC showed higher serum IFN-γ concentration compared to those immunized with OCC. In mice immunized with OCC, NK1.1+ cells were the IFN-γ major producers, and IFN-γ was essential for OVA-specific IgG2c switching. These findings illustrate how this nanostructure improves vaccine's response.

Polymeric Nanoparticles for Drug Delivery

The recent emergence of nanomedicine has revolutionized the therapeutic landscape and necessitated the creation of more sophisticated drug delivery systems. Polymeric nanoparticles sit at the forefront of numerous promising drug delivery designs, due to their unmatched control over physiochemical properties such as size, shape, architecture, charge, and surface functionality. Furthermore, polymeric nanoparticles have the ability to navigate various biological barriers to precisely target specific sites within the body, encapsulate a diverse range of therapeutic cargo and efficiently release this cargo in response to internal and external stimuli. However, despite these remarkable advantages, the presence of polymeric nanoparticles in wider clinical application is minimal. This review will provide a comprehensive understanding of polymeric nanoparticles as drug delivery vehicles. The biological barriers affecting drug delivery will be outlined first, followed by a comprehensive description of the various nanoparticle designs and preparation methods, beginning with the polymers on which they are based. The review will meticulously explore the current performance of polymeric nanoparticles against a myriad of diseases including cancer, viral and bacterial infections, before finally evaluating the advantages and crucial challenges that will determine their wider clinical potential in the decades to come.

Dual-Modality Imaging-Guided Manganese-Based Nanotransformer for Enhanced Gas-Photothermal Therapy Combined Immunotherapeutic Strategy Against Triple-Negative Breast Cancer

Activating the stimulator of the interferon gene (STING) is a promising immunotherapeutic strategy for converting "cold" tumor microenvironment into "hot" one to achieve better immunotherapy for malignant tumors. Herein, a manganese-based nanotransformer is presented, consisting of manganese carbonyl and cyanine dye, for MRI/NIR-II dual-modality imaging-guided multifunctional carbon monoxide (CO) gas treatment and photothermal therapy, along with triggering cGAS-STING immune pathway against triple-negative breast cancer. This nanosystem is able to transfer its amorphous morphology into a crystallographic-like formation in response to the tumor microenvironment, achieved by breaking metal-carbon bonds and forming coordination bonds, which enhances the sensitivity of magnetic resonance imaging. Moreover, the generated CO and photothermal effect under irradiation of this nanotransformer induce immunogenic death of tumor cells and release damage-associated molecular patterns. Simultaneously, the Mn acts as an immunoactivator, potentially stimulating the cGAS-STING pathway to augment adaptive immunity, resulting in promoting the secretion of type I interferon, the proliferation of cytotoxic T lymphocytes and M2-macrophages repolarization. This nanosystem-based gas-photothermal treatment and immunoactivating therapy synergistic effect exhibit excellent antitumor efficacy both in vitro and in vivo, reducing the risk of triple-negative breast cancer recurrence and metastasis; thus, this strategy presents great potential as multifunctional immunotherapeutic agents for cancer treatment.

Nucleic acids based integrated macromolecular complexes for SiRNA delivery: Recent advancements

The therapeutic potential of small interfering RNA (siRNA) is monumental, offering a pathway to silence disease-causing genes with precision. However, the delivery of siRNA to target cells in-vivo remains a formidable challenge, owing to degradation by nucleases, poor cellular uptake and immunogenicity. This overview examines recent advancements in the design and application of nucleic acid-based integrated macromolecular complexes for the efficient delivery of siRNA. We dissect the innovative delivery vectors developed in recent years, including lipid-based nanoparticles, polymeric carriers, dendrimer complexes and hybrid systems that incorporate stimuli-responsive elements for targeted and controlled release. Advancements in bioconjugation techniques, active targeting strategies and nanotechnology-enabled delivery platforms are evaluated for their contribution to enhancing siRNA delivery. It also addresses the complex interplay between delivery system design and biological barriers, highlighting the dynamic progress and remaining hurdles in translating siRNA therapies from bench to bedside. By offering a comprehensive overview of current strategies and emerging technologies, we underscore the future directions and potential impact of siRNA delivery systems in personalized medicine.

An Overview of Biopolymers for Drug Delivery Applications

Nowadays, drug delivery has an important role in medical therapy. The use of biopolymers in developing drug delivery systems (DDSs) is increasingly attracting attention due to their remarkable and numerous advantages, in contrast to conventional polymers. Biopolymers have many advantages (biodegradability, biocompatibility, renewability, affordability, and availability), which are extremely important for developing materials with applications in the biomedical field. Additionally, biopolymers are appropriate when they improve functioning and have a number of positive effects on human life. Therefore, this review presents the most used biopolymers for biomedical applications, especially in drug delivery. In addition, by combining different biopolymers DDSs with tailored functional properties (e.g., physical properties, biodegradability) can be developed. This review summarizes and provides data on the progress of research on biopolymers (chitosan, alginate, starch, cellulose, albumin, silk fibroin, collagen, and gelatin) used in DDSs, their preparation, and mechanism of action.

