Exopolysaccharides from endophytic Glutamicibacter halophytocota KLBMP 5180 functions as bio-stimulants to improve tomato plants growth and salt stress tolerance.

Microbial exopolysaccharides (EPSs) can promote plants growth and protect them against various abiotic stresses, but the role of actinobacteria-produced EPSs in plant growth promoting is still less known. Here, we aim to explore the effect of EPSs from an endophyte Glutamicibacter halophytocota KLBMP 5180 on tomato seeds germination and seedlings growth under salt stress. Our study revealed that 2.0 g/L EPSs resulted in increased seed germination rate by 23.5 % and 11.0 %, respectively, under 0 and 200 mM NaCl stress conditions. Further pot experiment demonstrated that EPSs significantly promoted seedlings growth under salt stress, with increased height, root length and fibrous roots number. Plant physiological traits revealed that EPSs increased chlorophyll content, enhanced the activity of antioxidant enzymes, soluble sugar, and K+ concentration in seedlings; malondialdehyde and Na+ contents were reduced. Additionally, auxin, abscisic acid, jasmonic acid, and salicylic acid were accumulated significantly in seedlings after EPSs treatment. Furthermore, we identified 1233 differentially expressed genes, and they were significantly enriched in phytohormone signal transmission, phenylpropanoid biosynthesis, and protein processing in endogenous reticulum pathways, etc. Our results suggest that KLBMP 5180-produced EPSs effectively ameliorated NaCl stress in tomato plants by triggering complex regulation mechanism, and showed application potentiality in agriculture.

Abundant and diverse endophytic bacteria associated with medicinal plant Arctium lappa L. and their potential for host plant growth promoting.

Arctium lappa L. is one of the medicinal and food homologous plants in China, which is rich in nutrients and medicinal ingredients. The use of plant growth-promoting (PGP) endophytic bacteria is an alternative to reducing chemical fertilizers in agricultural production. The aim of this study was to analyze the diversity of endophytic bacteria in different cultivars of A. lappa L. collected from two geographical locations in China and evaluate PGP traits of the isolates and their potential PGP ability in greenhouse condition. Endophytic bacterial community was investigated by culture-dependent and culture-independent methods. Isolates were screened and investigated for multiple PGP traits, and representative strains were inoculated host seedlings to evaluate the growth promoting effect. A total of 348 endophytic bacteria were obtained and they were distributed into 4 phyla and 30 genera. In addition, high throughput sequencing revealed more abundant bacterial community, including 17 bacterial phyla and 207 genera. A high proportion of PGP traits were detected, including production of indole acetic acid, siderophore, ammonia and phosphate solubilization. Four representative strains with multiple PGP traits of the most dominant genera (Bacillus, Pantoea, Microbacterium and Pseudomonas) were further selected for host inoculation and growth promoting evaluation, and they significantly increase seedlings length, root length and fresh weight. This study demonstrated that A. lappa L. harbors abundant endophytic bacteria, and some endophytic bacteria showed good potential for the development of microbial fertilizer in the future.

Antifungal Volatile Organic Compounds from Streptomyces setonii WY228 Control Black Spot Disease of Sweet Potato.

Volatile organic compounds (VOCs) produced by microorganisms are considered promising environmental-safety fumigants for controlling postharvest diseases. Ceratocystis fimbriata, the pathogen of black spot disease, seriously affects the quality and yield of sweet potato in the field and postharvest. This study tested the effects of VOCs produced by Streptomyces setonii WY228 on the control of C. fimbriata in vitro and in vivo. The VOCs exhibited strong antifungal activity and significantly inhibited the growth of C. fimbriata. During the 20-day storage, VOC fumigation significantly controlled the occurrence of the pathogen, increased the content of antioxidants and defense-related enzymes and flavonoids, and boosted the starch content so as to maintain the quality of the sweet potatoes. Headspace analysis showed that the volatiles 2-ethyl-5-methylpyrazine and dimethyl disulfide significantly inhibited the mycelial growth and spore germination of C. fimbriata in a dose-dependent manner. Fumigation with 100 µL/L 2-ethyl-5-methylpyrazine completely controlled the pathogen in vivo after 10 days of storage. Transcriptome analysis showed that volatiles mainly downregulated the ribosomal synthesis genes and activated the proteasome system of the pathogen in response to VOC stress, while the genes related to spore development, cell membrane synthesis, mitochondrial function, and hydrolase and toxin synthesis were also downregulated, indicating that WY228-produced VOCs have diverse modes of action for pathogen control. Our study demonstrates that fumigation of sweet potato tuberous roots with S. setonii WY228 or use of formulations based on the VOCs is a promising new strategy to control sweet potato and other food and fruit pathogens during storage and shipment. IMPORTANCE Black spot disease caused by Ceratocystis fimbriata has caused huge economic losses to worldwide sweet potato production. At present, the control of C. fimbriata mainly depends on toxic fungicides, and there is a lack of effective alternative strategies. The research on biological control of sweet potato black spot disease is also very limited. An efficient biocontrol technique against pathogens using microbial volatile organic compounds could be an alternative method to control this disease. Our study revealed the significant biological control effect of volatile organic compounds of Streptomyces setonii WY228 on black spot disease of postharvest sweet potato and the complex antifungal mechanism against C. fimbriata. Our data demonstrated that Streptomyces setonii WY228 and its volatile 2-ethyl-5-methylpyrazine could be a candidate strain and compound for the creation of fumigants and showed the important potential of biotechnology applications in the field of food and agriculture.

