Human Eosinophil Cell Manipulation by Optical Tweezers

In this work, lateral deformation of human eosinophil cell during the lateral indentation by an optically trapped microbead of diameter 4.5 µm is studied. The images were captured using a CCD camera and the Boltzmann statistics method was used for force calibration. Using the Hertz model, we calculated and compared the elastic moduli resulting from the lateral force, showing that the differences are important and the force should be considered. Besides the lateral component, the setup also allows us to examine the lateral cell-bead interaction. The mean values of the properties obtained, in particular the elastic stiffness and the shear stiffness, were Eh = (37.76 ± 2.85) µN/m and Gh = (12.57 ± 0.32) µN/m. These results show that the lateral indentation can therefore be used as a routine method for cell study, because it enabled us to manipulate the cell without contact with the laser.

Using Optical Tweezers to Study the Friction of the Red Blood Cells

In the last two decades the study of red blood cell elasticity using optical tweezers has known a rise appearing in the scientific research with regard to the various works carried out. Despite the various work done, no study has been done so far to study the influence of friction on the red blood cell indentation response using optical tweezers. In this study, we have developed a new approach to determine the coefficient of friction as well as the frictional forces of the red blood cell. This approach therefore allowed us to simultaneously carry out the indentation and traction test, which allowed us to extract the interfacial properties of the microbead red blood cell couple, among other things, the friction coefficient. This property would be extremely important to investigate the survival and mechanical features of cells, which will be of great physiological and pathological significance. But taking into account the hypothesis of friction as defined by the isotropic Coulomb law. The experiment performed for this purpose is the Brinell Hardness Test (DB).

Synthesis and Characterization of Novel Schiff Base for Enhanced Dye-Sensitized Solar Cell Photo-Response Mechanism

The efficient photo-response mechanism is one of the key factors in the commercialization of dye-sensitized solar cells in a bid to satisfy renewable energy demands. Progress in green technology has put solar energy on the front burner as a provider of clean and affordable energy for a sustainable society. We report the synthesis of a novel Schiff base with optical transparency in the visible and near IR region of the solar spectrum that can find application in the DSSCs photo-response mechanism. The synthesized crystal exhibited features that could handle some of the shortcomings of dye-sensitized solar cells which include wide band solar spectrum absorption and capability for swift charge transfer within the photoelectrodes. The synthesized Schiff base was characterized using x-ray diffractometer, UV/Visible spectrometer, Frontier transmission infrared spectrometer and conductometer. XRD data revealed the grown crystal to have an average crystallite size of 2.08 nm with average microstrain value of about 269.43. The FT-IR recorded transmission wave ѵ (CO) at 1207.7 cm−1 while dominant wave occurred at ѵ1654.9 and ѵ1592.3 cm−1 relating to ѵ (CN) stretching and ѵ (NH) bending respectively were observed. The IR spectrum revealed the bonding species and a probable molecular structure of 2,6-bis(benzyloxy)pyridine. The UV/Visible spectra convoluted to maximum peak within the near IR region suggesting that 2,6-bis(benzyloxy)pyridine can absorb both the visible and near IR region while its electrical conductivity was determined to be 4.58 µS/cm. The obtained result of the present study revealed promising characteristics of a photosensitizer that can find application in the photo-response mechanism of DSSCs.

Retinal ganglion cell complex changes using spectral domain optical coherence tomography in diabetic patients without retinopathy

