Effect of long-term inorganic arsenic exposure on erythropoietin production in vitro.

Arsenic is widely present in the environment in trivalent and pentavalent forms; long-term arsenic exposure due to environmental pollution has become a problem. Previous reports have shown that 24-h exposure to arsenate (as pentavalent arsenic) potentiates erythropoietin (EPO) production via reactive oxygen species (ROS) in EPO-producing HepG2 cells. However, the effects of long-term arsenate exposure on EPO production remain unclear. In HepG2 cells subcultured for 3 weeks in the presence of arsenate, EPO mRNA levels were lower than those in untreated cells. Levels of ARSENITE METHYLTRANSFERASE mRNA, as well as those of Nuclear factor erythroid 2-related factor 2, glutathione, and superoxide dismutase proteins, were increased compared to untreated cells, but levels of malondialdehyde were not significantly altered. Thus, long-term exposure to arsenate enhances ROS scavenging, suggesting that the ROS-induced accumulation of EPO mRNA is attenuated by arsenate exposure. The induction of EPO accumulation by hypoxia also was attenuated by long-term arsenate exposure, suggesting an impairment in responsivity of EPO production. Furthermore, mRNA levels of SIRTUIN-1, which affects EPO transcription, were potentiated by long-term arsenate exposure. These results suggest that long-term arsenate exposure has multiple, distinct effects on EPO production in vitro.

Modification of ibuprofen to improve the medicinal effect; structural, biological, and toxicological study.

Ibuprofen is classified as a non-steroidal anti-inflammatory drug (NSAID) that is employed as an initial treatment option for its non-steroidal anti-inflammatory, pain-relieving, and antipyretic properties. However, Ibuprofen is linked to specific well-known gastrointestinal adverse effects like ulceration and gastrointestinal bleeding. It has been linked to harmful effects on the liver, kidney, and heart. The purpose of the study is to create novel and potential IBU analogue with reduced side effects with the enhancement of their medicinal effects, so as to advance the overall safety profile of the drug. The addition of some novel functional groups including CH3, F, CF3, OCF3, Cl, and OH at various locations in its core structure suggestively boost the chemical as well as biological action. The properties of these newly designed structures were analyzed through chemical, physical, and spectral calculations using Density Functional Theory (DFT) and time-dependent DFT through B3LYP/6-31 g (d,p) basis set for geometry optimization. Molecular docking and non-bonding interaction studies were conducted by means of the human prostaglandin synthase protein (PDB ID: 5F19) to predict binding affinity, interaction patterns, and the stability of the protein-drug complex. Additionally, ADMET (Absorption, Distribution, Metabolism, Excretion, and Toxicity) and PASS (Prediction of Activity Spectra for Substances) predictions were employed to evaluate the pharmacokinetic and toxicological properties of these structures. Importantly, most of the analogues displayed reduced hepatotoxicity, nephrotoxicity, and carcinogenicity in comparison to the original drug. Moreover, molecular docking analyses indicated improved medicinal outcomes, which were further supported by pharmacokinetic calculations. Together, these findings suggest that the modified structures have reduced adverse effects along with improved therapeutic action compared to the parent drug.

Color-switching hydrogels as integrated microfluidic pressure sensors.

Precisely measuring pressure in microfluidic flows is essential for flow control, fluid characterization, and monitoring, but faces specific challenges such as achieving sufficient resolution, non-invasiveness, or ease of use. Here, we demonstrate a fully integrated multiplexed optofluidic pressure sensor, entirely decoupled from the flow path, that enables local pressure measurements along any microfluidic channel without altering its flow geometry. The sensor itself relies on the compression of a soft mechano-actuated hydrogel, changing color in response to a pressure change. The hydrogel is separated from the fluid circulating in the channel by a thin membrane, allowing for the unrestricted use of different types of fluids. Imaging the gel through the transparent PDMS with a color camera provides a direct, easy, and contact-free determination of the fluid pressure at the sensing location for pressures as small as 20mbar with a resolution of around 10mbar. The sensitivity and accessible pressure range can be tuned via the mechanical properties of the sensing unit. The photonic gel can also be used to acquire 2D pressure or deformation maps, taking advantage of the fast response time and fine spatial resolution.

