Publications by authors named "Sello Lebohang Manoto"

9 Publications

  • Page 1 of 1

Exploring optical spectroscopic techniques and nanomaterials for virus detection.

Saudi J Biol Sci 2021 Jan 27;28(1):78-89. Epub 2020 Aug 27.

Council for Scientific and Industrial Research (CSIR), National Laser Centre, P.O. Box 395, Pretoria 0001, South Africa.

Viral infections pose significant health challenges globally by affecting millions of people worldwide and consequently resulting in a negative impact on both socioeconomic development and health. Corona virus disease 2019 (COVID-19) is a clear example of how a virus can have a global impact in the society and has demonstrated the limitations of detection and diagnostic capabilities globally. Another virus which has posed serious threats to world health is the human immunodeficiency virus (HIV) which is a lentivirus of the retroviridae family responsible for causing acquired immunodeficiency syndrome (AIDS). Even though there has been a significant progress in the HIV biosensing over the past years, there is still a great need for the development of point of care (POC) biosensors that are affordable, robust, portable, easy to use and sensitive enough to provide accurate results to enable clinical decision making. The aim of this study was to present a proof of concept for detecting HIV-1 pseudoviruses by using anti-HIV1 gp41 antibodies as capturing antibodies. In our study, glass substrates were treated with a uniform layer of silane in order to immobilize HIV gp41 antibodies on their surfaces. Thereafter, the HIV pseudovirus was added to the treated substrates followed by addition of anti-HIV gp41 antibodies conjugated to selenium nanoparticle (SeNPs) and gold nanoclusters (AuNCs). The conjugation of SeNPs and AuNCs to anti-HIV gp41 antibodies was characterized using UV-vis spectroscopy, transmission electron microscopy (TEM) and zeta potential while the surface morphology was characterized by fluorescence microscopy, atomic force microscopy (AFM) and Raman spectroscopy. The UV-vis and zeta potential results showed that there was successful conjugation of SeNPs and AuNCs to anti-HIV gp41 antibodies and fluorescence microscopy showed that antibodies immobilized on glass substrates were able to capture intact HIV pseudoviruses. Furthermore, AFM also confirmed the capturing HIV pseudoviruses and we were able to differentiate between substrates with and without the HIV pseudoviruses. Raman spectroscopy confirmed the presence of biomolecules related to HIV and therefore this system has potential in HIV biosensing applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.sjbs.2020.08.034DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7449958PMC
January 2021

Editorial Commentary: Is Medical Ozone Therapy Beneficial in the Treatment of Knee Osteoarthritis?

Arthroscopy 2020 01;36(1):287-288

Pretoria, South Africa.

Osteoarthritis is a degenerative joint disease that is difficult to manage and a major cause of disability in the elderly population. The use of ozone for treatment of knee osteoarthritis (KOA) is controversial and of interest. Although the exact mechanism of ozone for the treatment of KOA is not fully understood, it has been shown that ozone administration may promote oxidative preconditioning or adaptation to oxidative stress, which in turn will result in the stimulation of antioxidant endogenous system which prevents tissue damage. A number of European studies show ozone injection for treatment of KOA results in pain relief, disappearance of edema, and improved mobility. Dosages and volume of injections vary among studies, risk of bias is generally high, and outcomes are inconsistent and not uniformly excellent. At present, there is insufficient evidence to support the effectiveness of ozone therapy for KOA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.arthro.2019.09.036DOI Listing
January 2020

Laser-enhanced drug delivery of antiretroviral drugs into human immunodeficiency virus-1 infected TZMbl cells.

J Biophotonics 2019 10 15;12(10):e201800424. Epub 2019 Jul 15.

Biophotonics, National Laser Centre, Council for Scientific and Industrial Research, Pretoria, South Africa.

The introduction of highly active antiretroviral therapy (HAART) has significantly increased life expectancy and improved management of the human immunodeficiency virus-1 (HIV-1) disease globally. This well-established treatment regime has shown to reduce viral capacity to undetectable limits when using traditional clinical assays. The establishment of viral reservoirs during the early stages of infection are the major contributors to failure of the current regimens to eradicate HIV-1 infection since the reservoirs are not affected by antiretroviral drugs (ARVs). Therefore, advanced modification of the present treatment and investigation of novel antiretroviral drug delivery system are needed. The aim of this study was to use femtosecond (fs) laser pulses to deliver ARVs into HIV-1 infected TZMbl cells. Different ARVs were translocated into TZMbl cells using fs pulsed laser (800 nm) with optimum power of 4 μW and 10 ms laser to cell exposure time. Changes in cellular processes were evaluated using cellular morphology, viability, cytotoxicity and luciferase activity assays. Cells treated with the laser in the presence of ARVs showed a significant reduction in viral infectivity, cell viability and an increase in cytotoxicity. This study demonstrated that fs laser pulses were highly effective in delivering ARVs into HIV-1 infected TZMbl cells, causing a significant reduction in HIV-1 infection.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201800424DOI Listing
October 2019

Point of Care Diagnostics for HIV in Resource Limited Settings: An Overview.

