A mutation-sensitive, multiplexed and amplification-free detection of nucleic acids by stretching single-molecule tandem hairpin probes.

The detection of nucleic acid sequences in parallel with the discrimination of single nucleotide variations (SNVs) is critical for research and clinical applications. A few limitations make the detection technically challenging, such as too small variation in probe-hybridization energy caused by SNVs, the non-specific amplification of false nucleic acid fragments and the few options of dyes limited by spectral overlaps. To circumvent these limitations, we developed a single-molecule nucleic acid detection assay without amplification or fluorescence termed THREF (hybridization-induced tandem DNA hairpin refolding failure) based on multiplexed magnetic tweezers. THREF can detect DNA and RNA sequences at femtomolar concentrations within 30 min, monitor multiple probes in parallel, quantify the expression level of miR-122 in patient tissues, discriminate SNVs including the hard-to-detect G-U or T-G wobble mutations and reuse the probes to save the cost. In our demonstrative detections using mock clinic samples, we profiled the let-7 family microRNAs in serum and genotyped SARS-CoV-2 strains in saliva. Overall, the THREF assay can discriminate SNVs with the advantages of high sensitivity, ultra-specificity, multiplexing, reusability, sample hands-free and robustness.

5-Methyl-cytosine stabilizes DNA but hinders DNA hybridization revealed by magnetic tweezers and simulations.

5-Methyl-cytosine (5mC) is one of the most important DNA modifications and plays versatile biological roles. It is well known that 5mC stabilizes DNA duplexes. However, it remains unclear how 5mC affects the kinetics of DNA melting and hybridization. Here, we studied the kinetics of unzipping and rezipping using a 502-bp DNA hairpin by single-molecule magnetic tweezers. Under constant loading rates, 5mC increases the unzipping force but counterintuitively decreases the rezipping force at various salt and temperature conditions. Under constant forces, the non-methylated DNA hops between metastable states during unzipping and rezipping, which implies low energy barriers. Surprisingly, the 5mC DNA can't rezip after fully unzipping unless much lower forces are applied, where it rezips stochastically in a one-step manner, which implies 5mC kinetically hinders DNA hybridization and high energy barriers in DNA hybridization. All-atom molecular dynamics simulations reveal that the 5mC kinetically hinders DNA hybridization due to steric effects rather than electrostatic effects caused by the additional methyl groups of cytosines. Considering the possible high speed of DNA unzipping and zipping during replication and transcription, our findings provide new insights into the biological roles of 5mC.

Dual-targeting multifunctional hyaluronic acid ligand-capped gold nanorods with enhanced endo-lysosomal escape ability for synergetic photodynamic-photothermal therapy of cancer.

Au nanorods (AuNRs) have attracted considerable interest as drug delivery systems because of their enhanced cell internalization and stronger drug-loading ability. In addition, the incorporation of photodynamic therapy (PDT) and photothermal therapy (PTT) into one nanosystem presents great promise to defect multiple drawbacks in cancer therapy. Herein, we fabricated a multifunctional and dual-targeting nanoplatform based on hyaluronic acid-grafted-(mPEG/triethylenetetramine-conjugated-lipoic acid/tetra(4-carboxyphenyl)porphyrin/folic acid) polymer ligand capped AuNRs (AuNRs@HA-g-(mPEG/Teta-co-(LA/TCPP/FA)) for combined photodynamic-photothermal therapy of cancer. The prepared nanoparticles displayed high TCPP loading capacity and excellent stability in different biological media. Furthermore, AuNRs@HA-g-(mPEG/Teta-co-(LA/TCPP/FA)) not only could produce a localized hyperthermia to conduct PTT, but also generate cytotoxic singlet oxygen (1 O2 ) to perform PDT under laser irradiation. Confocal imaging results disclosed that this nanoparticle endowing the specific function of polymeric ligand could enhance cellular uptake, accelerate endo/lysosomal escape, as well as produce higher reactive oxygen species. Importantly, this combination therapy strategy could also induce higher anticancer potential than PDT or PTT only against MCF-7 tumor cells in vitro. Therefore, this work presented an AuNRs-based therapeutic nanoplatform with great potential in dual-targeting and photo-induced combination therapy of cancer.

[Adjuvant rice optimization of rice-steamed Rehmanniae Radix and its anti-osteoporosis effect].