Ultrafast and simultaneous removal of four tetracyclines from aqueous solutions using waste material-derived graphene oxide-supported cobalt-iron magnetic nanocomposites.

In this work, a graphene oxide-supported cobalt-iron oxide (GO/Co-Fe) magnetic nanocomposite was successfully synthesized using waste dry cells for the efficient and simultaneous removal of tetracycline (TC), chlortetracycline (CTC), oxytetracycline (OTC), and doxycycline (DTC) from aqueous solutions. The GO/Co-Fe nanocomposite was thoroughly characterized using Fourier transform infrared spectroscopy, vibrating sample magnetometry, X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and zeta potential analysis. This multi-faceted characterization provided clean insights into the composition and properties of the synthesized nanocomposite. The adsorption of tetracyclines (TCs) was systematically investigated by assessing the influence of critical factors, such as adsorbent dosage, contact duration, initial pH of the solution, initial concentration, and temperature. The GO/Co-Fe adsorbent showed high removal efficiencies of 94.1% TC, 94.32% CTC, 94.22% OTC, and 96.94% DTC within 30 s contact period. The maximum removal efficiency of TCs was found at a low adsorbent dose of 0.15 g L-1. Notably, this superior removal efficiency was achieved at neutral pH and room temperature, demonstrating the adsorbent's efficacy under environmentally viable conditions. The kinetic studies demonstrated that the adsorption process was fitted satisfactorily with the pseudo-second-order model. Additionally, the adsorption behaviour of TCs on the GO/Co-Fe adsorbent was assessed by isotherm models, Langmuir and Freundlich. The experimental data followed the Langmuir isotherm, signifying a monolayer adsorption mechanism on the surface of the adsorbent. The adsorption capacities (qm) of GO/Co-Fe for TC, CTC, OTC and DTC were determined to be 64.10, 71.43, 72.46 and 99.01 mg g-1, respectively. Importantly, the GO/Co-Fe adsorbent showed reusability capabilities. The super magnetic properties of GO/Co-Fe made it easy to use for several cycles. These results clearly establish GO/Co-Fe as an exceptionally effective adsorbent for the removal of TCs from aqueous systems, highlighting its great potentiality in water treatment applications.

Effect of long-term treatment with trivalent chromium on erythropoietin production in HepG2 cells.

Trivalent chromium (Cr(III)) is sometimes taken as a long-term supplement, but its effectiveness is unclear. Recently, Cr(III) reportedly modulates peroxisome proliferator-activated receptor gamma (PPARγ) expression. Our previous study reported that increased PPARγ after 24 h Cr(III) treatment promoted erythropoietin (EPO) production in HepG2 cells. In the current study, we analyzed 4-week Cr(III) treatment effects on PPARγ and EPO production in HepG2 cells. Long-term Cr(III) treatment resulted in significantly elevated mRNA expression levels of PPARγ and EPO compared to controls. Additionally, treatment with a PPARγ inhibitor suppressed EPO mRNA expression. Increased EPO mRNA expression due to stimulation with hypoxia or cobalt was unaffected by long-term Cr(III) treatment. Administration of lipopolysaccharide and pyocyanin which causes oxidative stress, promoted EPO production, but this effect was attenuated in cells treated with Cr(III). Long-term Cr(III) treatment increased hypoxia inducible factor (HIF)-1α and 2α mRNA expression and protein levels. Increased PPARγ, induced by long-term Cr(III) treatment, suppressed sirtuin1 (SIRT1) mRNA expression and increased EPO mRNA expression, suggesting that increased PPARγ attenuated the suppressive effect of SIRT1 on HIF. These results suggest that the sustained increase in PPARγ during long-term Cr(III) treatment maintains increased EPO production through a mechanism different from that observed under hypoxia.

Exploring the potential of mahogany extract as a natural dye for the coloration of jute fabric.

