The missing link: exploring the intersection of gender, capabilities, and depressive symptoms in the context of chronic HIV.

Depressive symptoms occur frequently among people living with HIV, especially women. These symptoms are associated with human, social, financial, and physical/natural capabilities and life stressors that differ between women and men. However, the link between depressive symptoms and functional limitations/disability is seldom discussed in the context of HIV, especially for gender-specific relationships. A cross-sectional survey of 1042 people living with HIV and using long-term antiretroviral therapy (ART) in South Africa was conducted from June to August 2014 to investigate the associations of disability, human, social, physical/natural, and financial capabilities, health, and adherence to ART, including possible gender-specific factors. Socio-demographic information, capabilities, health indicators, functional limitations/disability, and depressive symptoms (CES-D 10) were measured. We applied descriptive and bivariate statistics and multiple regression. Overall, 26% of people presented with depressive symptoms. Greater functional limitations and health symptoms and lower food security were strongly associated with depressive symptoms, while associations with financial capital and body mass index were gender-specific. The results call for the improvement of comprehensive care, including gender-sensitive mental health interventions. The results further indicate that functional limitations/disability needs to be considered, along with linking rehabilitation and livelihood programs with comprehensive HIV-care, in particular for those who experience depressive symptoms.

Physalis Mottle Virus-Like Particles as Nanocarriers for Imaging Reagents and Drugs.

Platform technologies based on plant virus nanoparticles (VNPs) and virus-like particles (VLPs) are attracting the attention of researchers and clinicians because the particles are biocompatible, biodegradable, noninfectious in mammals, and can readily be chemically and genetically engineered to carry imaging agents and drugs. When the Physalis mottle virus (PhMV) coat protein is expressed in Escherichia coli, the resulting VLPs are nearly identical to the viruses formed in vivo. Here, we isolated PhMV-derived VLPs from ClearColi cells and carried out external and internal surface modification with fluorophores using reactive lysine-N-hydroxysuccinimide ester and cysteine-maleimide chemistries, respectively. The uptake of dye-labeled particles was tested in a range of cancer cells and monitored by confocal microscopy and flow cytometry. VLPs labeled internally on cysteine residues were taken up with high efficiency by several cancer cell lines and were colocalized with the endolysosomal marker LAMP-1 within 6 h, whereas VLPs labeled externally on lysine residues were taken up with lower efficiency, probably reflecting differences in surface charge and the propensity to bind to the cell surface. The infusion of dye and drug molecules into the cavity of the VLPs revealed that the photosensitizer (PS), Zn-EpPor, and the drugs crystal violet, mitoxantrone (MTX), and doxorubicin (DOX) associated stably with the carrier via noncovalent interactions. We confirmed the cytotoxicity of the PS-PhMV and DOX-PhMV particles against prostate cancer, ovarian and breast cancer cell lines, respectively. Our results show that PhMV-derived VLPs provide a new platform technology for the delivery of imaging agents and drugs, with preferential uptake into cancer cells. These particles could therefore be developed as multifunctional tools for cancer diagnosis and therapy.

Determinants of livelihood in the era of widespread access to ART.

We have only just begun to understand the long-term impact of living with chronic HIV on health and livelihood after a decade of widespread access to treatment in southern Africa. This paper explores health and well-being, disability, and livelihood dynamics among people living with HIV (PLHIV) in a public healthcare setting in South Africa. We undertook a cross-sectional survey among a cohort of 1042 people on ART and explored associations between socio-demographic characteristics, treatment adherence, measures of disability (functional and activity limitations), livelihood resources (capitals) and outcomes, including food security, and exposure to livelihood shocks. A range of dynamic relationships relevant for decision-makers is evident. Age, gender, and marital status all had significant associations with levels of livelihood capitals and outcomes. Those who had been on ART for longer periods of time also had significantly higher aggregate livelihood capital. This was particularly driven by social and financial capital. Livelihoods are built within specific social and health contexts. Of particular importance is that the resources drawn on to build a livelihood differ significantly between men and women, and that different forms of disability also have gender-specific pathways in influencing livelihood and livelihood outcomes. Our results support the need for a gender-sensitive approach to supporting the well-being and livelihoods of PLHIV. Of equal importance is an approach that considers more comprehensively the new experiences of comorbidities and disabilities that may occur with a long life on ART.