Medicina (Kaunas) 2018 Mar 13;54(1). Epub 2018 Mar 13.

National Laser Centre, Council for Scientific and Industrial Research, PO Box 395, Pretoria 0001, South Africa.

Human immunodeficiency virus (HIV) is a global health problem. Early diagnosis, rapid antiretroviral therapy (ART) initiation and monitoring of viral load are the key strategies for effective HIV management. Many people in resource limited settings where timely access to medical care is a challenge and healthcare infrastructure is poor have no access to laboratory facilities and diagnosis is dependent on the presence of point of care (POC) devices. POC instruments have shown to be easy to operate, maintain and transport and can easily be operated by less skilled health workers. Additionally, POC tests do not require laboratory technicians to operate. POC devices have resulted in a growing number of people testing for HIV and thereby receiving treatment early. In recent years, there has been great improvement in the development of POC technologies for early HIV diagnosis, HIV viral load and cluster of differentiation 4 (CD4) measurement. This review discusses POC technologies that are currently available and in the pipeline for diagnosing and monitoring HIV. We also give an overview of the technical and commercialization challenges in POC diagnostics for HIV.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/medicina54010003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6037236PMC
March 2018

Medical ozone therapy as a potential treatment modality for regeneration of damaged articular cartilage in osteoarthritis.

Saudi J Biol Sci 2018 May 9;25(4):672-679. Epub 2016 Feb 9.

Faculty of Science, Department of Biomedical Sciences, Tshwane University of Technology, Pretoria, South Africa.

Osteoarthritis (OA) is the most common degenerative joint disease and a growing health problem affecting more than half of the population over the age of 65. It is characterized by inflammation in the cartilage and synovium, resulting in the loss of joint structure and progressive damage to the cartilage. Many pro-inflammatory mediators are elevated in OA, including reactive oxygen species (ROS) such as nitric oxide (NO) and hydrogen peroxide (HO). Damaged articular cartilage remains a challenge to treat due to the limited self-healing capacity of the tissue and unsuccessful biological interventions. This highlights the need for better therapeutic strategies to heal damaged articular cartilage. Ozone (O) therapy has been shown to have positive results in the treatment of OA; however the use of O therapy as a therapeutic agent is controversial. There is a perception that O is always toxic, whereas evidence indicates that when it is applied following a specified method, O can be effective in the treatment of degenerative diseases. The mechanism of action of O therapy in OA is not fully understood and this review summarizes the use of O therapy in the treatment of damaged articular cartilage in OA.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.sjbs.2016.02.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5935866PMC
May 2018

The effects of low level laser therapy on both HIV-1 infected and uninfected TZM-bl cells.

J Biophotonics 2017 Oct 27;10(10):1335-1344. Epub 2017 Jan 27.

Council of Scientific and Industrial Research, National Laser Centre, P.O. Box 395, Building 46A, Pretoria, 0001, South Africa.

Human immunodeficiency virus (HIV-1) infection remains a major health problem despite the use of highly active antiretroviral therapy (HAART), which has greatly reduced mortality rates. Due to the unavailability of an effective vaccine and treatment that would completely eradicate the virus in infected individuals, the quest for new therapies continues. Low level laser therapy (LLLT) involves the exposure of cells to low levels of red or infrared light. LLLT has been widely used in different medical conditions, but not in HIV-1 infection. This study aimed to determine the effects of LLLT on HIV-1 infected and uninfected TZM-bl cells. Both infected and uninfected cells were irradiated at a wavelength of 660 nm with different fluences from 2 J/cm to 10 J/cm . Changes in cellular responses were assessed using cell morphology, viability, proliferation, cytotoxicity and luciferase activity assays. Upon data analysis, uninfected irradiated cells showed no changes in cell morphology, viability, proliferation and cytotoxicity, while the infected irradiated cells did. In addition, laser irradiation reduced luciferase activity in infected cells. Finally, laser irradiation had no inhibitory effect in uninfected cells, whereas it induced cell damage in a dose dependent manner in infected cells.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/jbio.201600217DOI Listing
October 2017

Resistance of lung cancer cells grown as multicellular tumour spheroids to zinc sulfophthalocyanine photosensitization.

Int J Mol Sci 2015 May 5;16(5):10185-200. Epub 2015 May 5.

Laser Research Centre, Faculty of Health Sciences, University of Johannesburg, Doornfontein 2028, South Africa.