The use of synthetic dyes in the textile industry is mostly non-degradable, which are carcinogenic and pollute the environment severely. Natural dyes have gained significant attention recently due to their potential to mitigate the environmental challenges associated with synthetic colorants. This investigation is centered around the extraction of natural dyes sourced from mahogany trees and the exploration of environmentally friendly techniques for coloring jute fabric. The derived dyes were procured from distinct segments of the mahogany tree: namely, the bark, fruits, and wood remnants. Employing an aqueous extraction methodology, inherent coloring agents were meticulously separated and subsequently applied to jute fabric subsequent to appropriate mordanting employing a variety of mordant categories. An exhaustive assessment encompassing wash, light, rubbing, and perspiration resistance was conducted on jute fabric that was subjected to dyeing using three distinct variants of mahogany tree-derived dyes. Notably, jute fabric treated with wood wastage-sourced dye exhibited commendable to exceptional resistance properties. The efficacy of this dyeing process was further substantiated through diverse characterization techniques, inclusive of scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR), which unequivocally affirmed the successful bonding of mahogany-derived dyes onto the surface of the jute fabric. The textile industry, particularly dyeing operations that use large, designed colors and synthetic chemicals, is wreaking havoc on the sea-going environment by dumping emissions directly into bodies of water. Synthetic colors are commonly used to dye jute fabric, which has major health and environmental consequences. Therefore, concerning the environmental challenges, the dyeing of jute fabric using naturally extracted dyes from mahogany trees can be a suitable alternative to synthetic dyes in the textile industry.

Assessment of risk perception and subjective norms related to Mpox (monkeypox) among adult males in Bangladesh: A cross-sectional study.

Background and Aims: Monkeypox (Mpox) has become a concern worldwide after spreading into nonendemic countries. The World Health Organization (WHO) has declared this a public health emergency of international concern and recommended to get vaccinated first who are at the highest risk. Risk perception and subjective norms can influence the decision of vaccine uptake. Therefore, we intended to perform a cross-sectional study on the male population in our country to assess their risk perception and subjective norms on Mpox. Methods: We measured participants' risk perception and subjective norms using Google form. Demographic profile of participants was obtained using a structured questionnaire. We performed a χ 2 test to compare the levels of risk perception and subjective norm perception and multiple logistic regression analysis to determine the association between the study parameters and the sociodemographic profile of the participants. Results: Among the participants, 93 (23.72%), 288 (73.47%), and 11 (2.81%) had high, medium, and low-risk perceptions, respectively. For subjective norms, we observed 288 (58.16%) participants had a medium, 117 (29.85%) had high, and 47 (11.99%) had low levels of subjective norms, respectively. Most participants possessed medium risk perception (73.47%) and subjective norms (58.16%). Moreover, we observed that moderate risk perception was prevalent in people with body mass index (BMI) level between 18.5 and 25 (73.3%), married (63.5%), low economic background (94.1%), living with a family (77.1%), smokers (68.4%), heterosexuals (99%), people with no/little impact of coronavirus disease 2019 (Covid-19) on life (91%). Proportions of people with moderate subjective norms BMI level of 18.5-25 (73.2%), married (60.5%), low economic status (93.9%), rural (58.8%), living with family (77.2%), nonsmokers (71.1%), and people with no/little impact of Covid-19 in their lives (91.2%). Conclusion: The majority of participants perceived medium risk perception and subjective norms related to Mpox. Furthermore, we observed a significant association between the study parameters and the sociodemographic characteristics of our study participants. We recommend that further longitudinal studies to yield more accurate results.

Assessment of vaccine perception and vaccination intention of Mpox infection among the adult males in Bangladesh: A cross-sectional study findings.