Utilizing Viral Nanoparticle/Dendron Hybrid Conjugates in Photodynamic Therapy for Dual Delivery to Macrophages and Cancer Cells.

Photodynamic therapy (PDT) is a promising avenue for greater treatment efficacy of highly resistant and aggressive melanoma. Through photosensitizer attachment to nanoparticles, specificity of delivery can be conferred to further reduce potential side effects. While the main focus of PDT is the destruction of cancer cells, additional targeting of tumor-associated macrophages also present in the tumor microenvironment could further enhance treatment by eliminating their role in processes such as invasion, metastasis, and immunosuppression. In this study, we investigated PDT of macrophages and tumor cells through delivery using the natural noninfectious nanoparticle cowpea mosaic virus (CPMV), which has been shown to have specificity for the immunosuppressive subpopulation of macrophages and also targets cancer cells. We further explored conjugation of CPMV/dendron hybrids in order to improve the drug loading capacity of the nanocarrier. Overall, we demonstrated effective elimination of both macrophage and tumor cells at low micromolar concentrations of the photosensitizer when delivered with the CPMV bioconjugate, thereby potentially improving melanoma treatment.

Synthesis, Characterization, and Antimicrobial Efficacy of Photomicrobicidal Cellulose Paper.

Toward our goal of scalable, antimicrobial materials based on photodynamic inactivation, paper sheets comprised of photosensitizer-conjugated cellulose fibers were prepared using porphyrin and BODIPY photosensitizers, and characterized by spectroscopic (infrared, UV-vis diffuse reflectance, inductively coupled plasma optical emission) and physical (gel permeation chromatography, elemental, and thermal gravimetric analyses) methods. Antibacterial efficacy was evaluated against Staphylococcus aureus (ATCC-2913), vancomycin-resistant Enterococcus faecium (ATCC-2320), Acinetobacter baumannii (ATCC-19606), Pseudomonas aeruginosa (ATCC-9027), and Klebsiella pneumoniae (ATCC-2146). Our best results were achieved with a cationic porphyrin-paper conjugate, Por((+))-paper, with inactivation upon illumination (30 min, 65 ± 5 mW/cm(2), 400-700 nm) of all bacterial strains studied by 99.99+% (4 log units), regardless of taxonomic classification. Por((+))-paper also inactivated dengue-1 virus (>99.995%), influenza A (∼ 99.5%), and human adenovirus-5 (∼ 99%). These results demonstrate the potential of cellulose materials to serve as scalable scaffolds for anti-infective or self-sterilizing materials against both bacteria and viruses when employing a photodynamic inactivation mode of action.

Antiviral, Antifungal and Antibacterial Activities of a BODIPY-Based Photosensitizer.

