Photosensitiser functionalised nanofiber fabric for efficient light driven water disinfection

Sunlight-driven water disinfection system could help provide clean water to some of the world’s poorest regions where contaminated surface water is a major public health problem and bright solar irradiation is available for free. In this work, photosensitiser - 5, 10, 15, 20-tetrakis (1-methyl-4-pyridinio) porphyrin tetra p-toluene sulfonate (TMPyP) was chosen and immobilised onto chitosan nanofiber mats and chitosan membranes for photodynamic disinfection of water since preliminary studies with TMPyP in solution showed it caused a high rate of photodynamic inactivation (PDI) of model viral organisms (bacteriophages MS2 and Qβ, murine norovirus and bovine enterovirus 2). Native gel electrophoresis, SDS-PAGE and western blotting, TEM and DLS were used to analyse pre- and post-PDI samples of the model viruses. The rate of PDI in model viruses was in the order MS2 > phage Qβ > murine norovirus > bovine enterovirus 2. Our data showed that PDI caused aggregation of MS2 particles and crosslinking of MS2 coat protein. However, the aggregation and crosslinking did not correlate to the rate of PDI we observed in MS2. Using sequence specific antibodies raised against MS2 A-protein (host attachment protein), our results suggest that the rate of PDI is relative to loss of antigenicity of sites on the A-protein. The differences in the rate of PDI were compared to amino acid compositions and surface accessibility of host attachment proteins/sites of the model viruses. Possible modes of action are discussed as a means to gaining insight to the targets and mechanisms of PDI of viruses. Chitosan electrospun nanofibers and chitosan membranes were modified by pyromellitic dianhydride in order to introduce carboxyl groups and facilitate adsorption of the cationic TMPyP. The physico-chemical properties of these modified nanofibers and membranes were investigated by microscopy, absorption spectroscopy, Fourier-transform infrared spectroscopy and Midland surface blotting approaches.The chitosan nanofiber/membrane-TMPyP composite showed photodynamic inactivation of MS2 and E. coli BL21

Connected Learning Initiative: A Novel Tool for Teacher Capacity Development in Nigeria

All three tiers of education in Nigeria (primary, secondary, tertiary) lay emphasis on STEM subjects. The methods and strategies employed by STEM teachers in most Nigerian schools have remained teacher-centred and textbook-oriented. This paper has brought together some elements of the innovation achieved in the Connected Learning Initiative (CLIx) to address the identified challenges in STEM education in Nigerian junior secondary schools through the CL4STEM project to build processes for long-term systemic dialogues and networking. CLIx was seeded by the Tata Trusts and led by TISS and MIT, USA, to strengthen secondary STEM learning, pedagogic content knowledge of teachers and their practice at scale in four states in India.  The programme’s interactive STEM OERs, subject teacher CoPs on mobile devices, tech design for under-resourced context, participatory and localised ecosystem approach to adoption and scaling, are identified as innovative and scalable models. Data were collected in three phases, baseline, midline, and endline. The findings from interviews indicate that teachers' understanding of CL4STEM innovation seem to improve from baseline to endline.At the baseline 2 teachers were still learning how to effectively navigate CL4STEM modules and Telegram group (CoPs) while none was at the endline. There is an increase in the number of teachers exploring ways of improving CL4STEM teaching strategies through further refinement of the modules and CoP participation and/or alternative ways of achieving better results from 1 at midline to 5 at endline. There is a decrease in the number of teachers that are exploring ways of collaboration with other teachers and educators to help impact student learning using CL4STEM teaching strategies from 11 at the midline to 3 at the endline. Other changes from baseline through midline to endline, generally positively, with respect to perception, voluntariness, relative advantage, compatibility, image, ease of use, research demonstrability, and visibility have been recorded here-in

Dye extract of calyces of Hibiscus sabdariffa has photodynamic antibacterial activity: A prospect for sunlight‐driven fresh produce sanitation

Abstract Photodynamic sanitation of fresh produce could help reduce spoilage and disease transmissions where conventional methods of sanitation are not available, and sunlight is available for free. In this study, we evaluated the photostability and photodynamic antibacterial activity of the dye extracts of calyces of Hibiscus sabdariffa. The dye extracts were very photostable in water but bleached in acetate‐HCl buffer (pH 4.6), phosphate buffer saline (pH 7.2), and tris base‐HCl buffer (pH 8.6). The photostability correlated with the photodynamic antibacterial activity of the dye extracts. Both the methanol and water dye extracts at the concentration of 0.0625 mg/ml caused complete inactivation of Bacillus subtilis (reductions of 8.5 log CFU/ml) within 2 min either with the visible light exposure at 10 mW/cm2 or in the dark without the light exposure. Reductions of 4.8 log CFU/ml and 2.2 log CFU/ml of Escherichia coli were observed when 1 mg/ml of methanol and water dye extracts were used, respectively, in water with the light exposure at 10 mW/cm2 for 20 min. Discussions are included about the ease of the dye extractions of the calyces of H. sabdariffa even in water without the need of energy for heating and the suitability of the dye extracts for the fresh produce sanitation. Dye extract of calyces of H. sabdariffa has photodynamic and nonphotodynamic antibacterial activity which could be exploited for the development of a low‐tech sunlight‐driven fresh produce sanitation system that is cheap, sustainable, and environmentally friendly