AIM：To assess the ganglion cell complex（GCC）thickness in diabetic eyes without retinopathy. METHODS：Two groups included 45 diabetic eyes without retinopathy and 21 non diabetic eyes. All subjects underwent full medical and ophthalmological history,full ophthalmological examination,measuring GCC thickness and central foveal thickness（CFT）using the RTVue~？ spectral domainoptical coherence tomography（SD-OCT）,and HbA1C level.RESULTS：GCC focal loss volume（FLV%）was significantly more in diabetic eyes（22.2% below normal）than normal eyes（P=0.024）. No statistically significant difference was found between the diabetic group and the control group regarding GCC global loss volume（GLV%）（P=0.160）. CFT was positively correlated to the average,superior and inferior GCC（P=0.001,0.000 and 0.001 respectively）and negatively correlated to GLV% and FLV%（P=0.002 and0.031 respectively）in diabetic eyes. C/D ratio in diabetic eyes was negatively correlated to average,superior and inferior GCC（P=0.015,0.007 and 0.017 respectively）. The FLV% was negatively correlated to the refraction and level of Hb A1c（P=0.019 and 0.013 respectively）and positively correlated to the best corrected visual acuity（BCVA）in log MAR in diabetic group（P=0.004）.CONCLUSION：Significant GCC thinning in diabetes predates retinal vasculopathy,which is mainly focal rather than diffuse. It has no preference to either the superior or inferior halves of the macula. Increase of myopic error is significantly accompanied with increased focal GCC loss. GCC loss is accompanied with increased C/D ratio in diabetic eyes.

Preparation, optical properties and cell staining of water soluble amine-terminated PAMAM G2.0-Au nanocomposites

The solution chemical and optical characteristics of formation of amine-terminated polyamidoamine dendrimer G2.0（NH2-PAMAM G2.0）-Au nanocomposites in the aqueous solution of NH2-PAMAM G2.0 at various mole ratios of Au（Ⅲ） to NH2-PAMAM G2.0 were studied by both UV-visible spectrometry and fluorospectrometry. The NH2-PAMAM G2.0-Au nanocomposites, with a type of structure in which one Au nanoparticle is surrounded by several NH2-PAMAM G2.0 dendrimers, emit strong bluish violet fluorescence, and are uniform, water soluble and biocompatible as well as very stable in frozen conditions. The size of gold nanoparticles in the nanocomposites is about 2.5 nm and decreases with the increase of NH2-PAMAM G2.0 concentration. The NH2-PAMAM G2.0 plays an important role in acting as host or micro-reactor for Au（Ⅲ） before Au（Ⅲ） reduction and acting as dispersant and stabilizer for gold nanoparticles after Au（Ⅲ） reduction. Preliminary experiments of cells staining to human embryonic lung fibroblast cell lines show that the NH2-PAMAM G2.0-Au nanocomposites can be used as optical imaging markers for bioanalyses and medical diagnoses.

Stem Cell Ophthalmology Treatment Study(SCOTS) for retinal and optic nerve diseases: a preliminary report

In this report, we present the results of a single patient with optic neuropathy treated within the Stem Cell Ophthalmology Treatment Study （SCOTS）. SCOTS is an Institutional Review Board approved clinical trial and is the largest ophthalmology stem cell study registered at the National Institutes of Health to date- www.clinicaltrials.gov Identifier NCT 01920867. SCOTS utilizes autologous bone marrow-derived stem cells in the treatment of optic nerve and retinal diseases. Pre- and post-treatment comprehensive eye exams were independently performed at the Wilmer Eye Institute at the Johns Hopkins Hospital, USA. A 27 year old female patient had lost vision approximately 5 years prior to enrollment in SCOTS. Pre-treatment best-corrected visual acuity at the Wilmer Eye Institute was 20/800 Right Eye （OD） and 20/4,000 Left Eye （OS）. Four months following treatment in SCOTS, the central visual acuity had improved to 20/100 OD and 20/40 OS.

Human umbilical cord blood stem cells and brainderived neurotrophic factor for optic nerve injury: a biomechanical evaluation

Treatment for optic nerve injury by brain-derived neurotrophic factor or the transplantation of human umbilical cord blood stem cells has gained progress, but analysis by biomechanical indicators is rare. Rabbit models of optic nerve injury were established by a clamp. At 7 days after injury, the vitreous body received a one-time injection of 50 μg brain-derived neurotrophic factor or 1 × 10^6 human umbilical cord blood stem cells. After 30 days, the maximum load, maximum stress, maximum strain, elastic limit load, elastic limit stress, and elastic limit strain had clearly improved in rabbit models of optical nerve injury after treatment with brain-derived neurotrophic factor or human umbilical cord blood stem cells. The damage to the ultrastructure of the optic nerve had also been reduced. These findings suggest that human umbilical cord blood stem cells and brain-derived neurotrophic factor effectively repair the injured optical nerve, improve biomechanical properties, and contribute to the recovery after injury.

