Tutorial 3

Fundamental in Immobilization Chemistry for Biomarker and Chemical Marker; The Centrepiece of Sensor Development

Nor Azah Yusof
Universiti Putra Malaysia

Abstract: Development of biosensors must consider the effects of the local environment on the binding capacity of the immobilized selective molecular recognition elements. In designing immobilization strategy, a few important factors must be considered which includes the nature of the solid substrate used, method of immobilization, solution conditions under which experiments are performed and probe effects such as the length of the probe, proximity to the surface, packing density. The aims for immobilization are to reduce the restriction of the probe and endpoint attachment, to have stable immobilization such that the probe does not leave the surface, to ensure the probe is accessible to the target molecule and the immobilization can limit non-specific binding.

The interface between a sensor surface and the chemical or biological systems is the most important component in sensor development. During this process, the recognition molecule should retain their original conformation and must be stable. The binding sites must be exposed enough to interact with the analyte in order to generate a readable and reproducible signal. The support must be resistant to nonspecific binding. Coupling chemistries utilize a chemical linker layer on the surface of the sensor that anchor the recognition molecule. Selection of the correct coupling chemistry requires careful consideration of certain factors like the orientation required for the recognition molecule, the material of the sensor surface as well as the local environment on the surface and possible effects of the coupling chemistry on components of the binding interaction

The choice of immobilization chemistry is vital for success development of sensor. Ideally the immobilization chemistry should adhere irreversibly to the biosensor transducer substrate. It also should be able to be characterized using certain techniques eg spectroscopic technique. This is to ensure reproducibility of the process and enable quantitative estimation of the attached biorecognition molecule. The chemistry should not interfere with the activity or conformation of the recognition molecule. The chemistry should also allow maximum transduction of binding event signal. The chemistry should also be highly resistant to nonspecific binding. The immobilization chemistry should as well not be affected by matrix effect.

Biography: Nor Azah Yusof, is a leading young academics at the University Putra Malaysia. She is known for its impressive achievements in various academic branches. She began her career as a research assistant at the Universiti Kebangsaan Malaysia and offered to participate as a lecturer in Universiti Putra Malaysia in 2002 after completing her PhD. Her research has resulted in more than 200 journal articles and 63 conference articles. Of this amount, 75% was as a main author and communicator. 60% of the journals are in the Q1 and Q2. Her articles have been cited 2000 times by international researchers, including leading researchers in her field. Her expertise in the field of sensor allows her to be elected as the auditor of articles by various international journals. She has 10 national and international patents. The result of her achievements, she was appointed a professor at the age of 39 years. She is also the recipient of research grants in total of almost MYR 10 million of funding from various national sources and abroad. She has guided 40 graduate students. Some of her students are now serving as academics and researchers in research institutions, universities and industry. She has been awarded as Top Research Scientist Malaysia (TRSM) for 2012 and received Oustanding Researcher Award (Anugerah Penyelidik Cemerlang) for 2017.

She started working on optical chemical sensor for toxic metal detection. She further developed her expertise on electrochemical based biosensor. She has been working on DNA based biosensor and protein based biosensor for 10 years. She wishes to further develop her electrochemical reader and biochip that she has started working on for 5 years into a prototype and later be commercialized. She is seeking partner to together develop the technology into a suitable kit and further commercialized the diagnostic kit for home use.