PMID- 32233419 OWN - NLM STAT- PubMed-not-MEDLINE DCOM- 20200818 LR - 20230816 IS - 1520-6882 (Electronic) IS - 0003-2700 (Print) IS - 0003-2700 (Linking) VI - 92 IP - 9 DP - 2020 May 5 TI - ToF-SIMS and Machine Learning for Single-Pixel Molecular Discrimination of an Acrylate Polymer Microarray. PG - 6587-6597 LID - 10.1021/acs.analchem.0c00349 [doi] AB - Combinatorial approaches to materials discovery offer promising potential for the rapid development of novel polymer systems. Polymer microarrays enable the high-throughput comparison of material physical and chemical properties-such as surface chemistry and properties like cell attachment or protein adsorption-in order to identify correlations that can progress materials development. A challenge for this approach is to accurately discriminate between highly similar polymer chemistries or identify heterogeneities within individual polymer spots. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) offers unique potential in this regard, capable of describing the chemistry associated with the outermost layer of a sample with high spatial resolution and chemical sensitivity. However, this comes at the cost of generating large scale, complex hyperspectral imaging data sets. We have demonstrated previously that machine learning is a powerful tool for interpreting ToF-SIMS images, describing a method for color-tagging the output of a self-organizing map (SOM). This reduces the entire hyperspectral data set to a single reconstructed color similarity map, in which the spectral similarity between pixels is represented by color similarity in the map. Here, we apply the same methodology to a ToF-SIMS image of a printed polymer microarray for the first time. We report complete, single-pixel molecular discrimination of the 70 unique homopolymer spots on the array while also identifying intraspot heterogeneities thought to be related to intermixing of the polymer and the pHEMA coating. In this way, we show that the SOM can identify layers of similarity and clusters in the data, both with respect to polymer backbone structures and their individual side groups. Finally, we relate the output of the SOM analysis with fluorescence data from polymer-protein adsorption studies, highlighting how polymer performance can be visualized within the context of the global topology of the data set. FAU - Gardner, Wil AU - Gardner W AD - Centre for Materials and Surface Science and Department of Chemistry and Physics, La Trobe University, Melbourne, Victoria 3086, Australia. AD - La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, Victoria 3086, Australia. AD - CSIRO Manufacturing, Clayton, Victoria 3168, Australia. FAU - Hook, Andrew L AU - Hook AL AD - Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, U.K. FAU - Alexander, Morgan R AU - Alexander MR AD - Advanced Materials and Healthcare Technologies, School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, U.K. FAU - Ballabio, Davide AU - Ballabio D AUID- ORCID: 0000-0002-5748-147X AD - Milano Chemometrics and QSAR Research Group, Department of Earth and Environmental Sciences, University of Milano-Bicocca, P.zza della Scienza 1, 20126 Milano, Italy. FAU - Cutts, Suzanne M AU - Cutts SM AUID- ORCID: 0000-0002-6055-0405 AD - La Trobe Institute for Molecular Sciences, La Trobe University, Melbourne, Victoria 3086, Australia. FAU - Muir, Benjamin W AU - Muir BW AUID- ORCID: 0000-0002-8858-3217 AD - CSIRO Manufacturing, Clayton, Victoria 3168, Australia. FAU - Pigram, Paul J AU - Pigram PJ AUID- ORCID: 0000-0002-7972-492X AD - Centre for Materials and Surface Science and Department of Chemistry and Physics, La Trobe University, Melbourne, Victoria 3086, Australia. LA - eng GR - WT_/Wellcome Trust/United Kingdom GR - 103882/WT_/Wellcome Trust/United Kingdom GR - 103884/WT_/Wellcome Trust/United Kingdom GR - 103882/WT_/Wellcome Trust/United Kingdom PT - Journal Article PT - Research Support, Non-U.S. Gov't DEP - 20200413 PL - United States TA - Anal Chem JT - Analytical chemistry JID - 0370536 SB - IM PMC - PMC7611022 MID - EMS127622 COIS- Conflicts of interest The authors declare no conflicts of interest. EDAT- 2020/04/03 06:00 MHDA- 2020/04/03 06:01 PMCR- 2021/06/21 CRDT- 2020/04/03 06:00 PHST- 2020/04/03 06:00 [pubmed] PHST- 2020/04/03 06:01 [medline] PHST- 2020/04/03 06:00 [entrez] PHST- 2021/06/21 00:00 [pmc-release] AID - 10.1021/acs.analchem.0c00349 [doi] PST - ppublish SO - Anal Chem. 2020 May 5;92(9):6587-6597. doi: 10.1021/acs.analchem.0c00349. Epub 2020 Apr 13.