Geng Report: Concerns regarding statistical rigor and data consistency in 'Transformative Antioxidant Testing of Chinese Herbal Medicine Polysaccharides with Colorimetric Assays Using Fe/NC Nanozymes' (ACS Appl. Nano Mater. 2025, 8, 8918−8926)

Academic fraud report · Geng Detector

Summary

This report assigns a verdict of 'Questionable' (🟡) to the paper by Liping Sun et al. published in ACS Applied Nano Materials (DOI: 10.1021/acsanm.5c01031). Three main concerns are raised. First, comparative analyses between the developed sensor and a commercial DPPH kit (Figure 4G) lack basic statistical reporting: no error bars (SD/SEM), sample sizes (n), or significance test values (p, t, F) are provided to support the claim of 'no significant difference.' Second, the reported linear correlation coefficients for polysaccharide detection appear marginal, particularly PNP at R² = 0.9559 and SMP at R² = 0.9779, raising concerns about curve fitting and possible cherry-picking of linear-range data points. Third, a logical inconsistency exists between sensitivity ranking (LOD of 0.38 μg/mL for LBP vs. 5.44 and 5.14 μg/mL for SMP and PNP) and the reported antioxidant potency at 500 μg/mL (SMP > LBP > PNP), suggesting possible nonlinear dose-response or data selection issues. No image manipulation was flagged. Verdict is provisional pending raw data review.

Verdict

🟡 Questionable — The paper raises statistical reporting and data-consistency concerns but does not meet the threshold for confirmed misconduct. Confidence is moderate; findings should be verified against raw data.

Key findings

Missing statistical support for comparative claims: Figure 4G and the surrounding text claim no significant difference between the developed sensor and a commercial DPPH kit, but no error bars (SD/SEM), replicate counts (n), p-values, t-values, or F-values are reported anywhere in the manuscript.
Marginal linear correlation coefficients: R² values of 0.9559 (PNP) and 0.9779 (SMP) are reported; in colorimetric sensor work, R² below 0.99 typically indicates a poor linear fit and may suggest selective inclusion of data points.
Anomalous LOD gap between similar analytes: LBP shows an LOD of 0.38 μg/mL, whereas SMP and PNP show LODs of 5.44 and 5.14 μg/mL respectively — a greater-than-ten-fold sensitivity gap between structurally related polysaccharides tested on the same nanozyme platform.
Apparent logical inconsistency between sensitivity and potency ranking: Although LBP exhibits the lowest LOD and widest linear range (starting at 3.91), the text states that at 500 μg/mL the antioxidant ranking is SMP > LBP > PNP. The reversal between sensitivity metrics and high-concentration performance is not explained mechanistically.

Evidence highlights

DOI: 10.1021/acsanm.5c01031
Journal: ACS Appl. Nano Mater. 2025, 8, 8918−8926
Authors: Liping Sun, Li Jin, Jianhua Shu, Jili Hu, Yunxia Yin, Zhi Li, Lei Wang, Hongxing Kan
Figure 4G: claim of 'no significant difference' vs. commercial DPPH kit, unsupported by reported statistics.
Figure 4C–E / Section 3.3: reported R² = 0.9559 (PNP), 0.9779 (SMP); LODs of 0.38 μg/mL (LBP), 5.44 μg/mL (SMP), 5.14 μg/mL (PNP).
Section 3.3: stated ranking at 500 μg mL⁻¹ is SMP > LBP > PNP.

Notes

These observations are statistical/reporting concerns rather than confirmed evidence of fabrication. The original absorbance scatter plots and statistical analysis outputs (Section 3.3 and 3.4) should be requested from the authors to confirm or refute the issues raised. No image manipulation concerns were identified in this report. The level of statistical omission noted is unfortunately common in materials-science publications but falls short of the rigor expected in analytical-chemistry and sensor literature.