A blue-shifted anion channelrhodopsin from the Colpodellida alga Vitrella brassicaformis.

Microbial rhodopsins, a family of photoreceptive membrane proteins containing the chromophore retinal, show a variety of light-dependent molecular functions. Channelrhodopsins work as light-gated ion channels and are widely utilized for optogenetics, which is a method for controlling neural activities by light. Since two cation channelrhodopsins were identified from the chlorophyte alga Chlamydomonas reinhardtii, recent advances in genomic research have revealed a wide variety of channelrhodopsins including anion channelrhodopsins (ACRs), describing their highly diversified molecular properties (e.g., spectral sensitivity, kinetics and ion selectivity). Here, we report two channelrhodopsin-like rhodopsins from the Colpodellida alga Vitrella brassicaformis, which are phylogenetically distinct from the known channelrhodopsins. Spectroscopic and electrophysiological analyses indicated that these rhodopsins are green- and blue-sensitive pigments (λmax = ~ 550 and ~ 440 nm) that exhibit light-dependent ion channeling activities. Detailed electrophysiological analysis revealed that one of them works as a monovalent anion (Cl-, Br- and NO3-) channel and we named it V. brassicaformis anion channelrhodopsin-2, VbACR2. Importantly, the absorption maximum of VbACR2 (~ 440 nm) is blue-shifted among the known ACRs. Thus, we identified the new blue-shifted ACR, which leads to the expansion of the molecular diversity of ACRs.

Effect of Duration of Macular Detachment on Visual Prognosis after Surgery for Macula-Off Retinal Detachment: Japan-Retinal Detachment Registry.

PURPOSE: To evaluate the association between the duration of macular detachment (DMD) and visual prognosis in patients with macula-off rhegmatogenous retinal detachment (RD). DESIGN: Prospective observational cohort study. PARTICIPANTS: This study analyzed 719 eyes with macula-off rhegmatogenous RD registered with the Japan-Retinal Detachment Registry created by the Japan Retina and Vitreous Society. METHODS: We included patients with macular detachment without a history of prior surgery, except cataract surgery and vitrectomy. Reoperation cases, hereditary RD, and macular hole RD were excluded. We compared the visual prognosis between patients with DMD of N days or less and those with DMD of N + 1 days or more (N = 2-5). For these 4 comparisons, the inverse probability of treatment weighting (IPTW) methodology was employed, to balance 20 baseline characteristics between the shorter and longer DMD groups. The baseline characteristics included age, sex, axial length, baseline visual acuity, operative procedures, and detailed characteristics of RD. P-values < 0.01 were considered statistically significant. MAIN OUTCOME MEASURES: The best-corrected visual acuity (BCVA) 6 months after surgery. RESULTS: The final analysis included 719 eyes. For all comparisons, the patients' backgrounds were well balanced after IPTW with standardized differences < 0.10. The IPTW regression analysis revealed that the BCVA after 6 months was significantly better after surgeries for DMD of ≤ 2 days than that for DMD of ≥ 3 days. Similarly, the 6-month BCVA for surgeries for DMD of ≤ 3 days was significantly better than that for surgeries for DMD of ≥ 4 days (differences in logarithm of the minimum angle of resolution: -0.113, P = 9.1 × 10-7; -0.076, P = 1.6 × 10-3, respectively). On the other hand, there were no statistically significant differences for the other comparisons. CONCLUSIONS: Earlier surgical treatment within 3 days from the onset of macular detachment should be considered, after accounting for social circumstances, such as weekends. FINANCIAL DISCLOSURE(S): The authors have no proprietary or commercial interest in any materials discussed in this article.

Genome-Wide Association Study of Age-Related Macular Degeneration Reveals 2 New Loci Implying Shared Genetic Components with Central Serous Chorioretinopathy.