Ionic Liquid-Based Polymer Matrices for Single and Dual Drug Delivery: Impact of Structural Topology on Characteristics and In Vitro Delivery Efficiency

Previously reported amphiphilic linear and graft copolymers, derived from the ionic liquid [2-(methacryloyloxy)ethyl]trimethylammonium chloride (TMAMA_Cl‾), along with their conjugates obtained through modification either before or after polymerization with p-aminosalicylate anions (TMAMA_PAS‾), were employed as matrices in drug delivery systems (DDSs). Based on the counterion type in TMAMA units, they were categorized into single drug systems, manifesting as ionic polymers with chloride counterions and loaded isoniazid (ISO), and dual drug systems, featuring ISO loaded in self-assembled PAS conjugates. The amphiphilic nature of these copolymers was substantiated through the determination of the critical micelle concentration (CMC), revealing an increase in values post-ion exchange (from 0.011-0.063 mg/mL to 0.027-0.181 mg/mL). The self-assembling properties were favorable for ISO encapsulation, with drug loading content (DLC) ranging between 15 and 85% in both single and dual systems. In vitro studies indicated ISO release percentages between 16 and 61% and PAS release percentages between 20 and 98%. Basic cytotoxicity assessments using the 2,5-diphenyl-2H-tetrazolium bromide (MTT) test affirmed the non-toxicity of the studied systems toward human non-tumorigenic lung epithelial cell line (BEAS-2B) cell lines, particularly in the case of dual systems bearing both ISO and PAS simultaneously. These results confirmed the effectiveness of polymeric carriers in drug delivery, demonstrating their potential for co-delivery in combination therapy.

Photoreactive silver-containing supramolecular polymers that form self-assembled nanogels for efficient antibacterial treatment

In this study, an efficient synthetic strategy and potential route to obtain a photo-reactive silver-containing cytosine-functionalized polypropylene glycol polymer (Ag-Cy-PPG) was developed by combining a hydrophilic oligomeric polypropylene glycol (PPG) backbone with dual pH-sensitive/photo-reactive cytosine-silver-cytosine (Cy-Ag-Cy) linkages. The resulting photo-responsive Ag-Cy-PPG holds great promise as a multifunctional biomedical material that generates spherical-like nanogels in water; the nanogels exhibit high antibacterial activity and thus may significantly enhance the efficacy of antibacterial treatment. Due to the formation of photo-dimerized Cy-Ag-Cy cross-linkages after UV irradiation, Ag-Cy-PPG converts into water-soluble cross-linked nanogels that possess a series of interesting chemical and physical properties, such as intense and stable fluorescence behavior, highly sensitive pH-responsive characteristics, on/off switchable phase transition behavior, and well-controlled release of silver ions (Ag+) in mildly acidic aqueous solution. Importantly, antibacterial tests clearly demonstrated that irradiated Ag-Cy-PPG nanogels exhibited strong antibacterial activity at low doses (MIC values of < 50 μg/mL) against gram-positive and gram-negative bacterial pathogens, whereas non-irradiated Ag-Cy-PPG nanogels did not inhibit the viability of bacterial pathogens. These results indicate that irradiated Ag-Cy-PPG nanogels undergo a highly sensitive structural change in the bacterial microenvironment due to their relatively unstable π-conjugated structures (compared to non-irradiated nanogels); this change results in a rapid structural response that promotes intracellular release of Ag+ and induces potent antibacterial ability. Overall, this newly created metallo-supramolecular system may potentially provide an efficient route to dramatically enhance the therapeutic effectiveness of antibacterial treatments.

Acid-sensitive stable polymeric micelle-based oxidative stress nanoamplifier as immunostimulating anticancer nanomedicine

Oxidative stress amplifying compounds could elicit selective killing of cancer cells with minimal toxicity to normal cells and also induce immunogenic cell death (ICD). However, compared to conventional anticancer drugs, oxidative stress amplifying compounds have inferior therapeutic efficacy. It can be postulated that the anticancer therapeutic efficacy and immunostimulating activity of oxidative stress amplifying hybrid prodrug (OSamp) could be fully maximized by employing ultrastable polymeric micelles as drug carriers. In this work, we developed tumour-targeted oxidative stress nanoamplifiers, composed of OSamp, amphiphilic poly(ethylene glycol) methyl ether-block-poly(cyclohexyloxy ethyl glycidyl ether)s (mPEG-PCHGE) and a lipopeptide containing Arg-Gly-Asp (RGD). Tumour targeted OSamp-loaded mPEG-PCHGE (T-POS) micelles exhibited excellent colloidal stability and significant cytotoxicity to cancer cells with the expression of DAMPs (damage-associated molecular patterns). In the syngeneic mouse tumour model, T-POS micelles induced significant apoptotic cell death to inhibit tumour growth without noticeable body weight changes. T-POS micelles also induced ICD and activated adaptive immune responses by increasing the populations of cytotoxic CD4+ and CD8+ T cells. Therefore, these results suggest that T-POS micelles hold great translational potential as immunostimulating anticancer nanomedicine.

