Sepsis is an extremely dangerous medical condition that emanates from the body’s response to a pre-existing infection. Early detection of sepsis-inducing bacterial infections can greatly enhance the treatment process and potentially prevent the onset of sepsis. However, current point-of-care (POC) sensors are often complex and costly or lack the ideal sensitivity for effective bacterial detection. Therefore, it is crucial to develop rapid and sensitive biosensors for the on-site detection of sepsis-inducing bacteria. Herein, we developed a graphene oxide CRISPR-Cas12a (GO-CRISPR) biosensor for the detection of sepsis-inducing bacteria in human serum. In this strategy, single-stranded (ssDNA) FAM probes were quenched with single-layer graphene oxide (GO). Target-activated Cas12a trans-cleavage was utilized for the degradation of the ssDNA probes, detaching the short ssDNA probes from GO and recovering the fluorescent signals. Under optimal conditions, we employed our GO-CRISPR system for the detection of Salmonella Typhimurium (S. Typhimurium) with a detection sensitivity of as low as 3 × 103 CFU/mL in human serum, as well as a good detection specificity toward other competing bacteria. In addition, the GO-CRISPR biosensor exhibited excellent sensitivity to the detection of S. Typhimurium in spiked human serum. The GO-CRISPR system offers superior rapidity for the detection of sepsis-inducing bacteria and has the potential to enhance the early detection of bacterial infections in resource-limited settings, expediting the response for patients at risk of sepsis.

On-Site Fluorescent Detection of Sepsis-Inducing Bacteria using a Graphene-Oxide CRISPR-Cas12a (GO-CRISPR) System

In traditional CRISPR-based biosensors, the cleavage-induced signal generation is insufficient because only a signals is generated at a CRISPR-induced cleavage. Herein, we developed an improved CRISPR/Cas12a-based biosensor with an enlarged signal generation which integrated the hybridization chain reaction (HCR) and low-background Förster Resonance Energy Transfer (FRET) signal output mode. The HCR with nucleic acid self-assembly capability was used as a signal carrier to load more signaling molecules. To get the best signal amplification, three different fluorescence signal output modes (fluorescence recovery, FRET and low-background FRET) generated by two fluoresceins, FAM and Cy5, were fully investigated and compared. The results indicated that the low-background FRET signal output mode with the strictest signal generation conditions yielded the highest signal-to-noise ratio (S/N) (19.17) and the most obvious fluorescence color change (from red to yellow). In optimal conditions, the proposed biosensor was successfully applied for Salmonella Typhimurium (S. Typhimurium) detection with 6 h (including 4 h for sample pre-treatment) from the initial target processing to the final detection result. The qualitative sensitivity, reliant on color changes, was 103 CFU/mL. The quantitative sensitivity, calculated by the fluorescence value, were 1.62 × 101 CFU/mL, 3.72 × 102 CFU/mL, and 8.71 × 102 CFU/mL in buffer solution, S. Typhimurium-spiked milk samples, and S.Typhimurium-spiked chicken samples, respectively. The excellent detection performance of the proposed biosensor endowed its great application potential in food and environment safety monitoring. 

A low-background and wash-free signal amplification F-CRISPR biosensor for sensitive quantitative and visible qualitative detection of Salmonella Typhimurium.

Portable, low-cost and efficient biosensing systems are valuable for single nucleotide polymorphisms (SNPs) analysis, particularly in resource-limited fields. Herein, a rapid, enzyme-free and ratiometric SNPs biosensor with portable electrochemical system enabling simultaneous recognition and signal amplification is proposed. To demonstrate its versatility and effectiveness, we have selected the human cancer-related KRAS gene and the soybean mosaic virus resistance Rsv3 gene as our analysis models. Our biosensor is constructed based on a combination of strand displacement reactions and hybridization chain reactions (HCR). This unique design enables to differentiate between mutant (MT) and wild (WD) sequences based on the differential release of HCR products on the electrode surfaces. Importantly, this enzyme-free SNPs biosensor concurrently achieves both SNPs recognition and signal amplification, significantly reducing the reaction time to just 40 minutes. Furthermore, we have developed a miniaturized biosensor system that incorporates screen printed gold electrodes (SPGE) and smartphones. This system is integrated with a ratiometric strategy with an limit of detection as low as 1.2 fM, enhancing accuracy and eliminating external interference. This simple SNPs biosensing system possesses high reliability, positioning it as a versatile biosensor for the determination of various SNPs mutations. 

