A method of collecting and in situ processing of aspirated fat tissue sampled from a human patient. The method involves providing a surgeon with a powered-assisted hand-held fat tissue aspiration instrument having a cannula, and a fat tissue sampling, processing and collection device installed between the power-assisted fat aspiration instrument and a vacuum source. The fat tissue sampling, collection and processing device includes a suction plate, mounted within a collection chamber, and having multiple hollow projections for supporting the open proximal ends of a plurality of tissue collection and processing tubes, wherein each tissue collection and processing tube has micro-pores formed in the side walls thereof, and its distal end opening is capped. Aspirated fat tissue is collected in a selected tissue collection and processing tube, while allowing fluid to flow and filter through the micro-pores as aspirated fat tissue flows through the cannula of the fat aspiration instrument.
