Tetrasulfide bond boosts the anti-tumor efficacy of dimeric prodrug nanoassemblies.

Dimeric prodrug nanoassemblies (DPNAs) stand out as promising strategies for improving the efficiency and safety of chemotherapeutic drugs. The success of trisulfide bonds (-SSS-) in DPNAs makes polysulfide bonds a worthwhile focus. Here, we explore the comprehensive role of tetrasulfide bonds (-SSSS-) in constructing superior DPNAs. Compared to trisulfide and disulfide bonds, tetrasulfide bonds endow DPNAs with superlative self-assembly stability, prolonged blood circulation, and high tumor accumulation. Notably, the ultra-high reduction responsivity of tetrasulfide bonds make DPNAs a highly selective "tumor bomb" that can be ignited by endogenous reducing agents in tumor cells. Furthermore, we present an "add fuel to the flames" strategy to intensify the reductive stress at tumor sites by replenishing exogenous reducing agents, making considerable progress in selective tumor inhibition. This work elucidates the crucial role of tetrasulfide bonds in establishing intelligent DPNAs, alongside the combination methodology, propelling DPNAs to new heights in potent cancer therapy.

An in situ dual-anchoring strategy for enhanced immobilization of PD-L1 to treat autoimmune diseases.

Immune checkpoints play key roles in maintaining self-tolerance. Targeted potentiation of the checkpoint molecule PD-L1 through in situ manipulation offers clinical promise for patients with autoimmune diseases. However, the therapeutic effects of these approaches are often compromised by limited specificity and inadequate expression. Here, we report a two-step dual-anchor coupling strategy for enhanced immobilization of PD-L1 on target endogenous cells by integrating bioorthogonal chemistry and physical insertion of the cell membrane. In both type 1 diabetes and rheumatoid arthritis mouse models, we demonstrate that this approach leads to elevated and sustained conjugation of PD-L1 on target cells, resulting in significant suppression of autoreactive immune cell activation, recruitment of regulatory T cells, and systematic reshaping of the immune environment. Furthermore, it restores glucose homeostasis in type 1 diabetic mice for over 100 days. This specific in situ bioengineering approach potentiates the functions of PD-L1 and represents its translational potential.

KERS-Inspired Nanostructured Mineral Coatings Boost IFN-γ mRNA Therapeutic Index for Antitumor Immunotherapy.

Tumor-associated macrophage (TAM) reprogramming is a promising therapeutic approach for cancer immunotherapy; however, its efficacy remains modest due to the low bioactivity of the recombinant cytokines used for TAM reprogramming. mRNA therapeutics are capable of generating fully functional proteins for various therapeutic purposes but accused for its poor sustainability. Inspired by kinetic energy recovery systems (KERS) in hybrid vehicles, a cytokine efficacy recovery system (CERS) is designed to substantially augment the therapeutic index of mRNA-based tumor immunotherapy via a "capture and stabilize" mechanism exerted by a nanostructured mineral coating carrying therapeutic cytokine mRNA. CERS remarkably recycles nearly 40% expressed cytokines by capturing them onto the mineral coating to extend its therapeutic timeframe, further polarizing the macrophages to strengthen their tumoricidal activity and activate adaptive immunity against tumors. Notably, interferon-γ (IFN-γ) produced by CERS exhibits ≈42-fold higher biological activity than recombinant IFN-γ, remarkably decreasing the required IFN-γ dosage for TAM reprogramming. In tumor-bearing mice, IFN-γ cmRNA@CERS effectively polarizes TAMs to inhibit osteosarcoma progression. When combined with the PD-L1 monoclonal antibody, IFN-γ cmRNA@CERS significantly boosts antitumor immune responses, and substantially prevents malignant lung metastases. Thus, CERS-mediated mRNA delivery represents a promising strategy to boost antitumor immunity for tumor treatment.

Scarless wound healing programmed by core-shell microneedles.