Antimicrobial photodynamic inactivation (aPDI) employing the BODIPY-based photosensitizer 2,6-diiodo-1,3,5,7-tetramethyl-8-(N-methyl-4-pyridyl)-4,4'-difluoro-boradiazaindacene (DIMPy-BODIPY) was explored in an in vitro assay against six species of bacteria (eight total strains), three species of yeast, and three viruses as a complementary approach to their current drug-based or non-existent treatments. Our best results achieved a noteworthy 5-6 log unit reduction in CFU at 0.1 µM for Staphylococcus aureus (ATCC-2913), methicillin-resistant S. aureus (ATCC-44), and vancomycin-resistant Enterococcus faecium (ATCC-2320), a 4-5 log unit reduction for Acinetobacter baumannii ATCC-19606 (0.25 µM), multidrug resistant A. baumannii ATCC-1605 (0.1 µM), Pseudomonas aeruginosa ATCC-97 (0.5 µM), and Klebsiella pneumoniae ATCC-2146 (1 µM), and a 3 log unit reduction for Mycobacterium smegmatis mc2155 (ATCC-700084). A 5 log unit reduction in CFU was observed for Candida albicans ATCC-90028 (1 µM) and Cryptococcus neoformans ATCC-64538 (0.5 µM), and a 3 log unit reduction was noted for Candida glabrata ATCC-15545 (1 µM). Infectivity was reduced by 6 log units in dengue 1 (0.1 µM), by 5 log units (0.5 µM) in vesicular stomatitis virus, and by 2 log units (5 µM) in human adenovirus-5. Overall, the results demonstrate that DIMPy-BODIPY exhibits antiviral, antibacterial and antifungal photodynamic inactivation at nanomolar concentrations and short illumination times.

Livelihoods of young women with and without disabilities in KwaZulu-Natal during COVID-19.

Background: Persons with disabilities are more likely to have poorer livelihood outcomes, including food insecurity. Inequalities are heightened for young women with disabilities, especially in times of crisis. Objectives: To understand the livelihood experience of young South African women with and without disabilities during the coronavirus pandemic (COVID-19). Method: We conducted a longitudinal study with 72 young women with and without disabilities enrolled in tertiary institutions in eThekwini, South Africa. We undertook a series of in-depth interviews collecting quantitative and qualitative data, prompting participants' experiences during the COVID-19 pandemic, including living arrangements, impact on education, access to resources and food security. Results: Participants reported livelihood changes related to living arrangements, education, income, and social connectedness during the pandemic. Social grants (old-age pension, child support, disability grant) and student stipends were critical financial resources to ensure food security. Participants with disabilities were more likely to experience food insecurities and moderate hunger, with their households having less access to mitigating resources such as land or livestock. Deaf participants also reported social isolation. Conclusion: The study shows that social protection mechanisms mitigated the financial impact of the lockdown for all recipients but that participants with disabilities still struggled more than others to ensure food security. These additional challenges may be related to pre-existing inequalities, with participants with disabilities and their households having less access to natural resources and financial stability. Contribution: This paper focuses on young women with and without disabilities and provides insight into the similarities and differences in their experiences.

Correlation of Fabrication Methods and Enhanced Wear Performance in Nanoporous Anodic Aluminum Oxide with Incorporated Molybdenum Disulfide (MoS2) Nanomaterials.

Wear performance is integral to component longevity, minimizing industrial waste and excess energy costs in a wide variety of applications. Anodized aluminum oxide (AAO) has many beneficial properties leading to its wide use across industries as a surface treatment for many aluminum components, but the wear properties of the coating could be improved significantly. Here, we used an electrochemical method to incorporate molybdenum disulfide (MoS2), a nanomaterial used as a dry lubricant, to modify alloys of aluminum during AAO preparation. Using Raman spectroscopy and tribological scratch measurements, we thoroughly characterized the structure and wear behavior of the films. The MoS2 deposition procedure was optimal on aluminum 5052 anodized in higher acid concentrations, with friction coefficients at around 0.05 (~10× better than unmodified AAO). Changing anodization conditions to produce harder films with smaller pores led to worsened wear properties, likely because of lower MoS2 content. Studying a commercial MoS2/AAO film of a different Al alloy (7075) showed that a heat treatment step intended to fully convert all deposited MoSx species to MoS2 can adversely affect wear in some alloys. While Al 6061 and 1100 produced films with worse wear performance compared to Al 5052 or 7075, our results show evidence that acid cleaning after initial anodization likely removes residual alloying elements, affecting MoS2 incorporation. This study demonstrates a nanomaterial modified AAO film with superior wear characteristics to unmodified AAO and relates fabrication procedure, film structure, and practical performance.