Research progress of stem cells on glaucomatous optic nerve injury

Glaucoma, the second leading cause of blindness, is an irreversible optic neuropathy. The mechanism of optic nerve injury caused by glaucoma is undefined at present. There is no effective treatment method for the injury. Stem cells have the capacity of self-renewal and differentiation. These two features have made them become the research focus on improving the injury at present. This paper reviews the application progress on different types of stem cells therapy for optic nerve injury caused by glaucoma.

Stem Cell Ophthalmology Treatment Study(SCOTS) for retinal and optic nerve diseases: a case report of improvement in relapsing auto-immune optic neuropathy

We present the results from a patient with relapsing optic neuropathy treated within the Stem Cell Ophthalmology Treatment Study （SCOTS）. SCOTS is an Institutional Review Board ap- proved clinical trial and has become the largest ophthalmology stem cell study registered at the National Institutes of Health to date （www.clinicaltrials.gov Identifier NCT 01920867）. SCOTS utilizes autologous bone marrow-derived stem cells （BMSCs） for treatment of retinal and optic nerve diseases. Pre-treatment and post-treatment comprehensive eye exams of a 54 year old female patient were performed both at the Florida Study Center, USA and at The Eye Center of Columbus, USA. As a consequence of a relapsing optic neuritis, the patient＇s previously normal visual acuity decreased to between 20/350 and 20/400 in the right eye and to 20/70 in the left eye. Significant visual field loss developed bilaterally. The patient underwent a right eye vitrectomy with injection of BMSCs into the optic nerve of the right eyeand retrobulbar, subtenon and in- travitreal injection of BMSCs in the left eye. At 15 months after SCOTS treatment, the patient＇s visual acuity had improved to 20/150 in the right eye and 20/20 in the left eye. Bilateral visual fields improved markedly. Both macular thickness and fast retinal nerve fiber layer thickness were maximally improved at 3 and 6 months after SCOTS treatment. The patient also reduced her mycophenylate dose from 1,500 mg per day to 500 mg per day and required no steroid pulse therapy during the 15-month follow up.

Cell proliferation and apoptosis in optic nerve and brain integration centers of adult trout Oncorhynchus mykiss after optic nerve injury

Fishes have remarkable ability to effectively rebuild the structure of nerve cells and nerve fibers after central nervous system injury.However,the underlying mechanism is poorly understood.In order to address this issue,we investigated the proliferation and apoptosis of cells in contralateral and ipsilateral optic nerves,after stab wound injury to the eye of an adult trout Oncorhynchus mykiss.Heterogenous population of proliferating cells was investigated at 1 week after injury.TUNEL labeling gave a qualitative and quantitative assessment of apoptosis in the cells of optic nerve of trout 2 days after injury.After optic nerve injury,apoptotic response was investigated,and mass patterns of cell migration were found.The maximal concentration of apoptotic bodies was detected in the areas of mass clumps of cells.It is probably indicative of massive cell death in the area of high phagocytic activity of macrophages/microglia.At 1 week after optic nerve injury,we observed nerve cell proliferation in the trout brain integration centers：the cerebellum and the optic tectum.In the optic tectum,proliferating cell nuclear antigen（PCNA）-immunopositive radial glia-like cells were identified.Proliferative activity of nerve cells was detected in the dorsal proliferative（matrix） area of the cerebellum and in parenchymal cells of the molecular and granular layers whereas local clusters of undifferentiated cells which formed neurogenic niches were observed in both the optic tectum and cerebellum after optic nerve injury.In vitro analysis of brain cells of trout showed that suspension cells compared with monolayer cells retain higher proliferative activity,as evidenced by PCNA immunolabeling.Phase contrast observation showed mitosis in individual cells and the formation of neurospheres which gradually increased during 1–4 days of culture.The present findings suggest that trout can be used as a novel model for studying neuronal regeneration.

