Search

Mass transport through nanopores occurs in various natural systems, including the human body. For example, ion transport across nerve cell membranes plays a significant role in neural signal transmission, which can be significantly affected by the electrolyte and temperature conditions. To better understand and control the underlying nanoscopic transport, it is necessary to develop multiphysical transport models as well as validate them using enhanced experimental methods for facile nanopore fabrication and precise nanoscale transport characterization. Here, we report a nanopore-integrated microfluidic platform to characterize ion transport in the presence of electrolyte and temperature gradients; we employ our previous self-assembled particle membrane (SAPM)-integrated microfluidic platform to produce various nanopores with different pore sizes. Subsequently, we quantify pore-size-dependent ionic transport by measuring the short circuit current (SCC) and open circuit voltage (OCV) across various nanopores by manipulating the electrolyte and temperature gradients. We establish three simple theoretical models that heavily depend on pore size, electrolyte concentration, and temperature and subsequently validate them with the experimental results. Finally, we anticipate that the results of this study would help clarify ion transport phenomena at low-temperature conditions, not only providing a fundamental understanding but also enabling practical applications of cryo-anesthesia in the near future.

Jungyul Park,1,2 Sunghyun Jo,1 Hee-Young Choi1,2 1Department of Ophthalmology, School of Medicine, Pusan National University Hospital, Busan, South Korea; 2Biomedical Research Institute, Pusan National University, Busan, South KoreaCorrespondence: Hee-Young Choi, Department of Ophthalmology, School of Medicine, Biomedical Research Institute, Pusan National University, 179 Gudeok-Ro, Seo-Gu, Busan, 49241, Republic of Korea, Tel +82-51-240-7324, Fax +82-51-242-7341, Email hychoi@pusan.ac.krBackground: Detachment of the inferior oblique muscle may be necessary under certain circumstances to repair a large inferomedial orbital fracture involving the orbital strut. This study aimed to evaluate the outcomes of patients who underwent surgeries with and without inferior oblique muscle reattachment after its detachment to repair the orbital wall fractures.Methods: Forty patients who underwent repair of combined floor and medial orbital wall fracture involving the orbital strut at a single tertiary institution between January 2014 and December 2020 were reviewed. Groups 1 and 2 comprised 20 patients each, who underwent surgery with inferior oblique muscle detachment without and with reattachment, respectively, and were followed up for at least 6 months postoperatively. Enophthalmos, Goldmann diplopia test, alignment test, ocular motility test, and orbital inferomedial angle ratio were the outcome measures.Results: Statistically significant improvement was observed in ocular motility, diplopia, and enophthalmos postoperatively at the 1- and 6-month follow-up (p < 0.01). The mean postoperative inferomedial angle ratio (102.28 ± 10.62%) was improved significantly compared with the preoperative inferomedial angle ratio (115.61 ± 4.38%) (p = 0.004) in all patients. After surgery, inferior oblique muscle underaction was observed in seven and six patients in groups 1 and 2, respectively, which was associated with preoperative extraocular movement limitation and strabismus. Two patients showed diplopia in both groups at the last follow-up; they had inferior oblique muscle underaction but no enophthalmos.Conclusion: Orbital fracture repair with or without inferior oblique muscle reattachment was clinically effective and safe; however, patients with preoperative strabismus and extraocular motility limitation should be informed of the increased risk of postoperative complications.Keywords: orbital fracture, inferior oblique muscle, diplopia, strabismus, post-operative complications

Smart contact lenses have the potential to serve as noninvasive healthcare devices or virtual displays. However, their implementation is limited by the lack of suitable power sources for microelectronic devices. This Article demonstrates smart contact lenses with fully embedded glucose fuel cells that are safe, flexible, and durable against deformations. These fuel cells produced stable power throughout the day or during intermittent use after storage for weeks. When the lenses were exposed to 0.05 mM glucose solution, a steady-state maximum power density of 4.4 μW/cm

Purpose: To report a case of traumatic optic neuropathy aggravated by orbital emphysema after an orbital fracture.Case summary: A 19-year-old man with no specific medical history was referred for a right orbital fracture caused by blunt trauma to the supraorbital rim of the right eye. Computed tomography (CT) showed a right orbital fracture involving the inferomedial wall and inferomedial strut. The corrected visual acuity was 0.4 in the right eye (RE) and 1.0 in the left and the intraocular pressure was 15 and 18 mmHg, respectively. Restriction on downgaze, abduction, and an indefinite relative afferent pupillary defect (RAPD) were observed in the RE. Fundus exam was non-specific other than commotio retinae on the temporal side of the macula in the RE. After 12 hours post trauma, the visual acuity of the RE had decreased to light perception. Definite RAPD was observed with optic disc swelling on the fundus photo and optical coherence tomography. Orbital CT showed air shadows, which were not seen on the initial evaluation, adjacent to the optic disc. We diagnosed traumatic optic neuropathy aggravated by orbital emphysema. High-dose intravenous steroid was given for 3 days. Despite a lateral canthotomy and cantholysis to decompress the right orbit, visual acuity did not improve above counting fingers.Conclusions: Increased intraorbital pressure and congestion caused by orbital emphysema may exacerbate traumatic optic neuropathy. Therefore, close observation is required.

