A new review published in Discover Surfaces maps the rapidly evolving field of nanoscale optical biosensing and concludes that these technologies are steadily moving from laboratory benches toward real clinical use in cancer detection. The review, led by Gundala Vasanthi, Balaji Ramachandran, Yesudasu Vasimalla and Santosh Kumar, surveys a decade of progress from 2015 to 2024 across surface plasmon resonance (SPR), fluorescence, Raman and surface-enhanced Raman scattering (SERS), optical fiber, photonic crystal and interferometric sensing platforms. Its central message is cautiously optimistic: optical biosensors can now detect cancer biomarkers at femtomolar and even attomolar concentrations, but only a handful of platforms have accumulated the large, prospective clinical evidence needed for routine adoption.
The urgency behind this work is stark. The review cites global statistics showing 20 million new cancer cases and 9.7 million cancer deaths in 2022, with the burden projected to rise nearly threefold by 2050 without better preventive and diagnostic measures. Lung cancer remains the deadliest malignancy, with an estimated 2.5 million new cases and 1.8 million deaths annually. The authors emphasize that stage I cancers often release biomarkers at levels below the sensitivity thresholds of conventional clinical assays, contributing to late diagnoses and poor treatment responses. Traditional methods such as medical imaging, histopathology, ELISA and PCR remain the backbone of cancer diagnosis, but they are frequently invasive, expensive, infrastructure-dependent and slow to deliver results.
At the heart of the review is a quantitative benchmarking exercise comparing platforms across five indicators: limit of detection, clinical sensitivity, clinical specificity, response time and multiplexing capacity. SPR and interferometric platforms emerge as the most mature, with reproducible analytical performance in the femtomolar to picomolar range, clinical sensitivity of 70 to 95 percent for protein biomarkers, and turnaround times of minutes. SERS and Raman systems achieve the lowest detection limits, down to attomolar and in some cases single-molecule levels, thanks to plasmonic hot spots generated by gold and silver nanostructures, though large prospective studies remain lacking. Fluorescence and quantum-dot assays offer highly multiplexable workflows with reported sensitivities of 65 to 97 percent, while photonic crystal and microcavity sensors show impressive device-level sensitivity but remain mostly at mid-level technology readiness with little clinical validation.
SPR technology, the most developed of these platforms, detects biomarkers by measuring refractive index changes at a metal-dielectric interface when biomolecules bind to a functionalized gold or silver surface. The review details how different excitation configurations trade off sensitivity against miniaturization: the Kretschmann prism geometry offers the highest sensitivity for low-concentration biomolecules, waveguide-based coupling provides stronger mode confinement and better signal-to-noise, and grating-coupled designs enable compact, prism-free devices at slightly reduced sensitivity. These label-free, real-time systems have been applied to screen cancer biomarkers including PSA, AFP, HER2 and CEA, and the review places commercially supported SPR platforms at technology readiness levels 8 to 9.
Nanomaterials are the engine driving much of this performance. Gold and silver nanoparticles exploit localized surface plasmon resonance to concentrate electromagnetic fields at the nanoscale, dramatically boosting signal intensity in SPR, LSPR and SERS assays. Graphene and other two-dimensional materials such as molybdenum disulfide, tungsten disulfide and tungsten diselenide offer atomic thickness, vast surface area and tunable electronic properties that enhance fluorescence, Raman scattering and refractive index sensitivity. Quantum dots and carbon dots contribute size-tunable emission, high photostability and resistance to photobleaching, making them valuable for multiplexed detection of proteins, nucleic acids and circulating tumor cells. Metal oxide nanostructures including zinc oxide, titanium dioxide and iron oxide provide chemical stability and favorable charge transport for hybrid sensing structures.
But the review is unsparing about the pitfalls. Silver nanostructures can generate reactive oxygen species under optical excitation, and cadmium-based quantum dots can release toxic heavy-metal ions as they photodegrade. Graphene oxide suffers from non-uniform oxidation and flake-size variability that undermines reproducible surface chemistry. Batch-to-batch polydispersity in nanoparticle synthesis directly affects resonance wavelengths and assay reproducibility. The authors argue that clinical-grade nanomaterial manufacturing demands tight control over polydispersity, ligand density, endotoxin removal and purification, along with toxicity testing covering hemolysis, viability, reactive oxygen species measurement and illumination-dependent cytotoxicity.