Dye extract of calyces of 'Hibiscus sabdariffa' has photodynamic antibacterial activity: A prospect for sunlight-driven fresh produce sanitation

Photodynamic sanitation of fresh produce could help reduce spoilage and disease transmissions where conventional methods of sanitation are not available, and sunlight is available for free. In this study, we evaluated the photostability and photodynamic antibacterial activity of the dye extracts of calyces of 'Hibiscus sabdariffa'. The dye extracts were very photostable in water but bleached in acetate-HCl buffer (pH 4.6), phosphate buffer saline (pH 7.2), and tris base-HCl buffer (pH 8.6). The photostability correlated with the photodynamic antibacterial activity of the dye extracts. Both the methanol and water dye extracts at the concentration of 0.0625 mg/ml caused complete inactivation of 'Bacillus subtilis' (reductions of 8.5 log CFU/ml) within 2 min either with the visible light exposure at 10 mW/cm2 or in the dark without the light exposure. Reductions of 4.8 log CFU/ml and 2.2 log CFU/ml of Escherichia coli were observed when 1 mg/ml of methanol and water dye extracts were used, respectively, in water with the light exposure at 10 mW/cm2 for 20 min. Discussions are included about the ease of the dye extractions of the calyces of 'H. sabdariffa' even in water without the need of energy for heating and the suitability of the dye extracts for the fresh produce sanitation. Dye extract of calyces of 'H. sabdariffa' has photodynamic and nonphotodynamic antibacterial activity which could be exploited for the development of a low-tech sunlight-driven fresh produce sanitation system that is cheap, sustainable, and environmentally friendly

Regulation of photo triggered cytotoxicity in electrospun nanomaterials: role of photosensitizer binding mode and polymer identity

Although electrospun nanomaterials containing photoactive dyes currently compete with the present state of art antimicrobial materials, relatively few structure–activity relationships have been established to identify the role of carrier polymer and photosensitizer binding mode on the performance of the materials. In this study scaffolds composed of poly(vinyl alcohol), polyacrylonitrile, poly(caprolactone), and tailor-made phthalocyanine-based photosensitizers are developed utilizing electrospinning as a simple, time and cost-effective method. The photoinduced activity of nanofibrous materials was characterized in vitro against E. coli and B. subtilis as models for Gram-negative and Gram-positive bacteria respectively, as well as against bacteriophages phi6 and MS2 as models for enveloped and non-enveloped viruses respectively. For the first time, we show how polymer-specific properties affect antifouling and antimicrobial activity of the nanofibrous material, indicating that the most promising way to increase efficiency is likely via methods that focus on increasing the number of short, but strong and reversible bacteria–surface interactions

Factors Associated with HPV Genital Warts: A Self-Reported Cross-Sectional Study among Students and Staff of a Northern University in Nigeria

The menace of human papillomavirus (HPV) infections among low- and middle-income countries with no access to a free HPV vaccine is a public health concern. HPV is one of the most common sexually transmitted infections (STIs) in Nigeria, while the most known types of HPV genotypes being transmitted are the high-risk HPV-16 and 18 genotypes. In this study, we explored the predictors of self-reported HPV infections and HPV genital warts infection among a population of students, non-academic staff, and academic staff of Ibrahim Badamasi Babangida (IBB) University located in Lapai, Nigeria. We also assessed their knowledge about HPV infections and genotypes, and sexual behaviors. An online cross-sectional study was conducted by setting up a structured questionnaire on Google Forms and it was distributed to the university community via Facebook and other social media platforms of the university. The form captured questions on HPV infection, and knowledge about HPV infection and genotypes, as well as the sexual health of the participants. All variables were described using frequencies and percentage distribution; chi-squared test statistics were used to explore the association between HPV infection (medical records of HPV infection) and the participants’ profile, and a logistic regression analysis was performed to examine the factors associated with HPV genital warts infection among the population. This study reveals those participants between the ages of 26–40 years (81.3%) and those currently not in a sexually active relationship—single/divorced (26.4%)—who have self-reported having the HPV-16 and -18 genotypes. Moreover, participants between 26–40 years of age (OR: 0.45, 95%CI: 0.22–0.89) reported themselves to be carriers of HPV genital warts. Therefore, this study reveals the factors associated with HPV infection and genital warts peculiar to IBB university students and staff. Hence, we suggest the need for HPV awareness programs and free HPV vaccine availability at IBB university