The present study aimed to investigate the effect of various adjuvant rice on the quality of rice-steamed Rehmanniae Radix(RSRR) with Japonica rice, millet, yellow rice, black rice, and glutinous rice as raw materials, and analyze the anti-osteoporosis effect of RSRR by the optimal adjuvant rice. On the basis of the established UPLC-MS/MS method for the determination of the content of catalpol and rehmannioside D, comprehensive weighted scoring method was employed to evaluate the effect of various auxiliary rice on the quality of RSRR with the content of catalpol and rehmannioside D, character score, and taste score as indicators to optimize adjuvant rice. The osteoporosis model was induced by ovariectomy in rats. SD rats were randomly divided into a sham operation group, a model group, a positive control group, and low-dose and high-dose groups of Rehmanniae Radix, RSRR, steamed Rehmanniae Radix, and Epimedii Folium-RSRR. After treatment for 12 weeks, body weight, bone calcium content, and bone mineral density were mea-sured. The results showed that Japonica rice was selected as the optimal adjuvant due to the highest comprehensive score of RSRR steamed by Japonica rice. Rehmanniae Radix, RSRR, steamed Rehmanniae Radix, as well as Epimedii Folium-RSRR, could improve osteoporosis by increasing bone calcium content and bone mineral density. RSRR was superior to Rehmanniae Radix in improving osteo-porosis. However, there was no significant difference between RSRR and steamed Rehmanniae Radix. This study confirmed that Japo-nica rice was the optimal adjuvant rice of RSRR and verified the anti-osteoporosis effect of RSRR, which laid a foundation for further research on the pharmacological action and mechanism of RSRR.

Biodegradable and Injectable Hydrogels in Biomedical Applications.

Injectable hydrogels are a unique class of hydrogels that are formed upon injection into living bodies. They possess features of typical hydrogels such as softness, 3D network structures, large contents of water, the ability to load water-soluble substances, and so on. Furthermore, their injectability allows injectable hydrogels to be implanted into living bodies using a syringe in a minimally invasive way. After being loaded with different active substances (drugs, proteins, genes, viruses, cells, etc.), injectable hydrogels have been demonstrated to be potential in many different biomedical applications including controlled release and tissue engineering. However, biodegradability is also an important property of injectable hydrogels and allows removal of the hydrogels after accomplishment of their tasks. In this Perspective, we aim at introducing several different types of biodegradable and injectable hydrogels and compare their differences in properties and applications. Lastly, we also point out some remaining problems and future trends in the field of biodegradable and injectable hydrogels.

Insights into the regulatory role of Plexin D1 signalling in cardiovascular development and diseases.

Plexin D1 (PLXND1), which was previously thought to mediate semaphorin signalling, belongs to the Plexin family of transmembrane proteins. PLXND1 cooperates mostly with the coreceptor neuropilin and participates in many aspects of axonal guidance. PLXND1 can also act as both a tumour promoter and a tumour suppressor. Emerging evidence suggests that mutations in PLXND1 or Semaphorin 3E, the canonical ligand of PLXND1, can lead to serious cardiovascular diseases, such as congenital heart defects, CHARGE syndrome and systemic sclerosis. Upon ligand binding, PLXND1 can act as a GTPase-activating protein (GAP) and modulate integrin-mediated cell adhesion, cytoskeletal dynamics and cell migration. These effects may play regulatory roles in the development of the cardiovascular system and disease. The cardiovascular effects of PLXND1 signalling have gradually been elucidated. PLXND1 was recently shown to detect physical forces and translate them into intracellular biochemical signals in the context of atherosclerosis. Therefore, the role of PLXND1 in cardiovascular development and diseases is gaining research interest because of its potential as a biomarker and therapeutic target. In this review, we describe the cardiac effects, vascular effects and possible molecular mechanisms of PLXND1 signalling.

CD44-Targeted and Enzyme-Responsive Photo-Cross-Linked Nanogels with Enhanced Stability for In Vivo Protein Delivery.

