@article { ISI:000261232200039, title = {Tunable surface modification of silica nanoparticles through {\textquoteleft}click{\textquoteright} chemistry}, journal = {Current Science}, volume = {95}, number = {9}, year = {2008}, month = {NOV}, pages = {1327-1333}, publisher = {INDIAN ACAD SCIENCES}, type = {Article}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

Tuning the surface functionality of silica nanoparticles through a {\textquoteleft}click{\textquoteright} chemistry-based protocol is demonstrated. Pyrene, a fluorophore that displays excimer emission specifically at higher density/concentration is chosen for highlighting the fidelity of surface functionalization. The UV-visible absorbance of the pyrene chromophore capping the nanoparticle is used to determine the amount of pyrene units present on the surface of a silica nanoparticle.

}, keywords = {pyrene, silica nanoparticles, surface functionality, {\textquoteleft}Click{\textquoteright} chemistry}, issn = {0011-3891}, author = {Chandran, S. Prathap and Hotha, Srinivas and Bhagavatula L. V. Prasad} } @article {47087, title = {Design and synthesis of a new topical agent for halting blood loss rapidly: a multimodal chitosan-gelatin xerogel composite loaded with silica nanoparticles and calcium}, journal = {Colloids and Surfaces B-Biointerfaces}, volume = {198}, year = {2021}, month = {FEB}, pages = {111454}, type = {Article}, abstract = {

Uncontrolled hemorrhage often causes death during traumatic injuries and halting exsanguination topically is a challenge. Here, an efficient multimodal topical hemostat was developed by (i) ionically crosslinking chitosan and gelatin with sodium tripolyphosphate for (ii) fabricating a robust, highly porous xerogel by lyophilization having 86.7 \% porosity, by micro-CT and large pores similar to 30 mu m by SEM (iii) incorporating 0.5 mg synthesized silica nanoparticles (SiNPs, 120 nm size, -22 mV charge) and 2.5 mM calcium in xemgel composite that was confirmed by FTIR analysis with peaks at 3372, 986 and 788 cm(-1), respectively. XPS analysis displayed the presence of SiNPs (Si2p peak for silicon) and calcium (Ca2p1, Ca2p3 transition peaks) in the composite. Interestingly, in silico percolation simulation for composite revealed interlinked 800 mu m long-conduits predicting excellent absorption capacity and validated experimentally (640 \% of composite dry weight). The composite achieved \>16-fold improved blood clotting in vitro than commercial Celox and Gauze through multimodal interaction of its components with RBCs and platelets. The composite displayed good platelet activation and thrombin generation activities. It displayed high compressive strength (2.45 MPa) and withstood pressure during application. Moreover, xerogel composite showed high biocompatibility. In vivo application of xerogel composite to lethal femoral artery injury in rats achieved hemostasis (2.5 min) significantly faster than commercial Celox (3.3 min) and Gauze (4.6 min) and was easily removed from the wound. The gamma irradiated composite was stable till 1.5 yr. Therefore, the xerogel composite has potential for application as a rapid topical hemostatic agent.

}, keywords = {Hemostatic, Polymer, silica nanoparticles, Xerogel}, issn = {0927-7765}, doi = {10.1016/j.colsurfb.2020.111454}, author = {Patil, Gokul and Torris, Arun and Suresha, P. R. and Jadhav, Sachin and Badiger, V. Manohar and Ghormade, Vandana} } @article {49900, title = {Tailoring of rheological properties through hydrophobic interactions in silica-based liquid crystal gels}, journal = {ChemPhysChem}, volume = {26}, year = {2025}, month = {NOV }, type = {Article}, abstract = {

Modification of the intrinsic hydrophilic character of the pristine silica nanoparticles (SiNP) decorated with silanol moieties into a hydrophobic state has been of substantial interest, owing to the amenability to gelation of desirable liquids. Many reports exist on composites of SiNP with liquid crystals (LCs), an epitome of anisotropic soft matter. The fumed SiNP, unlike its precipitated counterpart, has been the preferred variety. A family of colloidal gel systems is reported, consisting of precipitated SiNP in a nematic LC, formed by substituting some native silanols with methyl, butyl, or dodecane chains. Detailed steady state and oscillatory rheological measurements are performed, along with analyses using the soft glass and other viscoelastic models. The study demonstrates that the sophisticated modified fractional models, Kelvin-Voight and Maxwell, proposed for generalized viscoelastic behavior of soft materials, are quite successful in describing these nematic gels as well. The observed nontrivial relationship between the ligand length and the strength of the gel network is elucidated on the basis of a judicious combination of the van der Waals, hydrogen bonding, and hydrophobic interactions, leading to a detailed understanding of the viscoelastic behavior of the composites and the influence of SiNP surface chemistry.

}, keywords = {fractional viscoelastic models, Hydrophobic, nematic, rheological studies, silica nanoparticles}, issn = {1439-4235}, doi = {10.1002/cphc.202500123}, author = {Sumana, S. and Chakrabortty, Pratyasha and Karumuthil, Subash Cherumannil and Prasad, S. Krishna and Prasad, Bhagavatula L. V.} }