PURPOSE: To investigate the genetic architecture of age-related macular degeneration (AMD) in a Japanese population. DESIGN: Genome-wide association study (GWAS). PARTICIPANTS: Three thousand seven hundred seventy-two patients with AMD and 16 770 control participants from the Japanese population were enrolled in the association analyses. METHODS: We conducted a meta-analysis of 2 independent GWASs that included a total of 2663 patients with AMD and 9471 control participants using the imputation reference panel for genotype imputation specified for the Japanese population (n = 3541). A replication study was performed using an independent set of 1109 patients with AMD and 7299 control participants. MAIN OUTCOME MEASURES: Associations of genetic variants with AMD. RESULTS: A meta-analysis of the 2 GWASs identified 6 loci significantly associated with AMD (P < 5.0 × 10-8). Of these loci, 4 were known to be associated with AMD (CFH, C2/FB, TNFRSF10A, and ARMS2), and 2 were novel (rs4147157 near WBP1L and rs76228488 near GATA5). The newly identified associations were confirmed in a replication study (P < 0.01). After the meta-analysis of all datasets, we observed strong associations in these loci (P = 1.88 × 10-12 and P = 1.35 × 10-9 for meta-analysis for rs4147157 and rs76228488, respectively). When we looked up the associations in the reported central serous chorioretinopathy (CSC) GWAS conducted in the Japanese population, both loci were associated significantly with CSC (P = 4.86 × 10-3 and P = 4.28 × 10-3 for rs4147157 and rs76228488, respectively). We performed a genetic colocalization analysis for these loci and estimated that the posterior probabilities of shared causal variants between AMD and CSC were 0.39 and 0.60 for WBP1L and GATA5, respectively. Genetic correlation analysis focusing on the epidemiologically suggested clinical risk factors implicated shared polygenic architecture between AMD and smoking cessation (rg [the measure of genetic correlation] = -0.33; P = 0.01; false discovery rate, 0.099). CONCLUSIONS: Our findings imply shared genetic components conferring the risk of both AMD and CSC. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Phototriggered Apoptotic Cell Death (PTA) Using the Light-Driven Outward Proton Pump Rhodopsin Archaerhodopsin-3.

Apoptosis is a type of programmed cell death that commonly occurs in multicellular organisms including humans and that is essential to eliminate unnecessary cells to keep organisms healthy. Indeed, inappropriate apoptosis leads to various diseases such as cancer and autoimmune disease. Here, we developed an optical method to regulate apoptotic cell death by controlling the intracellular pH with outward or inward proton pump rhodopsins, Archaerhodopsin-3 (AR3) or Rubricoccus marinas xenorhodopsin (RmXeR), respectively. The alkalization-induced shrinking of human HeLa cells cultured at pH 9.0 was significantly accelerated or decelerated by light-activated AR3 or RmXeR, respectively, implying the contribution of intracellular alkalization to the cell death. The light-activated AR3 induced cell shrinking at a physiologically neutral pH 7.4 and biochemical analysis revealed that the intracellular alkalization caused by AR3 triggered the mitochondrial apoptotic signaling pathway, which resulted in cell death accompanied by morphological changes. Phototriggered apoptosis (PTA) was also observed for other human cell lines, SH-SY5Y and A549 cells, implying its general applicability. We then used the PTA method with the nematode Caenorhabditis elegans as a model for living animals. Irradiation of transgenic worms expressing AR3 in chemosensing amphid sensory neurons significantly decreased their chemotaxis responses, which suggests that AR3 induced the cell death of amphid sensory neurons and the depression of chemotaxis responses. Thus, the PTA method has a high applicability both in vivo and in vitro, which suggests its potential as an optogenetic tool to selectively eliminate target cells with a high spatiotemporal resolution.

Microbial Rhodopsins as Multi-functional Photoreactive Membrane Proteins for Optogenetics.