Disability, a priority area for health research in South Africa: an analysis of the burden of disease study 2017.

PURPOSE: Disabilities are increasing globally, which is attributed to the overall ageing of populations in affluent countries. This trend may differ in low and middle-income countries. This paper assesses the change over time in Years Lived with Disability (YLD) for South Africa and how this compares to regional and global trends. MATERIALS AND METHODS: This secondary analysis of the Global Burden of Disease Study 2017 dataset describes the observed contribution of YLD to Disability-Adjusted Life Years (DALYs) per 100 000 people over the period 1990-2016, and forecast to 2030 using simple linear prediction. South African trends are compared to global and sub-Saharan African (SSA) trends to highlight the effect of HIV and policy implications. RESULTS: Globally, the contribution of YLD to DALYs has increased from ±21.7% in 1990 to ±34% by 2016, with high socio-demographic index countries having a higher contribution (49%). HIV, mental health, musculoskeletal, neurological, and sense organ disorders are the five main contributors to YLD in South Africa (54%). Removing the effects of HIV/AIDS and sexually transmitted infections on YLD, South Africa's trend appears similar to the global trend, yet opposite to the SSA trend. CONCLUSION: Our analysis shows there is a growing burden of disability in South Africa. Differences in trends with the regional and global patterns can be attributed to the high burden of HIV and non-communicable diseases in South Africa. Therefore, strategies are urgently needed to increase integration of disability and rehabilitation services into chronic HIV and non-communicable disease management. This calls for disability screening to identify functional limitations in routine data collection and case management.IMPLICATIONS FOR REHABILITATIONSouth Africa has experienced an increase in disability prevalence over time.This requires strengthening of services such as mental health interventions, physiotherapy, optometry, and audiology, and linking major disease clusters, such as HIV and the NCDs, to rehabilitation services.The greatest contributors towards disability adjusted life years in South Africa are currently mental disorders (13.8%), HIV and sexually transmitted infections (11.8%), musculoskeletal disorders (10.4%), neurological disorders (8.2%), and sense organ diseases (7.5%).Routine data collection and case management needs to include disability screening to identify developing functional limitations.

Trends in health and disability in Botswana. An analysis of the global burden of disease study.

PURPOSE: Globally, years of life lost are declining, while years lived with disability are increasing. In high socio-demographic index countries, this trend has been attributed to an overall ageing population and rehabilitation services have begun to adjust to this change. In low- and middle-income countries, this trend is less well understood. Hence, the WHO's 'Rehabilitation 2030 Call for Action' and 'Rehabilitation in Health Systems Guide' call for better assessment of the situation. In order to understand trends and causes in middle income countries such as Botswana, we examine the change over time in causes and number of years lived with disability and years of life lost. METHODS: We conducted a secondary analysis of the Global Burden of Disease 2017 data, exploring the change over time in Disability Adjusted Life Years per 100 000 people over the period 1990-2016. The descriptive analysis focuses on the contribution of years lived with disability towards the burden of disease within Botswana compared with the world, sub-Saharan Africa, and high-income countries. RESULTS: Our results show that Botswana's top causes of years of life lost are HIV and other sexually transmitted infections, cardiovascular diseases, maternal and neonatal disorders, respiratory infections and tuberculosis, and neoplasms. Years lived with disability have increased over time, which is driven by mental disorders, HIV and other sexually transmitted infections, musculoskeletal disorders, neurological disorders, and skin and subcutaneous diseases. CONCLUSIONS: Botswana needs better data to prepare its emerging health systems to accommodate the increased need for disability support and rehabilitation services caused by communicable and non-communicable diseases.Implications for RehabilitationBotswana has an increase in disability prevalence over time that requires the development of disability and rehabilitation services.The greatest contributors towards disability adjusted life years in Botswana are currently mental disorders (13.7%), HIV and other sexual transmitted diseases, (13.0%), musculoskeletal disorders (9.9%), neurological disorders (8.0%), and sense organ diseases (6.2%).This requires strengthen of services such as mental health interventions, physiotherapy, optometry and audiology as well as linkages from major disease clusters such as HIV to rehabilitation services.