BACKGROUND: Mpox (monkeypox) infection has become a global concern for healthcare authorities after spreading in multiple non-endemic countries. Following the sudden multi-country outbreak of Mpox, the World Health Organization (WHO) declared a public health emergency of international concern. We do not have any vaccines approved for the prevention of Mpox infection. Therefore, international healthcare authorities endorsed smallpox vaccines for the prevention of Mpox disease. Here we intended to perform this cross-sectional study among the adult males in Bangladesh to assess the Mpox vaccine perception and vaccination intention. METHODS: We conducted this web-based survey among the adult males in Bangladesh from September 1, 2022, to November 30, 2022, using Google Forms. We assessed the Mpox vaccine perception and vaccination intention. We performed a chi-square test to compare vaccine perception and vaccination intention levels. Also, we performed multiple logistic regression analyses to determine the association between the study parameters and the sociodemographic profile of the participants. RESULTS: According to the present study, the Mpox vaccine perception was high among 60.54% of the respondents. Also, 60.05% of respondents showed medium vaccination intention. Mpox vaccine perception and vaccination intention were strongly associated with the sociodemographic profiles of the participants. Furthermore, we discovered a significant association between the level of education and vaccination intention among the respondents. Also, age and marital status played a role in the Mpox vaccine perception and vaccination intention. CONCLUSION: Our findings showed a significant association between sociodemographic characteristics and the Mpox vaccine perception/vaccination intention. Along with the country's long experience in mass immunization, campaigns about Covid-19 vaccines and high vaccination rates might play a role in Mpox vaccine perception and vaccination intention. We recommend more social awareness and educational communications or seminars for the target population to bring more positive changes in their attitude towards Mpox prevention.

COVID-19 vaccination success in Bangladesh: Key strategies were prompt response, early drives for vaccines, and effective awareness campaigns.

Bangladesh is located in Southeast Asia that has a high population density. It is a lower-middle-income country. The COVID-19 pandemic severely impacted the nation that slowed its economic growth. It halted major industries, crippling the nation's economy. The students were uncertain after the declaration of school closures. Hospitals could not treat other patients properly due to the vast health burden of COVID-19. Bangladesh put up a solid fight during COVID-19 as a lower-middle-income country. Prompt action, early vaccination drives, effective awareness campaigns, and widespread public involvement have enabled Bangladesh to bring more than 90% of its population into COVID-19 vaccination coverage. It was possible by the effective diplomatic and local health strategy implemented by the Bangladeshi government, the country's extensive prior experience, and its long history of achieving a high success rate in other vaccination campaigns. Bangladesh was able to flatten the curve sooner than other developed countries. Therefore, the cogs of everyday social life and the economy begin to turn once more. The strategy Bangladesh used to combat the COVID-19 pandemic through vaccination and diplomatic policy by calling on its prior experience has the potential to serve as a model for other low- and middle-income countries and an example for developed nations.

Comparative Performance Evaluation of Personal Protective Measures and Antiviral Agents Against SARS-CoV-2 Variants: A Narrative Review.

Scientists identified SARS-CoV-2 in December 2019 in Wuhan city of China. Soon after its identification, Covid-19 spreads almost everywhere. The World Health Organization (WHO) declared the Covid-19 outbreak as a pandemic on March 11, 2020. Countries are facing multiple waves due to the different variants of the coronavirus. Personal preventive measures, vaccines, and antiviral drugs are the approaches to control Covid-19. However, these approaches are being implemented in different countries at different levels because of the availability of personal protective measures and antiviral agents. The objective of this study was to evaluate the effectiveness of practicing measures to fight the Covid-19 pandemic. Here we searched relevant literature from PubMed and Scopus using the keywords such as personal protective measures, antiviral agents, and vaccine effectiveness. According to the present findings, protective measures were found comparatively less effective. Nevertheless, these measures can be used to limit the spreading of Covid-19. Antiviral agents can reduce the hospitalization rate and are more effective than personal protective measures. The most effective strategy against Covid-19 is early vaccination or multiple vaccination dose. The respective authorities should ensure equal distribution of vaccines, free availability of antiviral drugs, and personal protective measure in poor and developing countries. We recommend more studies to describe the effectiveness of practicing preventive measures and antiviral agents against recent variants of the coronavirus.

