Fluorescently-tagged polyamines for the staining of siliceous materials

Abstract

Siliceous frustules of diatom algae contain unique long-chain polyamines, including those having more than six nitrogen atoms. These polyamines participate in the formation of the siliceous frustules of the diatoms but their precise physiological role is not clear. The main hypotheses include formation of a polyamine and polyphosphate supramolecular matrix. We have synthesized novel fluorescent dyes from a synthetic oligomeric mixture of polyamines and the fluorophore 7-nitro-2,1,3-benzoxadiazole. The long polyamine chain ensures the high affinity of these dyes to silica, which allows their application in the staining of siliceous materials, such as valves of diatom algae and fossilized samples from sediments. The fluorescently stained diatom valves were found to be promising liquid flow tracers in hydrodynamic tests. Furthermore, complexation of the polyamine component of the dyes with carbonic polymeric acids results in changes to the visible spectrum of the fluorophore, which allows study of the stability of the complex vs the length of the polyamine chain. Using poly (vinyl phosphonic acid) as a model for phosphate functionality in silaffins (a potential matrix in the formation of biogenic silica) little complexation with the polyamine fluorophores was observed, bringing into question the role of a polyamine - polymeric phosphate matrix in biosilicification.

Therapeutic Applications of Phytoplankton, with an Emphasis on Diatoms and Coccolithophores

“…Extracted siliceous frustules of Aulacoseira sp., Cyclotella sp., Ulnaria ferefusiformis Kulikovskiy, and Stephanodiscus meyerii Genkal et Popovsk diatoms can be mixed with NBD‐LCPA to produce fluorescently labeled diatoms. NBD‐LCPA fluorescently labeled diatoms showed higher staining activity than that of the previously described non‐LCPA‐based fluorophores …”

“…Polyamines naturally occur in living diatoms, therefore a high binding efficiency is expected for LCPAs to silica . LCPA can be obtained by condensation of short‐chain polyamines with 1,3‐dibrompropane.…”

Polyamines in Microalgae: Something Borrowed, Something New

“…Even after thousands of years, polyamines could be still measured in the siliceous frustules buried in marine and lake sediments [64,65]. The polyamines found in the frustule are mainly LCPAs [66,67,68,69]. Interestingly, LCPAs are also found in sponge bone needles that are also composed of silicon dioxide [70].…”

“…In fact, they have high affinity to siliceous material and promote the precipitation of silica [44,45,46,47]. Several fluorescently-tagged polyamines were synthesized as a staining dye for the study of biomineralization process of the diatom cell wall [67]. Recently, Pawolski et al has demonstrated that LCPAs are the key component for in vitro synthesis silica patterns in diatom-like hierarchically porous plate [47].…”

Vital fluorescent dyes for study of silicifying organisms

“…A set of new dyes containing relatively long polyamine substituents (≥3 nitrogen atoms) was prepared in this work (Fig. 7, Annenkov et al, 2018). The longer polyamine chain in these dyes increase activity in association with silica due to coordination with surface silanol groups.…”