Effective reprogramming of chronic wound healing remains challenging due to the limited drug delivery efficacy hindered by physiological barriers, as well as the inappropriate dosing timing in distinct healing stages. Herein, a core-shell structured microneedle array patch with programmed functions (PF-MNs) is designed to dynamically modulate the wound immune microenvironment according to the varied healing phases. Specifically, PF-MNs combat multidrug-resistant bacterial biofilm at the early stage via generating reactive oxygen species (ROS) under laser irradiation. Subsequently, the ROS-sensitive MN shell gradually degrades to expose the MN core component, which neutralizes various inflammatory factors and promotes the phase transition from inflammation to proliferation. In addition, the released verteporfin inhibits scar formation by blocking Engrailed-1 (En1) activation in fibroblasts. Our experiments demonstrate that PF-MNs promote scarless wound repair in mouse models of both acute and chronic wounds, and inhibit the formation of hypertrophic scar in rabbit ear models.

Structure-Activity Relationship of pH-Sensitive Doxorubicin-Fatty Acid Prodrug Albumin Nanoparticles.

Albumin has emerged as a versatile drug carrier. To harness albumin as a carrier for doxorubicin (DOX), we synthesized three acid-labile DOX prodrugs using stearic acid (SA), oleic acid (OA), and linoleic acid (LA) as the albumin-binding motif, respectively. Different from conventional albumin nanodrugs (such as Abraxane, with a drug loading of 10%), the DOX prodrugs assembled albumin nanoparticles (NPs) have an ultrahigh drug loading (>35%). Noteworthy, we demonstrated that the saturation of fatty acids exerted great influence on colloidal stability of prodrug NPs, thus affecting their in vivo pharmacokinetics, tumor accumulation and antitumor efficacy. Furthermore, the hydrazone bond-bridged DOX prodrugs could remain intact in the bloodstream but allow DOX to be released in the acidic tumor environment, resulting in improved antitumor efficacy and safety. Our work gives novel insights into the structure-to-efficacy relationship of albumin-bound fatty acid prodrugs and provides a simple strategy for advanced albumin-bound nanomedicines.

Recent Advances in Oral and Transdermal Protein Delivery Systems.

Protein and peptide drugs are predominantly administered by injection to achieve high bioavailability, but this greatly compromises patient compliance. Oral and transdermal drug delivery with minimal invasiveness and high adherence represent attractive alternatives to injection administration. However, oral and transdermal administration of bioactive proteins must overcome biological barriers, namely the gastrointestinal and skin barriers, respectively. The rapid development of new materials and technologies promises to address these physiological obstacles. This review provides an overview of the latest advances in oral and transdermal protein delivery, including chemical strategies, synthetic nanoparticles, medical microdevices, and biomimetic systems for oral administration, as well as chemical enhancers, physical approaches, and microneedles in transdermal delivery. We also discuss challenges and future perspectives of the field with a focus on innovation and translation.

Paclitaxel derivative-based liposomal nanoplatform for potentiated chemo-immunotherapy.

The combination of chemotherapy with the immune checkpoint blockade (ICB) therapy is bringing a tremendous hope in the treatment of malignant tumors. However, the treatment efficacy of the existing chemo-immunotherapy is not satisfactory due to the high cost and immunogenicity of ICB antibodies, low response rate to ICB, off-target toxicity of therapeutic agents, and low drug co-delivery efficacy. Therefore, a high-efficient nanosystem combining the delivery of chemotherapeutics with small molecule ICB inhibitors may be promising for an efficient cancer therapy. Herein, a novel reactive oxygen species (ROS)-activated liposome nanoplatform was constructed by the loading of a ROS-sensitive paclitaxel derivative (PSN) into liposomes to overcome the difficulties on delivering paclitaxel mostly represented by premature drug release and a low amount accumulated into the tumor. The innovative liposomal nanosystem was rationally designed by a remote loading of BMS-202 (a small molecule PD-1/PD-L1 inhibitor) and PSN into the liposomes for a ROS-sensitive paclitaxel release and sustained BMS-202 release. The co-loaded liposomes resulted in a high co-loading ability and improved pharmacokinetic properties. An orthotopic 4 T1 breast cancer model was used to evaluate the efficiency of our nanoplatform in vivo, resulting in a superior antitumor activity. The antitumor immunity was activated by paclitaxel-mediated immunogenic cell death, while BMS-202 continuously blocked PD-L1 which could be up-regulated by paclitaxel in tumors to increase the response to ICB and further recover the host immune surveillance. These results revealed that this dual-delivery liposome might provide a promising strategy for a high-efficient chemo-immunotherapy, exhibiting a great potential for clinical translation.