Participants' characteristics and motivations to screen for HIV vaccine and monoclonal antibody trials in KwaZulu-Natal, South Africa.

BACKGROUND: HIV is one of the greatest public health challenges in South Africa. Potential HIV vaccines and antibodies are thought to be cost-effective biomedical HIV prevention methods and are currently under investigation in phase I, II, and III trials. Consequently, current and future clinical trials need to ensure sufficient recruitment and retention. To achieve this goal, clinical trial staff need to understand the socio-demographic and behavioural characteristics of people volunteering to screen for these trials and their reasons for volunteering. METHODS: We conducted a secondary analysis of participant screening data across five vaccine and monoclonal antibody trials at four sites in KwaZulu-Natal, South Africa. Our study reviewed the demographic, behavioural, motivational, and health-related data from the case report forms and screening questionnaires. Descriptive statistics, chi-squared, and one-way ANOVA tests were used to analyse participants' characteristics and motivation to participate in HIV vaccine and monoclonal antibody trials. Analyses were conducted using R version 3.5.2. RESULTS: Screening data from 1934 participants, including 79.2% of women, were obtained across all five trials (1034 enrolled, 900 screened out/declined). Screened participants predominately self-identified as black, heterosexual, cisgender women or men, many with lower educational backgrounds (43.9% did not complete secondary/high school), and several self-reported HIV-risk behaviours among themselves and their partners. 10.8% of the screened participants were living with HIV. Avoiding HIV risk was the main motivation to participate in clinical trials, followed by altruistic reasons such as a desire to help the community or helping to find a vaccine. DISCUSSION: The current recruitment approach of these trials attracts heterosexual participants who seek to reduce HIV risk and support their community. Hence, the data suggest the need for and potential acceptance of continued ongoing HIV prevention efforts. Current trials attract participants with lower educational levels, which may be driven by the site locations, current community mobilisation strategies and research site opening hours. The sites could consider more flexible working hours to accommodate working participants and find ways to connect participants to educational support and opportunities to upgrade education levels for the current clientele. TRIAL REGISTRATION: HVTN 100: A Safety and Immune Response Study of 2 Experimental HIV Vaccines, NCT02404311 . Registered on March 17, 2015. HVTN 111: Safety and Immune Response to a Clade C DNA HIV Vaccine, NCT02997969. Registered on December 16, 2016. HVTN 108: Evaluating the Safety and Immunogenicity of HIV Clade C DNA Vaccine and MF59- or AS01B-Adjuvanted Clade C Env Protein Vaccines in Various Combinations in Healthy, HIV-Uninfected Adults, NCT02915016. Registered on September 22, 2016. HVTN 702: Pivotal Phase 2b/3 ALVAC/Bivalent gp120/MF59 HIV Vaccine Prevention Safety and Efficacy Study in South Africa, NCT02968849. Registered on November 1, 2016. HVTN 703/HPTN 081: Evaluating the Safety and Efficacy of the VRC01 Antibody in Reducing Acquisition of HIV-1 Infection in Women, NCT02568215 . Registered on October 1, 2015.

Looking at antiretroviral adherence through a disability lens: a cross-sectional analysis of the intersection of disability, adherence, and health status.

