Objective clustering protocol for single-molecule data: A lifetime vs. intensity study

Fuente: arXiv
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Main Authors: Lovemore, Michael, Botha, Joshua, van Heerden, Bertus, Kruger, Tjaart
Format: Preprint
Published: 2025
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author Lovemore, Michael
Botha, Joshua
van Heerden, Bertus
Kruger, Tjaart
author_facet Lovemore, Michael
Botha, Joshua
van Heerden, Bertus
Kruger, Tjaart
contents Single-molecule spectroscopy (SMS) is an exceptionally sensitive technique, but its inherently limited photon budget produces noisy data that can readily lead to subjective analyses, fitting errors, and reduced statistical power, obscuring true subpopulations and their dynamics. Here, we present an unbiased, objective method to cluster two-dimensional single-molecule data and demonstrate it on fluorescence lifetime--intensity correlations. The clustering method is based on Gaussian mixture modeling, with the optimal number of clusters determined through {information criteria (the Akaike and Bayesian information criteria and integrated completed likelihood) and supplemented by cluster quality metrics such as average cluster tightness and the fraction of points outside confidence ellipses, which guide the selection of statistically robust and physically meaningful clusters. The protocol was benchmarked on simulated datasets spanning clean, smeared, and noisy overlap-limited regimes, and applied to experimental data from Alexa Fluor 647 and QD 605. This approach reliably recovers relevant subpopulations even in the presence of noise and overlapping distributions, providing an objective framework for analyzing single-molecule heterogeneity, with limitations arising primarily under severe geometric overlap or extreme state-occupancy imbalance where distinct populations are no longer separable.
format Preprint
id arxiv_https___arxiv_org_abs_2510_05665
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Objective clustering protocol for single-molecule data: A lifetime vs. intensity study
Lovemore, Michael
Botha, Joshua
van Heerden, Bertus
Kruger, Tjaart
Biological Physics
Single-molecule spectroscopy (SMS) is an exceptionally sensitive technique, but its inherently limited photon budget produces noisy data that can readily lead to subjective analyses, fitting errors, and reduced statistical power, obscuring true subpopulations and their dynamics. Here, we present an unbiased, objective method to cluster two-dimensional single-molecule data and demonstrate it on fluorescence lifetime--intensity correlations. The clustering method is based on Gaussian mixture modeling, with the optimal number of clusters determined through {information criteria (the Akaike and Bayesian information criteria and integrated completed likelihood) and supplemented by cluster quality metrics such as average cluster tightness and the fraction of points outside confidence ellipses, which guide the selection of statistically robust and physically meaningful clusters. The protocol was benchmarked on simulated datasets spanning clean, smeared, and noisy overlap-limited regimes, and applied to experimental data from Alexa Fluor 647 and QD 605. This approach reliably recovers relevant subpopulations even in the presence of noise and overlapping distributions, providing an objective framework for analyzing single-molecule heterogeneity, with limitations arising primarily under severe geometric overlap or extreme state-occupancy imbalance where distinct populations are no longer separable.
title Objective clustering protocol for single-molecule data: A lifetime vs. intensity study
topic Biological Physics
url https://arxiv.org/abs/2510.05665