In life science research, methods to control biological activities with stimuli such as light, heat, pressure and chemicals have been widely utilized to understand their molecular mechanisms. The knowledge obtained by those methods has built a basis for the development of medicinal products. Among those various stimuli, light has the advantage of a high spatiotemporal resolution that allows for the precise control of biological activities. Photoactive membrane protein rhodopsins from microorganisms (called microbial rhodopsins) absorb visible light and that light absorption triggers the trans-cis photoisomerization of the chromophore retinal, leading to various functions such as ion pumps, ion channels, transcriptional regulators and enzymes. In addition to their biological significance, microbial rhodopsins are widely utilized as fundamental molecular tools for optogenetics, a method to control biological activities by light. In this review, we briefly introduce the molecular basis of representative rhodopsin molecules and their applications for optogenetics. Based on those examples, we discuss the high potential of rhodopsin-based optogenetics tools for basic and clinical research in pharmaceutical sciences.

Membrane Reactor for Methanol Synthesis Using Si-Rich LTA Zeolite Membrane.

We successfully demonstrated the effect of a membrane reactor for methanol synthesis to improve one-pass CO2 conversion. An Si-rich LTA membrane for dehydration from a methanol synthesis reaction field was synthesized by the seed-assisted hydrothermal synthesis method. The H2O permselective performance of the membrane showed 1.5 × 10-6 mol m-2 s-1 Pa-1 as H2O permeance and around 2000 as selectivity of H2O/MeOH at 473 K. From the results of membrane reactor tests, the CO2 conversion of the membrane reactor was higher than that of the conventional packed-bed reactor under the all of experimental conditions. Especially, at 4 MPa of reaction pressure, the conversion using the membrane reactor was around 60%. In the case of using a packed-bed reactor, the conversion was 20% under the same conditions. In addition, the calculated and experimental conversion were in good agreement in both the case of the membrane reactor and packed-bed reactor.

Functional expression of the eukaryotic proton pump rhodopsin OmR2 in Escherichia coli and its photochemical characterization.

Microbial rhodopsins are photoswitchable seven-transmembrane proteins that are widely distributed in three domains of life, archaea, bacteria and eukarya. Rhodopsins allow the transport of protons outwardly across the membrane and are indispensable for light-energy conversion in microorganisms. Archaeal and bacterial proton pump rhodopsins have been characterized using an Escherichia coli expression system because that enables the rapid production of large amounts of recombinant proteins, whereas no success has been reported for eukaryotic rhodopsins. Here, we report a phylogenetically distinct eukaryotic rhodopsin from the dinoflagellate Oxyrrhis marina (O. marina rhodopsin-2, OmR2) that can be expressed in E. coli cells. E. coli cells harboring the OmR2 gene showed an outward proton-pumping activity, indicating its functional expression. Spectroscopic characterization of the purified OmR2 protein revealed several features as follows: (1) an absorption maximum at 533 nm with all-trans retinal chromophore, (2) the possession of the deprotonated counterion (pKa = 3.0) of the protonated Schiff base and (3) a rapid photocycle through several distinct photointermediates. Those features are similar to those of known eukaryotic proton pump rhodopsins. Our successful characterization of OmR2 expressed in E. coli cells could build a basis for understanding and utilizing eukaryotic rhodopsins.

Bench-Scale Membrane Reactor for Methylcyclohexane Dehydrogenation Using Silica Membrane Module.

Methylcyclohexane-toluene system is one of the most promising methods for hydrogen transport/storage. The methylcyclohexane dehydrogenation can be exceeded by the equilibrium conversion using membrane reactor. However, the modularization of the membrane reactor and manufacturing longer silica membranes than 100 mm are little developed. Herein, we have developed silica membrane with practical length by a counter-diffusion chemical vapor deposition method, and membrane reactor module bundled multiple silica membranes. The developed 500 mm-length silica membrane had high hydrogen permselective performance (H2 permeance > 1 × 10-6 mol m-2 s-1 Pa-1, H2/SF6 selectivity > 10,000). In addition, we successfully demonstrated effective methylcyclohexane dehydrogenation using a flange-type membrane reactor module, which was installed with 6 silica membranes. The results indicated that conversion of methylcyclohexane was around 85% at 573 K, whereas the equilibrium conversion was 42%.

