Tag Archives: Nima Sayyadi

Shedding light on golden staph

3 July 2019:

A groundbreaking new technique will slash the time it takes to detect potentially lethal golden staph infection from two days to just two hours.

Researchers from the ARC Centre of Excellence for Nanoscale BioPhotonics (CNBP) targeted the bacterium with a luminescent DNA probe.

“This allows us to find the “needle in the haystack” because only the “needle” lights up,” says Dr Nima Sayyadi, Research Fellow at the Macquarie University node of the CNBP and lead author on the paper.

Golden staph, or Staphylococcus aureus, lives on the skin or in the nose. It is usually harmless, but if it enters the skin through a cut it can cause a range of infections, which in some cases are fatal.

Dr Nima Sayyadi in the lab

In the most at-risk patients, such as the elderly, it is vital to identify the infection and begin treatment with appropriate antibiotics as soon as possible. However, current identification techniques require culturing cells for up to two days to provide a positive infection result.

The new approach, known as Time-Gated Luminescent in Situ Hybridization (LISH), takes just two hours and could have a range of other applications. While it cannot yet separately identify drug resistance strains of golden staph, researchers are working on it.

CNBP scientists are also working on a range of transformational research projects based on the luminescence based detection of single cells in human body fluid samples, which will help them label antibodies and molecules as well as DNA.

“We’ve also done work in prostate cancer and bladder cancer where the target cell can be quickly and easily identified in urine samples,” says Project Lead and CNBP node leader at Macquarie University, Professor James Piper AM.

The research was reported in the journal Molecules, which you can read here.

Luminescent In Situ Hybridization (LISH)

School science conference impresses

15 June 2017:

Dr Nima Sayyadi, CNBP researcher, has undertaken guest judging duties at the 2017 Sydney Girls High School Science Conference.

Each year students at Sydney Girls High School complete a research project as part of the NSW Science Curriculum. This project provides Year 9 students with an opportunity to design and perform an investigation into an area of their choice. The annual Science Conference then gives the students a forum where they can present their research to an expert panel.

The panel not only provides students with feedback relating to their investigation, but also determines the projects worthy of further recognition. The determination considers both experimental design and the ability of the student to communicate their ideas.

According to Nima, the standard of work on display was of an incredibly high standard.

“The way that the young students designed their research projects – the hypotheses and preparation and understanding of data limitations was generally quite remarkable.”

Projects being showcased included DNA extraction from fruits with limited facilities through to the analysis of the plastic waste found in water on different beaches in Sydney.

“It was a great experience for me to meet the students, teachers, and other judges from different universities at this event,” concluded Nima.

“Hopefully the passion that these students show for science continues through High School and into tertiary education and beyond.”

Detection of prostate cancer cells

Nima Sayyadi_web5 September 2016:

The latest paper published by CNBP researchers (lead author Nima Sayyadi, pictured left), reports on a bright red water soluble luminescent molecular probe that was successfully synthesized, with multiple platforms developed for sensitive immunodetection of prostate cancer cells. The probe has immediate potential for sensitive detection of a wide range of proteins and disease-specific cellular antigens.

Journal: Analytical Chemistry.

Publication title: Sensitive time-gated immunoluminescence detection of prostate cancer cells using a TEGylated europium ligand.

Authors: Nima Sayyadi, Irene Justiniano, Russell Edwin Connally, Run Zhang, Bingyang Shi, Liisa Kautto, Arun V Everest-Dass, Jingli Yuan, Bradley John Walsh, Dayong Jin, Robert Drant Willows, James A. Piper, and Nicolle H. Packer.

Abstract: We describe the application of a synthetically developed tetradentate β-diketonate-europium chelate with high quan-tum yield (39%), for sensitive immunodetection of prostate cancer cells (DU145). MIL38 antibody, a mouse monoclonal antibody against Glypican 1, conjugated directly to the chelate via lysine residues, resulted in soluble (hydrophilic) and stable immunoconjugates. Indirect labeling of the antibody by a europium chelated secondary polyclonal antibody and a streptavidin/biotin pair was also performed. All of these bright luminescent conjugates were used to stain DU145 cells, a prostate cancer cell line, using time gated luminescence microscopy for imaging, and their performances were compared to conventional FITC labelling. For all prepared conjugates, the europium chelate in conjunction with a gat-ed auto-synchronous luminescence detector (GALD) completely suppressed the cellular autofluorescence background to allow capture of vivid, high contrast images of immune-stained cancer cells.

The paper is available online.