Effect of pentavalent inorganic arsenic salt on erythropoietin production and autophagy induction.

Arsenic is abundant in the environment and takes the form of trivalent and pentavalent arsenic compounds. Arsenite has been reported to both promote and suppress erythropoietin (EPO) production and autophagy induction. EPO production is involved in hematopoiesis, and autophagy induction is involved in cytoprotection, both of which are thought to be cellular responses to arsenic stress. While there are reports that show the effects of EPO on autophagy induction, the relationship between EPO production and autophagy induction is unclear. Therefore, this study analyzed the effect of the pentavalent inorganic arsenic salt arsenate on EPO production in vitro and in vivo and EPO-induced autophagy in HepG2 cells. Exposure of HepG2 cells to low-concentration arsenate was observed to increase EPO production and induced autophagy. Moreover, a ROS scavenger suppressed the arsenate-induced increase in autophagy and EPO mRNA levels. Both EPO production and autophagy induction contributed to protection from arsenate-induced cytotoxic stress. HepG2 cells expressed the EPO receptor and production of EPO by HepG2 cells acted in an autoregulatory manner to suppress autophagy induction. In vivo administration of low-concentration arsenate to rats increased EPO mRNA levels in the liver and kidney. These results suggested that low-concentration arsenate promotes EPO production and autophagy induction in HepG2 cells, and the resultant EPO production contributes to cytoprotection of cultured cells via EPO receptor activation.

Green synthesis of zinc oxide nanoparticles using Cocos nucifera leaf extract: characterization, antimicrobial, antioxidant and photocatalytic activity.

Zinc oxide nanoparticles (ZnO NPs) have been successfully prepared using Cocos nucifera leaf extract and their antimicrobial, antioxidant and photocatalytic activity investigated. The structural, compositional and morphological properties of the NPs were recorded and studied systematically to confirm the synthesis. The aqueous suspension of NPs showed an ultraviolet-visible (UV-Vis) absorption maxima of 370 nm, indicating primarily its formation. X-ray diffraction analysis identified the NPs with a hexagonal wurtzite structure and an average particle size of 16.6 nm. Fourier transform infrared analysis identified some biomolecules and functional groups in the leaf extract as responsible for the encapsulation and stabilization of ZnO NPs. Energy-dispersive X-ray analysis showed the desired elemental compositions in the material. A flower-shaped morphology of ZnO NPs was observed by scanning electron microscopy, with a grain size of around 15 nm. The optical properties of the NPs were studied by UV-Vis spectroscopy, and the band gap was calculated as 3.37 eV. The prepared ZnO NPs have demonstrated antimicrobial activity against T. harzianum and S. aureus, with a zone of inhibition of 14 and 10 mm, respectively. The photocatalytic behaviour of ZnO NPs showed absorbance degradation at around 640 nm and it discoloured methylene blue dye after 1 h, with a degradation maximum of 84.29%. Thus, the prepared ZnO NPs could potentially be used in antibiotic development and pharmaceutical industries, and as photocatalysts.

A Brief Report on Monkeypox Outbreak 2022: Historical Perspective and Disease Pathogenesis.

Monkeypox is a zoonotic disease caused by the monkeypox virus (MPXV). It was an epidemic infection among African countries over the last few decades. In 2022, MPXV has been broke through in Africa, America, Eastern Mediterranean, Europe, South-East Asia, and Western Pacific region. This widespread infection of MPXV has created panic across the nations, and the WHO has declared a global public health emergency due to the multi-country MPX outbreak. We prepared this brief report on the MPX outbreak 2022 by extracting data from Scopus, PubMed, and website databases. We manually read all the relevant articles from our target databases. The rapid spread of MPX infection in around a 100 countries has threatened the global healthcare systems. The available epidemiological data revealed that sexual orientations and encounters are potential contributing factors for monkeypox infections. However, it has not been categorized as a sexually transmitted infection. Also, MPXV can transfer from 1 individual to others in many ways. The empowerment of this old foe has created additional pressure and threat on the healthcare authorities during the ongoing Covid-19 pandemic. Effective preventive measures, social awareness, and therapeutic approaches can reduce this extra burden on the healthcare system across the countries. Focusing only on sexual orientations and encounters as risk factors for MPX infection might increase stigma that will be another barrier to controlling and preventing MPXV spread. Therefore, we should be careful in delivering messages about MPX infection to the general population. Also, we recommend repositioning the existing smallpox vaccines and antivirals in MPX infection until the development of specific antiviral agents against this infection.

