Tailoring stimuli-responsive delivery system driven by metal-ligand coordination bonding

A xanthan gum and carbomer-codispersed divalent manganese ion-loaded tannic acid nanoparticle adjuvanted inactivated pseudorabies virus vaccine induces balanced humoral and cellular immune responses

Adjuvants including aluminum adjuvant (Alum) and oil-water emulsion have been widely used in inactivated pseudorabies virus (PRV) vaccines to improve their performance, however, they are not sufficient to protect from PRV infection because of the weak immune response and poor Th1-type immune response. Divalent manganese ion (Mn2+) has been reported to increase the cellular immune response significantly. In this work, a xanthan gum and carbomer-dispersed Mn2+-loaded tannic acid-polyethylene glycol (TPMnXC) nanoparticle colloid is developed and used as an adjuvant to improve the performance of the inactivated PRV vaccine. The good in vitro and in vivo biocompatibility of the developed TPMnXC colloid has been confirmed by the cell viability assay, erythrocyte hemolysis, blood routine analysis, and histological analysis of mouse organs and injection site. The TPMnXC-adjuvanted inactivated PRV vaccine (TPMnXC@PRV) significantly promotes higher and more balanced immune responses indicating with an increased specific total IgG antibody and IgG2a/IgG1 ratio, efficient splenocytes proliferation, and elevated Th1- and Th2-type cytokine secretion than those of control groups. Wild PRV challenge experiment is performed using mice as a model animal, achieving a protection rate of up to 86.67 %, which is much higher than those observed from the commercial Alum. This work not only demonstrates the high potentiality of TPMnXC in practical applications but also provides a new way to develop the Mn2+-loaded nanoadjuvant for veterinary vaccines.

Combined Chemo-Immuno-Photothermal Therapy for Effective Cancer Treatment via an All-in-One and One-for-All Nanoplatform

Tumor metastasis and recurrence are recognized to be the main causes of failure in cancer treatment. To address these issues, an "all in one" and "one for all" nanoplatform was established for combined "chemo-immuno-photothermal" therapy with the expectation to improve the antitumor efficacy. Herein, Docetaxel (DTX, a chemo-agent) and cynomorium songaricum polysaccharide (CSP, an immunomodulator) were loaded into zein nanoparticles coated by a green tea polyphenols/iron coordination complex (GTP/Fe^III, a photothermal agent). From the result, the obtained nanoplatform denoted as DTX-loaded Zein/CSP-GTP/Fe^III NPs was spherical in morphology with an average particle size of 274 nm, and achieved pH-responsive drug release. Moreover, the nanoplatform exhibited excellent photothermal effect both in vitro and in vivo. It was also observed that the nanoparticles could be effectively up take by tumor cells and inhibited their migration. From the results of the in vivo experiment, this nanoplatform could completely eliminate the primary tumors, prevent tumor relapses on LLC (Lewis lung cancer) tumor models, and significantly inhibit metastasis on 4T1 (murine breast cancer) tumor models. The underlying mechanism was also explored. It was discovered that this nanoplatform could induce a strong ICD effect and promote the release of damage-associated molecular patterns (DAMPs) including CRT, ATP, and HMGB1 by the dying tumor cells. And the CSP could assist the DAMPs in inducing the maturation of dendritic cells (DCs) and facilitate the intratumoral infiltration of T lymphocytes to clear up the residual or disseminated tumor cells. In summary, this study demonstrated that the DTX-loaded Zein/CSP-GTP/Fe^III is a promising nanoplatform to completely inhibit tumor metastasis and recurrence.

Dietary supplementation with nanoparticle CMCS-20a enhances the resistance to GCRV infection in grass carp (Ctenopharyngodon idella)

Combination of antimicrobial proteins and nanomaterials provides a platform for the development of immunopotentiators. Oral administration of immunopotentiators can significantly enhance the immunity of organisms, which provides ideas for disease prevention. In this study, we confirmed that nanoparticles CMCS-20a can efficiently prevent grass carp reovirus (GCRV) infection. Firstly, we verified that CiCXCL20a is involved in the immune responses post GCRV challenge in vivo and alleviates the cell death post GCRV challenge in CIK cells. Then, we prepared nanoparticles CMCS-20a using carboxymethyl chitosan (CMCS) loaded with grass carp (Ctenopharyngodon idella) CXCL20a (CiCXCL20a). Meanwhile, we confirmed nanoparticles CMCS-20a can alleviate the degradation in intestine. Subsequently, we added it to the feed by low temperature vacuum drying method and high temperature spray drying method, respectively. Grass carp were oral administration for 28 days and challenged by GCRV. Low temperature vacuum drying group (LD-CMCS-20a) significantly improve grass carp survival rate, but not high temperature spray drying group (HD-CMCS-20a). To reveal the mechanisms, we investigated the serum biochemical indexes, intestinal mucus barrier, immune gene regulation and tissue damage. The complement component 3 content, lysozyme and total superoxide dismutase activities are highest in LD-CMCS-20a group. LD-CMCS-20a effectively attenuates the damage of GCRV to the number of intestinal villous goblet cells and mucin thickness. LD-CMCS-20a effectively regulates mRNA expressions of immune genes (IFN1, Mx2, Gig1 and IgM) in spleen and head kidney tissues. In addition, LD-CMCS-20a obviously alleviate tissue lesions and viral load in spleen. These results indicated that the nanoparticles CMCS-20a can enhance the disease resistance of fish by improving their immunity, which provides a new perspective for fish to prevent viral infections.