Less blood loss in supercapsular percutaneously assisted versus posterolateral total hip arthroplasty.

BACKGROUND: Although excellent clinical outcomes of supercapsular percutaneously assisted total hip arthroplasty (SuperPath) have been reported, the peri-operative blood loss has rarely been reported. The current study determined the blood loss during SuperPath and compared the blood loss with conventional posterolateral total hip arthroplasty (PLTH). METHODS: This retrospective study enrolled patients who underwent unilateral primary THA between January 2017 and December 2019. The demographic data, diagnoses, affected side, radiographic findings, hemoglobin concentration, hematocrit, operative time, transfusion requirements, and intra-operative blood loss were recorded. The peri-operative blood loss was calculated using the OSTHEO formula. Blood loss on the 1st, 3rd, and 5th post-operative days was calculated. Hidden blood loss (HBL) was determined by subtracting the intra-operative blood loss from the total blood loss. RESULTS: Two hundred sixty-three patients were included in the study, 85 of whom were in the SuperPath group and 178 in the posterolateral total hip arthroplasty (PLTH) group. Patient demographics, diagnoses, affected side, operative times, and pre-operative hemoglobin concentrations did not differ significantly between the two groups (all P > 0.05). Compared to the PLTH group, the SuperPath group had less blood loss, including intra-operative blood loss, 1st, 3rd, and 5th post-operative days blood loss, and HBL (all P < 0.05). Total blood loss and HBL was 790.07 ± 233.37 and 560.67 ± 195.54 mL for the SuperPath group, respectively, and 1141.26 ± 482.52 and 783.45 ± 379.24 mL for the PLTH group. PLTH led to a greater reduction in the post-operative hematocrit than SuperPath (P < 0.001). A much lower transfusion rate (P = 0.028) and transfusion volume (P = 0.019) was also noted in the SuperPath group. CONCLUSION: SuperPath resulted in less perioperative blood loss and a lower transfusion rate than conventional PLTH.

Duodenal gastrointestinal stromal tumors: A retrospective study based on a 13 years experience of a single center in China.

AIM: Duodenal gastrointestinal stromal tumors (GISTs) constitute a small rare subset. This study aims to analyze the prognostic differences between duodenal and jejunoileal GISTs and evaluate the clinical treatment and prognostic characteristics of patients with duodenal GISTs. METHODS: Data of patients with primary duodenal or jejunoileal GISTs were collected. Patients were matched through propensity score matching (PSM). Perioperative and long-term outcomes of patients with duodenal GISTs were compared based on surgical approach. RESULTS: Altogether, 101 duodenal and 219 jejunoileal GISTs were identified. In patients with duodenal GISTs, 79 (78%) underwent local resection (LR) and 22 (22%) underwent pancreaticoduodenectomy (PD). Patients undergoing PD had a longer postoperation stay (18.5 vs 13 days, P = 0.001) and more complications (Clavien-Dindo I-II complications for PD vs LR, 31.8 vs 15.2%; Clavien-Dindo III-V complications for PD vs LR, 22.7 vs. 2.5%; P < 0.001). There was no difference in recurrence-free survival (RFS) (P = 0.8) or overall survival (OS) (P = 0.9) when comparing patients who underwent LR versus PD. Multivariable analysis showed that tumor size >5 cm was the only independent predictor of shorter RFS (P = 0.004) and OS (P = 0.012). After matching, there was no significant difference in RFS and OS between patients with duodenal versus jejunoileal GISTs (both P > 0.05). CONCLUSION: The prognosis of duodenal and jejunoileal GISTs are similar. Recurrence and OS of duodenal GISTs primarily depend on tumor size. For duodenal GISTs, LR is associated with comparable long-term survival when compared to PD, but with superior short-term outcomes.