Small changes in the length of diselenide bond-containing linkages exert great influences on the antitumor activity of docetaxel homodimeric prodrug nanoassemblies.

Homodimeric prodrug-based self-assembled nanoparticles, with carrier-free structure and ultrahigh drug loading, is drawing more and more attentions. Homodimeric prodrugs are composed of two drug molecules and a pivotal linkage. The influence of the linkages on the self-assembly, in vivo fate and antitumor activity of homodimeric prodrugs is the focus of research. Herein, three docetaxel (DTX) homodimeric prodrugs are developed using different lengths of diselenide bond-containing linkages. Interestingly, compared with the other two linkages, the longest diselenide bond-containing linkage could facilitate the self-delivery of DTX prodrugs, thus improving the stability, circulation time and tumor targeting of prodrug nanoassemblies. Besides, the extension of linkages reduces the redox-triggered drug release and cytotoxicity of prodrug nanoassemblies in tumor cells. Although the longest diselenide bond-containing prodrug nanoassemblies possessed the lowest cytotoxicity to 4T1 cells, their stable nanostructure maintained intact during circulation and achieve the maximum accumulation of DTX in tumor cells, which finally "turned the table". Our study illustrates the crucial role of linkages in homodimeric prodrugs, and gives valuable proposal for the development of advanced nano-DDS for cancer treatment.

Low dose shikonin and anthracyclines coloaded liposomes induce robust immunogenetic cell death for synergistic chemo-immunotherapy.

Chemo-immunotherapy based on immunogenic cell death (ICD) is a promising strategy for cancer therapy. However, the effective ICD requires a high dosage of ICD stimulus, which could be associated to a dose-dependent toxicity. Therefore, in this study, a liposome remote-loaded with shikonin (a potent ICD stimulus) was developed, with the ability to effectively induce ICD at high dosage in vivo. However, a hepatotoxic effect was observed. To circumvent this problem, shikonin was combined with the anthracycline mitoxantrone or doxorubicin to develop co-loaded liposomes inducing a synergistic ICD effect and cytotoxicity to tumor cells. Cytotoxicity and uptake experiment in vitro were performed to analyze the optimal synergistic ratio of shikonin and anthracyclines based on a "formulated strategy". Interestingly, copper mediated co-loaded liposomes resulted in a pH and GSH dual-responsive release property. More importantly, pharmacokinetics and tumor biodistribution studies revealed an outstanding capacity of ratiometric delivery of dual drugs. Thus, the dual-loaded liposome enhanced the antitumor effect by the stimulation of a robust immune response at lower doses of the drugs with a higher safety compared to single-loaded liposomes. Summarized, the current work provided a reference for a rational design and development of liposomal co-delivery system of drugs and ICD-induced chemo-immunotherapy, and established a potential clinical application of shikonin-based drug combinations as a new chemo-immunotherapeutic strategy for cancer treatment.

Disulfide bond based cascade reduction-responsive Pt(IV) nanoassemblies for improved anti-tumor efficiency and biosafety.