Purpose: To demonstrate the efficacy of subcutaneous tocilizumab (TCZ-SC) treatment for recalcitrant thyroid eye disease (TED) refractory to intravenous methylprednisolone (MP) and oral methotrexate (MTX).Case summary: (Case 1) A 52-year-old man, smoker, with hyperthyroidism presented with a 3-months history of TED. The initial clinical activity score (CAS) was 5 (total score of 7). High-dose intravenous MP and oral MTX failed to improve the symptoms. He was treated with four doses of 162 mg TCZ-SC at an interval of 2 weeks. Pre-treatment laboratory test results were within normal limits. CAS was reduced to 2 weeks after the final injection, and there were no recurrences during the 6-month follow-up. (Case 2) A 37-year-old woman, non-smoker, with a 3-months history of hyperthyroidism presented with conjunctival injection and upper eyelid erythema. The initial CAS was 4, and thyroid-stimulating immunoglobulin level was raised (475% of normal). The symptoms did not improve with 7.5 g intravenous MP and oral MTX. The patient was treated with 162 mg TCZ-SC. Pre-treatment laboratory test results were within normal limits. CAS was reduced to 1 after the final injection, and there were no recurrences during the 6-months follow-up.Conclusions: TCZ-SC improves symptoms of corticosteroid-resistant TED, and may be a reasonable option in recalcitrant TED cases. However, further studies are required to justify the use of TCZ-SC for TED.

Diffusioosmosis (DO) results from ion transport near charged surfaces in the presence of electrolyte gradients and is critical in nanofluidic systems. However, DO has not yet been comprehensively studied because nanofabrication materials have limitations of low throughput and difficult quantification. Herein, we describe a self-assembled particle membrane (SAPM)-integrated microfluidic platform that can modulate the material properties (e.g., zeta-potential) and transport flux of nanopores. We quantify the effect of the zeta-potential on DO by measuring the electrical signals across three different nanopores/nanochannels of the SAPM. We then empirically quantify the effects of the temperature and ionic strength of the electrolytes on DO and reveal a nonlinear relationship with DO-driven ion transport; the ionic strengths govern the DO- or diffusion-effective ion transport phenomena. Finally, we demonstrate DO-driven electric power generation with enhanced performance as a potential application under optimized experimental conditions.

Purpose: Chondroid syringoma of the skin is a rare subcutaneous tumor and localization in the eyelid and orbital region that has rarely been described. We report a case of chondroid syringoma that involved the sub-brow region and was accompanied by hair loss. Case summary: A 57-year-old women presented with a mass on the lateral side of the left sub-brow region which was observed 25 years earlier. The mass, which recurred 2 months after surgery at another hospital through a skin incision was accompanied by an itching sensation. The mass was not tender or ulcerated but was reddish with superficial blood vessels and had a smooth surface with hair loss at the site of the mass. The mass showed high signal intensity on a T2-weighted magnetic resonance image and a round echogenic nodule with an irregular hypoechoic portion was observed on ultrasonography. A full-thickness excision including the adjacent normal tissue of the sub-brow mass and direct closure were subsequently performed. The pathological diagnosis was chondroid syringoma which was revealed as numerous tubular structures with various lumens in a collagenous stroma. Mucinous and fibrous findings were also observed. No recurrence was detected during the first 2 years after surgery. Conclusions: Chondroid syringoma in the eyelid and sub-brow region is uncommon. Complete resection is required to differentiate it from a malignancy and reduce the possibility of recurrence. Incomplete resection or capsular rupture during removal of the tumor could induce recurrence or a malignant change in the tumor.

Photocatalysis, which utilizes solar energy to electrochemically decompose water pollutants into harmless products, has attracted considerable attention to address serious environmental issues. The photocatalytic effect can be enhanced using an external electric field owing to the inhibition of the recombination of photoexcited electrons and holes. However, the typical linear potential bias that induces a small potential drop across a thin photocatalyst film exhibits a limited photocatalytic reaction. Herein, we propose an ion-concentration-polarization-assisted photocatalytic reactor that generates a nonlinear electric field across the microchannel of this system, which enables an 85.5% increase in the reaction rate compared to that achieved using a linear potential, and a high reaction rate constant up to 12.7 min