A Fast Adsorption of Azithromycin on Waste-Product-Derived Graphene Oxide Induced by H-Bonding and Electrostatic Interactions.

Graphene oxide (GO) was prepared from the graphite electrode of waste dry cells, and the application of the prepared GO as a potential adsorbent for rapid and effective removal of an antibiotic, azithromycin (AZM), has been investigated. The synthesis process of GO is very simple, cost-effective, and eco-friendly. As-prepared GO is characterized by field-emission scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, X-ray diffractometry, Fourier transform infrared spectroscopy, elemental analysis, Brunauer-Emmett-Teller sorptometry, and zeta potential analysis. The obtained GO has been employed for removal of the widely used AZM antibiotic from an aqueous solution. The quantitative analysis of AZM before and after adsorption has been carried out by liquid chromatography tandem mass spectrometry. The adsorption of AZM by GO was performed in a batch of experiments where the effects of adsorbent (GO) dose, solution pH, temperature, and contact time were investigated. Under optimum conditions (pH = 7.0, contact time = 15 min, and adsorbent dose = 0.25 g/L), 98.8% AZM was removed from the aqueous solution. The rapid and effective removal of AZM was significantly controlled by the electrostatic attractions and hydrogen bonding on the surface of GO. Adsorption isotherms of AZM onto GO were fitted well with the Freundlich isotherm model, while the kinetic data were fitted perfectly with the pseudo-second order. Therefore, the simple, cost-effective, and eco-friendly synthesis of GO from waste material could be applicable to fabricate an effective and promising low-cost adsorbent for removal of AZM from aqueous media.

Surfactant induced bilayer-micelle transition for emergence of functions in anisotropic hydrogel.

Tuning the self-assembled structures in amorphous hydrogels will enrich the functionality of hydrogels. In this study, we tuned the structure of a photonic hydrogel, which consists of polymeric lamellar bilayers entrapped inside a polyacrylamide network, simply by molecular triggering using an ionic surfactant. Owing to the binding of ionic surfactants (sodium dodecyl sulfate), the lamellar bilayers comprising non-ionic polymeric surfactants [poly(dodecyl glyceryl itaconate)] changed to micelles, whereas the unidirectional lamellar structure was preserved in the hydrogel. The bilayer-micelle structure transition caused a dramatic decrease in the swelling anisotropy and mechanical softening of the photonic gel. With the micelle structure, the softened gel shows fast (0.3 s) and reversible color change over the entire visible light range in response to a small mechanical pressure (5 kPa). This low stress-induced color-changing hydrogel could be applied as a visual tactile sensor in various fields, especially in biomedical engineering.

Flower-like Photonic Hydrogel with Superstructure Induced via Modulated Shear Field.

Biological tissues usually have complex superstructures and elaborated functionalities. However, creating superstructures in soft and wet hydrogels is challenging because of the absence of effective approaches to control the molecular orientation. Here we introduce a method to create superstructures in photonic hydrogels comprising lamellar bilayers intercalated in the cross-linked polymer network. The orientation of lamellar bilayers in the photonic gel, which are sensitive to shear, is modulated by applying a gradient shear field on the precursor solution using a customized rheometer. The difference in orientation of lamellar bilayers leads to swelling mismatch in the radial direction, endowing the disk-shape hydrogel with a macroscopic flower-like shape with a central dome and an edge petal, along with a bright photonic color. By characterization of the swelling anisotropy of the radial profile, the shear rate required for the unidirectional orientation of lamellar bilayers was extracted. Moreover, a delayed polymerization experiment was designed to measure the lifetime of aligned lamellar bilayers, which reveals the domain size of lamellar bilayers in the precursor solution. Furthermore, we also demonstrated that the hydrogel flowers could fade and rebloom reversibly in response to external stimuli. This work presents a strategy to develop superstructures in hydrogels and sheds light on designing biomimetic materials with intricately architectural superstructure.