Prospective effect of dietary intake of fat on menarche among girls / 中国学校卫生

Objective@#To explore the prospective effect of dietary intake of total fat and fatty acids on menarcheal timing among girls,and to provide a theoretical basis for preventing the early puberty development of Chinese children.@*Methods@#Using the data from 1997-2015 China Health and Nutrition Survey (CHNS), 1 240 girls aged 6-13 with menarche information, baseline dietary survey data and at least one follow up assessment were selected. Cox regression analysis was performed to examine the prospective effect of dietary intake of total fat and fatty acids before menarche on age at menarche.@*Results@#The mean baseline age of the participants was (8.3±1.8). After adjustment for year of birth, residence, household income, dietary energy intake and body mass index Z score at baseline, girls in the highest quartile of intake of total fat and polyunsaturated fatty acid (PUFA) had a 30% and 34% higher probability of experiencing menarche at an earlier age than those in the lowest quartile [ HR(HR 95%CI )=1.30 (1.01~1.68)，1.34(1.05~1.70)]. After adjusting for the confounders, there were no correlations between the intake of saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) and the onset of menarche [ HR(HR 95%CI )=1.24(0.98~1.58),1.25(0.97~ 1.62 )]( P >0.05).@*Conclusion@#Higher dietary intake of total fat and PUFA before menarche may lead to earlier age at menarche and no correlation between intake of SFA and MUFA before menarche with age at menarche is found among Chinese girls.

Prospective association between peripubertal diet quality and puberty timing / 中国学校卫生

Objective@#To examine the prospective association between peripubertal diet quality and pubertal timing.@*Methods@#Multivariate regression analyses were performed using data obtained from 1 588 SCCNG (Southwest China Childhood Nutrition and Growth) study participants, which included dietary data, anthropometric parameters, and information about potential confounders during peri puberty, two and four years before the onset of menarche or voice break. Dietary intake in peri puberty was assessed using a validated food frequency questionnaire. Diet quality was determined using the Chinese Children Dietary Index (CCDI), which measures adherence to current dietary recommendations. Age at menarche or voice break (M/VB) were used as pubertal markers.@*Results@#The CCDI score ranged from 58.0 to 132.5 for girls and from 48.3 to 129.9 for boys. The pubertal markers consistently indicated that girls and boys with a higher peripubertal diet quality entered puberty later than their counterparts with lower CCDI scores (higher vs. lower CCDI tertiles: age at M was 13.1 years (11.2-13.3) and 12.5 years (12.0-13.9)(P<0.01); VB was 13.8 years (12.1-14.8) and 13.4 years (12.5-15.1)（P=0.03), after adjusting for paternal education level, energy intake, and pre pubertal body fat.@*Conclusion@#Children with a higher diet quality during peri puberty entered puberty at a later age. Dietary guidance and intervention are needed for better dietary quality among children during pubertal transition.

Biomechanical comparison between single-row with triple-loaded suture anchor and suture-bridge double-row rotator cuff repair.