Effect of pH-sensitive nanoparticles on inhibiting oral biofilms

Dental caries is a biofilm-related preventable infectious disease caused by interactions between the oral bacteria and the host’s dietary sugars. As the microenvironments in cariogenic biofilms are often acidic, pH-sensitive drug delivery systems have become innovative materials for dental caries prevention in recent years. In the present study, poly(DMAEMA-co-HEMA) was used as a pH-sensitive carrier to synthesize a chlorhexidine (CHX)-loaded nanomaterial (p(DH)@CHX). In vitro, p(DH)@CHX exhibited good pH sensitivity and a sustained and high CHX release rate in the acidic environment. It also exhibited lower cytotoxicity against human oral keratinocytes (HOKs) compared to free CHX. Besides, compared with free CHX, p(DH)@CHX showed the same antibacterial effects on S. mutans biofilms. In addition, it had no effect on eradicating healthy saliva-derived biofilm, while free CHX exhibited an inhibitory effect. Furthermore, the 16s rDNA sequencing results showed that p(DH)@CHX had the potential to alter oral microbiota composition and possibly reduce caries risk. In conclusion, the present study presents an alternative option to design an intelligent material to prevent and treat dental caries.

Fabrication of pH-responsive nanoparticles for high efficiency pyraclostrobin delivery and reducing environmental impact

In this work, a pH-responsive pesticide delivery system using mesoporous silica nanoparticles (MSNs) as the porous carriers and coordination complexes of Cu ions and tannic acid (TA-Cu) as the capping agent was established for controlling pyraclostrobin (PYR) release. The results showed the loading capacity of PYR@MSNs-TA-Cu nanoparticles for pyraclostrobin was 15.7 ± 0.5% and the TA-Cu complexes deposited on the MSNs surface could protect pyraclostrobin against photodegradation effectively. The nanoparticles had excellent pH responsive release performance due to the decomposition of TA-Cu complexes under the acid condition, which showed 8.53 ± 0.37%, 82.38 ± 1.67% of the encapsulated pyraclostrobin were released at pH 7.4, pH 4.5 after 7 d respectively. The contact angle and adhesion work of PYR@MSNs-TA-Cu nanoparticles on rice foliage were 86.3° ± 2.7° and 75.8 ± 3.1 mJ/m² after 360 s respectively, indicating that TA on the surface of the nanoparticles could improve deposition efficiency and adhesion ability on crop foliage. The control effect of PYR@MSNs-TA-Cu nanoparticles against Rhizoctonia solani with 400 mg/L of pyraclostrobin was 85.82% after 7 d, while that of the same concentration of pyraclostrobin EC was 53.05%. The PYR@MSNs-TA-Cu nanoparticles did not show any phytotoxicity to the growth of rice plants. Meanwhile, the acute toxicity of PYR@MSNs-TA-Cu nanoparticles to zebrafish was decreased more than 9-fold compared with that of pyraclostrobin EC. Thus, pH-responsive PYR@MSNs-TA-Cu nanoparticles have great potential for enhancing targeting and environmental safety of the active ingredient.

Combining anti-PD-1 antibodies with Mn2+-drug coordinated multifunctional nanoparticles for enhanced cancer therapy

Immune checkpoint blockade therapy, particularly the use of engineered monoclonal antibodies against programmed cell death protein 1 (α-PD1) for activating T cells to kill cancer cells, becomes an effective strategy for cancer treatment. Despite its durable clinical responses, the modest response rates largely restrict the extensive implementation of this approach. Here, a combination of chemotherapy and photodynamic therapy to augment antitumor responses of α-PD1 has been achieved by core-shell metal ion-drug nanoparticles. The core and shell are separately formed by self-assembly of manganese ions with chemotherapeutic doxorubicin and photosensitizer chlorin e6, resulting in nanoparticles with drug loading up to 90 weight%. To assist systemic delivery and prolong circulation time, the obtained nanoparticles are coated with red blood cell membranes that can improve their dispersity and stability. Following intravenous injection into immunocompetent tumor-bearing mice, the coated nanoparticles initiate enhanced antitumor responses of α-PD1 against both primary and distant tumors. In addition, the presence of manganese ions offers strong contrast in T₁-weighted magnetic resonance imaging of tumors. Multimodal core-shell metal ion-drug nanoparticles suggest an alternative to boost anticancer responses and open a window for improving the response rates of immune checkpoint blockade therapy.