Background: Antiretroviral adherence is vital to the successful long-term rollout of the antiretroviral therapy program in South Africa. At present, there are no studies that look at the effects of disability on antiretroviral adherence.Methods: Drawing on the baseline data from an existing cohort of 1042 people on antiretrovirals in a public healthcare setting in KwaZulu-Natal, the paper investigated a variety of existing covariates relating to antiretroviral adherence, together with functional limitations, depressive symptoms, and health symptoms. Disability was defined according to the International Classification of Functioning, Disability, and Health framework and measured using the World Health Organization Disability Assessment Schedule.Results: In a proportional odds logistic regression functional limitations, depressive symptoms, health symptoms and gender emerged as significant associated with decreased adherence to antiretrovirals (Odds ratio [95% confidence interval]: 1.86 [1.31, 2.66], 1.61 [1.02, 2.55], 2.33 [1.47, 3.69], and 1.65 [1.16, 2.35], respectively). This was found for both severe and milder forms of functional limitations/disability.Conclusion: The paper highlights the need to better understand the role of these limitations in achieving adequate adherence to antiretrovirals and viral suppression. It also calls for investigations into integrated mitigating services such as integrating rehabilitation into routine human immunodeficiency virus care.Implications for RehabilitationThis study provides a starting point to understand the association between functional limitations and challenges in maintaining adherence to antiretroviral therapy.Addressing functional limitations is currently a neglected factor in efforts targeting HIV-treatment adherence and retention.Rehabilitation is a key intervention that could address this gap.Even mild forms of disability can have profound effects on adherence to antiretroviral therapy, which highlights the need for better screening, early identification, and referrals to rehabilitative support and treatment.

Disability and health outcomes - from a cohort of people on long-term anti-retroviral therapy.

Human-immunodeficiency virus (HIV)/Acquired immunodeficiency Syndrome (AIDS) remains a major health problem in South Africa - even after two decades since the introduction of antiretroviral therapy (ART). Long-term survival with HIV is associated with new health-related issues and a risk of functional limitation/disability. The aim of this study was to assess functional limitation associated with HIV/AIDS among people living with HIV (PLHIV) in South Africa. This study is a cross-sectional survey using a cohort in an urban area in Gauteng province, South Africa. Data were collected using questionnaires through an interview process. The information collected included aspects such as demographics, livelihood, the state of mental and physical health, adherence and disability. A total of 1044 participants with an average age of 42 ± 12 years were included in the study, with 51.9% of the participants reporting functional limitations (WHODAS ≥ 2). These were reported mainly in the domains of participation (40.2%) and mobility (38.7%). In addition, adherence to ART, symptoms of poor physical health and depression were strongly associated with their functional limitations/disability. HIV as a chronic disease is associated with functional limitations that are not adequately addressed and pose a risk of long-term disability and negative adherence outcomes. Therefore, wellness for PLHIV/AIDS needs to include interventions that can prevent and manage disability.

Prevalence and factors associated with recent intimate partner violence and relationships between disability and depression in post-partum women in one clinic in eThekwini Municipality, South Africa.

Intimate partner violence (IPV) experienced by pregnant and post-partum women has negative health effects for women, as well as the foetus, and the new-born child. In this study we sought to assess the prevalence and factors associated with recent IPV amongst post-partum women in one clinic in eThekwini Municipality, South Africa, and explore the relationship between IPV, depression and functional limitations/disabilities. Past 12 month IPV-victimisation was 10.55%. Logistic regression modelled relationships between IPV, functional limitations, depressive symptoms, socio-economic measures, and sexual relationship power. In logistic regression models, overall severity of functional limitations were not associated with IPV-victimisation when treated as a continuous overall score. In this model relationship power (aOR0.22, p = 0.001) and depressive symptoms (aOR1.26, p = 0.001) were significant. When the different functional limitations were separated out in a second model, significant factors were relationship power (aOR0.20, p = 0.001), depressive symptoms (aOR1.20, p = 0.011) and mobility limitations (aOR2.96, p = 0.024). The study emphasises that not all functional limitations are associated with IPV-experience, that depression and disability while overlapping can also be considered different drivers of vulnerability, and that women's experience of IPV is not dependent on pregnancy specific factors, but rather wider social factors that all women experience.

High Aspect Ratio Nanotubes Formed by Tobacco Mosaic Virus for Delivery of Photodynamic Agents Targeting Melanoma.