One of the biggest challenges of the protein delivery system is to realize stable and high protein encapsulation efficiency in blood circulation and rapid release of protein in the targeted tumor cells. To overcome these hurdles, we fabricated enzyme-responsive photo-cross-linked nanogels (EPNGs) through UV-triggered chemical cross-linking of cinnamyloxy groups in the side chain of PEGylation hyaluronic acid (HA) for CD44-targeted transport of cytochrome c (CC). The EPNGs showed high loading efficiency and excellent stability in different biological media. Notably, CC leakage effectively suppressed under physiological conditions but accelerated release in the presence of hyaluronidase, an overexpressed enzyme in tumor cells. Moreover, thiazolylblue tetrazolium bromide (MTT) results indicated that the vacant EPNGs showed excellent nontoxicity, while CC-loaded EPNGs exhibited higher killing efficiency to CD44-positive A549 cells than to CD44-negative HepG2 cells and free CC. Confocal images confirmed that CC-loaded EPNGs could effectively be internalized by CD44-mediated endocytosis pathway and rapidly escape from the endo/lysosomal compartment. Human lung tumor-bearing mice imaging assays further revealed that CC-loaded EPNGs actively target tumor locations. Remarkably, CC-loaded EPNGs also exhibited enhanced antitumor activity with negligible systemic toxicity. These results implied that these EPNGs have appeared as stable and promising nanocarriers for tumor-targeting protein delivery.

Hypermethylated PAX1 and ZNF582 genes in the tissue sample are associated with aggressive progression of oral squamous cell carcinoma.

BACKGROUND: DNA methylation of paired box gene 1 (PAX1) and zinc finger 582 (ZNF582) is promising cancer biomarkers for oral squamous cell carcinoma detection. This study aims to investigate the correlation between PAX1 or ZNF582 methylation and the progression of oral squamous cell carcinoma (OSCC). MATERIALS AND METHODS: A total of 135 OSCC cases from Peking University School and Hospital of Stomatology were enrolled in this study. Tissue specimens were collected from the lesion site and corresponding adjacent normal site. The methylation level of these two genes was evaluated in primary and recurrent OSCC group. RESULTS: Hypermethylation of PAX1 or ZNF582 was observed in lesion sites among primary and recurrent OSCC cases. In the lesion site of primary cases, promoter methylation was observed in T3/T4 (PAX1: P = .02; ZNF582: P = .01), stage III/IV (PAX1: P = .03; ZNF582: P = .01), and bone invasion cases (PAX1: P = .02; ZNF582: P = .047). In the subgroup analysis, the correlation between hypermethylation and OSCC severity remains significant with exposure to smoking/alcohol consumption. CONCLUSIONS: Hypermethylated PAX1 and ZNF582 can sufficiently act as biomarkers to reflect the severity or progression of OSCC.

Recent Advances of pH-Induced Charge-Convertible Polymer-Mediated Inorganic Nanoparticles for Biomedical Applications.

The incorporation of functional polymers and inorganic nanoparticles into nanoplatforms has the potential to produce personalized nanomedicine systems for further biomedical applications. Polymers that endow inorganic nanoparticles with unique surface properties for prolonged blood circulation and improved tumor targeting and cellular uptake are especially desired. pH-induced charge-switchable polymers are sensitive to the pH of the tumor environment and maintain a negative or neutral charge in blood circulation, increasing their circulation time and enhancing tumor accumulation via the enhanced permeability and retention effect. This type of polymer further transforms its charge to positive in acidic tumor locations to promote cellular uptake. Furthermore, the combination of pH-induced charge-switchable polymers with various inorganic nanoparticles (e.g., magnetic nanoparticles, gold nanoparticles, quantum dots, and upconversion materials) activates their intrinsic functions in in situ diagnosis and disease therapy. This review briefly overviews the recent progress in the development and application of various pH-induced charge-convertible polymers functionalized with different types of inorganic nanoparticles for different biomedical applications. More importantly, future developments in this field are also discussed.

Factors Affecting Volume Change of Anterolateral Thigh Flap in Head and Neck Defect Reconstruction.

PURPOSE: The anterolateral thigh flap (ALTF) volume will decrease over time after surgery. We measured and identified the risk factors for postoperative volume changes in the ALTF. MATERIALS AND METHODS: We designed and performed a retrospective cohort study of patients who had undergone reconstruction of oral and maxillofacial defects using ALTFs at the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from June 2012 to December 2018. We measured the volume of the ALTFs at 1, 3, 6, 12, and 24 months postoperatively; the flap volume at 1 month postoperatively was taken as the baseline. The primary outcome variables were the residual ALTF rates at 3, 6, 12, and 24 months postoperatively, defined as the ratio between the present volume at each month and at baseline. The primary predictor variables were the clinical variables that might be associated with ALTF volume loss. Descriptive and bivariate statistics were computed, and the P value for statistical significance was set at ≤ .05. RESULTS: The sample included 70 subjects with a mean age of 53.8 years (46 men and 24 women). The postoperative residual rates at 3, 6, 12, and 24 months were 72.3, 69.0, 67.9, and 68.7%, respectively, of the baseline volume. The use of postoperative radiotherapy (P < .01) and low body mass index (BMI; P = .006) were significantly associated with postoperative ALTF volume loss. CONCLUSIONS: The results of the present study suggest that ALTF volume shrinkage mainly occurs within 6 months postoperatively and that postoperative radiotherapy and a low BMI are risk factors for volume loss. Overcorrection should be performed to account for the shrinkage of ALTFs, and postoperative nutrition management is important to avoid ALTF volume loss.