Myopia Prevalence and Ocular Biometry Features in a General Japanese Population: The Nagahama Study.

PURPOSE: To describe the distribution of ocular biometry and refraction in Japanese adults. DESIGN: Cross-sectional analysis of a prospective cohort study. PARTICIPANTS: A total of 9850 individuals participated in the first follow-up of the Nagahama Prospective Cohort for Comprehensive Human Bioscience (the Nagahama Study) conducted between 2013 and 2016. Participants were between 34 and 80 years of age. METHODS: All participants underwent axial length (AL; in millimeters), anterior chamber depth (ACD; in millimeters), corneal diameter (white to white; in millimeters), and central corneal thickness (CCT; in micrometers) measurement (IOL Master; Carl Zeiss Meditec, Dublin, CA) and refraction (spherical equivalent [SE]; in diopters [D]) and corneal curvature (CC; in millimeters) measurement (ARK-530A; Nidek, Aichi, Japan). Distribution of these ocular biometric parameters and prevalence of myopia, high myopia, and extreme myopia were summarized. MAIN OUTCOME MEASURES: Distribution of ocular biometry and refraction. RESULTS: After standardization to the national population of 2015, estimates of mean AL and SE were 24.21 mm and -1.44 D, respectively. Estimates of mean CC, corneal diameter, CCT, and ACD were 7.69 mm, 12.01 mm, 543.96 µm, and 3.21 mm, respectively. After standardization of age and gender, the prevalence of myopia (SE, ≤-0.5 D) and high myopia (SE, ≤-6.0 D) were 49.97% and 7.89%, respectively. Approximately 70% of the younger participants (34-59 years of age) showed myopia, whereas high myopia was observed in approximately 10%. Although the number of individuals with myopia or high myopia was higher in the younger age groups, the prevalence of more extreme phenotypes remained stable across all ages, especially in women. Axial length of more than 30 mm was observed only in older women (n = 5 [0.05%]). CONCLUSIONS: We showed detailed distributions of various ocular biometry and refraction parameters using a large general Japanese cohort. Prevalences of myopia and high myopia from 2013 through 2016 were higher than those in earlier studies, which reflects recent environmental change. However, constant prevalence of extreme myopia across all ages suggests high genetic predisposition of the extreme phenotype.

The New Strategy for the Treatment of Cerebrospinal Fluid Leak Following Lumbar Surgery.

INTRODUCTION: Cerebrospinal fluid (CSF) leak is a common complication of surgery involving the lumbar spine. However, although there are various therapeutic options for CSF leak, there is currently no optimal technique, and the choice of therapy often depends on the surgeon's cumulative experience. The aim of this study was to describe the successful treatment of CSF leakage using blood injection therapy along the drain removal tract. TECHNICAL NOTE: We enrolled 7 consecutive patients who underwent lumbar surgery at our institute. The surgeries performed included decompression in two patients (one microendoscopic surgery), fusion in four, and an epidural cyst resection in one. After finding a CSF leak, we injected about 10 ml of blood from the patient into the drain tract. CSF leak did not recur after the blood injection in any of the seven patients. Following just one day of bed rest, the symptoms of intracranial hypotension disappeared with no instances of worsened symptoms of back pain, lower limb pain or fever. CONCLUSIONS: We propose this route of blood injection therapy as a novel method for the treatment of CSF leak after lumbar surgery.

Effect of Carbonic Anhydrase on CO2 Separation Performance of Thin Poly(amidoamine) Dendrimer/Poly(ethylene glycol) Hybrid Membranes.