The platinum-based drugs prevail in the therapy of malignant tumors treatment. However, their clinical outcomes have been heavily restricted by severe systemic toxicities. To ensure biosafety and efficiency, herein, we constructed a disulfide bond inserted Pt(IV) self-assembled nanoplatform that is selectively activated by rich glutathione (GSH) in tumor site. Disulfide bond was introduced into the conjugates of oxaliplatin (IV) and oleic acid (OA) which conferred cascade reduction-responsiveness to nanoassemblies. Disulfide bond cleavage and reduction of Pt(IV) center occur sequentially as a cascade process. In comparison to oxaliplatin solution, Pt(IV) nanoparticles (NPs) achieved prolonged blood circulation and higher maximum tolerated doses. Furthermore, Oxa(IV)-SS-OA prodrug NPs exhibited potent anti-tumor efficiency against 4T1 cells and low toxicities in other normal tissues, which offers a promising nano-platform for potential clinical application.

Iron-doxorubicin prodrug loaded liposome nanogenerator programs multimodal ferroptosis for efficient cancer therapy.

Ferroptosis is a new mode of cell death, which can be induced by Fenton reaction-mediated lipid peroxidation. However, the insufficient H2O2 and high GSH in tumor cells restrict the efficiency of Fenton reaction-dependent ferroptosis. Herein, a self-supplying lipid peroxide nanoreactor was developed to co-delivery of doxorubicin (DOX), iron and unsaturated lipid for efficient ferroptosis. By leveraging the coordination effect between DOX and Fe3+, trisulfide bond-bridged DOX dimeric prodrug was actively loaded into the core of the unsaturated lipids-rich liposome via iron ion gradient method. First, Fe3+could react with the overexpressed GSH in tumor cells, inducing the GSH depletion and Fe2+generation. Second, the cleavage of trisulfide bond could also consume GSH, and the released DOX induces the generation of H2O2, which would react with the generated Fe2+in step one to induce efficient Fenton reaction-dependent ferroptosis. Third, the formed Fe3+/Fe2+ couple could directly catalyze peroxidation of unsaturated lipids to boost Fenton reaction-independent ferroptosis. This iron-prodrug liposome nanoreactor precisely programs multimodal ferroptosis by integrating GSH depletion, ROS generation and lipid peroxidation, providing new sights for efficient cancer therapy.

Trisulfide bond-mediated doxorubicin dimeric prodrug nanoassemblies with high drug loading, high self-assembly stability, and high tumor selectivity.

Rational design of nanoparticulate drug delivery systems (nano-DDS) for efficient cancer therapy is still a challenge, restricted by poor drug loading, poor stability, and poor tumor selectivity. Here, we report that simple insertion of a trisulfide bond can turn doxorubicin homodimeric prodrugs into self-assembled nanoparticles with three benefits: high drug loading (67.24%, w/w), high self-assembly stability, and high tumor selectivity. Compared with disulfide and thioether bonds, the trisulfide bond effectively promotes the self-assembly ability of doxorubicin homodimeric prodrugs, thereby improving the colloidal stability and in vivo fate of prodrug nanoassemblies. The trisulfide bond also shows higher glutathione sensitivity compared to the conventional disulfide bond, and this sensitivity enables efficient tumor-specific drug release. Therefore, trisulfide bond-bridged prodrug nanoassemblies exhibit high selective cytotoxicity on tumor cells compared with normal cells, notably reducing the systemic toxicity of doxorubicin. Our findings provide new insights into the design of advanced redox-sensitive nano-DDS for cancer therapy.

Probing the Superiority of Diselenium Bond on Docetaxel Dimeric Prodrug Nanoassemblies: Small Roles Taking Big Responsibilities.