BACKGROUND: Numerous biomechanical and clinical studies comparing different techniques for rotator cuff repair have been reported, yet universal consensus regarding the superior technique has not achieved. A medially-based single-row with triple-loaded suture anchor (also referred to as the Southern California Orthopedic Institute [SCOI] row) and a suture-bridge double-row (SB-DR) with Push-Locks have been shown to result in comparable improvement in treating rotator cuff tear, yet the biomechanical difference is unknown. The purpose of the current study was to determine whether a SCOI row repair had comparable initial biomechanical properties to a SB-DR repair. METHODS: Six matched pairs of fresh-frozen cadaveric shoulders with full-thickness supraspinatus tendon tears we created were included. Two different repairs were performed for each pair (SCOI row and SB-DR methods). Specimens were mounted on a material testing machine to undergo cyclic loading, which was cycled from 10 to 100 N at 1 Hz for 500 cycles. Construct gap formation was recorded at an interval of 50 cycles. Samples were then loaded to failure and modes of failure were recorded. Repeated-measures analysis of variance and pair-t test were used for statistical analyses. RESULTS: The construct gap formation did not differ between SCOI row and SB-DR repairs (P = 0.056). The last gap displacement was 1.93 ± 0.37 mm for SCOI row repair, and 1.49 ± 0.55 mm for SB-DR repair. The tensile load for 5 mm of elongation and ultimate failure were higher for SCOI row repair compared to SB-DR repair (P = 0.011 and 0.028, respectively). The ultimate failure load was 326.34 ± 11.52 N in the SCOI row group, and 299.82 ± 27.27 N in the SB-DR group. Rotator cuff repair with the SCOI row method failed primarily at the suture- tendon interface, whereas pullout of the lateral row anchors was the primary mechanism of failure for repair with the SB-DR method. CONCLUSION: Rotator cuff repair with the SCOI row method has superior biomechanical properties when compared with the SB-DR method. Therefore, SCOI row repair using a medially-based single-row technique with triple-loaded suture anchor is recommended to improve the initial strength in treating full-thickness rotator cuff tears.

Elevated preoperative platelet-to-lymphocyte ratio predicts poor prognosis of patients with primary gastrointestinal stromal tumor.

BACKGROUND: The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are considered to reflect the systemic inflammatory response and clinical prognosis. However, the independent prognostic values of the NLR and PLR for patients with gastrointestinal stromal tumor (GIST) remain debatable. This study aims to evaluate the prognostic value of preoperative NLR and PLR in GIST patients. METHODS: We retrospectively reviewed all GIST patients diagnosed and surgically treated at Union Hospital between 2005 and 2018. The preoperative NLR and PLR were calculated to evaluate recurrence-free survival (RFS) and overall survival (OS) by Kaplan-Meier analysis. Univariate and multivariate Cox regression analyses were performed to estimate the independent prognostic values. RESULTS: The median follow-up time was 49 months (interquartile range, 22-74 months). The preoperative PLR was significantly increased in the GIST patients with intermediate and high tumor risks. Increases in the NLR (≥2.34) and PLR (≥185.04) were associated with shorter RFS and OS (P < 0.01). Moreover, the multivariate analysis revealed that elevated PLR was an independent factor for shorter RFS (hazard ratio [HR]: 3.041; 95% confidence interval [CI]: 2.001-4.622; P < 0.001) and OS (HR: 1.899; 95% CI: 1.136-3.173; P = 0.014). CONCLUSIONS: The preoperative PLR is a potential biomarker of GIST and is related to the clinical outcome. An elevated preoperative PLR predicts poor prognosis of patients with primary GIST after complete surgical resection.

Transcutaneous implantation of valproic acid-encapsulated dissolving microneedles induces hair regrowth.

The interest in alternative material systems and delivery methods for treatment of androgenetic alopecia has been increasing in the recent decades. Topical application of valproic acid (VPA), an FDA-approved anticonvulsant drug, has been shown to effectively stimulate hair follicle (HF) regrowth by upregulating Wnt/ß-catenin, a key pathway involved in initiation of HF development. Moreover, a majority of studies have suggested that cutaneous wound re-epithelialization is capable of inducing HF through Wnt/ß-catenin pathway. Here, we report fabrication and evaluation of a novel VPA-encapsulating dissolving microneedle (DMN-VPA) that creates minimally invasive dermal micro-wounds upon application, significantly improving the VPA delivery efficiency. DMN-VPA not only delivers encapsulated VPA with higher accuracy than topical application, it also stimulates wound re-epithelialization signals involved in HF regrowth. Through a series of in vivo studies, we show that micro-wounding-mediated implantation of DMN-VPA upregulates expression of Wnt/ß-catenin pathway, alkaline phosphatase, proliferating cell nuclear antigen, loricrin and HF stem cell markers, including keratin 15, and CD34 more effectively than topical application.

