Tag Archives: Ayad Anwer

Gold nanoparticles for bioimaging

22 March 2017:

A new publication from CNBP researchers (lead author Sandhya Clement pictured) reports on a more effective and less harmful gold-based nano-agent for bioimaging and photodynamic therapy treatment for deep tissue tumors.

The work has just been reported in the journal ‘Microchimica Acta ’ and is accessible online.

Journal: Microchimica Acta.

Title: Verteprofin conjugated to gold nanoparticles for fluorescent cellular bioimaging and X-ray mediated photodynamic therapy.

Authors: Sandhya Clement, Wenjie Chen, Ayad G. Anwer & Ewa M. Goldys.

Abstract: Photodynamic therapy (PDT) uses photosensitizers, light and molecular oxygen to generate cytotoxic reactive oxygen species. Its effectiveness is limited to <1 cm due to the limited penetration depth of light. The present study compares the PDT effectivity of the photosensitizer verteporfin (VP) conjugated to gold nanoparticles (AuNPs) (a) by using deeply penetrating X-rays administered in standard radiotherapy doses, and (b) by using red light (690 nm). VP was conjugated to AuNPs of around 12 nm size to enhance the interaction of ionizing radiation with PS. For comparison, VP also was directly exposed to X-rays. It is found that VP alone is stimulated by X-rays to generate singlet oxygen. The conjugate to AuNPs also generated a significant amount of singlet oxygen on irradiation with X-rays in comparison to illumination with 690-nm light. It is also found that the rate of singlet oxygen generation is amplified in case of AuNP-conjugated VP compared to VP alone. The performance of the AuNP-VP conjugate and of the VP alone was tested in Panc 1 cells. Their viability was impaired much more in these two scenarios than with the X-ray radiation only. This suggests excellent perspectives for PDT based on VP and with X-ray stimulation, both as a stand-alone photosensitizer and in Au-NP conjugates. Moreover, both VP and AuNP-VP conjugates show bright fluorescence in physiological media for excitation/emission wavelengths in the range of 405/690 nm; hence they can also be used for simultaneous bioimaging.

Investigating cell metabolism

Aziz Rehman1 March 2017:

A new publication from CNBP researchers (lead author Aziz Ul Rehman pictured) reports on the application of hyperspectral imaging in combination with fluorescence spectroscopy and chemical quenching to provide a new methodology to investigate cell metabolism.

The work has just been reported in the journal ‘Biomedical Optics Express’ and is accessible online.

Journal: Biomedical Optics Express.

Title: Fluorescence quenching of free and bound NADH in HeLa cells determined by hyperspectral imaging and unmixing of cell autofluorescence.

Authors: Aziz Ul Rehman, Ayad G. Anwer, Martin E. Gosnell, Saabah B. Mahbub, Guozhen Liu, and Ewa M. Goldys.

Abstract: Carbonyl cyanide-p-trifluoro methoxyphenylhydrazone (FCCP) is a well-known mitochondrial uncoupling agent. We examined FCCP-induced fluorescence quenching of reduced nicotinamide adenine dinucleotide / nicotinamide adenine dinucleotide phosphate (NAD(P)H) in solution and in cultured HeLa cells in a wide range of FCCP concentrations from 50 to 1000µM. A non-invasive label-free method of hyperspectral imaging of cell autofluorescence combined with unsupervised unmixing was used to separately isolate the emissions of free and bound NAD(P)H from cell autofluorescence. Hyperspectral image analysis of FCCP-treated HeLa cells confirms that this agent selectively quenches fluorescence of free and bound NAD(P)H in a broad range of concentrations. This is confirmed by the measurements of average NAD/NADH and NADP/NADPH content in cells. FCCP quenching of free NAD(P)H in cells and in solution is found to be similar, but quenching of bound NAD(P)H in cells is attenuated compared to solution quenching possibly due to a contribution from the metabolic and/or antioxidant response in cells. Chemical quenching of NAD(P)H fluorescence by FCCP validates the results of unsupervised unmixing of cell autofluorescence.