Gene Expression Profiling Reveals Enhanced Defense Responses in an Invasive Weed Compared to Its Native Congener During Pathogenesis.

Invasive plants are a huge burden on the environment, and modify local ecosystems by affecting the indigenous biodiversity. Invasive plants are generally less affected by pathogens, although the underlying molecular mechanisms responsible for their enhanced resistance are unknown. We investigated expression profiles of three defense hormones (salicylic acid, jasmonic acid, and ethylene) and their associated genes in the invasive weed, Alternanthera philoxeroides, and its native congener, A. sessilis, after inoculation with Rhizoctonia solani. Pathogenicity tests showed significantly slower disease progression in A. philoxeroides compared to A. sessilis. Expression analyses revealed jasmonic acid (JA) and ethylene (ET) expressions were differentially regulated between A. philoxeroides and A. sessilis, with the former having prominent antagonistic cross-talk between salicylic acid (SA) and JA, and the latter showing weak or no cross-talk during disease development. We also found that JA levels decreased and SA levels increased during disease development in A. philoxeroides. Variations in hormonal gene expression between the invasive and native species (including interspecific differences in the strength of antagonistic cross-talk) were identified during R. solani pathogenesis. Thus, plant hormones and their cross-talk signaling may improve the resistance of invasive A. philoxeroides to pathogens, which has implications for other invasive species during the invasion process.

Comparison the sensitivity of amphibian metamorphosis assays with NF 48 stage and NF 51 stage Xenopus laevis tadpoles.

The amphibian metamorphosis assay (AMA) was proposed by the Organization for Economic Cooperation and Development (OECD) to screen thyroid disruptors of vertebrate species. The general experimental design of the AMA exposes Nieuwkoop and Faber (NF) stage 51 Xenopus laevis tadpoles to test chemical concentrations for 21 d. However, recent studies demonstrated that thyroid gland began to function after NF stage 45 in X. laevis. Thus, in this study, we initiated exposure with NF stage 48 tadpoles when the thyroid gland is still in a preliminary development period, to compare the sensitivity of the AMA with NF 48 stage and NF 51 stage tadpoles. Further, the application and sensitivity of the optimized AMA were evaluated and validated by two known thyroid toxicants methimazole (MMI) and sodium perchlorate (SP). The observational endpoints are developmental stage, hind limb length (HLL), snout-vent length (SVL), wet weight, and daily observations of mortality. The results were as follows. Although the sensitivity to endpoint of growth, such as wet weight and SVL was similar between the two assays, our optimized AMA detected delaying effects of 1 mg/L MMI and 32 µg/L SP on metamorphosis development both on day 7 and at test termination, which were lower than those in AMA. Additionally, it is easier to get a large number of animals at NF stage 48 than NF stage 51 in a short time. Thus, it is suggested that the NF stage 48 tadpoles might be applied to the AMA for efficiently screening the thyroid-active substances.

One-Step Preparation of pH-Responsive Polymeric Nanogels as Intelligent Drug Delivery Systems for Tumor Therapy.

In this work, pH-responsive polypeptide-based nanogels are reported as potential drug delivery systems. By the formation of pH-sensitive benzoic imine bonds, pH-responsive nanogels are constructed using hydrophilic methoxy poly(ethylene glycol)- b-poly[ N-[ N-(2-aminoethyl)-2-aminoethyl]-l-glutamate] (MPEG- b-PNLG) and hydrophobic terephthalaldehyde (TPA) as a cross-linker. At pH 7.4, MPEG- b-PNLG nanogels exhibit high stabilities with hydrophobic inner cores, which allow encapsulation of hydrophobic therapeutic agents. Under tumoral acidic environments (pH ∼6.4), the cleavage of benzoic imine bonds induces the destruction of MPEG- b-PNLG nanogels and leads to rapid release of their payloads. The formation and pH sensitivity of the nanogels are investigated by dynamic light scattering. These nanogels exhibit excellent stabilities in the presence of salt or against dilution. The globular morphologies of the nanogels are confirmed using transmission electron microscopy. Doxorubicin is used as a model drug to evaluate drug encapsulation and release. Finally, the anticancer activities of the drug-encapsulated nanogels are assessed in vitro.