Recent development of polymer nanomicelles in the treatment of eye diseases

The eye, being one of the most intricate organs in the human body, hosts numerous anatomical barriers and clearance mechanisms. This highlights the importance of devising a secure and efficacious ocular medication delivery system. Over the past several decades, advancements have been made in the development of a nano-delivery platform based on polymeric micelles. These advancements encompass diverse innovations such as poloxamer, chitosan, hydrogel-encapsulated micelles, and contact lenses embedded with micelles. Such technological evolutions allow for sustained medication retention and facilitate enhanced permeation within the eye, thereby standing as the avant-garde in ocular medication technology. This review provides a comprehensive consolidation of ocular medications predicated on polymer nanomicelles from 2014 to 2023. Additionally, it explores the challenges they pose in clinical applications, a discussion intended to aid the design of future clinical research concerning ocular medication delivery formulations.

Functionalization of Octacalcium Phosphate Bone Graft with Cisplatin and Zoledronic Acid: Physicochemical and Bioactive Properties

Bones are the fourth most frequent site of metastasis from malignant tumors, including breast cancer, prostate cancer, melanoma, etc. The bioavailability of bone tissue for chemotherapy drugs is extremely low. This requires a search for new approaches of targeted drug delivery to the tumor growth zone after surgery treatment. The aim of this work was to develop a method for octacalcium phosphate (OCP) bone graft functionalization with the cytostatic drug cisplatin to provide the local release of its therapeutic concentrations into the bone defect. OCP porous ceramic granules (OCP ceramics) were used as a platform for functionalization, and bisphosphonate zoledronic acid was used to mediate the interaction between cisplatin and OCP and enhance their binding strength. The obtained OCP materials were studied using scanning electron and light microscopy, high-performance liquid chromatography, atomic emission spectroscopy, and real-time PCR. In vitro and in vivo studies were performed on normal and tumor cell lines and small laboratory animals. The bioactivity of initial OCP ceramics was explored and the efficiency of OCP functionalization with cisplatin, zoledronic acid, and their combination was evaluated. The kinetics of drug release and changes in ceramics properties after functionalization were studied. It was established that zoledronic acid changed the physicochemical and bioactive properties of OCP ceramics and prolonged cisplatin release from the ceramics. In vitro and in vivo experiments confirmed the biocompatibility, osteoconductivity, and osteoinductivity, as well as cytostatic and antitumor properties of the obtained materials. The use of OCP ceramics functionalized with a cytostatic via the described method seems to be promising in clinics when primary or metastatic tumors of the bone tissue are removed.

Research Progress of Design Drugs and Composite Biomaterials in Bone Tissue Engineering

Bone, like most organs, has the ability to heal naturally and can be repaired slowly when it is slightly injured. However, in the case of bone defects caused by diseases or large shocks, surgical intervention and treatment of bone substitutes are needed, and drugs are actively matched to promote osteogenesis or prevent infection. Oral administration or injection for systemic therapy is a common way of administration in clinic, although it is not suitable for the long treatment cycle of bone tissue, and the drugs cannot exert the greatest effect or even produce toxic and side effects. In order to solve this problem, the structure or carrier simulating natural bone tissue is constructed to control the loading or release of the preparation with osteogenic potential, thus accelerating the repair of bone defect. Bioactive materials provide potential advantages for bone tissue regeneration, such as physical support, cell coverage and growth factors. In this review, we discuss the application of bone scaffolds with different structural characteristics made of polymers, ceramics and other composite materials in bone regeneration engineering and drug release, and look forward to its prospect.

Box-Behnken Design of Experiments of Polycaprolactone Nanoparticles Loaded with Irinotecan Hydrochloride

BACKGROUND

The Box-Behnken design of experiments (BBD) is a statistical modelling technique that allows the determination of the significant factors in developing nanoparticles (NPs) using a limited number of runs. It also allows the prediction of the best levels of variables to obtain the desired characteristics (size, charge, and encapsulation efficiency) of the NPs. The aim of this study was to examine the effect of the independent variables (amount of polymer and drug, and surfactant concentration) and their interaction on the characteristics of the irinotecan hydrochloride (IRH)-loaded polycaprolactone (PCL) NPs and to determine the most optimum conditions for producing the desired NPs.

METHODS

The development of the NPs was carried out by a double emulsion solvent evaporation technique with yield enhancement. The NPs data were fitted in Minitab software to obtain the best fit model.

RESULTS

By using BBD, the most optimum conditions for producing the smallest size, highest magnitude of charge, and highest EE% of PCL NPs were predicted to be achieved by using 61.02 mg PCL, 9 mg IRH, and 4.82% PVA, which would yield 203.01 nm, -15.81 mV, and 82.35% EE.

CONCLUSION

The analysis by BBD highlighted that the model was a good fit to the data, confirming the suitability of the design of the experiments.

