Xinlong Zhou

Cronobacter sakazakii (C. sakazakii) is a food pathogen that has drawn attention in the area of food safety, especially in relation to infant formula and other food matrices. However, the typical methods for detecting C. sakazakii can be tedious, time-consuming, and need complex tools and equipment, which restricts their use for quick detection. As a result, sensitive and quick detection techniques are essential. In the present study, a new type of optical fiber biosensor was developed, which combines CeCoMOF@Ag@MoS₂ nanomaterials and gold nanorods (AuNRs). The sensor adopts a multimode fiber (MMF)–lanthanum-doped fiber (LDF)–MMF (MLM) fiber structure, and the integration of CeCoMOF, Ag@MoS₂, and AuNRs combines the structural advantages of the porous framework with the plasmonic response of the metallic nanostructures, providing a composite sensing interface for optical fiber LSPR detection and measuring the refractive-index sensitivity of different concentrations of C. sakazakii. The sensing interface was designed by integrating CeCoMOF@Ag@MoS₂ and AuNRs on the probe surface to optimize the LSPR response and provide a suitable platform for antibody functionalization. The probe was subsequently functionalized with monoclonal antibodies against C. sakazakii to facilitate target recognition. According to the experimental findings, the developed sensor’s detection range is 1 × 10⁰–1 × 10⁷ CFU/mL, the sensitivity is 5.1447 nm/[CFU/mL], and the detection limit is 0.78 CFU/mL. Moreover, the sensor has good repeatability, stability, selectivity, and reusability. The performance of the suggested sensor was analyzed in terms of sensing capabilities with starch-based matrix under the conditions tested. Note that the enhanced performance is not just due to La doping but due to the combined effect of the multi-tapered MLM structure, La doping and the nanomaterial–antibody interaction.

Acrylamide (AA), a harmful aliphatic amide, is produced during the thermal processing of food as a result of the Maillard reaction between asparagine and reducing sugars. It has neurotoxic effects and can cause cognitive impairment with long-term exposure. Moreover, chronic intake of AA may increase the risk of various types of cancer, including pancreatic and thyroid cancer. AA is often found in foods cooked at high temperatures, thereby highlighting its role in food quality assessment. Therefore, there is a need for more accurate, practical, rapid, and straightforward methods to detect AA in various samples. In this study, a highly sensitive and selective smart fiber-optic WaveFlex biosensing method based on localized surface plasmon resonance (LSPR) is proposed for the detection of AA. The fiber surface is functionalized with gold nanoparticles (AuNPs), multi-walled carbon nanotubes (MWCNTs) and zinc oxide nanowires (ZnO-NWs) to provide a larger surface area for the immobilization of AA antibodies, which in turn significantly improved the sensor's performance. The results showed that the developed sensor could efficiently detect AA with high specificity due to the presence of AA antibodies. Subsequent research confirmed that the proposed biosensor exhibited excellent stability, repeatability, and reusability, with a limit of detection (LOD) of 0.438 μg/mL and a sensitivity of 0.685 nm/(μg/mL). Thus, the proposed optical fiber sensor holds significant potential for detecting the presence of AA in various deep-fried foods prepared at high temperatures.

Acrylamide (AA), a detrimental aliphatic amide, is generated during food thermal processing as a result of the Maillard reaction occurring between asparagine and reducing sugars. WaveFlex fiber is a fiber-optic flexible sensor designed to enhance the evanescent wave for effectively exciting the localized surface plasmon resonance (LSPR) phenomenon, and in this study, the authors use this type of sensor to detect varying levels of AA. By immobilizing gold nanoparticles (AuNPs) on the probe’s surface, the evanescent field has the capability to trigger the activation of AuNPs and induce the occurrence of LSPR phenomena. In order to excite LSPR better and generate stronger evanescent field, WaveFlex biosensor is fabricated using single-mode fiber. Cerium oxide nanorods (CeO ₂ -NRs) and MXene are used to modulate the LSPR phenomenon by altering the dielectric environment of AuNPs. As a result, the sensing performance of the sensor is improved and the surface area of the fiber probe is increased, providing an additional attachment point for the AA antibody. The AA sensor’s specific selectivity is enhanced by functionalizing the surface of the sensing probe with acrylamide antibody. The sensor has a linear range of 3 to 13 μg/mL with a detection limit of 1.13 μg/mL. Finally, the recoveries of AA in biscuits and chips are 82.8% ~ 99.7% and 83.7% ~ 100.4%, respectively. Furthermore, the probe’s potential for detecting AA levels is demonstrated through rigorous testing of its reusability, reproducibility, stability, pH, and selectivity. The obtained results indicate a promising application scope for this WaveFlex biosensor.

The increasing enhancement in the modulation accuracy of spatial light modulators has garnered significant attention towards real-time control technology for light fields based on these modulators. It has been demonstrated that this technology possesses a remarkable capability to generate vector beams with arbitrary complex amplitude distributions. Nevertheless, past studies indicate that the generation of only one vector beam at a time has been observed. The simultaneous generation of numerous vector light fields can give rise to several challenges, including compromised picture quality, limited single-mode operation, and intricate optical path configurations. In pursuit of this objective, we present a novel methodology that integrates the coding methodology of modified off-axis interferometric holography with the idea of optical superposition. This technique facilitates the concurrent generation of several vector beams. In this study, we present a demonstration of the simultaneous creation of twelve vector beams using a single spatial light modulator (SLM) as a proof of concept. Significantly, this technology has the ability to generate an unlimited quantity of vector light fields concurrently under the assumption that the resolution of the SLM does not impose any limitations. The findings indicate that the imaging quality achieved by this technology is of a high standard. Furthermore, it is possible to separately control the beam waist radius, topological charge, polarization order, and extra phase of each beam.