Tag Archives: Georgina Sylvia

Sensing magnesium

17 April 2018:

A new publication from CNBP researchers (lead author Georgina Sylvia pictured), presents the rational design and photophysical characterisation of spiropyran-based chemosensors for magnesium.

Journal: Chemosensors.

Publication title: A Rationally Designed, Spiropyran-Based Chemosensor for Magnesium.

Authors: Georgina M. Sylvia, Adrian M. Mak, Sabrina Heng, Akash Bachhuka, Heike Ebendorff-Heidepriem, and Andrew D. Abell.

Abstract: Magnesium ions (Mg2+) play an important role in mammalian cell function; however, relatively little is known about the mechanisms of Mg2+ regulation in disease states. An advance in this field would come from the development of selective, reversible fluorescent chemosensors, capable of repeated measurements. To this end, the rational design and fluorescence-based photophysical characterisation of two spiropyran-based chemosensors for Mg2+ are presented. The most promising analogue, chemosensor 1, exhibits 2-fold fluorescence enhancement factor and 3-fold higher binding affinity for Mg2+ (Kd 6.0 µM) over Ca2+ (Kd 18.7 µM). Incorporation of spiropyran-based sensors into optical fibre sensing platforms has been shown to yield significant signal-to-background changes with minimal sample volumes, a real advance in biological sensing that enables measurement on subcellular-scale samples. In order to demonstrate chemosensor compatibility within the light intense microenvironment of an optical fibre, photoswitching and photostability of 1 within a suspended core optical fibre (SCF) was subsequently explored, revealing reversible Mg2+ binding with improved photostability compared to the non-photoswitchable Rhodamine B fluorophore. The spiropyran-based chemosensors reported here highlight untapped opportunities for a new class of photoswitchable Mg2+ probe and present a first step in the development of a light-controlled, reversible dip-sensor for Mg2+.

A spiropyran with enhanced fluorescence

10 November 2017:

A new rationally designed, photostable, red-emitting calcium sensor with enhanced fluorescence intensity has been presented by CNBP researchers in a paper published in the journal ‘Tetrahedron’. Lead author on the paper is CNBP’s Georgina Sylvia (pictured – University of Adelaide).

Journal: Tetrahedron.

Publication titleA spiropyran with enhanced fluorescence: A bright, photostable and red-emitting calcium sensor.

Authors: Georgina M. Sylvia, Sabrina Heng, Akash Bachhuka, Heike Ebendorff-Heidepriem,
Andrew D. Abell.

A rationally designed, pyrene-spiropyran hybrid Ca2+ sensor (Py-1) with enhanced fluorescence intensity compared to a standalone spiropyran analogue is presented. Importantly, Py-1 retains the characteristic red emission profile of the spiropyran, while fibre-based photostability studies show the sensor is stable after multiple cycles of photoswitching, without any sign of photodegradation. Such properties are of real advantage for cell-based sensing applications. An interesting observation is that, Py-1 presents with two excitation options; direct green excitation (532 nm) of the photoswitch for a red emission, and UV excitation (344 nm) of the component pyrene, which gives rise to distinct blue and red emissions. This proof-of-concept hybrid sensing system presents as a more general approach to brighter spiropyran-based sensors.

Children’s University Regional Lecture Series

17 September 2017:

Georgina Sylvia, CNBP researcher, was recently involved in two outreach events organised as part of the Children’s University Regional Lecture Series, which aims to stimulate interest in Science, Technology, Engineering and Mathematics (STEM subjects) for school children in Years 6-9.

At the first event at Renmark, she presented exciting chemistry demonstrations to year 7 and 8 students from the local community at the McCormick Centre for the Environment. The students were engaged in groups of 25 and encouraged to participate in the experiments and to ask and discuss science related queries.

The best quote of the day heard by Georgina – “Chemistry is awesome!”

The second outreach event was held at ‘Riverland Field Days’, 15-16th September, 2017. This community event is held annually “showcasing horticultural, agricultural and general farming products and services along with many general exhibitors.”

Children’s University, as a part of the Regional Lecture Series, set up a stall where Georgina and other researchers demonstrated and engaged kids in activities such as Engineering (building catapults from popsicle sticks), Chemistry (Slime making) and Biology (an aroma-sensory panel activity).

Feedback from Georgina – “The best part of this event was encouraging parents and caregivers to get involved in the activities with their kids, and to learn things together. Another great experience for me was encouraging a little girl to get involved in the catapult-making engineering activity, and seeing her so excited to participate!”

Below – Georgina (second right) at the Field Days event.

School tour of Braggs labs

31 August 2017:

Caritas College students visiting the University of Adelaide for a ‘science day’ were shown around laboratory spaces in the Braggs Building by CNBP PHD students Kathryn Palasis (pictured) and Georgina Sylvia.

The 23 Year 9 school students were given a tour through a synthetic chemistry lab and then spoke with both CNBP researchers about the work being done and their journeys through University. This was followed by a further tour through a fibre-optics laboratory.

According to Kathryn, “The students seemed engaged and interested, particularly with the fibre-optics tour. And feedback from Amy (who organised the day) was that the students enjoyed it and that the teachers were very appreciative. Personally I spoke to a girl who said she was interested in studying science at university which was very pleasing to hear, and hopefully we encouraged others to see it as an appealing career path as well.”

Poster win at Pacifichem 2015

Georgina-Sylvia20 December 2015:

Congratulations to CNBP PhD student Georgina Sylvia – one of the winners in the Pacifichem Conference 2015 Student Poster Competition!

Georgina attended the 2015 Pacifichem meeting (Hawaii) where she had been elected as a finalist (limited to the top 10% out of 3,500 student abstract submissions). Out of the 350 students in the poster competition, she was then selected as one of the 54 winners.

Georgina’s poster was titled, ‘Peptide-based tunable molecular wires’. The full list of students who competed in the poster competition can be found online , with her entry at #252 under section (7) Biological.