The current state of chemotherapy is far from satisfaction, restricted by the inefficient drug delivery and the off-target toxicity. Prodrug nanoassemblies are emerging as efficient platforms for chemotherapy. Herein, three docetaxel dimeric prodrugs are designed using diselenide bond, disulfide bond, or dicarbide bond as linkages. Interestingly, diselenide bond-bridged dimeric prodrug can self-assemble into stable nanoparticles with impressive high drug loading (≈70%, w/w). Compared with disulfide bond and dicarbide bond, diselenide bond greatly facilitates the self-assembly of dimeric prodrug, and then improves the colloidal stability, blood circulation time, and antitumor efficacy of prodrug nanoassemblies. Furthermore, the redox-sensitive diselenide bond can specifically respond to the overexpressed reactive oxygen species and glutathione in tumor cells, leading to tumor-specific drug release. Therefore, diselenide bond bridged prodrug nanoassemblies exhibit discriminating cytotoxicity between tumor cells and normal cells, significantly alleviating the systemic toxicity of docetaxel. The present work gains in-depth insight into the impact of diselenide bond on the dimeric prodrug nanoassemblies, and provides promising strategies for the rational design of the high efficiency-low toxicity chemotherapeutical nanomedicines.

A Novel Star Like Eight-Arm Polyethylene Glycol-Deferoxamine Conjugate for Iron Overload Therapy.

The traditional iron chelator deferoxamine (DFO) has been widely used in the treatment of iron overload disease. However, DFO has congenital disadvantages, including a very short circular time and non-negligible toxicity. Herein, we designed a novel multi-arm conjugate for prolonging DFO duration in vivo and reducing cytotoxicity. The star-like 8-arm-polyethylene glycol (8-arm-PEG) was used as the macromolecular scaffold, and DFO molecules were bound to the terminals of the PEG branches via amide bonds. The conjugates displayed comparable iron binding ability to the free DFO. Furthermore, these macromolecule conjugates could significantly reduce the cytotoxicity of the free DFO, and showed satisfactory iron clearance capability in the iron overloaded macrophage RAW 246.7. The plasma half-life of the 8-arm-PEG-DFO conjugate was about 190 times than that of DFO when applied to an intravenously administered rat model. In conclusion, research indicated that these star-like PEG-based conjugates could be promising candidates as long circulating, less toxic iron chelators.

Mitochondria-targeting nanomedicine: An effective and potent strategy against aminoglycosides-induced ototoxicity.

We report a proof-of-concept for the development of mitochondria-targeting nanoparticles (NPs) loaded with geranylgeranylacetone (GGA) to protect against a wide range of gentamicin-induced ototoxicity symptoms in a zebrafish model. The polymeric NPs were functionalized with a mitochondrial-homing peptide (d­Arg­Dmt­Orn­Phe­NH2) and exhibited greater mitochondrial uptake and lower gentamicin uptake in hair cells via mechanotransduction (MET) channels and tuned machinery in the hair bundle than the ordinary NPs did. Blockade of MET channels rapidly reversed this effect, indicating the reversible responses of hair cells to the targeting NPs were mediated by MET channels. Pretreatment of hair cells with mitochondria-targeting GGA-loaded NPs exhibited a superior acute or chronic protective efficacy against subsequent exposure to gentamicin compared with unmodified formulations. Mitochondrial delivery regulating the death pathway of hair cells appeared to cause the therapeutic failure of untargeted NPs. Thus, peptide-directed mitochondria-targeting NPs may represent a novel therapeutic strategy for mitochondrial dysfunction-linked diseases.

Novel SS-31 modified liposomes for improved protective efficacy of minocycline against drug-induced hearing loss.

Hearing loss, which is regarded as a worldwide public health concern, lacks approved therapeutic strategies. Current drug candidates used to treat hearing loss commonly have low efficacy. To achieve the optimum drug efficacy, we designed a liposome system to preload a clinically approved, water-soluble drug, minocycline. Inspired by our previous research, we used a mitochondria-targeting tetrapeptide, SS-31, to modify the surface of liposomes. The results revealed that SS-31 modified, minocycline-loaded liposomes significantly increased hair cell survival against chronic exposure to gentamicin in a zebrafish model. The designed formulation maintained the activity of mechanotransduction channels in the hair cells, and thus did not result in any alteration in gentamicin uptake. This suggested that the protective efficacy of the liposomes was induced by modulating targets associated with cell death. Further studies are required to clarify the exact intracellular mechanism of the designed formulation and to determine its clinical benefits in patients with hearing dysfunction.