Rapamycin enhances the anti-angiogenesis and anti-proliferation ability of YM155 in oral squamous cell carcinoma.

YM155, a small molecule inhibitor of survivin, has been studied in many tumors. It has been shown that YM155 inhibited oral squamous cell carcinoma through promoting apoptosis and autophagy and inhibiting proliferation. It was found that YM155 also inhibited the oral squamous cell carcinoma-mediated angiogenesis through the inactivation of the mammalian target of rapamycin pathway. Rapamycin, a mammalian target of rapamycin inhibitor, played an important role in the proliferation and angiogenesis of oral squamous cell carcinoma cell lines. In our study, cell proliferation assay, transwell assay, tube formation assay, and western blot assay were used to investigate the synergistic effect of rapamycin on YM155 in oral squamous cell carcinoma. Either in vitro or in vivo, rapamycin and YM155 exerted a synergistic effect on the inhibition of survivin and vascular endothelial growth factor through mammalian target of rapamycin pathway. Overall, our results revealed that low-dose rapamycin strongly promoted the sensitivity of oral squamous cell carcinoma cell lines to YM155.

Long non-coding RNA UCA1 contributes to the progression of oral squamous cell carcinoma by regulating the WNT/ß-catenin signaling pathway.

With the development of functional genomics studies, a mass of long non-coding RNAs (LncRNA) were discovered from the human genome. Long non-coding RNAs serve as pivotal regulators of genes that are able to generate LncRNA-binding protein complexes to modulate a great number of genes. Recently, the LncRNA urothelial carcinoma-associated 1 (UCA1) has been revealed to be dysregulated, which plays a critical role in the development of a few cancers. However, the role of the biology and clinical significance of UCA1 in the tumorigenesis of oral squamous cell carcinoma (OSCC) remain unknown. We found that UCA1 expression levels were upregulated aberrantly in tongue squamous cell carcinoma tissues and associated with lymph node metastasis and TNM stage. We explored the expression, function, and molecular mechanism of LncRNA UCA1 in OSCC. In the present work, we revealed that UCA1 silencing suppressed proliferation and metastasis and induced apoptosis of OSCC cell lines in vitro and in vivo, which might be related to the activation level of the WNT/ß-catenin signaling pathway. Our research results emphasize the pivotal role of UCA1 in the oncogenesis of OSCC and reveal a novel LncRNA UCA1-ß-catenin-WNT signaling pathway regulatory network that could contribute to our understanding in the pathogenesis of OSCC and assist in the discovery of a viable LncRNA-directed diagnostic and therapeutic strategy for this fatal disease.

Polymer-Based and pH-Sensitive Nanobiosensors for Imaging and Therapy of Acidic Pathological Areas.

Nanobiosensors with high sensitivity and specificity have shown great potential in the detection of diseases. The incorporation of therapeutic agents with nanobiosensors allows the simultaneous diagnosis and therapy of diseases. The delivery of nanobiosensors and therapeutic agents using polymers is a common strategy to improve imaging and therapeutic efficacies. These polymers play important roles in several aspects during a successful delivery process, such as increasing the stability and biocompatibility of the nanobiosensors and improving their cell endocytosis. The pH-sensitivity of the nanobiosensors endows them with various capabilities, such as enabling the selective targeting of pathological areas, activation of imaging signals and controlled release of payloads. This review focuses on the design, preparation and characterization of polymer-based and pH-sensitive nanobiosensors and the in intro/in vivo assessment of their ability to serve as efficient agents for the diagnosis and therapy of acidic pathological areas.

Assessment of Utilization and Cost-Effectiveness of Telemedicine Program in Western Regions of China: A 12-Year Study of 249 Hospitals Across 112 Cities.

