An improved pin array assembly and method of manufacture of the pin array assembly are provided. A pin array assembly includes a single crystal silicon wafer. The single crystal silicon wafer is formed to define a base and an array of pins. Each of the pins has a shaft and a tip surface. The pin shaft is hydrophobic and the pin tip surface is hydrophilic. The method of manufacture of the pin array assembly includes the steps of forming an initial shape of a single crystal silicon wafer to define a base and an array of pins. The initial shape of a single crystal silicon wafer is etched and the array of pins is polished. The step of forming an initial shape of a single crystal silicon wafer to define a base and an array of pins includes mechanically sawing the single crystal silicon wafer to define a base and an array of pins. Chemical treatment of the pins is performed to make the shaft of the pins hydrophobic and to make the pin tip surfaces hydrophilic.