Recent Advances in Nanoparticle Development for Drug Delivery: A Comprehensive Review of Polycaprolactone-Based Multi-Arm Architectures

Controlled drug delivery is a crucial area of study for improving the targeted availability of drugs; several polymer systems have been applied for the formulation of drug delivery vehicles, including linear amphiphilic block copolymers, but with some limitations manifested in their ability to form only nanoaggregates such as polymersomes or vesicles within a narrow range of hydrophobic/hydrophilic balance, which can be problematic. For this, multi-arm architecture has emerged as an efficient alternative that overcame these challenges, with many interesting advantages such as reducing critical micellar concentrations, producing smaller particles, allowing for various functional compositions, and ensuring prolonged and continuous drug release. This review focuses on examining the key variables that influence the customization of multi-arm architecture assemblies based on polycaprolactone and their impact on drug loading and delivery. Specifically, this study focuses on the investigation of the structure-property relationships in these formulations, including the thermal properties presented by this architecture. Furthermore, this work will emphasize the importance of the type of architecture, chain topology, self-assembly parameters, and comparison between multi-arm structures and linear counterparts in relation to their impact on their performance as nanocarriers. By understanding these relationships, more effective multi-arm polymers can be designed with appropriate characteristics for their intended applications.

Photoreactive Mercury-Containing Metallosupramolecular Nanoparticles with Tailorable Properties That Promote Enhanced Cellular Uptake for Effective Cancer Chemotherapy

A new potential route to enhance the efficiency of supramolecular polymers for cancer chemotherapy was successfully demonstrated by employing a photosensitive metallosupramolecular polymer (Hg-BU-PPG) containing an oligomeric poly(propylene glycol) backbone and highly sensitive pH-responsive uracil-mercury-uracil (U-Hg-U) bridges. This route holds great promise as a multifunctional bioactive nano-object for development of more efficient and safer cancer chemotherapy. Owing to the formation of uracil photodimers induced by ultraviolet irradiation, Hg-BU-PPG can form a photo-cross-linked structure and spontaneously forms spherical nanoparticles in aqueous solution. The irradiated nanoparticles possess many unique characteristics, such as unique fluorescence behavior, highly sensitive pH-responsiveness, and intriguing phase transition behavior in aqueous solution as well as high structural stability and antihemolytic activity in biological media. More importantly, a series of cellular studies clearly confirmed that the U-Hg-U photo-cross-links in the irradiated nanoparticles substantially enhance their selective cellular uptake by cancer cells via macropinocytosis and the mercury-loaded nanoparticles subsequently induce higher levels of cytotoxicity in cancer cells (compared to non-irradiated nanoparticles), without harming normal cells. These results are mainly attributed to cancer cell microenvironment-triggered release of mercury ions from disassembled nanoparticles, which rapidly induce massive levels of apoptosis in cancer cells. Overall, the pH-sensitive U-Hg-U photo-cross-links within this newly discovered supramolecular system are an indispensable factor that offers a potential path to remarkably enhance the selective therapeutic effects of functional nanoparticles toward cancer cells.

Nanotechnology in cervical cancer immunotherapy: Therapeutic vaccines and adoptive cell therapy

Immunotherapy is an emerging method for the treatment of cervical cancer and is more effective than surgery and radiotherapy, especially for recurrent cervical cancer. However, immunotherapy is limited by adverse effects in clinical practice. In recent years, nanotechnology has been widely used for tumor diagnosis, drug delivery, and targeted therapy. In the setting of cervical cancer, nanotechnology can be used to actively or passively target immunotherapeutic agents to tumor sites, thereby enhancing local drug delivery, reducing drug adverse effects, achieving immunomodulation, improving the tumor immune microenvironment, and optimizing treatment efficacy. In this review, we highlight the current status of therapeutic vaccines and adoptive cell therapy in cervical cancer immunotherapy, as well as the application of lipid carriers, polymeric nanoparticles, inorganic nanoparticles, and exosomes in this context.

Size-adjustable self-assembled nanoparticles through microfluidic platform promotes neuronal differentiation of mouse embryonic stem cells

Neuronal differentiation from stem cells is one of the most potent therapeutic approaches for recovering neurological function in individuals with neurodegenerative disorders. Herein, an on-demand intracellular retinoic acid released nanoparticles with tunable size and accurately controlled physico-biological properties have been prepared for achieving efficient neuronal differentiation. The amphiphilic chitosan oligosaccharide-cholesterol copolymers were synthesized by varying cholesterol content and self-assembled into spherical micelle in a microfluidic chip with different flow rates. Notably, the results indicated that by increasing the lipophilicity of the chitosan chain as well as mixing rate, the size of micelles was decreased. Retinoic acid (RA) was efficiently encapsulated in the core of micelles. The retinoic acid-containing nanoparticles could escape lysosome, accumulate in the cytoplasm, and release payload with a sustained pattern. The cytotoxicity assay of free retinoic acid and retinoic acid-loaded formulations against P19 embryonic stem cells confirmed the desirable safety of micelles. The result obtained from the uptake study showed that internalization of micelles occurs predominantly via lipid-raft endocytosis in the presence of higher cholesterol content. Moreover, the intracellular RA release upregulated the expression levels of neuronal factors. The micelles described here offer a promising nanomedicine strategy for neuronal differentiation of stem cells.