Perhaps the most striking recent advances involve artificial intelligence fused with plasmonic sensing. The review highlights an AI-based plasmonic sensor that identifies colorectal cancer DNA methylation patterns at approximately 25 femograms per milliliter in blood, with a reported detection accuracy of about 99 percent across stages I to IV, outperforming conventional qPCR in clinical pilot studies. In comparative terms, that sensitivity limit sits well below the roughly 1 picogram per milliliter typical of PCR, and SPR-based HER2 sensing has reportedly reached around 10 femograms per milliliter, exceeding ELISA. Machine learning is also being woven into wearable patches to denoise signals, remove motion artifacts and flag subtle cancer-relevant anomalies in continuous monitoring data, while explainable AI and federated learning techniques are being developed to address clinical interpretability and data privacy.
New device architectures are pushing sensing out of the laboratory entirely. A wireless multicolour fluorescence CMOS implant has demonstrated the ability to image immune cell activity through five centimeters of tissue while being powered and transmitting data wirelessly. Wearable imaging patches using magnetoelectric nanoparticles with machine learning interpretation are in early clinical prototyping. Hybrid nanophotonic-microfluidic lab-on-chip devices now detect dilute analytes in blood with microliter sample volumes, and multiplexed lab-on-chip immunoassays have achieved detection limits below 1 picogram per milliliter for PSA and HER2. A plasmonic nanostructure and microfluidic lab-on-chip has shown continuous monitoring of PSA, CA125 and HER2 in microliter blood samples, delivering a panel-based readout in 20 minutes, while Raman nanotag multiplexing has enabled simultaneous detection of six cancer biomarkers.
The clinical evidence picture is uneven, however. The review finds that Raman and SERS-based detectors have accumulated the most momentum toward validation, including an FDA-sponsored multisite study of a handheld Raman device for skin and breast cancer screening and retrospective multi-cohort SERS studies involving hundreds of patients with breast, lung, colorectal and ovarian cancers. Fluorescence-based intraoperative imaging systems have been evaluated in large multicenter populations and have progressed to Phase II and III trials in breast, ovarian and glioma cancers. By contrast, liquid-biopsy-oriented SPR, LSPR, interferometric, fiber-optic and photonic crystal platforms remain largely confined to pilot studies of tens to hundreds of patients, and no SPR or LSPR liquid biopsy platform has yet received FDA approval or CE marking, though early prototypes have shown high diagnostic accuracy for PSA, CEA, CA-125 and circulating tumor DNA in small pilot groups.
The authors also stress that impressive laboratory detection limits frequently collapse in real-world biofluids. Blood, plasma, serum, saliva and urine are laden with proteins, lipids, salts and metabolites that cause non-specific adsorption, autofluorescence and optical scattering, particularly problematic at the femtogram-per-milliliter concentrations typical of early-stage disease. Preanalytical variables such as hemolysis, anticoagulant choice, storage temperature and freeze-thaw cycles can dramatically alter biomarker integrity and optical readouts. The review calls for standardized operating procedures, inter-laboratory proficiency testing, on-chip reference channels, multicenter prospective longitudinal trials and unified reporting standards as prerequisites for translation. It projects that SPR, fluorescence and Raman/SERS platforms, backed by regulatory experience, will see clinical adoption within a five-to-ten-year window in liquid biopsy screening, intraoperative guidance and therapy surveillance, while more complex photonic crystal and two-dimensional material systems will follow as fabrication scalability and long-term clinical validation mature.
Subject of Research: Optical nanoscale biosensor technologies for early cancer detection and diagnosis
Article Title: Recent progress in nanoscale optical sensor technologies for early cancer detection and diagnosis
Article References: Vasanthi, G., Ramachandran, B., Vasimalla, Y., & Kumar, S. (2026). Recent progress in nanoscale optical sensor technologies for early cancer detection and diagnosis. Discover Surfaces, 1(1), Article 6. https://doi.org/10.1007/s44507-026-00007-5
Image Credits: AI Generated
DOI: 10.1007/s44507-026-00007-5
Keywords: optical biosensors, cancer diagnostics, surface plasmon resonance, SERS, nanomaterials, liquid biopsy, quantum dots, early detection, AI-assisted diagnostics, lab-on-chip, biomarkers, technology readiness
News Source: Nathaniel Bowman. (October 28, 2026). Optical Nanosensors Edge Closer to Catching Cancer at Its Earliest Stages. Scienmag.