The effect of carbonic anhydrase (CA) on the separation performance of thin poly(amidoamine) (PAMAM) dendrimer/poly(ethylene glycol) (PEG) hybrid membranes was investigated. CA, a type of enzyme, was used to promote CO2 hydration and dehydration reactions and to assess whether these reactions were the rate-limiting step in CO2 permeation through the membrane. The relationship between the membrane thickness and the CO2 permeance was evaluated in CO2/H2 or CO2/He separation using PAMAM/PEG hybrid membranes (thickness: 10-100 µm) with and without CA. Without CA, the CO2 permeance of PAMAM/PEG hybrid membranes was not inversely proportional to the membrane thickness. On the other hand, with CA, the CO2 permeance was inversely proportional to the membrane thickness. It was implied that, without CA, the rate-limiting step of CO2 transport was either the CO2 hydration reaction at the feed side or the CO2 dehydration reaction at the permeate side. On the other hand, with CA addition, the rate-limiting step of CO2 transport was diffusion, and CO2 permeance could be increased without sacrificing the selectivity by reducing membrane thickness. The effect of the position of CA (i.e., on the surface and/or reverse surface) on CO2 separation performance was investigated to evaluate which reaction was the rate-limiting step of CO2 permeation through the membrane. It was suggested that the rate-limiting step of CO2 permeation was CO2 dehydration reaction at the permeate side.

Development of CVD Silica Membranes Having High Hydrogen Permeance and Steam Durability and a Membrane Reactor for a Water Gas Shift Reaction.

Water gas shift reaction of carbon monoxide (CO) with membrane reactors should be a promising method for hydrogen mass-production because of its high CO conversion, high hydrogen purity and low carbon dioxide emission. For developing such membrane reactors, we need hydrogen permselective membranes with high hydrogen permeance with order of 10-6 mol m-2 s-1 Pa-1 at 573 K and high steam durability. In this study, we have optimized the kind of substrates, precursors, vapor concentration, and chemical vapor deposition (CVD) time using the counter-diffusion CVD method for developing such membranes. The developed membrane prepared from hexamethyldisiloxane has a hydrogen permeance of 1.29 × 10-6 mol m-2 s-1 Pa-1 at 573 K and high steam durability. We also conducted water gas shift reactions with membrane reactors installed the developed silica membranes. The results indicated that reactions proceed efficiently with the conversion around 95-97%, hydrogen purity around 94%, and hydrogen recovery around 60% at space velocity (SV) 7000.

Aqueous Two-Phase System Formation in Small Droplets by Shirasu Porous Glass Membrane Emulsification Followed by Water Extraction.

By utilizing water transport phenomena between two different water-in-oil (W/O) emulsion droplets through continuous oil phase, we developed a novel method of aqueous two-phase system (ATPS) formation in small droplets prepared by Shirasu porous glass (SPG) membrane emulsification technique. When we mixed W/O emulsion droplets containing poly(ethylene glycol) (PEG) and dextran (DEX) at concentrations below the threshold of the phase separation, with droplets containing other solutes at high concentrations, water extraction from the droplets containing PEG and DEX to those containing the other solutes occurred, owing to the osmotic pressure difference. This effect increased the concentrations of PEG and DEX in the droplets above the phase separation threshold. We demonstrated the feasibility of the preparation method by varying the pore sizes of the SPG membranes, the solutes, and their concentrations. Only when the concentration of the solute was high enough to extract sufficient amounts of water did the homogeneous disperse phase consisting of PEG and DEX in droplets turn into a PEG-rich phase and DEX-rich phase, showing ATPS. This result was irrespective of the solute itself and pore size of the SPG membrane. In particular, we successfully demonstrated monodisperse ATPS droplets with diameters of approximately 10 µm under a certain condition.

Direct Observation of Splitting in Oil-In-Water-In-Oil Emulsion Droplets via a Microchannel Mimicking Membrane Pores.

Direct observation of double emulsion droplet permeation through a microchannel that mimicked 100 µm membrane pores with a porosity of 66.7% provided insights regarding splitting mechanisms in porous membranes. The microchannel was fabricated by standard soft lithography, and the oil-in-water-in-oil double emulsion droplets were prepared with a glass capillary device. By changing the flow rate from 0.5 to 5.0 × 10-2 m s-1, three characteristic behaviors were observed: (a) passage into one channel without splitting; (b) division into two smaller components; and (c) stripping of the middle water phase of the double emulsion droplets into a smaller double emulsion droplet and a smaller water-in-oil single emulsion droplet. The mechanisms are discussed with respect to the balance of viscous forces and interfacial tension, the contact point with the tip of the channel, and the relative position of the innermost droplet within the middle droplet.

