## 2 Results and Discussion
### Self-Aggregation of FYNF-NH\({}_{2}\) Investigations
#### 2.4.2 Fluorescence Studies  
The fluorescence studies conducted in sodium acetate at pH 7.4, along with the concentration-dependent experiments, provide essential contributions to understanding the dynamics of self-assembly. To universally excite the two aromatic amino acids, phenylalanine and tyrosine, embedded within the peptide backbone, an excitation wavelength of 275 nm was employed [39]. As represented in Figure 5, the noticeable decline in fluorescence intensity at 304 nm, coupled with the concurrent decrease in the shoulder within the 322-335 nm range after 20 min, alongside a reduction in fluorescence intensity in the violet  
Figure 4: FTIR spectrum corresponding to the amide I region evidencing the secondary structures of FEYNF-NH\({}_{2}\) peptide in the solid state, achieved through deconvolution (Gaussian curves positioned at peaks predetermined by the second derivative spectrum of the initial data).  
blue region (390-450 nm), collectively signifies significant changes in the microenvironment enveloping the aromatic amino acids (phenylalanine and tyrosine). These observed alterations strongly suggest a compelling correlation with the gelation process [40]. Furthermore, the dityrosine formation characterized by a emission signal at around 409 nm cannot be excluded [41].  
Expanding the investigation to include the violet-blue region is particularly insightful. The violet-blue region encompasses emissions from both phenylalanine and tyrosine, revealing additional nuances in their fluorescence behavior. This broader spectral analysis allows discerning changes in the electronic environment, potential shifts in molecular conformations, or alterations in the interactions among aromatic amino acids during gelation. The reduction in fluorescence intensity in the violet-blue region suggests a complex interplay of factors affecting the electronic states of both phenylalanine and tyrosine. This could include changes in solvent accessibility, local structural rearrangements, or variations in intermolecular interactions, all of which contribute to the observed fluorescence behavior. By considering these additional spectral features, the understanding of the molecular events associated with gelation becomes more nuanced and provides valuable insights into the intricate dynamics of the peptide's structural transformation.  
This quenching phenomenon was observed within a brief timeframe for two distinct concentrations of the FEYNF-NH\({}_{2}\) peptide: 27 uM and 0.5 mM (Figure 5). The quenching effect in fluorescence, observed in the blue region of emission spectra, can be attributed to a multitude of factors, encompassing alterations in fluorophore proximity and interactions with neighboring molecules. Particularly, in the context of gelation, the formation of a three-dimensional network is believed to foster heightened interactions among aromatic amino acids, thereby influencing their fluorescence properties [42; 43]. It is well known that tyrosine quenching and a tyrosine-tyrosine homotransfer might be interconnected [44]. Further  
Figure 5: Fluorescence emission spectra recorded at \(\lambda_{\text{ex}}=275\) nm. The initial spectra (1, 4) of peptide at 27 uM respectively 0.5 mM are displayed. The emission spectra of peptide after 10 min (2 and 5) and 20 min (3 and 6) incubation at room temperature (20 degrees) are presented.  
insights into these intricate dynamics can be crucial for a comprehensive understanding of the peptide's behavior under different concentrations and temporal conditions.