Hyperspectral unmixing methodology validated

Aziz Rehman10 February 2017:

A new publication from CNBP researchers Aziz Ul Rehman (pictured), Ayad Anwer, Martin Gosnell, Saabah Mahbub, Guozhen Liu and Ewa Goldys demonstrates the validation of an innovative hyperspectral unmixing methodology, that can derive chemical information from cell colour.

The work has just been reported in the journal ‘Biomedical Optics Express’ and is accessible online.

Journal: Biomedical Optics Express.

Title: Fluorescence quenching of free and bound NADH in HeLa cells determined by hyperspectral imaging and unmixing of cell autofluorescence.

Authors: Aziz Ul Rehman, Ayad G. Anwer, Martin E. Gosnell, Saabah B. Mahbub, Guozhen Liu, and Ewa M. Goldys.

Abstract: Carbonyl cyanide-p-trifluoro methoxyphenylhydrazone (FCCP) is a well-known mitochondrial uncoupling agent. We examined FCCP-induced fluorescence quenching of reduced nicotinamide adenine dinucleotide / nicotinamide adenine dinucleotide phosphate (NAD(P)H) in solution and in cultured HeLa cells in a wide range of FCCP concentrations from 50 to 1000µM. A non-invasive label-free method of hyperspectral imaging of cell autofluorescence combined with unsupervised unmixing was used to separately isolate the emissions of free and bound NAD(P)H from cell autofluorescence. Hyperspectral image analysis of FCCP-treated HeLa cells confirms that this agent selectively quenches fluorescence of free and bound NAD(P)H in a broad range of concentrations. This is confirmed by the measurements of average NAD/NADH and NADP/NADPH content in cells. FCCP quenching of free NAD(P)H in cells and in solution is found to be similar, but quenching of bound NAD(P)H in cells is attenuated compared to solution quenching possibly due to a contribution from the metabolic and/or antioxidant response in cells. Chemical quenching of NAD(P)H fluorescence by FCCP validates the results of unsupervised unmixing of cell autofluorescence.

Online talk at Biophotonics Symposium, University of Baghdad

ayad_anwer-low-rez121 April 2016:

Researchers in Iraq at the University of Baghdad have learnt more about the CNBP as well as the current trends in nanoscale biophotonics, following an invited talk, provided by CNBP researcher Dr Ayad Anwer.

The talk, delivered remotely via the web, featured as part of a Biophotonics Symposium that took place at the University’s Institute of Laser for Postgraduate Studies. The Institute responds to the requirements of scientific fields and modern technologies related to laser and its applications in a wide variety of fields across medicine, biology, dentistry and engineering.

Said Dr Anwer, ” My talk explored recent research as well as applications related to nanoscale biophotonics. I also provided an overview of CNBP’s structure, research themes, activities, research projects and aims. Questions following my talk tended to focus on label free imaging technology and specific nanoparticle applications.”

Concluding, he commented, “Feed back from the talk was extremely positive and potential collaborations between our two groups was also discussed. The session went extremely well!”

 

Dr Mustafa visits key collaborators at Macquarie University

Sanam Mustafa High Res Edit 016620 October 2014: Dr Mustafa visit key collaborators at Macquarie University to discuss novel and interdisciplinary projects.

During her visit to Macquarie University, Dr Mustafa met with Prof Ewa Goldys and Dr Ayad Anwer to discuss the progress of a collaborative project. During her visit, Dr Mustafa shared her expertise in cell culture with Dr Anwer and discussed the progress of the project. Dr Anwer provided a tour of the facilities and explained the process behind image acquisition and data analysis for hyperspectral studies.

Dr Mustafa also discussed a new collaborative project with Prof Nicki Packer and Dr Arun Dass. This project is now in its initial planning stages and experimental work will start shortly.