Patent ID: 8252337

Claim:
A composition comprising: a positively charged mesoporous silica nanoparticle (MSN), which comprises: (a) a silica matrix, the entire substance of which comprises a plurality of silanol (Si—OH) and quaternary ammonium functional groups wherein the quaternary ammonium functional groups are from an organosilane quaternary ammonium compound comprising the formula: wherein R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 and R 8 are the same or different; R 1 , R 2 , and R 3 are, independently of each other, selected from the group consisting of alkyl and alkene groups; R 4 , R 5 , R 6 , R 7 and R 8 are, independently of each other, selected from the group consisting of alkyl, ammonium, and hydrogen; n is an integer and 20≧n≧1; and (b) an array of pores and/or nanochannels in the matrix, each pore and/or nanochannel having a surface lining the wall thereof; wherein the surface lining the wall of each pore and/or nanochannel comprises a plurality of silanol (Si—OH) and quaternary ammonium functional groups, and the positively charged MSN, in the absence of adsorption of a negatively charged compound, has a total pore volume of no smaller than 0.967 cm 3 g −1 .