To 2.75 ppm at pH on Figure ofisthe crucial shift ofBut uponfrom
To 2.75 ppm at pH on Figure ofisthe important shift ofBut uponfrom 3.2 ppm at pH amine group is changed 12. COSY spectra recorded at each and every pH enables the disappear. Nevertheless,of those amide group, this shifting with pH must confirming in the belonging what may be o peaks to PEG (Figure S1). Since it is exactly the behaviour observed totally free PEG [4],two.75 ppm a on Figure 3 is an critical shift of this peak from 3.2 ppm at pH six to this 1st study enables therefore to conclude that most of the present PEG is totally free in resolution. It COSY spectra recorded at every single pH allows the confirming on the belonging of the does, nonetheless, not prevent some PEG covalently grafted towards the silica NP from also to PEG (Figure peak corresponding for the CH2 near the amide group free of charge too modest becoming present, the S1). As it is specifically the behaviour observed forbeing PEG [4], this fir or also broad toto conclude that most oftool to study the covalent coupling of organicdoes, n allows as a result be detected. A much more robust the present PEG is free of charge in remedy. It molecules protect against as a result needed covalently grafted to introduction, the usage of DOSY less, not on NP is some PEG and, as described inside the the silica NP from also being pre experiments is quite acceptable.peak corresponding to the CH2 near the amide group being also smaller or also bro detected. A far more robust tool to study the covalent coupling of organic molecule is as a result required and, as described within the introduction, the use of DOSY experiment appropriate.Appl. Nano 2021, two Appl. Nano 2021, 2, FOR PEER REVIEWAppl. Nano 2021, two, FOR PEER REVIEW3.1.two. NMR Evaluation on the Silica Nanoparticles Grafted with PEG and with La-p-NH2Bn-DTPA Synthesized with a Reaction Time of 24 hA reaction time of 24 h was 1st applied for the TSH Receptor Proteins Purity & Documentation grafting of PEG on the NP surfac and because the NMR characterization was enough to prove the covalent grafting (information no shown), La-p-NH2-Bn-DTPA was also grafted. An NMR spectrum was recorded on these silica NP and shows the signals CD11c/Integrin alpha X Proteins manufacturer character istic of PEG and with the La-complex (Figure S3). Even so, as observed in the preceding portion, thi doesn’t prove at all the covalent grafting of PEG and with the La-complex. A DOSY spec trum was thus recorded having a sufficiently extended diffusion time of 600 ms (Figure 3). On Figure two.2. 1D NMR spectra6.68 ithwith 2/s wasnoesypr1d on water suspensions prepared ready diffusion NMR spectra recorded 10-11 m the sequence noesypr1d on water suspensions Figure 1D coefficient of recorded the sequence obtained for each of the peaks of PEG and La with ten DD2O on the silica NP grafted with PEG at distinctive pH: in the to theLa-complex the th complex, O with the silica NP prove the PEG at various pH: of PEG and in the leading, the best, with ten 2which tends to grafted with covalent grafting in the bottom bottom tothe pH on pH is equal to 6,6, 9,surface. 12. nanoparticle 10.five and is equal to 9, ten.5 and 12.DOSY spectra had been also recorded at unique pH and the extracted diffusion coeffi cients of PEG are almost equal to that of free of charge PEG (Table 1), which tends to prove that PEG is mostly ungrafted around the NP surface and is basically adsorbed by an ionic interaction. A small raise of the diffusion coefficient of PEG with pH is often observed, which can b explained by a much less effective adsorption of PEG on the NP surface when the pH is increas ing because the amine function of PEG becomes unprotonated and so uncharged. Neverthe much less, a DOSY spectrum recorded at pH 7 using a longer diffusion time favouring sl.