Optimization and evaluation of lipid emulsions for intravenous co-delivery of artemether and lumefantrine in severe malaria treatment.

Parenteral therapy for severe and complicated malaria is necessary, but currently available parenteral antimalarials have their own drawbacks. As for recommended artemisinin-based combination therapy, antimalarial artemether and lumefantrine are limited in parenteral delivery due to their poor water solubility. Herein, the aim of this study was to develop the lipid-based emulsions for intravenous co-delivery of artemether and lumefantrine. The lipid emulsion was prepared by high-speed shear and high-pressure homogenization, and the formulations were optimized mainly by monitoring particle size distribution under autoclaved conditions. The final optimal formulation was with uniform particle size distribution (~ 220 nm), high encapsulation efficiency (~ 99%), good physiochemical stability, and acceptable hemolysis potential. The pharmacokinetic study in rats showed that Cmax of artemether and lumefantrine for the optimized lipid emulsions were significantly increased than the injectable solution, which was critical for rapid antimalarial activity. Furthermore, the AUC0-t of artemether and lumefantrine in the lipid emulsion group were 5.01- and 1.39-fold of those from the solution, respectively, suggesting enhanced bioavailability. With these findings, the developed lipid emulsion is a promising alternative parenteral therapy for the malaria treatment, especially for severe or complicated malaria.

A sensitive, high-throughput, and ecofriendly method for the determination of lumefantrine, artemether, and its active metabolite dihydroartemisinin by supercritical fluid chromatography and tandem mass spectrometry.

A quick and sensitive supercritical fluid chromatography with tandem mass spectrometry method for the simultaneous determination of lumefantrine, artemether, and its active metabolite dihydroartemisinin in rat plasma was developed and validated. The chromatographic separation was performed on an ACQUITY UPC2 ™ BEH 2-EP column within 2.5 min by gradient elution using compressed CO2 and methanol containing 2 mM ammonium acetate as the mobile phases. Detection was achieved by multiple reaction monitoring using electrospray ionization in the positive ionization mode. For sample preparation, 50 µL of the sample was processed by modified high-throughput, one-step protein precipitation using hydrogen peroxide as a stabilizer to protect the endoperoxide-containing artemisinin derivatives from degradation. The calibration curves were linear over the concentration range of 2.0-1000 ng/mL for both artemether and dihydroartemisinin, and 1.0-5000 ng/mL for lumefantrine. The values of selectivity, lower limit of quantification, linearity, accuracy, precision, matrix effects, stability, and recovery met the acceptable range according to the Food and Drug Administration guidelines. The developed method enables high resolution and speed as well as low cost, low solvent consumption, and short time and was successfully applied to pharmacokinetic studies through the intravenous administration of an artemether-lumefantrine lipid emulsion in rats.

Optimization, characterization and in vitro/vivo evaluation of azilsartan nanocrystals.

Azilsartan (AZL), a poorly soluble drug, was considered to be fit for nanocrystals to improve its solubility. Our study intended to prepare AZL nanocrystals by means of bead milling method. Eight stabilizers or their binary combination and the milling time were set to be variable factors to optimize AZL nanosuspension formulation, and six types of freeze-drying supports were investigated to reduce the aggregation of particles during the solidification. AZL nanocrystals with or without sodium deoxycholate (NaDC) as combined stabilizer with Poloxamer 188 (F68) were prepared owning mean particle sizes of about 300 nm and 460 nm. During the screening processes, the formulation containing NaDC showed a smaller particle size and better stability during lyophilization. The irregular shape and crystal form changing in AZL nanocrystals were discovered by various characterizations. And with physical mixture as reference, nanocrystals showed its improvement about in-vitro dissolution and in-vivo bioavailability. In conclusion, the nanocrystals of AZL could be prepared well in our study. Additionally, our results suggested that NaDC was an appreciated excipient on the nanocrystals platform, which can exhibit the abilities of size-reduction and stability-maintaining on freeze-drying.