Molecular cloning and characterization of (β -1, 3-Dextran gene (Glu) in endangered tropic medicinal plant Dendrobium officinale

Objective:Dendrobium officinale (Orchidaceae) (D. officinale) is one of the world’s most endangered plants with great medicinal value. It is mainly distributed in south China, and is often used as auxiliary treatment for a variety of tropical diseases. The strictly demanding for growing environment and climate conditions making its wild resources endangered. In nature, the relationship between seeds of D. officinale and fungi must be established by symbiotic system. Our purpose is to analyze the molecular events involved in the interaction between fungus and plant during this process, and provide scientific basis for the protection of its germplasm resources.Methods:Beta-1,3-glucan (Glu) is a key enzyme in the biosynthesis of polyamines, which is essential to the basic physiological and biochemical processes of plants. In this study, the full-length cDNA of Glu gene was obtained from symbiotic germinating seeds of medicinal plants by rapid amplified cDNA terminal (RACE) - PCR, and its expression characteristics were analyzed for the first time.Results:Glu has a full length cDNA of 1 317 bp, with one open reading frame (ORF). The deduced protein was 356 amino acids (aa) with molecular weight of 37.24 KDa and a theoretical isoelectric point of 5.17. The deduced β-1,3-Dextran protein, without signal peptide, had three transmembrane domain each contained 23,17 and 20 aa. Multiple sequence alignment and phylogenetic analysis showed that the sequence similarity between beta-1,3-glucan and rice beta-1,3-glucan was higher than that of dicotyledons. The expression pattern analyzed by qPCR showed that Glu transcripts were expressed in four tissues (non-infected fungi) without significant change. In symbiotic germinating seeds, the expression level is 23.67 times higher than that of ungerminated seeds.Conclusion:These results indicated that β-1,3-Dextran was possible involved in the symbiotic seed germination of D. officinale, and played an important role in the symbiosis system of mycorrhizal mutual.

Anti-obesity effect of a novel caffeine-loaded dissolving microneedle patch in high-fat diet-induced obese C57BL/6J mice.

Natural products such as caffeine have been found to be effective in reducing body weight through lipolysis. Here, we report the successful loading of caffeine onto dissolving microneedle following inhibition of its crystal growth by hyaluronic acid (HA), the matrix material of the dissolving microneedle (DMN). Further, the anti-obesity activity of caffeine was evaluated in high-fat diet-induced obese C57BL/6J mice. After 6weeks of caffeine loaded dissolving microneedle patch (CMP) administration, lipolysis improved significantly as shown by leptin and adiponectin activity, which resulted in considerable weight loss of about 12.8±0.75% in high-fat diet-induced obese mice. Comparison of the levels of triglyceride, total cholesterol, high-density lipoprotein (HDL)-cholesterol, and low-density lipoprotein (LDL)-cholesterol after CMP administration with the initial levels in obese mice indicated significant anti-obesity activity of CMP. These findings suggested that a novel CMP with an increased amount of caffeine loaded onto DMN has therapeutic activity against obesity.

Minimally invasive curved-micro-drainer (CMD) capable of innocuous drainage of subretinal fluid for the treatment of retinal detachment.

Retinal detachment is a serious vision threatening disease. Current consensus for the treatment of retinal detachment is to reattach the retina onto the choroid layer by drainage of accumulated subretinal fluid. Although several surgical methods have been developed, no satisfactory visual outcome has been obtained without surgical complications such as unintended puncture and hemorrhage of the retina and choroid tissue. In this study, we developed a novel Curved-Micro-Drainer (CMD) for the innocuous drainage of subretinal fluid. It is a curved structure with a 15° beveled tip that is 5 mm in length, with an 80 µm inner diameter and a 100 µm outer diameter. This high inner-to-outer diameter ratio of CMD with a 100 µm outer diameter allows efficient drainage of highly viscous subretinal fluid in a minimally invasive manner. In addition, the curved structure precisely matches the spherical ocular structure, which facilitates the CMD insertion into the subretinal space without choroid tissue damage. We demonstrate that the optimized CMD allows for the innocuous drainage of the viscous subretinal fluid from the porcine eye, whereas the traditional hypodermic needle (31-gauge) induces severe retinal and choroid damage. CMD can overcome a critical safety issue and is a potential alternative to conventional surgical interventions for the innocuous drainage of subretinal fluid.

Innovative polymeric system (IPS) for solvent-free lipophilic drug transdermal delivery via dissolving microneedles.

Lipophilic drugs are potential drug candidates during drug development. However, due to the need for hazardous organic solvents for their solubilization, these drugs often fail to reach the pharmaceutical market, and in doing so highlight the importance of solvent free systems. Although transdermal drug delivery systems (TDDSs) are considered prospective safe drug delivery routes, a system involving lipophilic drugs in solvent free or powder form has not yet been described. Here, we report, for the first time, a novel approach for the delivery of every kind of lipophilic drug in powder form based on an innovative polymeric system (IPS). The phase transition of powder form of lipophilic drugs due to interior chemical bonds between drugs and biodegradable polymers and formation of nano-sized colloidal structures allowed the fabrication of dissolving microneedles (DMNs) to generate a powerful TDDS. We showed that IPS based DMN with powder capsaicin enhances the therapeutic effect for treatment of the rheumatic arthritis in a DBA/1 mouse model compared to a solvent-based system, indicating the promising potential of this new solvent-free platform for lipophilic drug delivery.

