Real-time tablet quality inspection system developed using CNT thin-film sensors
Led by Assistant Professor Kou Li, a research group in Chuo University, Japan, has developed a synergetic strategy among non-destructive terahertz (THz)-infrared (IR) photo-monitoring techniques and ultrabroadband sensitive imager sheets toward demonstrating in-line realtime multi-scale quality inspections of pharmaceutical agent pills, with a recent paper publication in Light: Science & Applications.
While non-destructive in-line monitoring at manufacturing sites is essential for safe distribution cycles of pharmaceuticals, efforts are still insufficient to develop analytical systems for detailed dynamic visualisation of foreign substances and material composition in target pills. Although spectroscopies, expected towards pharma testing, have faced technical challenges in in-line setups for bulky equipment housing, this work demonstrates compact dynamic photo-monitoring systems by selectively extracting informative irradiation-wavelengths from comprehensive optical references of target pills. This work develops a non-destructive in-line dynamic inspection system for pharma agent pills with carbon nanotube (CNT) photo-thermoelectric imagers and the associated ultrabroadband sub-terahertz (THz)-infrared (IR) multi-wavelength monitoring. The CNT imager in the proposed system functions in ultrabroadband regions over existing sensors, facilitating multi-wavelength photo-monitoring against external sub-THz-IR-irradiation. Under recent advances in the investigation of functional optical materials (e.g., gallium arsenide, vanadium oxide, graphene, polymers, transition metal dichalcogenides), CNTs play advantageous leading roles in collectively satisfying informative and efficient photo-absorption and solution-processable configurations for printable device fabrication into freely attachable thin-film imagers in pharmaceutical monitoring sites. The above non-destructive dynamic monitoring system maintains in-line experimental setups by integrating the functional thin-film imager sheets and compact multiple photo-sources. Furthermore, permeable sub-THz-IR-irradiation, which provides different transmittance values specific to non-metallic materials per wavelength or composition, identifies constituent materials for pharmaceutical agents themselves and concealed foreign substances in a non-contact manner. This work finally inspects invisible detailed features of pharmaceutical pills with the non-destructive in-line dynamic photo-monitoring system by incorporating performances of CNT imagers and compact optical setups.
Research background
While in-line non-destructive monitoring techniques at manufacturing sites are essential for safe distribution cycles of pharmaceutical products, efforts are still insufficient to develop analytical systems for detailed and dynamic visualisation operations of foreign substances and material compositions in target pills. Despite typical spectroscopy measurements widely handle raw materials composing pharmaceutical pills at early stages, inherent complicated and bulky optical setups crucially regulate their operations from in-line situations.
The importance and novelty of this work
To this end, this manuscript made the following significant contributions.
The paper was published online in the international scientific journal, Light: Science & Applications (September 11, 2025).