Laser-based approaches in HIV diagnostics

Dr Patience Mthunzi-Kufa. Source: TED

“We are excited to be presenting our research findings on laser-driven label-free approaches of detecting HIV-1, which is the most widespread type worldwide, in living biological cells. While laser technology is used in the detection and treatment of cancer cells, it is rarely used as a technological tool to investigate HIV-infected cells,” says CSIR research group leader for biophotonics, Dr Patience Mthunzi-Kufa.

One of the research papers, written and prepared for oral presentation by CSIR senior researcher in biophotonics, Dr Saturnin Ombinda-Lemboumba and Dr Mthunzi-Kufa, will focus on novel tag-free detection of HIV-1 infected and uninfected cells via Raman and transmission spectroscopy coupled with optical trapping, which are techniques used to improve the reliability of data when cells are being analysed.

Compared to gold-standard HIV-1 diagnostics such as the enzyme-linked immunosorbent assay (ELISA) and nucleic acid based tests that require the use of labels and substrates respectively, for the first time in HIV research; coupling of laser trapping with Raman spectroscopy (LTRS) allows a non-invasive immobilisation and label-free analysis of single infected cells.

This optical system allows single cells to be isolated so that their chemical fingerprint can be analysed by shining laser light of varying wavelengths and carefully structured beams on them, says Ombinda-Lemboumba.

He says this technique, compared to the labelled detection technique is more likely to provide accurate results within a short period of time at a cost-effective rate.

“Addressing issues of accuracy, cost and time were important for the purpose of this research. In light of HIV/Aids being a serious disease claiming the lives of many in developing countries, particularly in sub-Saharan Africa, it is important that our research addresses the challenges of the day,” adds Mthunzi-Kufa.

An invention disclosure and a South African provisional patent for this work have been filed.

The nine presentations the team will make at the conference are:

• In-vitro photo-translocation of antiretroviral drug delivery into TZMbl cells (oral presentation), Rudzani Malabi, Sello L Manoto, Saturnin Ombinda-Lemboumba and Patience Mthunzi-Kufa
• Photo-transfection and differentiation of mouse embryonic stem cells using femtosecond laser pulses (oral presentation), Lebogang S Thobakgale, Sello L Manoto, Satuurnin Ombinda-Lemboumba, Malik Maaza and Patience Mthunzi-Kufa
• Real-time Raman spectroscopy for the characterisation of biochemical changes in differentiated embryonic stem cells (poster presentation), Lebogang S Thobakgale, Sello L Manoto, Satuurnin Ombinda-Lemboumba, Malik Maaza and Patience Mthunzi-Kufa
li>Targeted femtosecond laser driven drug delivery within HIV-1 infected cells: in-vitro study (oral presentation), Charles Maphanga, Saturnin Ombinda-Lemboumba, Sello L Manoto, and Patience Mthunzi-Kufa
• Pros and cons of characterising an optical translocation setup (poster presentation), Charles Maphanga, Rudzani Malabi, Saturnin Ombinda-Lemboumba
• Could low level laser therapy and highly active antiretroviral therapy lead to complete eradication of HIV-1 in vitro? (oral presentation), Masixole Y Lugongolo, Sello L Manoto, Saturnin. Ombinda-Lemboumba and Patience. Mthunzi-Kufa
• Photodynamic activity of zinc monocarboxyphenoxy phthalocyanine (ZnMCPPc) conjugated to gold silver (AuAg) nanoparticles in melanoma cancer cells (poster presentation), Sello L Manoto, David Oluyinka Oluwole, Saturnin Ombinda-Lemboumba, Patience Mthunzi-Kufa and Tebello Nyokong
• Phototoxic effects of free phthalocyanine and phthalocyanine conjugated to gold nanoparticles for targeted photodynamic therapy of melanoma cancer (oral presentation), Sello L Manoto, David Oluyinka Oluwole, Saturnin Ombinda-Lemboumba, Patience Mthunzi-Kufa and Tebello Nyokong