Surface Adsorption-Mediated Ultrahigh Efficient Peptide Encapsulation with a Precise Ratiometric Control for Type 1 and 2 Diabetic Therapy

A surface adsorption strategy is developed to enable the engineering of microcomposites featured with ultrahigh loading capacity and precise ratiometric control of co-encapsulated peptides. In this strategy, peptide molecules (insulin, exenatide, and bivalirudin) are formulated into nanoparticles and their surface is decorated with carrier polymers. This polymer layer blocks the phase transfer of peptide nanoparticles from oil to water and, consequently, realizes ultrahigh peptide loading degree (up to 78.9%). After surface decoration, all three nanoparticles are expected to exhibit the properties of adsorbed polymer materials, which enables the co-encapsulation of insulin, exenatide, and bivalirudin with a precise ratiometric control. After solidification of this adsorbed polymer layer, the release of peptides is synchronously prolonged. With the help of encapsulation, insulin achieves 8 days of glycemic control in type 1 diabetic rats with one single injection. The co-delivery of insulin and exenatide (1:1) efficiently controls the glycemic level in type 2 diabetic rats for 8 days. Weekly administration of insulin and exenatide co-encapsulated microcomposite effectively reduces the weight gain and glycosylated hemoglobin level in type 2 diabetic rats. The surface adsorption strategy sets a new paradigm to improve the pharmacokinetic and pharmacological performance of peptides, especially for the combination of peptides.

Improved Core Viscosity Achieved by PDLLA10kCo-Incorporation Promoted Drug Loading and Stability of mPEG2k-b-PDLLA2.4k Micelles

PURPOSE

This study aims to investigate the effect of poly(D, L-lactic acid)10K (PDLLA10K) incorporation on the drug loading and stability of poly(ethylene glycol)2K-block-poly(D, L-lactide)2.4K (mPEG2k-b-PDLLA2.4k) micelles. In addition, a suitable lyophilization protector was screened for this micelle to obtain favorable lyophilized products.

METHODS

The incorporation ratios of PDLLA10k were screened based on the particle size and drug loading. The dynamic stability, core viscosity, drug release, stability in albumin, and in vivo pharmacokinetic characteristics of PDLLA10k incorporated micelles were compared with the original micelles. In addition, the particle size variation was used as an indicator to screen the most suitable lyophilization protectant for the micelles. DSC, FTIR, XRD were used to illustrate the mechanism of the lyophilized protectants.

RESULTS

After the incorporation of 5 wt% PDLLA10K, the maximum loading of mPEG2k-b-PDLLA2.4k micelles for TM-2 was increased from 26 wt% to 32 wt%, and the in vivo half-life was increased by 2.25-fold. Various stability of micelles was improved. Also, the micelles with hydroxypropyl-β-cyclodextrin (HP-β-CD) as lyophilization protectants had minimal variation in particle size.

CONCLUSIONS

PDLLA10k incorporation can be employed as a strategy to increase the stability of mPEG2k-b-PDLLA2.4k micelles, which can be attributed to the viscosity building effect. HP-β-CD can be used as an effective lyophilization protectant since mPEG and HP-β-CD form the pseudopolyrotaxanesque inclusion complexes.

Novel ROS-responsive marine biomaterial fucoidan nanocarriers with AIE effect and chemodynamic therapy

Chemodynamic therapy (CDT) has been widely used in the treatment of many kinds of tumors, which can effectively induce tumor cell apoptosis by using produced reactive oxygen species (ROS). In this paper, ROS-sensitive multifunctional marine biomaterial natural polysaccharide nanoparticles were designed. Aggregation-induced emission (AIE) molecules tetraphenylethylene (TPE) labeled and caffeic acid (CA) modified fucoidan (FUC) amphiphilic carrier material (CA-FUC-TK-TPE, CFTT) was fabricated, in which the thioketal bond(TK) was used as the linkage arm between TPE and fucoidan chain, giving the CFTT material ROS sensitivity. In addition, amphiphilic carrier material (FUC-TK-VE, FTVE) composed of thioketal-linked vitamin E and fucoidan was synthesized. The mixed carrier material CFTT and FTVE self-assembled in water to form nanoparticles (CFTT - FTVE@PTX-Fe³⁺) loaded with PTX and Fe³⁺. The CDT effect was combined with the chemotherapeutic drug PTX to achieve tumor inhibition. In vitro cell studies have proved that CT/PTX nanoparticles have excellent cell permeability and tumor cytotoxicity. In vivo antitumor experiments confirmed effective antitumor activity and reduced side effects.