Microfluidic-assisted nanoprecipitation of biodegradable nanoparticles composed of PTMC/PCL (co)polymers, tannic acid and doxorubicin for cancer treatment

This study was aimed towards the development of a novel microfluidic approach for the preparation of (co)polymeric and hybrid nanoparticles (NPs) composed of (co)polymers/tannic acid (TA) in the microfluidic flow-focusing glass-capillary device. The MiliQ water was used as water phase, whereas the organic phase was composed of poly(ε-caprolactone) (PCL) and poly(trimethylene carbonate) (PTMC) homopolymers and (co)polymers with different proportion of comonomers which were prepared via enzymatic polymerization that allows avoiding the usage of potentially toxic catalyst. To prepare hybrid NPs, TA was additionally added to the organic phase. Subsequently, as a result of mixing between these distinct phases in microfluidic channels, the nanoprecipitation in the form of spherical NPs occurs. The size of NPs was tuned over the range of 140-230 nm by controlling phase flow rates and the composition of NPs. Moreover, the release studies of the encapsulated anticancer drug doxorubicin (DOX) demonstrated that the drug release is greatly influenced by the (co)polymers composition, their molecular weight, NPs size, and the presence of TA. The antitumor activities of the (co)polymeric and hybrid NPs toward breast cancer cells (MCF-7) were tested in vitro. Among all tested formulation, the NPs composed of PCL/TA most efficiently inhibit the cell proliferation of MCF-7 cells, most importantly, their efficiency was higher than free DOX. The proposed strategy may provide an efficient alternative for the construction of nanocarriers with great potential in anticancer therapy.

Imaging techniques in nanomedical research

About twenty years ago, nanotechnology began to be applied to biomedical issues giving rise to the research field called nanomedicine. Thus, the study of the interactions between nanomaterials and the biological environment became of primary importance in order to design safe and effective nanoconstructs suitable for diagnostic and/or therapeutic purposes. Consequently, imaging techniques have increasingly been used in the production, characterisation and preclinical/clinical application of nanomedical tools. This work aims at making an overview of the microscopy and imaging techniques in vivo and in vitro in their application to nanomedical investigation, and to stress their contribution to this developing research field.

Layered self-assemblies for controlled drug delivery: A translational overview

Self-assembly is a prominent phenomenon observed in nature. Inspired by this thermodynamically favorable approach, several natural and synthetic materials have been investigated to develop functional systems for various biomedical applications, including drug delivery. Furthermore, layered self-assembled systems provide added advantages of tunability and multifunctionality which are crucial for controlled and targeted drug release. Layer-by-layer (LbL) deposition has emerged as one of the most popular, well-established techniques for tailoring such layered self-assemblies. This review aims to provide a brief overview of drug delivery applications using LbL deposition, along with a discussion of associated scalability challenges, technological innovations to overcome them, and prospects for commercial translation of this versatile technique. Additionally, alternative self-assembly techniques such as metal-phenolic networks (MPNs) and Liesegang rings are also reviewed in the context of their recent utilization for controlled drug delivery. Blending the sophistication of these self-assembly phenomena with material science and technological advances can provide a powerful tool to develop smart drug carriers in a scalable manner.

Outlook on the Application of Metal-Liganded Bioactives for Stimuli-Responsive Release

Direct metal-liganded bioactive coordination complexes are known to be sensitive to stimuli such as pH, light, ion activation, or redox cues. This results in the controlled release of the bioactive(s). Compared to other drug delivery strategies based on metal complexation, this type of coordination negates a multi-step drug loading methodology and offers customized physiochemical properties through judicious choice of modulating ancillary ligands. Bioactive release depends on simple dissociative kinetics. Nonetheless, there are challenges encountered when translating the pure coordination chemistry into the biological and physiological landscape. The stability of the metal-bioactive complex in the biological milieu may be compromised, disrupting the stimuli-responsive release mechanism, with premature release of the bioactive. Research has therefore progressed to the incorporation of metal-liganded bioactives with established drug delivery strategies to overcome these limitations. This review will highlight and critically assess current research interventions in order to predict the direction that pharmaceutical scientists could pursue to arrive at tailored and effective metal-liganded bioactive carriers for stimuli-responsive drug release.