A major group focus is the design and selection of peptides that target amyloidogenic proteins involved in age-related diseases. Amyloid proteins are known to be important in a number of such diseases that include Alzheimer’s, Parkinson’s, Lewy Body Dementia, Huntington’s, and CJD. We use a novel in cellulo library-screening platform to select peptides that can bind amyloidogenic target proteins to sequester and detoxify them. Utimising a Protein-fragment Complementation approach (PCA), we have identified both strand and helix-based peptide antagonists of α-synuclein proteins implicated in PD and related synucleinopathies. PCA is multiplexed, making no mechanistic assumptions about the target oligomeric state or conformer populated. Rather, library members must bind to and reduce associated toxicity to become selected. Those that either generate, or fail to prevent formation of a toxic species, result in cell death or retarded cell growth rates relative to effective binders. Library members that confer the most rapid bacterial growth are then selected from the PCA by increased stringency during further competition selection. Our antagonists have been characterised using a range of biophysical and cell-based approaches and been downsized / refined using truncation, alanine-scanning, and incorporation of structure-inducing constraints and non-natural sequences. Our work in this area is currently funded by an Alzheimer’s Research UK Major Project Award.