Disclosed is a spotter device and methods for the formation of microassays, biochips, biosensors, and cell cultures. The spotter may be used to deposit highly concentrated spots of protein or other materials on a microarray slide, wafer, or other surface. It may also be used to perform various chemistry steps on the same spots. The spotter increases the surface density of substances at each spot by directing a flow the desired substance (or a solution thereof) over the spot area until surface saturation is accomplished. The spotter may be loaded by well plate handling equipment. The spotter uses wells, microfluidic conduits, and orifices to deposit proteins, other biomolecules, or chemicals on a spot on a separate surface. Each orifice is connected to two wells via microconduits. When the spotter contacts a surface, a seal is formed between the orifices and the surface. The same or different substances may be flowed across each orifice. Any number of orifices may be incorporated into a spotter. The spotter is particularly useful for depositing proteins in high concentrations on a surface, since the spotter may be placed on a surface for an extended period of time.