Microendoscopic laminotomy versus conventional laminoplasty for cervical spondylotic myelopathy: 5-year follow-up study.

OBJECTIVE The goal of this study was to characterize the long-term clinical and radiological results of articular segmental decompression surgery using endoscopy (cervical microendoscopic laminotomy [CMEL]) for cervical spondylotic myelopathy (CSM) and to compare outcomes to conventional expansive laminoplasty (ELAP). METHODS Consecutive patients with CSM who required surgical treatment were enrolled. All enrolled patients (n = 78) underwent CMEL or ELAP. All patients were followed postoperatively for more than 5 years. The preoperative and 5-year follow-up evaluations included neurological assessment (Japanese Orthopaedic Association [JOA] score), JOA recovery rates, axial neck pain (using a visual analog scale), the SF-36, and cervical sagittal alignment (C2-7 subaxial cervical angle). RESULTS Sixty-one patients were included for analysis, 31 in the CMEL group and 30 in the ELAP group. The mean preoperative JOA score was 10.1 points in the CMEL group and 10.9 points in the ELAP group (p > 0.05). The JOA recovery rates were similar, 57.6% in the CMEL group and 55.4% in the ELAP group (p > 0.05). The axial neck pain in the CMEL group was significantly lower than that in the ELAP group (p < 0.01). At the 5-year follow-up, cervical alignment was more favorable in the CMEL group, with an average 2.6° gain in lordosis (versus 1.2° loss of lordosis in the ELAP group [p < 0.05]) and lower incidence of postoperative kyphosis. CONCLUSIONS CMEL is a novel, less invasive technique that allows for multilevel posterior cervical decompression for the treatment of CSM. This 5-year follow-up data demonstrates that after undergoing CMEL, patients have similar neurological outcomes to conventional laminoplasty, with significantly less postoperative axial pain and improved subaxial cervical lordosis when compared with their traditional ELAP counterparts.

Reduced blood loss and operation time in lumbar posterolateral fusion using a bipolar sealer.

PURPOSE: A bipolar sealer using Transcollation® technology, a combination of radiofrequency energy and saline, can provide hemostasis at 100 °C, which is lower than that used in standard electrocautery. Previous studies of joint arthroplasty have shown that use of the bipolar sealer reduces blood loss and tissue damage during the operation. However, it is unknown whether a bipolar sealer reduces blood loss and tissue damage in lumbar posterolateral fusion (PLF) surgery. The purpose of this study was to analyze the efficacy of this device in limiting blood loss during exposure of the lumbar spine in the treatment of PLF and postoperative pain. METHODS: Fifty patients who underwent PLF were prospectively enrolled between October 2011 and March 2013. Twenty-five patients were randomized to the bipolar sealer group (BS group) and 25 patients to the standard electrocautery group (control group). Operative time and blood loss during exposure of posterior bony elements including the transverse process for PLF, visual analog scale (VAS) to quantify postoperative pain, and the interval from the surgery to hospital discharge were compared. RESULTS: Operative time and blood loss expressed per level of exposure were significantly lower in the BS group than in the control group. There was a tendency toward a lower VAS at postoperative week 1 in the BS group. The duration of hospitalization was 15 and 26 days in the BS and control groups, respectively. CONCLUSIONS: A large randomized control trial adjusted for the number of fusion levels and body mass index is required to confirm the novelty value of this new bipolar sealers.

[Therapeutic agents for osteoporotic pain].