A higher rectification degree in ionic diodes is required to achieve better performance in applications. Nonetheless, the active geometrical change that is critical for inducing electrical potential asymmetry is difficult to realize in typical ionic diodes because of the intrinsic limitation of the fabrication method. Here, we propose a nanochannel-network-based bipolar diode with a high rectification degree of ∼1600─the highest value realized until now, to the best of our knowledge. Such a high rectification is obtained based on the synergetic effect of the bipolar surface charge and the optimization of the microchannel through experimental studies and multiphysics numerical simulations. It induces ion concentrations at the heterogeneous junction based on the accumulation effect under the forward potential bias. In particular, this proposed molecular concentration occurs in the ohmic region without vortex and instability that is inevitable at the conventional nano-electrokinetic concentration. Combining this accumulation with the horizontally aligned configuration of the nanochannel network membrane (NCNM), a highly sensitive and quantitative mercury ion (Hg

Microscopic visualization of DNA molecules is a simple, intuitive, and powerful method. Nonetheless, DNA-molecule quantification methods that employ microscopic visualization have not been reported so far. In this study, a new quantitative approach is presented that enables the counting of individual DNA molecules that have been rendered visible by fluorescence microscopy. Toward this, a microfluidic device was employed that directed DNA molecules into microchannels and deposited the molecules onto a positively charged surface. This microfluidic device had a vertically tapered channel inlet structure that prevented the accumulation of excess DNA molecules in the channel inlet while creating a tapering flow, thereby ensuring the even distribution of the DNA molecules in the microchannels. The channel heights and the density of positive charges on the surface were optimized for analysis. The linearity of this method with respect to the determination of the concentration of DNA in solutions was subsequently determined. The limit of detection was 0.48 fg/μL, which corresponds to 64 molecules of 7.25 kbp DNA in 1 μL of sample. This quantitative approach was finally used to count two types of plasmids co-transformed in an E. coli cell; a measurement that is typically considered challenging with gel electrophoresis.

Background To evaluate the risk of general orbital decompression in patients with thyroid eye disease (TED).Methods In this study, we replicated the behavior of intraorbital tissue in patients with TED based on finite element analysis. The orbit and intraorbital tissues of TED patient who underwent orbital decompression were modeled as finite element models. The stress was examined at a specific location of the removed orbital wall of a patient with TED who had undergone orbital decompression, and its variation was investigated and analyzed as a function of the shape and dimension (to be removed).Results In orbital decompression surgery which removes the orbital wall in a rectangular shape, the stress at the orbital wall decreased as the width and depth of the removed orbital wall increased. In addition, the stress of the non-chamfered model (a form of general orbital decompression) was higher than that of the chamfered model. Especially, in the case of orbital decompression, it can be seen that the chamfered model compared to the non-chamfered model have the stress reduction rate from 11.08% to 97.88%.Conclusions It is inferred that if orbital decompression surgery considering the chamfered model is performed on an actual TED patient, it is expected that the damage to the extraocular muscle caused by the removed orbital wall will be reduced.

Various microfluidic devices have overcome many disadvantages common to conventional bioreactor systems by enabling active manipulation of cell-culture conditions, monitoring of cellular responses in high-throughput mode, and extraction of target cells in a relatively rapid and low-cost manner. However, existing microfluidic devices still have limitations, including the complexity of their operation and a lack of availability of dynamic control of the chemical environment. Here, we present a novel microfluidic bioreactor array device capable of not only the stable and dynamic programing of cell-culture environments but also the selective extraction of target cells. This device comprises 64 microchambers in a 16 × 4 array format, and each microchamber is integrated with a robust and nanoporous membrane on one side and an H-shaped entrance on the other. The membrane made of self-assembled particles allowed continuous and sequential delivery of various nutrients containing gene inducers to compartmentalized microbial cells, thereby enabling dynamic cell culturing. Additionally, the H-shaped entrance was used for local and selective blocking of the microchamber by employing UV-curable material, thereby enabling the retrieval of target cells from the device while sequestering nontarget cells in the microchambers. Our results demonstrated that the targeted rare cells could be isolated and separated from a mixture of cells by repeating the extraction procedure. Therefore, we anticipate that this microfluidic bioreactor array device will be widely used for not only screening/extraction but also off-chip postanalyses of various microorganisms.

