What is the minimum charge on a particle?

1. The minimum real charge is a charge of an electron and its value is $e=1.6\times {10}^{-19}C$
2. $1.6\times {10}^{-19}C$ is the smallest charge that a particle may have.
3. A particle's charge cannot be lower than this.
4. From the Quantisation of charge property, All other charges are its integral multiple i.e $q=ne$, n is an integer