Lactational optic neuritis - A case series with a review of the literature.

PURPOSE: Optic neuritis is the most common optic neuropathy affecting adults, especially women. Lactational optic neuritis is a rare entity occurring during the postpartum period with a high chance of recurrence. Through this study, we evaluated the clinical profile and visual outcome of lactational optic neuritis. METHODS: This was a retrospective study where patients with optic neuritis presenting during the first year of the postpartum period to the neuro-ophthalmology clinic between January 2016 and December 2022 were included in the study. RESULTS: This study included seven eyes of six patients. The mean age of presentation was 24.6 years, with all patients presenting after the first 3 months of the postpartum period. All patients had unilateral involvement except one, presenting with painful vision loss. Best corrected visual acuity ranged from 6/18 to hand movements. Relative afferent pupillary defect and dyschromatopsia were present in all patients. Disc edema was seen in all but one case. Three patients were treated with steroids along with multivitamins, and the remaining three refused treatment with steroids, receiving multivitamins alone. All patients had complete recovery by the end of 12 weeks. CONCLUSION: Optic neuritis during lactation is attributed more to post-pregnancy immunological changes rather than lactation itself. The presentation and clinical features are similar to classic optic neuritis and remain an important differential diagnosis for visual dysfunction in the postpartum period.

A Panorama of Extracellular Vesicle Applications: From Biomarker Detection to Therapeutics.

Extracellular vesicles (EVs) secreted by all cell types are involved in the cell-to-cell transfer of regulatory factors that influence cell and tissue phenotypes in normal and diseased tissues. EVs are thus a rich source of biomarker targets for assays that analyze blood and urinary EVs for disease diagnosis. Sensitive biomarker detection in EVs derived from specific cell populations is a key major hurdle when analyzing complex biological samples, but innovative approaches surveyed in this Perspective can streamline EV isolation and enhance the sensitivity of EV detection procedures required for clinical application of EV-based diagnostics and therapeutics, including nanotechnology and microfluidics, to achieve EV characterizations. Finally, this Perspective also outlines opportunities and challenges remaining for clinical translation of EV-based assays.

Ultrasensitive detection of aromatic water pollutants through protein immobilization driven organic electrochemical transistors.

Xenobiotic aromatic water pollutants pose an extreme threat to environmental sustainability. Due to the lack of detectable functional groups in these compounds and scarcity of selective bio-recognition scaffolds, easy-to-use sensing strategies capable of on-site detection remain unavailable. Herein, to address this lacune, we entail a strategy that combines biosensor scaffolds with organic electronics to create a compact device for environmental aromatic pollution monitoring. As proof of principle, a sensor module capable of rapid, economic, reliable, and ultrasensitive detection of phenol down to 2 ppb (0.02 µM) was designed wherein biosensing protein MopR was coupled with an organic electrochemical transistor (OECT). For effective interfacing of the sensing scaffold MopR, graphene oxide (GO) nanosheets were optimized as a host immobilization matrix. The MopR-GO immobilized sensor module was subsequently substituted as the gate electrode with PEDOT:PSS serving as an organic semiconductor material. The resulting OECT sensor provided a favourable microenvironment for protein activity, maintaining high specificity. Exclusive phenol detection with minimal loss of sensitivity (<5% error) could be achieved in both complex pollutant mixtures and real environmental samples. This fabrication strategy that amalgamates biological biosensors with organic electronics harnesses the potential to achieve detection of a host of emerging pollutants.

Fluorescent ZnO-Au Nanocomposite as a Probe for Elucidating Specificity in DNA Interaction.