BACKGROUND: The imbalance in healthcare between urban and rural areas is still a problem in China. In recent decades, China has aimed to develop telemedicine. We assessed the implementation, utilization, and cost-effectiveness of a large telemedicine program across western China. MATERIALS AND METHODS: In 2002-2013, a government-sponsored major telemedicine program was established by West China Hospital of Sichuan University (hub), covering 249 spoke hospitals in 112 cities throughout western China and in 40 medical expertise areas. We analyzed the cross-sectional data from 11,987 consultations conducted at West China Hospital using the telemedicine network over a 12-year period. The types of diseases as well as the diagnosis and treatment changes were assessed. We also performed a cost-savings analysis and a one-way sensitivity analysis. RESULTS: Of the 11,987 teleconsultations, we noted that neoplasms (19.4%), injuries (13.9%), and circulatory diseases (10.3%) were the three most common diagnoses. Teleconsultations resulted in a change of diagnosis in 4,772 (39.8%) patients, and 3,707 (77.7%) of them underwent major diagnosis changes. Moreover, it led to a change of treatment in 6,591 (55.0%) patients, including 3,677 (55.8%) changes not linked to diagnosis changes. The telemedicine network resulted in an estimated net saving of $2,364,525 (if the patients traveled to the hub) or $3,759,014 (if the specialists traveled to the spoke hospitals). CONCLUSIONS: The introduction of telemedicine in China, linking highly specialized major hospitals (hub) with hundreds of small rural hospitals (spoke), can greatly improve the quality, efficiency, and cost-effectiveness of healthcare delivery and utilization. This new Internet-based healthcare model should be utilized more widely in developing countries.

Loading of a coordination polymer nanobelt on a functional carbon fiber: a feasible strategy for visible-light-active and highly efficient coordination-polymer-based photocatalysts.

To improve the photocatalytic properties of coordination polymers under irradiation in the visible-light region, coordination polymer nanobelts (CPNB) were loaded on functional carbon fiber (FCF) through the use of a simple colloidal blending process. The resulting coordination polymer nanobelt loaded functional carbon fiber composite material (CPNB/FCF) exhibited dramatically improved photocatalytic activity for the degradation of rhodamine B (RhB) under visible-light irradiation. Optical and electrochemical methods illustrated the enhanced photocatalytic activity of CPNB/FCF originated from high separation efficiency of photogenerated electrons and holes on the interface of CPNB and FCF, which was produced by the synergy effect between them. In the composite material, the role of FCF could be described as photosensitizer and good electron transporter. For FCF, the number of functional groups on its surface has a significant influence on the photocatalytic performance of the resulting CPNB/FCF composite material, and an ideal FCF carrier was obtained as a highly efficient CPNB/FCF photocatalyst. CPNB/FCF showed outstanding stability during the degradation of rhodamine B (RhB); thus, the material is suitable for use as a photocatalyst in the treatment of organic dyes in water.

Chemotherapy combined with bevacizumab for small cell lung cancer with brain metastases: A case report.

BACKGROUND: Small cell lung cancer (SCLC) is a common and aggressive subtype of lung cancer. It is characterized by rapid growth and a high mortality rate. Approximately 10% of patients with SCLC present with brain metastases at the time of diagnosis, which is associated with a median survival of 5 mo. This study aimed to summarize the effect of bevacizumab on the progression-free survival (PFS) and overall survival of patients with brain metastasis of SCLC. CASE SUMMARY: A 62-year-old man was referred to our hospital in February 2023 because of dizziness and numbness of the right lower extremity without headache or fever for more than four weeks. The patient was diagnosed with limited-stage SCLC. He received 8 cycles of chemotherapy combined with maintenance bevacizumab therapy and achieved a PFS of over 7 mo. CONCLUSION: The combination of bevacizumab and irinotecan effectively alleviated brain metastasis in SCLC and prolonged PFS.

Enhancing cell-scale performance via sustained release of the varicella-zoster virus antigen from a microneedle patch under simulated microgravity.

The immune system of astronauts might become weakened in the microgravity environment in space, and the dormant varicella-zoster virus (VZV) in the body might be reactivated, seriously affecting their work and safety. For working in orbit for the long term, there is currently no efficient and durable delivery system of general vaccines in a microgravity environment. Accordingly, based on the previous foundation, we designed, modified, and synthesized a biodegradable and biocompatible copolymer, polyethylene glycol-polysulfamethazine carbonate urethane (PEG-PSCU) that could be mainly adopted to fabricate a novel sustained-release microneedle (S-R MN) patch. Compared with conventional biodegradable microneedles, this S-R MN patch could not only efficiently encapsulate protein vaccines (varicella-zoster virus glycoprotein E, VZV gE) but also further prolong the release time of VZV gE in a simulated microgravity (SMG) environment. Eventually, we verified the activation of dendritic cells by VZV gE released from the S-R MN patch in an SMG environment and the positive bioeffect of activated dendritic cells on lymphocytes using an in vitro lymph node model. This study is of great significance for the exploration of long-term specific immune responses to the VZV in an SMG environment.