Melanoma is a highly aggressive cancer that is unresponsive to many traditional therapies. Recently, photodynamic therapy has shown promise in its treatment as an adjuvant therapy. However, conventional photosensitizers are limited by poor solubility and limited accumulation within target tissue. Here, we report the delivery of a porphyrin-based photosensitizer encapsulated within a plant viral nanoparticle. Specifically, we make use of the hollow, high aspect ratio nanotubes formed by the nucleoprotein components of tobacco mosaic virus (TMV) to encapsulate the drug for delivery and targeting of cancer cells. The cationic photosensitizer was successfully and stably loaded into the interior channel of TMV via electrostatic interactions. Cell uptake and efficacy were evaluated using a model of melanoma. The resulting TMV-photosensitizer exhibited improved cell uptake and efficacy when compared to free photosensitizer, making it a promising platform for improved therapy of melanoma.

Disability and Living with HIV: Baseline from a Cohort of People on Long Term ART in South Africa.

BACKGROUND: Through access to life saving antiretroviral treatment (ART) in southern Africa, HIV has been reconceptualised as a chronic disease. This comes with new challenges of HIV-related co-morbidities and disabilities. We still lack an understanding of the types and scope of disabilities experienced by people on long term ART and how this impacts health, adherence, and livelihood. This paper describes the results of a cohort study examining the new health- and disability-related needs of the millions of people on ART in the region. METHODS: Data was collected from a cohort of people who had been on ART for six months or longer in a semi-urban public health care setting in South Africa. 1042 adults (18 and older) participated in the cross-sectional study which investigated disabilities/activity limitations, health, ART adherence, depression symptoms, and livelihood. We analysed the associations between these constructs using descriptive statistics, and bivariate and multivariate analyses. RESULTS: A large number of participants (35.5%) obtained a weighted score of two or more on the WHODAS 2.0 indicating possible activity limitations. A positive relationship was found between activity limitations and depression symptoms, adherence, and worse health outcomes, while none was found for BMI or CD4 count. These associations varied by type of activity limitations and, in some cases, by gender. CONCLUSION: Activity limitations are potentially experienced by a large portion of people on ART in southern Africa which impacts health and ART adherence negatively. These results highlight the importance of better understanding the new health-related needs of people who are on long term ART, as well as the nuances of the disability they experience. This is urgently needed in order to enable HIV-endemic countries to better prepare for the new health-related needs of the millions of people on ART in southern Africa.

Porphyrin-cellulose nanocrystals: a photobactericidal material that exhibits broad spectrum antimicrobial activity.

Towards our overall objectives of developing potent antimicrobial materials to combat the escalating threat to human health posed by the transmission of surface-adhering pathogenic bacteria, we have investigated the photobactericidal activity of cellulose nanocrystals that have been modified with a porphyrin-derived photosensitizer (PS). The ability of these previously synthesized porphyrin-cellulose-nanocrystals (CNC-Por (1)) to mediate bacterial photodynamic inactivation was investigated as a function of bacterial strain, incubation time and illumination time. Despite forming an insoluble suspension, CNC-Por (1) showed excellent efficacy toward the photodynamic inactivation of Acinetobacter baumannii, multidrug-resistant Acinetobacter baumannii (MDRAB) and methicillin-resistant Staphylococcus aureus (MRSA), with the best results achieving 5-6 log units reduction in colony forming units (CFUs) upon illumination with visible light (400-700 nm; 118 J cm(-2)). CNC-Por (1) mediated the inactivation of Pseudomonas aeruginosa, although at reduced activity (2-3 log units reduction). Confocal laser scanning microscopy of CNC-Por (1) after incubation with A. baumannii or S. aureus suggested a lack of internalization of the PS. Research into alternative materials such as CNC-Por (1) may lead to their application in hospitals and healthcare-related industries wherein novel materials with the capability of reducing the rates of transmission of a wide range of bacteria, particularly antibiotic resistant strains, are desired.