In this work, we report the interaction of a fluorescent ZnO-Au nanocomposite with deoxyribonucleic acid (DNA), leading to AT-specific DNA interaction, which is hitherto not known. For this study, three natural double-stranded (ds) DNAs having different AT:GC compositions were chosen and a ZnO-Au nanocomposite has been synthesized by anchoring a glutathione-protected gold nanocluster on the surface of egg-shell-membrane (ESM)-based ZnO nanoparticles. The ESM-based bare ZnO nanoparticles did not show any selective interaction toward DNA, whereas intrinsic fluorescence of the ZnO-Au nanocomposite shows an appreciable blue shift (Δλmax = 18 nm) in the luminescence wavelength of 520 nm in the presence of ds calf thymus (CT) DNA over other studied DNAs. In addition, the interaction of the nanocomposite through fluorescence studies with single-stranded (ss) CT DNA, synthetic polynucleotides, and nucleobases/nucleotides (adenine, thymine, deoxythymidine monophosphate, deoxyadenosine monophosphate) was also undertaken to delineate the specificity in interaction. A minor blue shift (Δλmax = 5 nm) in the emission wavelength at 520 nm was observed for single-stranded CT DNA, suggesting the proficiency of the nanocomposite for discriminating ss and ds CT DNA. More importantly, fluorescence signals from the nano-bio-interaction could be measured directly without any modification of the target, which is the foremost advantage emanated from this study compared with other previous reports. The AT base-pair-induced enhancement was also found to be highest for the melting temperature of CT DNA (ΔTmCT = 6.7 °C). Furthermore, spectropolarimetric experiments followed by calorimetric analysis provided evidence for specificity in AT-rich DNA interaction. This study would lead to establish the fluorescent ZnO-Au nanocomposite as a probe for nanomaterial-based DNA-binding study, featuring its specific interaction toward AT-rich DNA.

Single-molecular and ensemble-level oscillations of cyanobacterial circadian clock.

When three cyanobacterial proteins, KaiA, KaiB, and KaiC, are incubated with ATP in vitro, the phosphorylation level of KaiC hexamers shows stable oscillation with approximately 24 h period. In order to understand this KaiABC clockwork, we need to analyze both the macroscopic synchronization of a large number of KaiC hexamers and the microscopic reactions and structural changes in individual KaiC molecules. In the present paper, we explain two coarse-grained theoretical models, the many-molecule (MM) model and the single-molecule (SM) model, to bridge the gap between macroscopic and microscopic understandings. In the simulation results with these models, ATP hydrolysis in the CI domain of KaiC hexamers drives oscillation of individual KaiC hexamers and the ATP hydrolysis is necessary for synchronizing oscillations of a large number of KaiC hexamers. Sensitive temperature dependence of the lifetime of the ADP bound state in the CI domain makes the oscillation period temperature insensitive. ATPase activity is correlated to the frequency of phosphorylation oscillation in the single molecule of KaiC hexamer, which should be the origin of the observed ensemble-level correlation between the ATPase activity and the frequency of phosphorylation oscillation. Thus, the simulation results with the MM and SM models suggest that ATP hydrolysis stochastically occurring in each CI domain of individual KaiC hexamers is a key process for oscillatory behaviors of the ensemble of many KaiC hexamers.

A new insight into the interaction of ZnO with calf thymus DNA through surface defects.

Experimental evidences on the binding interaction of ZnO and Calf Thymus (CT) DNA using several biophysical techniques are the centre of interest of the present study. The interaction of ZnO with CT DNA has been investigated in detail by absorption spectral study, fluorescence titration, Raman analysis, zeta potential measurement, viscometric experiment along with thermal melting study and microscopic analysis. Steady-state fluorescence study revealed the quenching (48%) of the surface defect related peak intensity of ZnO on interaction with DNA. The optimized concentration of ZnO and DNA to obtain this level of quenching has been found to be 0.049mM and 1.027µM, respectively. Additional fluorescence study with 8-hydroxy-5-quinoline (HQ) as a fluorescence probe for Zn2+ ruled out the dissolution effect of ZnO under the experimental conditions. DNA conjugation on the surface of ZnO was also supported by Raman study. The quantitative variation in conductivity as well as electrophoretic mobility indicated significant interaction of ZnO with the DNA molecule. Circular dichroism (CD) and viscometry titrations provided clear evidence in support of the conformational retention of the DNA on interaction with ZnO. The binding interaction was found to be predominantly entropy driven in nature. The bio-physical studies presented in this paper exploring ZnO-CT DNA interaction could add a new horizon to understand the interaction between metal oxide and DNA.

Role of ATP Hydrolysis in Cyanobacterial Circadian Oscillator.

A cyanobacterial protein KaiC shows a stable oscillation in its phosphorylation level with approximately one day period when three proteins, KaiA, KaiB, and KaiC, are incubated in the presence of ATP in vitro. During this oscillation, KaiC hydrolyzes more ATP molecules than required for phosphorylation. Here, in this report, a theoretical model of the KaiABC oscillator is developed to elucidate the role of this ATP consumption by assuming multifold feedback relations among reactions and structural transition in each KaiC molecule and the structure-dependent binding reactions among Kai proteins. Results of numerical simulation showed that ATP hydrolysis is a driving mechanism of the phosphorylation oscillation in the present model, and that the frequency of ATP hydrolysis in individual KaiC molecules is correlated to the frequency of oscillation in the ensemble of many Kai molecules, which indicates that the coherent oscillation is generated through the coupled microscopic intramolecular and ensemble-level many-molecular regulations.

