Chitin-based scaffolds are an integral part of the skeleton of the marine demosponge Ianthella basta.
The skeletons of demosponges, such as Ianthella basta, are known to be a composite material containing organic constituents. Here, we show that a filigree chitin-based scaffold is an integral component of the I. basta skeleton. These chitin-based scaffolds can be isolated from the sponge skeletons using an isolation and purification technique based on treatment with alkaline solutions. Solid-state (13)C NMR, Raman, and FT-IR spectroscopies, as well as chitinase digestion, reveal that the isolated material indeed consists of chitin. The morphology of the scaffolds has been determined by light and electron microscopy. It consists of cross-linked chitin fibers approximately 40-100 nm in diameter forming a micro-structured network. The overall shape of this network closely resembles the shape of the integer sponge skeleton. Solid-state (13)C NMR spectroscopy was used to characterize the sponge skeleton on a molecular level. The (13)C NMR signals of the chitin-based scaffolds are relatively broad, indicating a high amount of disordered chitin, possibly in the form of surface-exposed molecules. X-ray diffraction confirms that the scaffolds isolated from I. basta consist of partially disordered and loosely packed chitin with large surfaces. The spectroscopic signature of these chitin-based scaffolds is closer to that of alpha-chitin than beta-chitin.
Brunner
E
E
TU Dresden, Fachrichtung Chemie und Lebensmittelchemie, Bioanalytische Chemie, Postfach, Dresden, Germany. eike.brunner@tu-dresden.de
Ehrlich
H
H
Schupp
P
P
Hedrich
R
R
Hunoldt
S
S
Kammer
M
M
Machill
S
S
Paasch
S
S
Bazhenov
V V
VV
Kurek
D V
DV
Arnold
T
T
Brockmann
S
S
Ruhnow
M
M
Born
R
R
D000818:Animals; D002686:Chitin / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011161:Porifera / Q000033:anatomy & histology* / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D014961:X-Ray Diffraction
D002686:Chitin