One-touch-activated blood multidiagnostic system using a minimally invasive hollow microneedle integrated with a paper-based sensor.

The development of real-time innocuous blood diagnosis has been a long-standing goal in healthcare; an improved, miniature, all-in-one point-of-care testing (POCT) system with low cost and simplified operation is highly desired. Here, we present a one-touch-activated blood multidiagnostic system (OBMS) involving the synergistic integration of a hollow microneedle and paper-based sensor, providing a number of unique characteristics for simplifying the design of microsystems and enhancing user performance. In this OBMS, all functions of blood collection, serum separation, and detection were sequentially automated in one single device that only required one-touch activation by finger-power without additional operations. For the first time, we successfully demonstrated the operation of this system in vivo in glucose and cholesterol diagnosis, showing a great possibility for human clinical application and commercialization. Additionally, this novel system offers a new approach for the use of microneedles and paper sensors as promising intelligent elements in future real-time healthcare monitoring devices.

A self-powered one-touch blood extraction system: a novel polymer-capped hollow microneedle integrated with a pre-vacuum actuator.

Blood is the gold standard sample medium that can provide a wide variety of useful biological information for the diagnosis of various diseases. For portable point-of-care diagnosis, blood extraction systems have attracted attention as easier, safer, and more rapid methods of collecting small blood volumes. In this paper, we introduce a novel self-powered one-touch blood extraction system created by assembling a smart polymer-capped hollow microneedle in a pre-vacuum polydimethylsiloxane actuator. The optimized hollow microneedle was precisely fabricated by drawing lithography for minimally invasive blood extraction, with a length of 1800 µm, an inner diameter of 60 µm, an outer diameter of 130 µm, and a bevel angle of 15°. The system utilizes only a single step for operation; a finger press activates the blood sampling process based on the negative pressure-driven force built into the pre-vacuum activated actuator. A sufficient volume of blood (31.3 ± 2.0 µl) was successfully extracted from a rabbit for evaluation using a micro total analysis system. The entire system was made of low-cost and disposable materials to achieve easy operation with a miniature structure and to meet the challenging requirements for single-use application in a point-of-care system without the use of any external power equipment.

An optimized hollow microneedle for minimally invasive blood extraction.

The healthcare system relies widely on biochemical information obtained from blood sample extracted via hypodermic needles, despite the invasiveness and pain associated with this procedure. Therefore, an alternative micro-scale needle for minimally invasive blood sampling is highly desirable. Traditional fabrication techniques to create microneedles do not generate needles with the combined features of a sharp tip, long length, and hollow structure concurrently. Here, we report the fabrication of a microneedle long enough to reach blood vessels and sharp enough to minimize nerve contact for minimally invasive blood extraction. The microneedle structure was precisely controlled using a drawing lithography technique, and a sharp tip angle was introduced using a laser-cutting system. We investigated the characteristics of a microneedle with a length of 1,800 µm length, an inner diameter of 60 µm, a tip diameter of 120 µm, and a 15° bevel angle through in-vitro liquid extraction and mechanical strength analysis. We demonstrated that the proposed structure results in blood extraction at a reasonable rate, and that a microneedle with this geometry can reliably penetrate skin without breaking. We integrated this microneedle into a blood extraction device to extract a 20 µl volume of mouse blood in-vivo. Our optimized, hollow microneedle can potentially be incorporated with other cutting-edge technologies such as microactuators, biosensors, and microfluidic chips to create blood analysis systems for point-of-care diagnostics.

A minimally invasive blood-extraction system: elastic self-recovery actuator integrated with an ultrahigh- aspect-ratio microneedle.

A minimally invasive blood-extraction system is fabricated by the integration of an elastic self-recovery actuator and an ultrahigh-aspect-ratio microneedle. The simple elastic self-recovery actuator converts finger force to elastic energy to provide power for blood extraction and transport without requiring an external source of power. This device has potential utility in the biomedical field within the framework of complete micro-electromechanical systems.