Cell spheroid culture can be an effective approach for providing an engineered microenvironment similar to an in vivo environment. Our group had recently developed a method for harvesting uniformly sized multicellular spheroids via self-assembly of micro-scaled cell sheets (μCSs) induced by the expansion of temperature-sensitive hydrogels. However, the μCS assembly process was not fully understood. In this study, we investigated the effects of cell number, pattern shape, and contractile force of cells on spheroid formation from micropatterned (width of square pattern from 100-300 μm) hydrogels. We used human dermal fibroblasts (HDFBs) as a model cell type and cultured them for 24 and 72 h. The self-assembly of μCSs cultured on square micropatterns for 72 h rapidly occurred within 4 min after reducing the temperature from 37 to 4 °C. In addition, the size distribution of spheroids was narrower with μCSs from a 72 h culture. Treatment with a ROCK1 inhibitor disrupted cytoskeletal actin fibers and the corresponding μCSs were not detached from the hydrogel. The assembly of the μCS was also affected by the micropattern shape, and the spheroid harvest efficiency was decreased to 60% when using a circular micropattern, which was explained by the stress direction on the circular versus square micropattern upon hydrogel expansion. Therefore, we confirmed that the factors controlling cell-cell interactions are important for spheroid formation using micropatterned hydrogel systems. Finally, the μCSs with dual layers of HDFBs labeled with DiD and DiO dyes resulted in the formation of spheroids with discretely localized colors within the core and shell, respectively, which suggests an outside-in assembly of detached μCSs. In consideration of these complex environmental factors, our system could be utilized in various applications as a three-dimensional culture system to fabricate cell spheroids.

Nanofluid diodes are used for controlling ions with the unidirectional flow and have the potential for increasing sensitivity in sensors. Commonly, nanofluidic diodes are realized by a single-nanochannel form fabricated by a nano process like e-beam. Here, we propose a bipolar ionic diode using a 3D nanochannel network membrane (NCNM) formed by self-assembly of nanoparticles. The diode can control ions in high throughput manner and shows a high ion current rectification (ICR) phenomenon. By exploring the I-V characterization according to geometry change of multi-layered NCNM, finally, we can achieve the maximum ICR up to 1475.45, which is the best performance of our knowledge, and maximize a fluorescence-based sensor performance by concentrating mercury ion at the junction of positive charge region, so that 1nM of mercury can be detected

Background To evaluate the patterns of distribution and clinical manifestations of ocular injuries referred to the level 1 trauma center of Pusan National University Hospital (PNUH) in Korea. Methods We analyzed 254 of 4,287 patients who were referred to the Department of Ophthalmology at the level 1 trauma center of the PNUH, from January 2016 through December 2018. Data on the incidence of ocular injuries, sex, age, monthly and seasonal distribution, day and time of injury, side of injury, cause, residence of patients, referral time to an ophthalmologist and subsequent examination time, final visual acuity (VA), and complications were obtained from medical records and retrospectively reviewed. The patients were grouped according to their main diagnosis using the Birmingham Eye Trauma Terminology System (BETTS) and Ocular Trauma Score (OTS). Results The incidence of ocular injuries with major trauma was higher in men (n = 207, 81.5%), the median age at time of injury was 54 years, and Pusan recorded the most cases. The incidences of ocular injury were 1.47/100,000, 1.57/100,000, 1.48/100,000 in 2016, 2017 and 2018, respectively. The most common cause was by a motorbike accident, followed by a pedestrian traffic accident and falls. According to the BETTS classification, open-globe injuries represented 4% of cases, closed-globe injuries represented 12.6%, and other injuries represented 83.1%. Open-globe injuries were significantly associated with low final VA (P = 0.01). In the OTS, 79.4% of patients received 4 or 5 points and 13.7% of patients received 1 or 2 points. The patients who received 1 or 2 points in the OTS score showed final VA below hand movement (P < 0.001), except for two patients. Lid laceration and low initial VA were highly correlated with poor final VA (P < 0.001). Conclusion This is the first study on the epidemiology and clinical manifestations in trauma patients with ocular injuries at a level 1 trauma center. The incidences of ocular injuries with major trauma were about 1.47–1.57/100,000. BETTS, OTS, lid laceration and initial VA were associated with final VA. We expect our study to provide a basis of data for the evaluation, prevention, and management of ocular injuries in patients with systemic trauma., Graphical Abstract

Glaucoma is a very common disease after cataracts and is dangerous enough to cause irreversible blindness. However, often the main symptom of glaucoma is difficult to recognize because it may be absent or appear late, so the risk of blindness is greater. Intraocular pressure (IOP) is a well-known primary factor indicating glaucoma. In this study, we demonstrate a smart IOP sensor embedded in a contact lens that works through visual color changes without an external power source such as a battery or RF-based wireless power transfer. A microhydraulic amplification mechanism is adopted to enhance the range of color change from a photonic crystal (PC)-based flexible membrane whose lattice distance between nanostructures varies according to the morphology changes of an eyeball caused by IOP. The performance of the sensor is quantitatively demonstrated using an artificial silicone eye model for in vitro evaluation and a porcine eyeball for ex vivo verification. It has a limit of detection (LOD) of 3.2 and 5.12 mmHg, which was measured and evaluated using a spectrometer and a smartphone camera, respectively. The results prove that our sensor embedded in the contact lens can continuously monitor the IOP change using color change, and a smartphone camera can be used as a quantitative IOP measurement system in a noninvasive manner without an expensive optical spectrometer.