Size dependent interaction of biofunctionalized CdS nanoparticles with tyrosine at different pH

Area of Science:

• Nanomaterials Science
• Photochemistry
• Biophysical Chemistry

Background:

• Cadmium sulfide (CdS) nanoparticles exhibit unique photoluminescent properties.
• Amino acids can interact with nanoparticles, modulating their optical characteristics.
• Understanding these interactions is crucial for developing novel sensing and imaging applications.

Purpose of the Study:

• To investigate the effect of tyrosine on the fluorescence of CdS nanoparticles.
• To determine the influence of pH on the interaction between tyrosine and CdS nanoparticles.
• To explore the role of nanoparticle size in these fluorescence modulation effects.

Main Methods:

• Synthesis of CdS nanoparticles of varying sizes.
• Steady-state fluorescence spectroscopy.
• pH-dependent measurements in the presence of tyrosine.

Main Results:

• Tyrosine enhanced the fluorescence of CdS nanoparticles at pH 10.
• Stern-Volmer quenching of CdS nanoparticle fluorescence by tyrosine was observed at pH 7.
• Both enhancement and quenching effects were dependent on the size of the CdS nanoparticles.

Conclusions:

• The pH-dependent interaction between tyrosine and CdS nanoparticles significantly alters their fluorescence.
• Nanoparticle size plays a critical role in modulating these fluorescence changes.
• These findings suggest potential applications in pH-sensitive fluorescent probes and biosensors.