Low back pain (LBP) is one of the major symptoms of elderly patients with osteoporosis. Pain control is important because pain hinders quality of life. The pathogenesis of the osteoporosis-related LBP is divided as follows, (1) vertebral fracture with bone fragility, (2) imbalance of sagittal alignment, (3) osteoporotic bone pain, (4) reduction of the descending pain inhibition system of serotonine, (5) psychological condition, (6) neural pain. For the treatment of osteoporosis-related LBP, there are two types of medicine. One is a medicine for osteoporosis with an analgetic action, another is an analgetic agent. In this chapter, we explained various analgetic agents for osteoporosis-related LBP.

Size-dependent interaction of cells and hemoglobin-albumin based oxygen carriers prepared using the SPG membrane emulsification technique.

Hemoglobin-based oxygen carriers (HBOCs) of various sizes have been developed so far, but their optimum size has not been clarified yet. Here, we examined the effect of HBOCs size on their interaction with cells using Shirasu porous glass (SPG) membrane emulsification technique, which enables precise tuning of particle size. Microspheres composed of bovine hemoglobin (bHb) and bovine serum albumin (BSA) was fabricated with the average diameters of 1.2-18.3 µm and the coefficient of variation of below 13%. Cellular uptake of the microspheres by RAW264.7 was observed at a diameter below 5 µm; however, uptake of the microspheres by HepG2 and HUVEC were not observed at any diameter. No enhancement of the generation of reactive oxygen species in the cytoplasm was detected at diameters above 9.8 µm in the three cell lines, due to their low cellular uptake. In addition, cytotoxicity of the microspheres decreased with increasing microsphere diameter in the three cell lines and microspheres of 18.3 µm showed good cellular compatibility regardless of the oxyhemoglobin percentage. Since cytotoxicity is a crucial factor in their applications, our systemic investigation would provide a new insight into the design of HBOCs.

Membrane-Integrated Glass Capillary Device for Preparing Small-Sized Water-in-Oil-in-Water Emulsion Droplets.

In this study, a membrane-integrated glass capillary device for preparing small-sized water-in-oil-in-water (W/O/W) emulsion droplets is demonstrated. The concept of integrating microfluidics to prepare precise structure-controlled double emulsion droplets with the membrane emulsification technique provides a simple method for preparing small-sized and structure-controlled double emulsion droplets. The most important feature of the integrated device is the ability to decrease droplet size when the emulsion droplets generated at the capillary pass through the membrane. At the same time, most of the oil shell layer is stripped away and the resultant double emulsion droplets have thin shells. It is also demonstrated that the sizes of the resultant double emulsion droplets are greatly affected by both the double emulsion droplet flux through membranes and membrane pore size; when the flux is increased and membrane pore size is decreased, the generated W/O/W emulsion droplets are smaller than the original. In situ observation of the permeation behavior of the W/O/W emulsion droplets through membranes using a high-speed camera demonstrates (1) the stripping of the middle oil phase, (2) the division of the double emulsion droplets to generate two or more droplets with smaller size, and (3) the collapse of the double emulsion droplets. The first phenomenon results in a thinner oil shell, and the second division phenomenon produces double emulsion droplets that are smaller than the original.

Preparation of uniform-sized hemoglobin-albumin microspheres as oxygen carriers by Shirasu porous glass membrane emulsification technique.

We have developed a new type of artificial oxygen carrier composed of bovine hemoglobin (bHb) and bovine serum albumin (BSA) prepared by Shirasu porous glass (SPG) membrane emulsification technique. The resultant emulsion droplets containing 10 wt% bHb and 5-20 wt% BSA were subsequently cross-linked by glutaraldehyde to form the microspheres. Due to the uniform pore structure of SPG membranes, the average diameters of bHb10-BSAm microspheres were successfully controlled at around 5 µm with a coefficient of variation of around 10%. In addition, the biocompatibility of the carriers depended on their oxyhemoglobin percentage regardless of their same size. Finally, the P50 values of these microspheres ranged from 8.08 to 11.60 mmHg, which showed a high oxygen affinity and an oxygen delivery function.