Photoreactive Cytosine-Functionalized Self-Assembled Micelles with Enhanced Cellular Uptake Capability for Efficient Cancer Chemotherapy

Design, fabrication, and control of photoreactive supramolecular macromers─which are composed of a thermoresponsive polymer backbone and photoreactive nucleobase end-groups─to achieve the desired physical-chemical performance and provide the high efficiency required for chemotherapy drug delivery purposes still present challenges. Herein, a difunctional cytosine-terminated supramolecular macromer was successfully obtained at high yield. UV-irradiation induces the formation of cytosine photodimers within the structure. The irradiated macromer can self-assemble into nanosized spherical micelles in water that possess a number of interesting and unique features, such as desired micellar size and morphology, tunable drug-loading capacity, and excellent structural stability in serum-containing medium, in addition to well-controlled drug-release behaviors in response to changes in environmental temperature and pH; these extremely desirable, rare features are required to augment the functions of polymeric nanocarriers for drug delivery. Importantly, a series of in vitro studies demonstrated that photodimerized cytosine moieties within the drug-loaded micelles substantially enhance their internalization and accumulation inside cells via endocytosis and subsequently lead to induction of massive apoptotic cell death compared with the corresponding nonirradiated micelles. Thus, this newly developed "photomodified" nanocarrier system could provide a potentially fruitful route to enhance the drug delivery performance of nanocages without the need to introduce targeting moieties or additional components.

Poly(disulfide)s: From Synthesis to Drug Delivery

Bioresponsive polymers have been widely used in drug delivery because of their degradability. For example, poly(disulfide)s with repeating disulfide bonds in the main chain have attracted considerable research attention. The characteristics of the disulfide bonds, including their dynamic and reversible properties and their responsiveness to stimuli such as reductants, light, heat, and mechanical force, make them ideal platforms for on-demand drug delivery. This review introduces the synthesis methods and applications of poly(disulfide)s. Furthermore, the synthesis methods of poly(disulfide)s are classified on the basis of the monomers used: oxidative step-growth polymerization with dithiols, ring-opening polymerization with cyclic disulfides, and polymerization with linear disulfides. In addition, recent advances in poly(disulfide)s for the delivery of small-molecule or biomacromolecular drugs are discussed. Quantum-dot-loaded poly(disulfide) delivery systems for imaging are also included. This review provides an overview of the various design strategies employed in the construction of poly(disulfide) platforms to inspire new applications in the field of drug delivery.

Targeted delivery by pH-responsive mPEG-S-PBLG micelles significantly enhances the anti-tumor efficacy of doxorubicin with reduced cardiotoxicity

Stimuli-responsive nanotherapeutics hold great promise in precision oncology. In this study, a facile strategy was used to develop a new class of pH-responsive micelles, which contain methoxy polyethylene glycol (mPEG) and poly(carbobenzoxy-l-glutamic acid, BLG) as amphiphilic copolymer, and β-thiopropionate as acid-labile linkage. The mPEG-S-PBLG copolymer was synthesized through one-step ring-opening polymerization (ROP) and thiol-ene click reaction, and was able to efficiently encapsulate doxorubicin (DOX) to form micelles. The physicochemical characteristics, cellular uptake, tumor targeting, and anti-tumor efficacy of DOX-loaded micelles were investigated. DOX-loaded micelles were stable under physiological conditions and disintegrated under acidic conditions. DOX-loaded micelles can be internalized into cancer cells and release drugs in response to low pH in endosomes/lysosomes, resulting in cell death. Furthermore, the micellar formulation significantly prolonged the blood circulation, reduced the cardiac distribution, and selectively delivered more drugs to tumor tissue. Finally, compared with free DOX, DOX-loaded micelles significantly improved the anti-tumor efficacy and reduced systemic and cardiac toxicity in two different tumor xenograft models. These results suggest that mPEG-S-PBLG micelles have translational potential in the precise delivery of anti-cancer drugs.

Phenylboronic acid-based core-shell drug delivery platform clasping 1,3-dicarbonyl compounds by a coordinate interaction

Along with the successful commercialization of chemotherapeutics, such as doxorubicin and paclitaxel, numerous natural compounds have been investigated for clinical applications. Recently, curcumin (CUR), a natural compound with various therapeutic effects, has attracted attention for cancer immunotherapy. Most chemotherapeutics, however, have poor water solubility due to their hydrophobicity, which makes them less suited to biomedical applications; CUR is no exception because of its low bioavailability and extremely high hydrophobicity. In the present study, we developed an easy but effective strategy using the interaction between the 1,3-dicarbonyl groups of drugs and phenylboronic acid (PBA) to solubilize hydrophobic drugs. First, we verified the coordinate interaction between 1,3-dicarbonyl and PBA using 3,5-heptanedione as a model compound, followed by CUR as a model drug. A PBA-grafted hydrophilic polymer was used to form a nanoconstruct by coordination bonding with CUR, which then made direct administration of the nanoparticles possible. The nanoconstruct exhibited remarkable loading capability, uniform size, colloidal stability, and pH-responsive drug release, attributed to the formation of core-shell nanoconstructs by coordinate interaction. The therapeutic nanoconstructs successfully showed both chemotherapeutic and anti-PD-L1 anticancer effects in cellular and animal models. Furthermore, we demonstrated the applicability of this technique to other 1,3-dicarbonyl compounds. Overall, our findings suggest a facile, but expandable strategy by applying the coordinate interaction between 1,3-dicarbonyl and PBA, which enables high drug loading and stimuli-responsive drug release.

