NIR Aquaphotomics Blood Test Uses Light With Water Patterns to Detect Esophageal Cancer

Rapid Detection Using NIR Spectroscopy

Esophageal cancer (EC) is among the deadliest cancers worldwide, with China accounting for nearly half of all new cases and deaths. Esophageal squamous cell carcinoma (ESCC) represents roughly 90% of these cases, with early detection being critical to improving survival rates. Traditional screening methods like endoscopy are time-consuming, costly, and rely on medical expertise, limiting their accessibility, especially in rural regions with high disease prevalence (1).

To address this, a team of researchers led by Q. Lu and L. Li at Zhejiang Cancer Hospital explored a new approach: combining near-infrared (NIR) spectroscopy with aquaphotomics for rapid ESCC screening. The study, published in Talanta, included contributions from W. Liang, G. Xu, J. Zhu, X. Ma, W. Tian, L. Gao, M. Tian, Z. Chen, and H. Zang (1).

NIR aquaphotomics blood test uses light with water patterns © By Aldona -chronicles-stock.adobe.com

Plasma Samples and Spectral Analysis

The study analyzed plasma samples from 278 ESCC patients (238 males, 40 females; mean age 60.76 ± 7.26 years) and 50 healthy controls (43 males, 7 females; mean age 60.10 ± 8.15 years). Approval was granted by the Ethics Committee of Zhejiang Cancer Hospital (Document Number: IRB-2023-757 (IIT)) (1).

Original NIR spectra revealed prominent absorption bands at 1300–1600 nm, 1850–2150 nm, and other regions dominated by water. Differences in absorption intensity between healthy and ESCC samples were subtle but detectable, reflecting changes in plasma water composition linked to disease progression (1).

Aquaphotomics and Water Patterns

Aquaphotomics leverages the NIR absorption characteristics of water molecules to detect subtle biochemical changes. In this study, principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were used to identify water matrix coordinates (WAMACS), which define the water absorption spectrum pattern (WASP). These patterns were visualized on aquagrams, revealing distinct differences between healthy and ESCC plasma samples (1).

Healthy plasma exhibited strong water absorption peaks at 1460 nm, 1480 nm, and 1494 nm, corresponding to strongly hydrogen-bonded water. ESCC plasma showed additional absorption in regions associated with weak hydrogen bonds (1434 nm) and free water (1390 nm), highlighting structural water changes linked to disease (1).

How Aquaphotomics Works

Aquaphotomics is a spectroscopic approach that interprets biological information through the interaction of water with NIR light. In this study, plasma samples from healthy individuals and ESCC patients were analyzed in the NIR region, focusing on the first overtone of water absorption (1300–1600 nm). Because plasma is a water-rich medium, its NIR spectrum is dominated by broad water absorption bands. Instead of treating this water signal as background noise, aquaphotomics extracts diagnostic information by analyzing subtle variations in water’s hydrogen bonding structures. Specific wavelengths, called water matrix coordinates (WAMACS), are identified and mapped into an aquagram, producing a water absorption spectrum pattern (WASP) that characterizes the biological state of the sample (1–3).

For ESCC detection, principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) were applied to the NIR spectra to identify diagnostic WAMACS. The aquaphotomic analysis revealed that healthy plasma showed strong signals at 1460, 1480, and 1494 nm, corresponding to water with strong hydrogen bonding. In contrast, ESCC plasma exhibited significant changes in regions associated with weakly bonded water (1434 nm) and free water (1390 nm), reflecting altered water molecular structures linked to disease processes. By tracking these specific changes in water absorption, aquaphotomics provided a biomarker-based fingerprint of ESCC, enabling the creation of a screening model that achieved high accuracy and sensitivity (1–3).

Screening Accuracy and Clinical Implications

The PLS-DA-based screening model achieved an accuracy of 95.12% and precision of 97.10%, with sensitivity and specificity rates of 97.10% and 84.62%, respectively. The area under the curve (AUC) was 0.9064, demonstrating strong discriminatory capability (1).

By monitoring WASP changes, this non-invasive method offers a feasible strategy for large-scale ESCC screening, particularly in resource-limited regions. Plasma-based NIR spectroscopy combined with aquaphotomics could complement existing techniques, providing faster results without the need for endoscopy or biopsy (1).

Next Steps

The study suggests that water absorption patterns in plasma may serve as a reliable biomarker for ESCC, opening opportunities for broader clinical application. Further research could explore larger cohorts and integrate this approach with other diagnostic tools to enhance early detection rates and patient outcomes (1).

References
(1) Lu, Q.; Li, L.; Liang, W.; Xu, G.; Zhu, J.; Ma, X.; Tian, W.; Gao, L.; Tian, M.; Chen, Z.; Zang, H. Rapid Screening of Esophageal Squamous Cell Carcinoma by Near-Infrared Spectroscopy Combined with Aquaphotomics. Talanta 2025, 285, 127399. DOI: 10.1016/j.talanta.2024.127399

(2) Surkova, A.; Boichenko, E.; Bibikova, O.; Artyushenko, V.; Muncan, J.; Tsenkova, R. Near-Infrared Spectroscopy and Aquaphotomics in Cancer Research: A Pilot Study. J. Chemom. 2024, 38 (12), e3600. DOI: 10.1002/cem.3600

(3) Tsenkova, R.; Munćan, J.; Pollner, B.; Kovacs, Z. Essentials of Aquaphotomics and Its Chemometrics Approaches. Front. Chem. 2018, 6, 363. DOI:10.3389/fchem.2018.00363