Supramolecular order following binding of the dichroic birefringent sulfonic dye Ponceau SS to collagen fibers

Abstract

The optical anisotropies (linear dichroism or LD and birefringence) of crystalline aggregates of the sulfonic azo-dye Ponceau SS and of dye complexed with chicken tendon collagen fibers were investigated in order to assess their polarizing properties and similarity to liquid crystals. In some experiments, the staining was preceded by treatment with picric acid. Crystalline fibrous aggregates of the dye had a negative LD, and their electronic transitions were oriented perpendicular to the filamentary structures. The binding of Ponceau SS molecules to the collagen fibers altered the LD signal, with variations in the fiber orientation affecting the resulting dichroic ratios. The long axis of the rod-like dye molecule was assumed to be bound in register, parallel to the collagen fiber. Picric acid did not affect the oriented binding of the azo dye to collagen fibers. There were differences in the optical anisotropy of Ponceau SS-stained tendons from 21-day-old and 41-day-old chickens, indicating that Ponceau SS was able to distinguish between different ordered states of macromolecular aggregation in chicken tendon collagen fibers. In the presence of dichroic rod-like azo-dye molecules such as Ponceau SS, collagen also formed structures with a much higher degree of orientation. The presence of LD in the Ponceau SS-collagen complex even in unpolarized light indicated that this complex can act as a polarizer.

Bouts of Passive Stretching after Immobilization of the Rat Soleus Muscle Increase Collagen Macromolecular Organization and Muscle Fiber Area

“…Although previous studies have demonstrated that the macromolecular reorganization of the collagen fibers in the muscle, tendon, bone, and cartilage can be evaluated by measuring birefringence using polarized light microscopy [15][16][17][18][19][20], few studies have investigated the macromolecular organization of the ICT after periods of immobilization by analyzing birefringence [20,21], which is considered to be an accurate morphological evaluation technique.…”

Topochemistry, optical anisotropy and FT-IR microspectroscopy of the cocoon of Lithurgus chrysurus (Hymenoptera, Megachilidae)

“…The filaments at the innermost region of the inner layer of the cocoon wall treated with the Ponceau SS solution stained light pink ( Fig. 2A-C), demonstrating presence of protein electropositive radicals (Vidal and Mello, 2005). This response also occurred in the laminar structure and encasing bubble elements of the foamy structures in the intermediate layer ( Fig.…”

“…Total protein electropositive radicals were investigated in sections stained with a 0.025% Ponceau SS (Sigma, St. Louis, MO, USA) solution in 3% acetic acid at pH 2.5 for 10 min (Vidal and Mello, 2005). Glycoproteins were searched with the periodic acid Schiff (PAS) reaction (Kiernan, 2008).…”

Supra-organization and optical anisotropies of the extracellular matrix in the amniotic membrane and limbal stroma before and after explant culture

“…However, in this study, the collagen fibers formed a complex with Ponceau SS, an azo dye that aligns its resonating electrons in parallel with the collagen, amplifying the birefringence signal [23,37]. The macromolecular complexes formed by the interaction of Ponceau SS with collagen have characteristics of photonic material [45], and can provide a basis for understanding the relationships between mesophase organization and functionality in biological structures [37,45].…”

“…Histological sections were stained with Ponceau SS acidic solution (Sigma-Aldrich), pH 2.5, for 3 min as previously suggested [37]. The evaluations were conducted on an Olympus BX-53P polarized light microscope (Olympus, Tokyo, Japan) equipped with 10 × and 40 × UPLFLN objectives, a 546-nm monochromatic band-pass filter, and a halogen lamp.…”