Tough and Variable-Band-Gap Photonic Hydrogel Displaying Programmable Angle-Dependent Colors.

One-dimensional photonic crystals or multilayer films produce colors that change depending on viewing and light illumination angles because of the periodic refractive index variation in alternating layers that satisfy Bragg's law. Recently, we have developed multilayered photonic hydrogels of two distinct bulk geometries that possess an alternating structure of a rigid polymeric lamellar bilayer and a ductile polyacrylamide (PAAm) matrix. In this paper, we focus on fabrication of composite gels with variable photonic band gaps by controlling the PAAm layer thickness. We report programmable angle-dependent and angle-independent structural colors produced by composite hydrogels, which is achieved by varying bulk and internal geometries. In the sheet geometry, where the lamellae are aligned parallel to the sheet surface, the photonic gel sheet exhibits strong angle-dependent colors. On the other hand, when lamellae are coaxially aligned in a cylindrical geometry, the gel rod exhibits an angle-independent color, in sharp contrast with the gel sheet. Rocking curves have been constructed to justify the diverse angle-dependent behavior of various geometries. Despite varying the bulk geometry, the tunable photonic gels exhibit strong mechanical performances and toughness. The distinct angle dependence of these tough photonic materials with variable band gaps could benefit light modulation in displays and sensor technologies.

Quasi-unidirectional shrinkage of gels with well-oriented lipid bilayers upon uniaxial stretching.

PDGI-PAAm gels with well oriented lipid bilayers show a quasi-unidirectional shrinkage upon uniaxial stretching along the bilayers. They shrink largely parallel to the bilayer but slightly perpendicular to it in order not to increase the bilayer area and its interfacial energy. Such an anisotropic deformation can be well-modelled based on classical theories for gel networks and lipid layers.

Mechano-actuated ultrafast full-colour switching in layered photonic hydrogels.

Photonic crystals with tunability in the visible region are of great interest for controlling light diffraction. Mechanochromic photonic materials are periodically structured soft materials designed with a photonic stop-band that can be tuned by mechanical forces to reflect specific colours. Soft photonic materials with broad colour tunability and fast colour switching are invaluable for application. Here we report a novel mechano-actuated, soft photonic hydrogel that has an ultrafast-response time, full-colour tunable range, high spatial resolution and can be actuated by a very small compressive stress. In addition, the material has excellent mechanical stability and the colour can be reversibly switched at high frequency more than 10,000 times without degradation. This material can be used in optical devices, such as full-colour display and sensors to visualize the time evolution of complicated stress/strain fields, for example, generated during the motion of biological cells.

Physical hydrogels composed of polyampholytes demonstrate high toughness and viscoelasticity.

Hydrogels attract great attention as biomaterials as a result of their soft and wet nature, similar to that of biological tissues. Recent inventions of several tough hydrogels show their potential as structural biomaterials, such as cartilage. Any given application, however, requires a combination of mechanical properties including stiffness, strength, toughness, damping, fatigue resistance and self-healing, along with biocompatibility. This combination is rarely realized. Here, we report that polyampholytes, polymers bearing randomly dispersed cationic and anionic repeat groups, form tough and viscoelastic hydrogels with multiple mechanical properties. The randomness makes ionic bonds of a wide distribution of strength. The strong bonds serve as permanent crosslinks, imparting elasticity, whereas the weak bonds reversibly break and re-form, dissipating energy. These physical hydrogels of supramolecular structure can be tuned to change multiple mechanical properties over wide ranges by using diverse ionic combinations. This polyampholyte approach is synthetically simple and dramatically increases the choice of tough hydrogels for applications.