Etomidate affects the anti-oxidant pathway to protect retinal ganglion cells after optic nerve transection

Our previous studies revealed that etomidate, a non-barbiturate intravenous anesthetic agent, has protective effects on retinal ganglion cells within 7 days after optic nerve transection. Whether this process is related to anti-oxidative stress is not clear. To reveal its mechanism, we established the optic nerve transection injury model by transecting 1 mm behind the left eyeball of adult male Sprague-Dawley rats. The rats received an intraperitoneal injection of etomidate(4 mg/kg) once per day for 7 days. The results showed that etomidate significantly enhanced the number of retinal ganglion cells retrogradely labeled with Fluorogold at 7 days after optic nerve transection. Etomidate also significantly reduced the levels of nitric oxide and malonaldehyde in the retina and increased the level of glutathione at 12 hours after optic nerve transection. Thus, etomidate can protect retinal ganglion cells after optic nerve transection in adult rats by activating an anti-oxidative stress response. The study was approved by the Animal Ethics Committee at Air Force Medical University, China(approval No. 20180305) on March 5, 2018.

Mesenchymal stem cell therapy in retinal and optic nerve diseases: An update of clinical trials

Retinal and optic nerve diseases are degenerative ocular pathologies which lead to irreversible visual loss. Since the advanced therapies availability, cell-based therapies offer a new all-encompassing approach. Advances in the knowledge of neuroprotection, immunomodulation and regenerative properties of mesenchymal stem cells(MSCs) have been obtained by several preclinical studies of various neurodegenerative diseases. It has provided the opportunity to perform the translation of this knowledge to prospective treatment approaches for clinical practice. Since 2008, several first steps projecting new treatment approaches, have been taken regarding the use of cell therapy in patients with neurodegenerative pathologies of optic nerve and retina. Most of the clinical trials using MSCs are in Ⅰ/Ⅱ phase, recruiting patients or ongoing, and they have as main objective the safety assessment of MSCs using various routes of administration. However, it is important to recognize that, there is still a long way to go to reach clinical trials phase Ⅲ-Ⅳ. Hence, it is necessary to continue preclinical and clinical studies to improve this new therapeutic tool. This paper reviews the latest progress of MSCs in human clinical trials for retinal and optic nerve diseases.

Effects of minocycline on apoptosis and neuronal changes in retinal ganglion cells from experimental optic neuritis rats

BACKGROUND： Minocycline, a tetracycline derivative, is neuroprotective in models of various neurological diseases. OBJECTIVE： To investigate the effects of minocycline on retinal ganglion cells （RGCs） in rats with optic neuritis, and to compare with the effects of methylprednisolone. DESIGN, TIME AND SETTING： This neuropathology controlled study was performed at the First Affiliated Hospital, Chongqing Medical University, China in May 2007. MATERIALS： A total of 22 female Wistar rats were randomly assigned into a normal control group （n ： 5） and an experimental group （n = 17）. The experimental group was composed of a model subgroup （n = 7）, a minocycline subgroup （n = 5）, and a methylprednisolone subgroup （n = 5）. Minocycline was supplied by Sigma, USA. METHODS： Antigen homogenate made from guinea pig spinal cord and complete Freund adjuvant was used to induce autoimmune encephalomyelitis, which could induce demyelinated optic neuritis models. Rats in the minocycline subgroup were intraperitoneally injected with minocycline （45 mg/kg） daily from day 8 following autoimmunity. Rats in the methylprednisolone subgroup were intraperitoneally injected with methylprednisolone （20 mg/kg） daily from day 8 following autoimmunity. MAIN OUTCOME MEASURES： On day 18 after autoimmunily induction, pathological changes in the optic nerve were observed by hematoxylin-eosin staining. The percentage area of axons in the transverse section of the optic nerve was measured by Bielschowsky staining. Apoptosis of RGCs was detected by TUNEL. RESULTS： Under an optical microscope, the optic nerve in rats with demyelinated optic neuritis showed a vacuole-like structure of fibers, irregular swelling of the axons, and infiltration of a large quantity of inflammatory cells. With an electron microscope, the optic nerve presented with vacuole-like structures in the axons, a small percentage area of axons in the transverse section, loose myelin sheaths, and microtubules and microfilaments disappeared. The pathological changes in the optic nerve met the changes in demyelinated optic neuritis. Moreover, there was significant apoptosis of RGCs. The percentage area of optic nerve axons in the transverse section was significantly increased and the number of apoptotic RGCs was increased after treatment with methylprednisolone and minocycline. Compared with methylprednisolone, minocycline had better effects on reducing RGC apoptosis （P 〈 0.05）. CONCLUSION： Minocycline has better inhibitory effects on RGC apoptosis than methylprednisolone. Minocycline can decrease the damage to axons of demyelinated optic neuritis rats, and has similar protective effects on neurons from demyelinated optic neuritis rats as methylprednisolone.

