## 4 Conclusions  
We have successfully synthesized silica-based ionogels using a biocompatible green solvent called choline dihydrogen phosphate ionic liquid at room temperature. The role of IL in the structural, thermal, viscoelastic, and morphological properties was investigated using various analytical techniques. FT-IR spectra confirmed the formation of a silica network structure and the presence of ionic liquid in the gel matrix. TGA studies showed that the confinement of IL improves the thermal stability of the prepared gels. Moreover, the formation of a siloxane network structure was evidenced from \({}^{29}\)Si solid-state NMR spectra. The presence of ionic liquid improves the rheological properties of the silica sols. Rheological studies show that gels with tunable gelation times can be prepared by changing the amount of IL. XRD patterns clearly indicate the amorphous nature of the prepared gels. Furthermore, SEM and TEM images confirm the particle structure and porous nature of the gel samples prepared with ionic liquid. The MTT assay confirmed that all the gel samples exhibit 50% cell viability in Swiss and HaCaT cells for concentrations up to 5 \(\upmu\)g/L. Hence, these ionogels could act as an excellent host material for biological molecules. **Supplementary Materials: The following are available online at [[https://www.mdpi.com/2076-341](https://www.mdpi.com/2076-341)]([https://www.mdpi.com/2076-341](https://www.mdpi.com/2076-341)) 7/11/1/206/s1, Figure S1: FT-IR, Figure S2: TGA, Figure S3: Solid-state NMR, Figure S4: Particle size, Figure S5: XRD, and Figures S6 and S7: SAXS. **  
Figure 8: Morphological changes observed in the HaCaT cells for the treatment with gels samples for a concentration of 1 \(\upmu\)g/mL. Figure 7: Morphological changes observed in the Swiss cells for the treatment with gels samples for a concentration of 1 \(\upmu\)g/mL. **Author Contributions:** Conceptualization, S.M.K.M., S.N.J., and A.B.M. ; methodology, S.M.K.M. and R.M.S. ; formal analysis, S.M.K.M., R.M.S., and M.S.K., data curation, S.M.K.M. ; writing--original draft preparation, S.M.K.M., writing--review and editing, S.N.J., A.B.M., and B.M. ; supervision, S.N.J. and A.B.M. All authors have read and agreed to the published version of the manuscript. This research received no external funding. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** Data sharing not applicable. **Acknowledgments:** One of the authors ([PERSON]) acknowledges CSIR, India (grant number 31/6(362) /2012-EMR-I) for the Senior Research Fellowship. A.B.M. is grateful to the Indian National Academy of Engineering (INAE) and CSIR-CGCRI for INAE Distinguished Professorship. We are grateful to [PERSON] and [PERSON], CSIR-CLRI, for their support in SAXS analysis. **Conflicts of Interest:** The authors declare no conflict of interest. * [PERSON] et al. (2011) [PERSON] [PERSON]; [PERSON]; [PERSON] Ionogels, ionic liquid based hybrid materials. _Chem. Soc. Rev._**2011**, _40_, 907-925. [CrossRef] [PubMed]
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