Recent progress on engineered micro/nanomaterials mediated modulation of gut microbiota for treating inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a type of chronic recurrent inflammation disease that mainly includes Crohn's disease and ulcerative colitis. Currently, the treatments for IBD remain highly challenging, with clinical treatment drugs showing limited efficacy and adverse side effects. Thus, developing drug candidates with comprehensive therapeutic effects, high efficiency, and low toxicity is urgently needed. Recently, micro/nanomaterials have attracted considerable interest because of their bioavailability, multitarget and efficient effects on IBD. In addition, gut modulation plays a substantial role in restoring intestinal homeostasis. Therefore, efficient microbiota-based strategies modulating gut microenvironment have great potential in remarkably treating IBD. With the development of micro- and nanomaterials for the treatment of IBD and more in-depth studies of their therapeutic mechanisms, it has been found that these treatments also have a tendency to positively regulate the intestinal flora, resulting in an increase in the beneficial flora and a decrease in the level of pathogenic bacteria, thus regulating the composition of the intestinal flora to a normal state. In this review, we first present the interactions among the immune system, intestinal barrier, and gut microbiome. In addition, recent advances in administration routes and methods that positively arouse the regulation of intestinal flora for IBD using probiotics, prebiotics, and redox-active micro/nanomaterials have been reviewed. Finally, the key challenges and critical perspectives of gut microbiota-based micro/nanomaterial treatment are also discussed.

Recent advances on emerging nanomaterials for diagnosis and treatment of inflammatory bowel disease.

Inflammatory bowel disease (IBD) is a chronic idiopathic inflammatory disorder that affects the entire gastrointestinal tract and is associated with an increased risk of colorectal cancer. Mainstream clinical testing methods are time-consuming, painful for patients, and insufficiently sensitive to detect early symptoms. Currently, there is no definitive cure for IBD, and frequent doses of medications with potentially severe side effects may affect patient response. In recent years, nanomaterials have demonstrated considerable potential for IBD management due to their diverse structures, composition, and physical and chemical properties. In this review, we provide an overview of the advances in nanomaterial-based diagnosis and treatment of IBD in recent five years. Multi-functional bio-nano platforms, including contrast agents, near-infrared (NIR) fluorescent probes, and bioactive substance detection agents have been developed for IBD diagnosis. Based on a series of pathogenic characteristics of IBD, the therapeutic strategies of antioxidant, anti-inflammatory, and intestinal microbiome regulation of IBD based on nanomaterials are systematically introduced. Finally, the future challenges and prospects in this field are presented to facilitate the development of diagnosis and treatment of IBD.

Combined Feature Extraction and Random Forest for Laser Self-Mixing Vibration Measurement without Determining Feedback Intensity.

To measure the vibration of a target by laser self-mixing interference (SMI), we propose a method that combines feature extraction and random forest (RF) without determining the feedback strength (C). First, the temporal, spectral, and statistical features of the SMI signal are extracted to characterize the original SMI signal. Secondly, these interpretable features are fed into the pretrained RF model to directly predict the amplitude and frequency (A and f) of the vibrating target, recovering the periodic vibration of the target. The results show that the combination of RF and feature extraction yields a fit of more than 0.94 for simple and quick measurement of A and f of unsmooth planar vibrations, regardless of the feedback intensity and the misalignment of the retromirror. Without a complex optical stage, this method can quickly recover arbitrary periodic vibrations from SMI signals without C, which provides a novel method for quickly implementing vibration measurements.

Real-time displacement reconstruction by an orthogonal Fabry-Perot interferometer.

A real-time reconstruction of the displacement method based on an orthogonal Fabry-Perot interferometer is presented. Two orthogonal polarization signals with a phase shift of π/2 are obtained using a He-Ne laser with internal-mirror multilayer coatings. The displacement of the vibration target is reconstructed in real time using the arctangent and unwrapping algorithm for two quadrature signals. Meanwhile, two quadrature signals are used to discriminate the direction of motion. The experimental results under different peak-to-peak amplitudes and frequencies show that the reconstruction errors are less than 58 nm.

All-fiber Fabry-Pérot interferometer for reducing noise on the basis of differential structure.

In this study, we propose a new optical fiber interferometer based on differential structure. The phase delay exists in the two output arms of the coupler. When the interference signal passes through the phase delay twice in the transmission, it produces a phase shift of π with the original signal. This feature can be used to differentially reduce noise. The experimental results show that the signal-to-noise ratio increases by 1.29 dB, and the waveform of the reconstructed signal is reduced by 12 nm. Thus, the structure can effectively improve the quality of the measured signal.

Signal enhancement method based on a Fabry-Perot etalon for a self-mixing laser diode.

An enhanced self-mixing interference (SMI) method in a laser diode (LD) based on a Fabry-Perot etalon (FPE) is presented. This method uses uncoated fused silica to form a FPE as a narrowband filter in the LD outer cavity, which can tune the laser wavelength to the edge of the FPE transmission spectrum profile to perform intensity demodulation. We compare the SMI signal based on the FPE filter with the conventional SMI signal. The experimental results show that the amplitude of the SMI signal based on the FPE filter is enhanced about 5 times in the range of 1 µm-5 µm; the displacement reconstruction errors are reduced by 30 nm; and the signal quality is significantly improved.

Secondary envelope extraction based on multiple Hilbert transforms for laser self-mixing micro-vibration measurement.

This paper presents a method that can be applied to weak feedback and full-range moderate feedback in the field of self-mixing interference measurement, and the target motion displacement can be obtained by multiple Hilbert transforms of the signal after the secondary envelope extraction. Simulations and experiments of multiple micro-vibration measurements were performed with different optical feedback factors, and the results were consistent with theoretical analysis. This method effectively eliminates the impact of the self-mixing interference signal with fringe shift on micro-vibration reconstruction.

Enhanced laser self-mixing Doppler velocity measurement with pre-feedback mirror.

On the basis of conventional measurement, a novel enhanced laser self-mixing Doppler velocimetry is proposed in this paper, with a pre-feedback structure added to enhance the signals. The improved velocimetry is applicable to the measure of the velocity when the feedback light is weak. Through the exploration of the theoretical model and the performance of experiments, the study results show that the proposed method has a significant signal enhancement effect, with experimental measurement relative errors being less than 0.9%.

An enhanced photoelectrochemical immunosensing platform: supramolecular donor-acceptor arrays by assembly of porphyrin and C60.

A novel self-assemble approach was developed for constructing a linear bicontinuous donor-acceptor, (H2BCPP)n-C60, arrays on indium-tin oxide electrode. Electronic absorption spectra, fluorescence spectra and atomic force microscopy were used as powerful tools to characterize H2BCPP, (H2BCPP)n arrays and (H2BCPP)n-C60 arrays. The (H2BCPP)n-C60 arrays enhanced the photocurrent generation capability, and presented an efficient photoelectrochemical immunosensing platform for the ultrasensitive detection of carcinoembryonic antigen (CEA). The quantitative measurement of CEA was based on the decrease in the photocurrent intensity of the (H2BCPP)n-C60 arrays, which was resulted from the competition between CEA and CEA-CdTe. A linear relationship between the photocurrent decrease and the CEA concentration was obtained in the wide range from 0.01 to 60 ng mL(-1) with a detection limit of 3.4 pg mL(-1). The proposed sensor showed high sensitivity, stability and reproducibility, and provided a promising platform for other biomolecular detection.