Human umbilical cord blood-derived stem cells and brain-derived neurotrophic factor protect injured optic nerve:viscoelasticity characterization

The optic nerve is a viscoelastic solid-like biomaterial.Its normal stress relaxation and creep properties enable the nerve to resist constant strain and protect it from injury.We hypothesized that stress relaxation and creep properties of the optic nerve change after injury.Moreover,human brain-derived neurotrophic factor or umbilical cord blood-derived stem cells may restore these changes to normal.To validate this hypothesis,a rabbit model of optic nerve injury was established using a clamp approach.At 7 days after injury,the vitreous body received a one-time injection of 50 μg human brain-derived neurotrophic factor or 1 × 106 human umbilical cord blood-derived stem cells.At 30 days after injury,stress relaxation and creep properties of the optic nerve that received treatment had recovered greatly,with pathological changes in the injured optic nerve also noticeably improved.These results suggest that human brain-derived neurotrophic factor or umbilical cord blood-derived stem cell intervention promotes viscoelasticity recovery of injured optic nerves,and thereby contributes to nerve recovery.

Acute changes in ganglion cell layer thickness in ischemic optic neuropathy compared to optic neuritis using optical coherence tomography

AIM:To elucidate the changes of different ganglion cell layer(GCL)thinning patterns between the optic neuritis(ON)and non-arteritic anterior ischemic optic neuropathy(NAION).METHODS:A prospective,observational study was conducted to evaluate the timing of GCL changes between acute ON and NAION using optical coherence tomography.RESULTS:Thinning on optical coherence tomography in the NAION group occurs as early as 11 d after symptomatic onset of vision loss and follows an altitudinal pattern.The mean superior-inferior GCL thickness difference in the NAION cohort was clinically significant at 5.7μm in the NAION cohort compared to controls of 0.8μm(P=0.032),but not significant in the ON group compared to controls with both groups measuring 1.1μm.Global thinning was significant for the ON group compared to controls at 7.2μm(P=0.011)but not the NAION group compared to controls at 1.35μm.CONCLUSION:These findings suggest that future treatments for NAION should be given early,and possibly before 11 d in order to prevent GCL and irreversible vision loss.

Diagnostic ability of ganglion cell complex thickness to detect glaucoma in high myopia eyes by Fourier domain optical coherence tomography

AIM：To evaluate the ability of macular ganglion cell complex（GCC） thickness using Fourier domain optical coherence tomography（FD-OCT） to detect glaucoma in highly myopic eyes.METHODS：Cross-sectional study.A total of 114 participants,consecutively were enrolled.Macular GCC thickness and peripapillary retinal nerve fiber layer（RNFL） thickness were obtained with RTVue FD-OCT.Receiver operating characteristics curves were constructed for each measurement parameter,and areas under the curves（AUCs） were compared.RESULTS：Both the average GCC and average RNFL thickness showed negative correlations with axial length（rGCC=-0.404,P=0.001;rRNFL=-0.561,P〈0.001）.The largest AUCs from GCC,and RNFL parameters were 0.968 [global loss volume（GLV）],and 0.855（average RNFL）,respectively.GLV was significantly better for detecting high myopic glaucoma than average RNFL（P〈0.001）.CONCLUSION：Macular GCC thickness has higher diagnostic power than peripapillary RNFL thickness to discriminate glaucoma patients from non-glaucoma subjects in high myopia.

