Genetic testing plays an important role in human health management and disease prevention. However, traditional genetic testing methods have been unable to fulfill the current diagnostic needs owing to several limitations, including high cost, complexity, and difficulty in performing. Smartphones have multiple inherent advantages, such as easy portability, ubiquity, fast processing speed, and excellent imaging capabilities, and have enormous potential in realizing rapid on‐site genetic testing. The present review documents the research progress of smartphone‐based optical imaging biosensors in the fields of colorimetry, fluorescence, and microscopic imaging for genetic testing. Furthermore, the review describes their potential applications in diagnostics, which range from infectious diseases to hereditary diseases and cancers. Finally, the challenges and perspectives of smartphone‐based optical imaging biosensors regarding genetic testing are discussed.

The rapid and precise identification of multiple pathogens is critical for ensuring food safety, controlling epidemics, diagnosing diseases, and monitoring the environment. However, traditional detection methods are hindered by complex workflows, the need for skilled operators, and reliance on sophisticated equipment, making them unsuitable for rapid, on-site testing. Optical biosensors, known for their rapid analysis, portability, high sensitivity, and multiplexing capabilities, offer a promising solution for simultaneous multi-pathogenic identification. This paper explores recent advancements in the utilization of optical biosensors for multiple pathogenic detection. First, it provides an overview of key sensing principles, focusing on colorimetric, fluorescence-based, surface-enhanced Raman scattering (SERS), and surface plasmon resonance (SPR) techniques, as well as their applications in pathogenic detection. Then, the research progress and practical applications of optical biosensors for multiplex pathogenic detection are discussed in detail from three perspectives: microfluidic devices, nucleic acid amplification technology (NAAT), and nanomaterials. Finally, the challenges presented by optical biosensing technologies in multi-pathogen detection are discussed, along with future prospects and potential innovations in the field.

Hypocalcemia is a disease that adversely affects the production and reproduction of dairy cows. A portable device for rapid bovine blood calcium sensing has been growing in demand. Herein, we report a smartphone-based ratiometric fluorescence probe (SRFP) platform as a new way to detect and quantify calcium ions (Ca²⁺) in blood serum. Specifically, we employed a cost-effective and portable smartphone-based platform coupled with customized software that evaluates the response of Ca²⁺ ions to ratiometric fluorescence probe in bovine serum. The platform consists of a three-dimensional (3D) printed housing and low-cost optical components that excite fluorescent probe and selectively transmit fluorescence emissions to smartphones. The customized software is equipped with a calibration model to quantify the acquired fluorescence images and quantify the concentration of Ca²⁺ ions. The ratio of the green channel to the red channel bears a highly reproducible relationship with Ca²⁺ ions concentration from 10 μM to 40 μM in bovine serum. Our detection system has a limit of detection (LOD) of 1.8 μM in bovine serum samples and the recoveries of real samples ranged from 92.8% to 110.1%, with relative standard deviation (RSD) ranging from 1.72% to 4.89%. The low-cost SRFP platform has the potential to enable campesino to rapidly detect Ca²⁺ ions content in bovine serum on-demand in any environmental setting.

A high-throughput instrument to measure the full spectral properties of biochemical agents is necessary for fast screening in fields such as medical tests, environmental monitoring, and food analysis. However, this need has currently not been fully met by the commercial microplate reader (CMR). In this study, we have developed an automated high-throughput efficient microplate reader (AHTEMR) platform by combining a spectrometer and high-precision ball screw two-dimensional motion slide together, for high-throughput and full-spectrum-required biochemical assays. A two-dimensional slide working on a ball screw was driven by a stepper motor with a custom-designed master control circuit and used as a motion system of the AHTEMR platform to achieve precise positioning and fast movement of the microplate during measurements. A compact spectrometer was coupled with an in-house designed optical pathway system and used to achieve rapid capture of the full spectral properties of biochemical agents. In a performance test, the AHTEMR platform successfully measured the full spectral absorbance of bovine serum albumin (BSA) and glucose solution in multiple wells of the microplate within several minutes and presented the real-time full spectral absorbance of BSA and glucose solution. Compared with the CMR, the AHTEMR is 79 times faster in full-spectrum measurements and 2.38 times more sensitive at the optimal wavelength of 562 nm. The rapid measurement also demonstrated the great capacity of the AHTEMR platform for screening out the best colorimetric wavelengths for tests of BSA and glucose development, which will provide a promising approach to achieving high-throughput and full-spectrum-required biochemical assays.

With the advancement of micro/nanotechnologies, multielectrodes arrays (MEAs) with different three‐dimensional (3D) micro/nanostructures have been developed to achieve intracellular action potential recording of cardiomyocytes. However, the effect of the 3D micro/nanostructures density on the intracellular recording has not been fully investigated. In this work, 3D tunable nanodensity electrode arrays (TNDEA) are fabricated by hydrothermal synthesis and standard microfabrication to explore the effect of nanodensity regulation on intracellular biosensing. By low‐voltage electroporation, the signal quality of intracellular potentials recorded by the low‐nanodensity TNDEA showed was significantly improved compared to those recorded by the high‐nanodensity TNDEA. The low‐nanodensity TNDEA improved the amplitude (up to 7.7 mV), signal‐to‐noise ratio (SNR) (up to 69.46 dB), recording duration (up to 83 min), and recording yield (∼100%). The 3D nanodensity regulating strategy has achieved sensitive and prolonged intracellular biosensing of action potentials and is expected to be a powerful electrophysiological research tool in the biomedical field.