Zacharias Janssen, with the help of his father, invented the first compound optical microscope. In doing so, he made it easier and more practical for future scientists to look at cells. This helped disprove the spontaneous generation theory because it marks the beginning of the cell theory.
Hooke discovered and named the cell while looking at a thin cork slice through a primitive microscope. While not knowing what exactly a cell was, he sparked an interest in cells that would later lead to more information about the cell. By discovering the cell, he would help start the cell theory, which now makes the spontaneous generation theory outdated.
Leeuwenhoek refined the microscope, making it 270 times more powerful. Therefore, he used his refined microscopes to view things such as pond water, yeast plants, etc.. Through his investigations, he also discovered bacteria. By refining the microscope and discovering bacteria, he assisted in making the theory that life comes from cells and not inanimate matter more prominent.
In his career, Schleiden found that all plants are made of cells. He also said that different parts of plants are made of cells. Finally, Schleiden also recognized the importance of the cell nucleus and its role in what is later to become cell division. By finding that plants are also made up of cells, Schleiden showed that all living matter comes from cells. That would mean that the theory of spontaneous generation isn't supported anymore.
A partner of Matthias Schleiden, Schwann found similar evidence to that of Schleiden's, in that all plants are made of cells. He therefore stated, "All living things are composed of cells and cell products." This statement became the cell theory for the time. Also, by stating this, he is saying that life, tissues, organs, etc... come from cells. This statement further contributed to the abandonment of the spontaneous generation theory because it doesn't comply with the theory that life comes from inanimate matter.
Virchow accepted a previously stated but unpopular theory that all cells come from the division of pre-existing cells. He then coined the term 'Omnis cellula e cellula.' This translates to 'all cells [come] from other cells'. The theory that all cells come from pre existing cells is a direct contradiction to spontaneous generation. Virchow's theory means that life comes from cells dividing and replicating, not generating out of mid-air. He also stated that diseases came from the cells of organs and tissues, and not from the tissues and organs themselves.
Louis Pasteur was the first person to actually disprove spontaneous generation. He did this in an experiment that proved that cells can only come from pre-existing cells. His experiment had dust particles of cells touch broth in a flask, which then created organisms. The organisms didn't form in the broth by itself, so this disproved spontaneous generation because it showed that the organisms came from the pre-existing cells in the dust when it touched the broth.