Complex sentence: Researchers have discovered that smooth (non-porous) surfaces like door knobs transmit bacteria and viruses better than porous materials like paper money because porous, especially fibrous, materials absorb and trap the contagion, making it harder to contract through simple touch.
Split into simpler sentences: Researchers have discovered that smooth (non-porous) surfaces (e.g. door knobs) transmit bacteria and viruses better than porous materials (e.g. paper money). The reason is that porous, especially fibrous, materials absorb and trap the contagion, making it harder to contract through simple touch.