Performance of colloidal CdS sensitized solar cells with ZnO nanorods/nanoparticles.

As an alternative photosensitizer in dye-sensitized solar cells, bovine serum albumin (BSA) (a nonhazardous protein) was used in the synthesis of colloidal CdS nanoparticles (NPs). This system has been employed to replace the commonly used N719 dye molecule. Various nanostructured forms of ZnO, namely, nanorod and nanoparticle-based photoanodes, have been sensitized with colloidal CdS NPs to evaluate their effective performance towards quantum dot sensitized solar cells (QDSSCs). A polysulphide (S x2-)-based electrolyte and Cu x S counter electrode were used for cell fabrication and testing. An interesting improvement in the performance of the device by imposing nanorods as a scattering layer on a particle layer has been observed. As a consequence, a maximum conversion efficiency of 1.06% with an open-circuit voltage (VOC) of 0.67 V was achieved for the ZnO nanorod/nanoparticle assembled structure. The introduction of ZnO nanorods over the nanoparticle led to a significant enhancement of the overall efficiency compared to the corresponding bare nanoparticles.

Selective Binding of Genomic Escherichia coli DNA with ZnO Leads to White Light Emission: A New Aspect of Nano-Bio Interaction and Interface.

Here, we report for the first time, a novel and intriguing application of deoxyribonucleic acid (DNA) in the area of optics by demonstrating white light emission by tuning the emission of a nanomaterial, ZnO rods, exhibiting surface defects, in the presence of genomic Escherichia coli DNA with a comparatively high quantum efficiency. In order to understand the DNA specificity, we have also studied the interaction of ZnO with CT, and ML DNA, ss EC DNA, synthetic polynucleotides and different mononucleosides and bases. Further, in order to understand the effect of particle shape and defects present in ZnO, we have also extended our study with ZnO rods prepared at higher temperature exhibiting red emission and ZnO particles exhibiting yellow emission. Interestingly, none of the above studies resulted in white light emission from ZnO-DNA complex. Our studies unequivocally confirmed that the concentration and the nature of DNA and ZnO together plays a crucial role in obtaining CIE coordinates (0.33, 0.33) close to white light. The much enhanced melting temperature (Tm) of EC DNA and the energetics factors confirm enhanced hydrogen bonding of ZnO with EC DNA leading to a new emission band. Our experimental observations not only confirm the selective binding of ZnO to EC DNA but also open a new perspective for developing energy saving light emitting materials through nano-bio interactions.

Enhanced stability of Zn2SnO4 with N719, N3 and eosin Y dye molecules for DSSC application.

In view of the increased prospects of Zn2SnO4 as an alternative photoanode for dye sensitized solar cells (DSSCs), we synthesized phase pure Zn2SnO4 nanostructures by a cost effective sonochemical technique. In order to establish the stability of this alternative photoanode in DSSCs, we further explored the interaction of the synthesized Zn2SnO4 with commonly used photosensitizers in DSSCs, such as N3, N719 and eosin Y. Based on the time dependent optical studies we could establish the prominence of anchoring groups in controlling the dye loading. Optical studies confirmed an enhanced stable interaction of Zn2SnO4 with all the studied sensitizers which could be beneficial in designing DSSC devices in future. In addition, we also established contact angle measurement as an indirect tool to understand the surface characteristics and thereby optimize the dye loading and stability of the photoanode surface. With the help of contact angle data, we could unequivocally establish the stability of the Zn2SnO4 photoanode surface modified with N3 and N719 dye molecules. Our studies further suggest the enhanced and superior stability of the prepared Zn2SnO4 compared to ZnO in different chemical environments. The quenching of the fluorescence and the abrupt decrease in the contact angle owing to an increase in the surface roughness further strengthen the above conclusion. To our best knowledge, this probably is the first report on the synthesis of Zn2SnO4 by a sonochemical process and its interaction with various photosensitizers. An exceptionally high open circuit voltage of >0.8 V was observed for all the devices fabricated with the synthesized ZTO as a photoanode. Our studies could pave way to future developments in the area of DSSCs using Zn2SnO4 as a photoanode.