Three-step one-way model in terahertz biomedical detection

Terahertz technology has broad application prospects in biomedical detection.However, the mixed characteristics of actual samples make the terahertz spectrumcomplex and difficult to distinguish, and there is no practical terahertz detectionmethod for clinical medicine. Here, we propose a three-step one-way terahertzmodel, presenting a detailed flow analysis of terahertz technology in the biomedicaldetection of renal fibrosis as an example: 1) biomarker determination: screeningdisease biomarkers and establishing the terahertz spectrum and concentrationgradient;2) mixture interference removal: clearing the interfering signals in the mixturefor the biomarker in the animal model and evaluating and retaining the effectivecharacteristic peaks;and 3) individual difference removal: excluding individualinterference differences and confirming the final effective terahertz parameters in thehuman sample. The root mean square error of our model is three orders ofmagnitude lower than that of the gold standard, with profound implications for therapid, accurate and early detection of diseases.

Nanoprobes in biomedical detection

Environmental problems caused by the development of nanotechnology have threatened human health. Investigating the biomedical effects of nanomaterials can help to solve these environmental safety issues. In studies on the biomedical effects of nanomaterials, several types of novel nanoscale probes that allow reliable, sensitive, accurate and rapid biomedical detection have emerged. We summarize recent developments in three categories of these nanoprobes, including noble metal nanocluster probes, carbon-based nanostructured probes, and unnatural amino acid-based probes. Besides reviewing the utility of different nanoprobes in cell imaging and protein detection, we also discuss the molecular mechanism of nanoprobe detection. Perspectives of novel nanoprobe design based on molecular details of biomedical detection are presented.

Review on near-field detection technology in the biomedical field

We review the recent biomedical detection developments of scanning near-field optical microscopy(SNOM),focusing on scattering-type SNOM,atomic force microscope-based infrared spectroscopy,peak force infrared microscopy,and photo-induced force microscopy,which have the advantages of label-free,noninvasive,and specific spectral recognition.Considering the high water content of biological samples and the strong absorption of water by infrared waves,we divide the relevant research on these techniques into two categories:one based on a nonliquid environment and the other based on a liquid environment.In the nonliquid environment,the chemical composition and structural information of biomedical samples can be obtained with nanometer resolution.In the liquid environment,these techniques can be used to monitor the dynamic chemical reaction process and track the process of chemical composition and structural change of single molecules,which is conducive to exploring the development mechanism of physiological processes.We elaborate their experimental challenges,technical means,and actual cases for three microbiomedical samples(including biomacromolecules,cells,and tissues).We also discuss the prospects and challenges for their development.Our work lays a foundation for the rational design and efficient use of near-field optical microscopy to explore the characteristics of microscopic biology.

Spherical nucleic acids for biomedical applications

Spherical nucleic acids(SNAs)are a 3D spherical nanostructure composed of highly oriented,dense layers of oligonucleotides conjugated to a hollow or solid core.This structure allows SNAs to show resistance to nuclease degradation,enter into nearly all cells without transfection agents and enable precise interactions with target molecules.Based on superior biological properties,SNAs can be tailored for diverse biological applications,rendering them a flexible and biosafe tool for biological applications as well as an enabling platform for therapy.In this review,we mainly discuss the structure and conjugation mode of SNAs and focus on recent advances in their applications,such as biomedical detection,imaging,and drug delivery.Finally,the remaining challenges and future directions of SNAs are also discussed and proposed.

Classification of hyperspectral images for detection of hepatic carcinoma cells based on spectral-spatial features of nucleus

A distinguishing characteristic of normal and cancer cells is the difference in their nuclear chromatin content and distribution.This difference can be revealed by the transmission spectra of nuclei stained with a pH-sensitive stain.Here,we used hematoxylin-eosin(HE)to stain hepatic carcinoma tissues and obtained spectral-spatial data from their nuclei using hyper-spectral microscopy.The transmission spectra of the nuclei were then used to train a support vector machine(SVM)model for cell classification.Especially,we found that the chromatin distribution in cancer cells is more uniform,because of which the correlation coefficients for the spectra at different points in their nuclei are higher.Consequently,we exploited this feature to improve the SVM model.The sensitivity and specificity for the identification of cancer cells could be increased to 99%and 98%,respectively.We also designed an image-processing method for the extraction of information from cell nuclei to automate the identification process.

Superhydrophobic Surface-Assisted Preparation of Microspheres and Supraparticles and Their Applications

Superhydrophobic surface(SHS) has been well developed, as SHS renders the property of minimizing the water/solid contact interface. Water droplets deposited onto SHS with contact angles exceeding 150°, allow them to retain spherical shapes, and the low adhesion of SHS facilitates easy droplet collection when tilting the substrate. These characteristics make SHS suitable for a wide range of applications. One particularly promising application is the fabrication of microsphere and supraparticle materials. SHS offers a distinct advantage as a universal platform capable of providing customized services for a variety of microspheres and supraparticles. In this review, an overview of the strategies for fabricating microspheres and supraparticles with the aid of SHS, including cross-linking process, polymer melting,and droplet template evaporation methods, is first presented. Then, the applications of microspheres and supraparticles formed onto SHS are discussed in detail, for example, fabricating photonic devices with controllable structures and tunable structural colors, acting as catalysts with emerging or synergetic properties, being integrated into the biomedical field to construct the devices with different medicinal purposes, being utilized for inducing protein crystallization and detecting trace amounts of analytes. Finally,the perspective on future developments involved with this research field is given, along with some obstacles and opportunities.

Metal-organic frameworks based surface-enhanced Raman spectroscopy technique for ultra-sensitive biomedical trace detection

Metal-organic frameworks(MOFs)have attracted widespread interest due to their unique and unprecedented advantages in microstructures and properties.Besides,surface-enhanced Raman scattering(SERS)technology has also rapidly developed into a powerful fingerprint spectroscopic technique that can provide rapid,non-invasive,non-destructive,and ultra-sensitive detection,even down to single molecular level.Consequently,a considerable amount of researchers combined MOFs with the SERS technique to further improve the sensing performance and broaden the applications of SERS substrates.Herein,representative synthesis strategies of MOFs to fabricate SERS-active substrates are summarized and their applications in ultra-sensitive biomedical trace detection are also reviewed.Besides,relative barriers,advantages,disadvantages,future trends,and prospects are particularly discussed to give guidance to relevant researchers.

On-chip immunomagnetic bead swarm based on magnetic actuation and mechanical vibration for biological detection

Immunomagnetic bead(IMB)-based detection has great potential for biomedical applications.Passive and active strategies,including microfluidics and magnetic actuation methods,have been developed to mix IMBs and analytes efficiently.However,cost-effective on-site detection using a simple microfluidic chip is challenging,and miniaturization of the magnetic driving device is imperative for portability.In this study,we propose a novel mixing method for an on-chip IMB swarm via magnetic actuation and mechanical vibration.A microfluidic chip system coupled with double spiral magnetic coils and a vibration motor was fabricated.The aggregation behavior of IMBs under magnetic fields and the diffusion behavior of the IMB swarm under mechanical vibration were analyzed in detail.Based on the synergetic effects of magnetic actuation and mechanical vibration,we achieved the highly efficient capturing of Vibrio parahaemolyticus DNA and goat anti-human immunoglobulin G by mixing the IMB swarm with the microfluidic chip.In this case,the antigen detection rate could reach~94.4%.Given its fascinating features,such IMB-microfluidic detection demonstrates significant potential for biomedical applications.