Effects of optical interference and annealing on the performance of poly(3-hexylthiophene):fullerene based solar cells

In this paper, the effects of optical interference and annealing on the performance of P3HT：PCBM based organic solar cells are studied in detail. Due to the optical interference effect, short circuit current density （Jsc） shows obvious oscillatory behaviour with the variation of active layer thickness. With the help of the simulated results, the devices are optimized around the first two optical interference peaks. It is found that the optimized thicknesses are 80 and 208 nm. The study on the effect of annealing on the performance indicates that post-annealing is more favourable than pre-annealing. Based on post-annealing, different annealing temperatures are tested. The optimized annealing condition is 160℃ for 10 min in a nitrogen atmosphere. The device shows that the open circuit voltage Voc achieves about 0.65V and the power conversion efficiency is as high as 4.0 % around the second interference peak.

Femtosecond Optical Trapping of Cells:Efficiency and Viability

The femtosecond optical trapping capability and the effect of femtosecond laser pulses on cell viability were studied.The maximum lateral velocity at which the particles just failed to be trapped,together with the measured average trapping power,were used to calculate the lateral trapping force(Q-value) .The viability of the cells after femtosecond laser trapping was ascertained by vital staining.Measurement of the Q-values shows that femtosecond optical tweezers are just as effective as continuous wave optical tweezers.The experiments demonstrate that there is a critical limit for exposure time at each corresponding laser power of femtosecond optical tweezers,and femtosecond laser tweezers are safe for optical trapping at low power with short exposure time.

Microstructure and optical properties of sprayed γ-CuI thin films for CuInS_2 solar cells

γ-CuI thin films were prepared by a spraying method using acetonitrile as a solvent,CuI and iodine as reagents.The influences of substrate temperature on the structure,topography,and optical properties of CuI films were investigated.Scanning electron microscope（SEM） photos revealed that the shape and grain size of CuI grains were related to substrate temperature.X-ray diffraction results showed that substrate temperature affected the crystalline quality of CuI films.When the substrate temperature was 110°C,CuI thin films showed γ-phase zinkblende structure with（111） preferred orientation.The dimension of the globular CuI crystallite was approximately 35 nm,the energy band gap was 2.97 eV,the maximum transmittance was 87.3% in the part of the visible region,and the open circuit voltage was close to 380 mV.This opened a route for a cadmium-free buffer layer for CuInS2 solar cells.

Structural impairment patterns in peripapillary retinal fiber layer and retinal ganglion cell layer in mitochondrial optic neuropathies

AIM：To evaluate the structural injure patterns in peripapillary retinal fiber layer （pRNFL）, retinal ganglion cell layer （RGCL） and their correlations to visual function in various mitochondrial optic neuropathies （MON） to offer help to their differential diagnosis.METHODS：Totally 32 MON patients （60 eyes） were recruited within 6mo after clinical onsets, including 20 Leber hereditary optic neuropathy （LHON） patients （37eyes）, 12 ethambutol-induced optic neuropathy （EON）patients （23 eyes）, and 41 age-gender matched healthy controls （HC, 82 eyes）. All subjects had pRNFL and RGCL examinations with optic coherence tomography （OCT） and visual function tests.RESULTS：In the early stages of MON, the temporal pRNFL thickness decreased （66.09±22.57μm）, but increased in other quadrants, compared to HC （76.95±14.81μm）. The other quadrants remaining stable for LHON and EON patients besides the second hour sector of pRNFL thickness reduced and the temporal pRNFL decreased （56.78±15.87μm） for EON. Total macular thickness in MON reduced remarkably（279.25±18.90μm; P=0.015）, which mainly occurring in the inner circle （3 mm diameter of circle） and the nasal temporal sectors in the outer circle （5.5 mm diameter of circle）, in contrast to those in HC. RGCL thickness reduced in each sector of the macula （61.90±8.73μm; P≤0.001）. It strongly showed the correlationship of best corrected visual acuity （R=0.50, P=0.0003） and visual field injury （R=0.54,P=0.0002） in MON patients.CONCLUSION：OCT is a potential tool for detecting structural alterations in the optic nerves of various MON. Different types of MON may have different damage patterns.