Photodynamic therapy (PDT) is phototherapeutic modality used in the treatment of neoplastic and non-neoplastic diseases. The photochemical interaction of light, photosensitizer (PS) and molecular oxygen produces singlet oxygen which induces cell death. Zinc sulfophthalocyanine (ZnPcSmix) has been shown to be effective in A549 monolayers, multicellular tumor spheroids (MCTSs) (250 µm) and not on MCTSs with a size of 500 µm. A549 cells used in this study were grown as MCTSs to a size of 500 µm in order to determine their susceptibility to PDT. ZnPcSmix distribution in MCTSs and nuclear morphology was determined using a fluorescent microscope. Changes in cellular responses were evaluated using cell morphology, viability, proliferation, cytotoxicity, cell death analysis and mitochondrial membrane potential. Untreated MCTSs, showed no changes in cellular morphology, proliferation, cytotoxicity and nuclear morphology. Photoactivated ZnPcSmix also showed no changes in cellular morphology and nuclear morphology. However, photoactivated ZnPcSmix resulted in a significant dose dependant decrease in viability and proliferation as well as an increase in cell membrane damage in MCTSs over time. ZnPcSmix photosensitization induces apoptotic cell death in MCTSs with a size of 500 µm and more resistantance when compared to monolayer cells and MCTSs with a size of 250 µm.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms160510185DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4463640PMC
May 2015

Localization and phototoxic effect of zinc sulfophthalocyanine photosensitizer in human colon (DLD-1) and lung (A549) carcinoma cells (in vitro).

Photodiagnosis Photodyn Ther 2012 Mar 16;9(1):52-9. Epub 2011 Sep 16.

Laser Research Centre, Faculty of Health Sciences, University of Johannesburg, P.O. Box 17011, Doornfontein 2028, South Africa.

Background: Photodynamic therapy (PDT) is a therapeutic modality used for treating cancerous cells. It has been previously shown that mixed sulfonated metallophthalocyanine complex, zinc sulfophthalocyanine (ZnPcS(mix)) is effective in destroying lung cancer cells. This study aimed to determine subcellular localization of ZnPcS(mix) and its effect on two cancer cell lines.

Methods: ZnPcS(mix) was activated at a wavelength of 680 nm with 5 J/cm². Colon (DLD-1) and lung (A549) cancer cell lines were used. Subcellular localization of ZnPcS(mix) was determined by fluorescence microscopy. Toxicity of PS alone and combination of light and PS (PDT) was determined by cell morphology, viability, proliferation and cytotoxicity. Cells which received no irradiation (0 J/cm²), irradiation alone (5 J/cm²) or treated with PS alone (no irradiation) served as controls.

Results: ZnPcS(mix) localized in both lysozomes and mitochondria in both A549 and DLD-1 cells. A549 cells treated with PDT showed a significant decrease in viability and proliferation in all PS concentrations used, while in DLD-1 cells a significant decrease was seen with concentrations of 10, 20 and 40 μM. In absence of light, ZnPcS(mix) did not result in cellular toxicity in A549 cells whereas in DLD-1 cells it resulted in a reduction in cell proliferation only at a concentration of 40 μM.

Conclusion: ZnPcS(mix) was effective in inducing cell death in both cell lines when localized in vital organelles such mitochondria and lysozomes which are essential for cell functioning. Photoactivated ZnPcS(mix) affected the cells at different concentration and yielded good therapeutic results in vitro.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.pdpdt.2011.08.006DOI Listing
March 2012

Effect of a newly synthesized Zn sulfophthalocyanine derivative on cell morphology, viability, proliferation, and cytotoxicity in a human lung cancer cell line (A549).

Lasers Med Sci 2011 Jul 29;26(4):523-30. Epub 2011 Jan 29.

Laser Research Centre, Faculty of Health Sciences, University of Johannesburg, PO Box 17011, Johannesburg, 2028, South Africa.

Photodynamic therapy (PDT) is a photochemotherapeutic process that is used for the treatment of cancer. Photofrin is the most widely used photosensitizer, however, the chemical composition of Photofrin is unclear and it has a low absorption in the therapeutic wavelength (600-900 nm). This factor has stimulated research in synthesis and testing of new photosensitizers. This in vitro study evaluated the effectiveness of a Zn sulfophthalocyanine (ZnPcS(mix)) as a potential photosensitizer in the treatment of human lung cancer. Lung cancer cells (A549) were divided into four groups: group 1 was control cells receiving neither light nor drug; group 2 was light control for cells exposed to laser irradiation at a fluence of 4.98 J/cm(2); group 3 was drug control for cells incubated with 15.8 μM photosensitizer and not exposed to laser irradiation, while group 4 was cells receiving the experimental treatment with 15.8 μM photosensitizer and irradiation with 4.98 J/cm(2). Laser irradiations were performed using a 636-nm diode laser with an output power of 110 mW at 4.98 J/cm(2). Changes in cellular responses were evaluated by cell morphology, viability, proliferation, and cytotoxicity. While control groups 1, 2, and 3 showed no changes in cell morphology, viability, proliferation, or cytotoxicity, group 4 receiving both photosensitizer and irradiation showed changes in cell morphology, a decrease in cell viability and proliferation, and an increase in cytotoxicity, cell death, and cell membrane damage. Irradiation or photosensitizer alone had no effect on the lung cancer cells since the cells remained viable and showed no evidence of damage. However, irradiation in the presence of a photosensitizer induced cell death.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10103-011-0887-0DOI Listing
July 2011