Rapidly labeling antibodies with luminescence

Labelled cells10 June 2016:

CNBP and Macquarie University researchers have successfully developed a novel indirect universal detection reagent that rapidly labels antibodies with luminescence within seconds and without the need for any complicated bioconjugation procedures. The reagent, reported in the journal ‘Scientific Reports’, can be used to directly label antibodies for several time-gated luminescence applications, e.g., bioimaging, cell labeling and detection, and flow cytometry.

The work was co-authored by CNBP researchers Dr Andrew Care and Dr Nima Sayyadi and led by CNBP Associate Investigator Dr Anwar Sunna.

Pictured (top left) – giardia cyst cells labeled with europium chelate.

Publication title: A Novel Universal Detection Agent for Time-Gated Luminescence Bioimaging

Authors: Nima Sayyadi and Andrew Care ( first co-authors), Russell E. Connally, Andrew C. Try, Peter L. Bergquist and Anwar Sunna

Abstract:
Luminescent lanthanide chelates have been used to label antibodies in time-gated luminescence (TGL) bioimaging. However, it is a challenging task to label directly an antibody with lanthanide-binding ligands and achieve control of the target ligand/protein ratios whilst ensuring that affinity and avidity of the antibody remain uncompromised. We report the development of a new indirect detection reagent to label antibodies with detectable luminescence that circumvents this problem by labelling available lysine residues in the linker portion of the recombinant fusion protein Linker-Protein G (LPG). Succinimide-activated lanthanide chelating ligands were attached to lysine residues in LPG and Protein G (without Linker) and the resulting Luminescence-Activating (LA-) conjugates were compared for total incorporation and conjugation efficiency. A higher and more efficient incorporation of ligands at three different molar ratios was observed for LPG and this effect was attributed to the presence of eight readily available lysine residues in the linker region of LPG. These Luminescence-Activating (LA-) complexes were subsequently shown to impart luminescence (upon formation of europium(III) complexes) to cell-specific antibodies within seconds and without the need for any complicated bioconjugation procedures. The potential of this technology was demonstrated by direct labelling of Giardia cysts and Cryptosporidium oocysts in TGL bioimaging.

The paper is available online.

New Research Fellow role for Nima Sayyadi

Nima Sayyadi_web25 May 2016:

Dr. Nima Sayyadi at Macquarie University, former CNBP Associate Investigator, has been employed as a CNBP Research Fellow.

Dr Sayyadi  has previously been responsible for designing  and developing a series of novel europium luminescent chelates which have successfully been applied to the detection of Staphylococcus aureus using luminescent in situ hybridization (LISH) techniques. He has also developed europium chelates using different immunoconjugate platforms for sensitive TGL detection of a wide range of bacteria, protozoa and human cancer cells.

His new CNBP related activity will involve exploring the synthesis and application of novel lanthanide chelates for the sensitive time-gated luminescence (TGL) detection of bio-targets in complex biological matrices.

More specifically Dr Sayyadi’s activity will be focused on the following –

* Synthesis of Europium chelate molecules with different conjugation functionality e.g. amino, sulphydryl, alkyne, hydrazide.

* Conjugation of Europium chelates to protein, sugars, nucleic acids, and characterization of the conjugates.

* Testing and application of time-gated orthogonal scanning automated microscopy (OSAM) and standing microscope (when developed) for single cell detection of Europium chelates

* Time-gated luminescent immunodetection (using IgG and IgM) for detection of target proteins in biological samples (urine, blood, and saliva).

Well done on the gaining of your new role Nima!

A new chelate for sensitive time-gated immunodetection

Nima Sayyadi_web23 November 2015:

CNBP researcher Nima Sayyadi is first author on a recently published paper titled, ‘A novel biocompatible europium chelate for sensitive time-gated immunodetection.’

The paper was published in the journal Chemical Communications.

Abstract: We describe the synthesis of a novel hydrophilic derivative of a tetradentate β-diketone europium chelate that was used to prepare an immunoconjugate probe against Giardia lamblia cysts. We used a Gated Autosynchronous Luminescence Detector (GALD) to obtain high quality delayed luminescence images of cells 30-fold faster than ever previously reported.

Additional information can be found online here.

Sayyadi gives seminar

Nima Sayyadi_web28 April 2015:

CNBP Associate Investigator, Dr Nima Sayyadi from Macquarie University, gave a well received seminar at the University of Adelaide on the topic, “Sensitive Cancer Immunodetection Using a Novel Europium Immunoconjugate.”

The seminar, on April 28th, 2015 was part of a week long visit to the University of Adelaide for Nima, who spent a large part of that time working with CNBP’s Dr Jingxian Yu in the Recognise team.

As a CNBP AI, the major aim of Nima’s current project is in aiding the development of luminescent probes for bio-sensing.