Asymmetric polymersomes, from the formation of asymmetric membranes to the application on drug delivery

Nano drug delivery systems have attracted researchers' growing attention and are gradually emerging into the public views. More and more nano-formulations are being approved for marketing or clinical use, representing the field's booming development. Copolymer self-assembly systems such as micelles, nanoparticles, polymersomes occupy a prominent position in the field of nano-drug delivery carriers. Among them, polymersomes, unlike micelles or nanoparticles, resemble liposomes' structure and possess large internal hollow hydrophilic reservoirs, allowing them to carry hydrophilic drugs. Nevertheless, their insufficient drug loading efficiency and unruly self-assembly morphology have somewhat constrained their applications. Especially for the delivery of biomacromolecule such as peptides, the encapsulation efficiency is always considered to be a formidable obstacle, even if the enormous hydrophilic core would render the polymersomes to have considerable potential in this regard. Reassuringly, the emergence of asymmetric polymersomes holds the prospect of solving this problem. With the development of synthetic technology and a deeper understanding of the self-assembly process, the asymmetric polymersomes which are with different inner and outer shell composition have been gradually recognized by researchers. It has made possible elevated drug loading, more controllable assembly processes and release performance. The internal hydrophilic blocks different from the outer shell could be engineered to have a more remarkable affinity to the cargos or could contain a non-watery aqueous phase to enable the thermodynamically preferred encapsulation of cargos, which would allow for a substantial improvement in drug encapsulation efficiency compared to the conventional approach. In this paper, we aim to deepen the understanding to asymmetric polymersomes and lay the foundation for the development of this field by describing four main elements: the mechanism of their preparation and asymmetric membrane formation process, the characterization of asymmetric membranes, the efficient drug loading, and the special stimulus-responsive release mechanism.

Anti-Cancer Activity Based on the High Docetaxel Loaded Poly(2-Oxazoline)s Micelles

PURPOSE

Nanocarriers, with a high drug loading content and good safety, to achieve desirable therapeutic effect are always the goals for industry and research.

METHODS AND RESULTS

In the present study, we developed a docetaxel loaded poly-2-oxazoline polymer micellar system which employed poly-2-butyl-2 oxazoline and poly-2-methyl-2 oxazoline as the hydrophobic chain and hydrophilic chain, respectively. This micellar system achieves a high load up to 25% against the docetaxel, and further demonstrates an IC50 as low as 40% of the commercialized docetaxel injection in vitro and a double maximum tolerated dose in MCF-7 cells in vivo.

CONCLUSION

The high drug loading content, superior safety, and considerable anti-cancer activity make this newly developed docetaxel loaded poly(2-oxazoline) micelle go further in future clinical research.

pH-Responsive Amphiphilic Polyether Micelles with Superior Stability for Smart Drug Delivery

Despite widespread interest in the amphiphilic polymeric micelles for drug delivery systems, it is highly desirable to achieve high loading capacity and high efficiency to reduce the side effects of therapeutic agents while maximizing their efficacy. Here, we present a novel hydrophobic epoxide monomer, cyclohexyloxy ethyl glycidyl ether (CHGE), containing an acetal group as a pH-responsive cleavable linkage. A series of its homopolymers, poly(cyclohexyloxy ethyl glycidyl ether)s (PCHGEs), and block copolymers, poly(ethylene glycol)-block-poly(cyclohexyloxy ethyl glycidyl ether)s (mPEG-b-PCHGE), were synthesized via anionic ring-opening polymerization in a controlled manner. Subsequently, the self-assembled polymeric micelles of mPEG-b-PCHGE demonstrated high loading capacity, excellent stability in biological media, tunable release efficiency, and high cell viability. Importantly, quantum mechanical calculations performed by considering prolonged hydrolysis of the acetal group in CHGE indicated that the CHGE monomer had higher hydrophobicity than three other functional epoxide monomer analogues developed. Furthermore, the preferential cellular uptake and in vivo therapeutic efficacy confirmed the enhanced stability and the pH-responsive degradation of the amphiphilic block copolymer micelles. This study provides a new platform for the development of versatile smart polymeric drug delivery systems with high loading efficiency and tailorable release profiles.

The design and synthesis of redox-responsive oridonin polymeric prodrug micelle formulation for effective gastric cancer therapy

Advanced gastric cancer (GC) is a significant threat to human health. Oridonin (ORI), isolated from the Chinese herb Rabdosia rubescens, has demonstrated great potential in GC therapy. However, the application of ORI in the clinic was greatly hindered by its poor solubility, low bioavailability, and rapid plasma clearance. Herein, a simple and novel redox-sensitive ORI polymeric prodrug formulation was synthesized by covalently attaching ORI to poly(ethylene glycol)-block-poly(l-lysine) via a disulfide linker, which can self-assemble into micelles (P-ss-ORI) in aqueous solutions and produce low critical micelle concentrations (about 10 mg L-1), characterized by small size (about 80 nm), negative surface charge (about -12 mV), and high drug loading efficiency (18.7%). The in vitro drug release study showed that P-ss-ORI can rapidly and completely release ORI in a glutathione (GSH)-rich environment and under low pH conditions. Moreover, in vitro and in vivo investigations confirmed that P-ss-ORI could remarkably extend the blood circulation time of ORI, enrich in tumor tissue, be effectively endocytosed by GC cancer cells, and quickly and completely release the drug under high intracellular GSH concentrations and low pH conditions, all these characteristics ultimately inhibit the growth of GC. This redox and pH dual-responsive P-ss-ORI formulation provides a useful strategy for GC treatment.

