Fig 3 - available via license: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Content may be subject to copyright.
1 H/ 31 P MRI in Manduca sexta caterpillars in vivo and degradation of the agents (FOV 20x20 mm 2 , 9.4 T). (A) Photograph of the M. sexta caterpillar, orange square denotes the region shown on MR images. (B) 1 H MRI showing the anatomy of caterpillar. (C) 31 P MRI overlaid on 1 H MRI image after the injection of the agents into the dorsal vessel (heart). PPnGRAD agents circulate in hemolymph. (D) After 24 h the agents can still be found back in the circulation, as expected for micelles with stealth surface. (E and F) Degradation of PPnGRAD in vivo. (E) After injection of the agents into the gut, overlay of 31 P MRI on 1 H MRI image confirms their localization. (F) 31 P NMR spectrum of feces (D2O, 158 MHz) collected after 24 h shows the characteristic signals of degradation products confirming that PPnGRAD agents are biodegradable.
Source publication
Imaging and tracing materials inside the body is essential to develop functional materials for personalized therapies, including drug delivering nanocarriers and artificial tissues. Magnetic Resonance Imaging (MRI) is a key whole-body imaging technology, where heteronuclear MRI agents enable background-free, quantitative labeling. However, many MRI...
Contexts in source publication
Context 1
... encouraging 31 P MRI in vitro, we confirmed that 31 P mCSSI imaging of gradient micelles PPnGRAD works in vivo. We used Manduca sexta caterpillars (Fig. 3A); M. sexta has a hemolymph volume of 1-2 mL, comparable to the blood volume of mice, making it a suitable, alternative animal model instead of mammalians according 3R principles of animal-friendly testing. To image the agents during the circulation in hemolymph (blood of insects), the agents were injected into the dorsal vessel of the ...
Context 2
... animals tolerated these injections well and continued their development as usual. The micelles distributed in the hemolymph homogenously after injection, as shown by overlaying the morphological 1 H MRI and 31 P mCSSI images (Fig. 3C Fig. S11, TAcq 17 min). After 24 h, the 31 P-signal was still located in the hemolymph and decreased only slightly (Fig. 3C). We assume that the previously reported stealth effect of EtPPn 31 prolonged the circulation time; thus, only a small fraction was excreted or ...
Context 3
... we confirmed the biodegradation of the PPnGRAD micelles in the M. Sexta model. The agents were directly injected into the anterior part of the gut; 31 P and 1 H MRI confirmed the localization of the agents into the target organ (Fig. 3E). After 24 h, we collected the feces of these animals and used 31 P NMR spectroscopy to analyze the degradation products (Fig. ...
Context 4
... the biodegradation of the PPnGRAD micelles in the M. Sexta model. The agents were directly injected into the anterior part of the gut; 31 P and 1 H MRI confirmed the localization of the agents into the target organ (Fig. 3E). After 24 h, we collected the feces of these animals and used 31 P NMR spectroscopy to analyze the degradation products (Fig. ...
Similar publications
In vivo monitoring of polymers is crucial for drug delivery and tissue regeneration. Magnetic resonance imaging (MRI) is a whole-body imaging technique, and heteronuclear MRI allows quantitative imaging. However, MRI agents can result in environmental pollution and organ accumulation. To address this, we introduce biocompatible and biodegradable po...
Citations
... a General structures of the polyphosphoester subclasses (phosphates, side-chain phosphonates, in-chain phosphonate, thiophosphate), b synthesis of various gradient copolymers from different polyphosphoester classes (side-chain phosphonates (1-3), phosphates (4, 5), thiophosphate (6), in-chain phosphonate (7). degradation 16 , and further functionalities, making them interesting candidates for new degradable theranostics 17 . ...
... In Fig. 6c, the T 1 times of each comonomer in the corresponding copolymers are plotted. In general, the hydrophobic monomers show shorter relaxation times, similar to our earlier results 17 . As the hydrophobic part of the copolymer is expected to form a core of a micellar structure, the higher density of polymer chains in the assembled part leads to lower mobility and, consequently, to a faster relaxation 17 . ...
... In general, the hydrophobic monomers show shorter relaxation times, similar to our earlier results 17 . As the hydrophobic part of the copolymer is expected to form a core of a micellar structure, the higher density of polymer chains in the assembled part leads to lower mobility and, consequently, to a faster relaxation 17 . Similarly, T 2 times are shown in Fig. 6d. ...
Polyphosphoesters (PPEs) are used in tissue engineering and drug delivery, as polyelectrolytes, and flame-retardants. Mostly polyphosphates have been investigated but copolymers involving different PPE subclasses have been rarely explored and the reactivity ratios of different cyclic phospholanes have not been reported. We synthesized binary and ternary PPE copolymers using cyclic comonomers, including side-chain phosphonates, phosphates, thiophosphate, and in-chain phosphonates, through organocatalyzed ring-opening copolymerization. Reactivity ratios were determined for all cases, including ternary PPE copolymers, using different nonterminal models. By combining different comonomers and organocatalysts, we created gradient copolymers with adjustable amphiphilicity and microstructure. Reactivity ratios ranging from 0.02 to 44 were observed for different comonomer sets. Statistical ring-opening copolymerization enabled the synthesis of amphiphilic gradient copolymers in a one-pot procedure, exhibiting tunable interfacial and magnetic resonance imaging (MRI) properties. These copolymers self-assembled in aqueous solutions, 31 P MRI imaging confirmed their potential as MRI-traceable nanostructures. This systematic study expands the possibilities of PPE-copolymers for drug delivery and theranostics.