Distinguishing the optimal binding mechanism through reversible and irreversible inhibition analysis of HSP72 protein in cancer therapy

Over the past two decades, covalent inhibitors have gained much interest and are living up to their reputation as a powerful tool in drug discovery. Covalent inhibitors possess several significant advantages, including increased biochemical efficiency, prolonged duration and the ability to target shallow, solvent-exposed substrate-binding domains. One of the enzymes that have been both covalently and non-covalently targeted is the heat shock protein 72 (HSP72). This elevated enzyme expression in cancer cells may be responsible for tumorigenesis and tumor progression by providing chemotherapy resistance. A critical gap remains in the molecular understanding of the structural mechanism's covalent and non-covalent binding to HSP72. In this study, we explore the most optimal binding mechanism in the inhibition of the HSP72. Based on the molecular dynamic analyses, it was evident that the non-covalent complex showed more stability than the covalent complex. The covalent ligand, however, was more able to induce and stabilize the sealed conformation of the HSP72-NBD ATP binding domain throughout the. Also, the non-covalent ligand does not induce any significant conformational change as it remained close to the shape of the unbound complex; and the affinity is only dependent on the multiple hydrogen bonds in contrast to the covalent ligand. This is supported by the secondary structure elements and principal component analysis that was more dominant in the covalently inhibited complex. Covalent bond induced the α-helices sealed conformation of the HSP72-NBD; based on our findings, this will prevent other small molecules from interacting at the ATP binding site domain. Moreover, inhibition of the ATP binding domain can directly affect the ATPs protein folding mechanism of the HSP72 enzyme. The essential dynamic analysis presented in this report compliments the binding mechanism of HSP72, establishing covalent inhibition as the preferred method of inhibiting the HSP72 protein. The findings from this study may assist in the design of more target-specific HSP72 covalent inhibitors exploring the surface-exposed lysine residues.

pH-Sensitive and Long-Circulation Nanoparticles for Near-Infrared Fluorescence Imaging-Monitored and Chemo-Photothermal Synergistic Treatment Against Gastric Cancer

Gastrectomy is the primary therapeutic option for gastric cancer. Postoperative treatment also plays a crucial role. The strategy to improve the postoperative prognosis of gastric cancer requires a combined system that includes a more efficient synergistic treatment and real-time monitoring after surgery. In this study, photothermal-chemotherapy combined nanoparticles (PCC NPs) were prepared via π-π stacking to perform chemo-photothermal synergistic therapy and continuous imaging of gastric cancer. PCC NPs had a spherical morphology and good monodispersity under aqueous conditions. The hydrodynamic diameter of PCC NPs was 59.4 ± 3.6 nm. PCC NPs possessed strong encapsulation ability, and the maximum drug loading rate was approximately 37%. The NPs exhibited extraordinary stability and pH-response release profiles. The NPs were rapidly heated under irradiation. The maximum temperature was close to 58°C. PCC NPs showed good biocompatibility both in vitro and in vivo. Moreover, the NPs could effectively be used for in vivo continuous monitoring of gastric cancer. After one injection, the fluorescent signal remained in tumor tissues for nearly a week. The inhibitory effect of PCC NPs was evaluated in a gastric cancer cell line and xenograft mouse model. Both in vitro and in vivo evaluations demonstrated that PCC NPs could be used for chemo-photothermal synergistic therapy. The suppression effect of PCC NPs was significantly better than that of single chemotherapy or photothermal treatment. This study lays the foundation for the development of novel postoperative treatments for gastric cancer.

Effect of temperature and pH on the encapsulation and release of β-carotene from octenylsuccinated oat β-glucan micelles

Effect and working mechanism of temperature and pH on encapsulation and release of β-carotene from octenylsuccinated-oat-β-glucan-micelles (OSβG-Ms) were investigated. The stability and solubility of β-carotene, and changes in surface hydrophilicity, core hydrophobicity, and size of β-carotene-loaded-OSβG-Ms were determined. When exposed to temperature (25-45 °C) and pH (4.5-8.5), β-carotene solubilization changed in parabolic manners. Size and absolute zeta-potential of β-carotene-loaded-OSβG-Ms decreased with temperature, while they gave parabolic changing patterns with pH. Those results were ascribed to their hydrophilicity, hydrophobicity, and core/shell compactness via regulating molecule mobility, orientation, and interactions by temperature/pH. The higher temperature concluded with higher β-carotene release, while a U-shaped release profile was observed with pH. Besides its diffusion, erosion-induced shrinking and collapsing of OSβG-Ms favored β-carotene release at pH 1.2-4.5, which was replaced by swelling-induced structural-relaxation at pH 6.8-8.5. The results were favourable in controlling the behavior of β-carotene-loaded-OSβG-Ms by selectively applying environmental parameters.