An enzyme-free and ratiometric biosensor for single nucleotide polymorphism with portable electrochemical system

Detection strategies of cancer biomarkers with various techniques based on the CRISPR-Cas system. 

CRISPR-Cas-based biosensors for cancer biomarkers detection

Although current cancer treatment technologies have advanced quickly, the patient's chance of recovering is still poor. Early detection enhances cancer prognosis and can considerably lower cancer-related fatalities. The most popular approaches for cancer diagnosis at the moment are tumor imaging and specimen biopsy. Unfortunately, these techniques are only capable of locating large tissue regions with malignant tumors. They eventually involve removing a solid specimen from the tumor area, which is then examined for particular biomarkers and the tumor's genetic makeup to ascertain whether its cancerous or otherwise. The removal of tissue is invasive and uncomfortable for the patient, and in some cancers that are challenging to surgically remove, it may not be possible. Furthermore, a solid sample cannot be used repeatedly and the surgical procedures and the subsequent analysis are costly and time-consuming. On top of these, safety may not be guaranteed, for example, when sampling tumors near important blood arteries, in sensitive parts of the brain, or individuals with significant co-morbidities. In such circumstances, these strategies may be clinically impractical. In such scenarios, non-invasive liquid biopsy becomes a significant option that may solve these limitations, where the biomarkers are studied in non-solid biological tissue samples, mostly blood. It offers several benefits including minimal risk, non-invasiveness, lower cost, and faster diagnosis. Recent developments in various fluorescent nano-biosensors for early detection of cancer, together with synthesis, surface functionalization and detection methodologies in the various tumor microenvironments will be discussed in this review. Several nanomaterials, including gold nanoparticles (AuNPs), magnetic nanoparticles, quantum dots (QDs), and carbon nanotubes (CTNs) will be explored. Emphasis on robustness, sensitivity, stability, linear detection ranges, and detection limits for these materials will also be highlighted. This review will be useful to researchers interested in understanding the chemistry and biochemical processes of these interesting materials in the identification of various cancer biomarkers. 

Fluorescent Chemo sensor nano-materials for Cancer bio-markers signalling: Towards development of non-invasive early detection strategies

Target-independent hybridization chain reaction-fluorescence resonance energy transfer for sensitive assay of ctDNA based on Cas12a.

Ultraviolet (UV), particularly UVB, is widely used in the treatment of skin diseases including psoriasis, atopic dermatitis, vitiligo, mycosis fungoides and pruritus. Recently, there has been a trend of replacing broad‐band UVB (BB‐UVB) units with narrow‐band UVB (NB‐UVB), as studies have demonstrated that NB‐UVB is more efficacious in the treatment of psoriasis. The purpose of this study is to evaluate the biological effects and transcriptome changes induced by light‐emitting diode‐based NB‐UVB (NB‐UVB LED) phototherapy. Cell viability and the cell migration ability were significantly decreased posttreatment, as well as apoptosis and ROS levels were remarkably increased. NB‐UVB‐induced S phase arrest was observed 12 h postirradiation. Bioinformatics analysis of transcriptome sequencing data revealed that NB‐UVB LED irradiation induced dose‐depended changes in multiple key signaling pathways, such as PI3K and cytoskeletal‐related pathways. The depolymerization of cytoskeleton induced by NB‐UVB was observed 24 h posttreatment. In addition, the expression levels of cytoskeleton‐related proteins FN1, ITGB4, ITGA1, RAC2 and DOCK1 decreased significantly 12 h after irradiation. Our results indicated that NB‐UVB LED may serve as a novel option for the development of NB‐UVB phototherapy devices.

Evaluation of Biological Effects and Transcriptome Changes Induced by LED‐Based Narrow‐Band UVB Phototherapy

Multi-functional Dumbbell DNA Probe Design and Its Application in Signal Amplification Cascade -based Assay of Human Immunodeficiency Virus

In this study, type II collagen was used to induce arthritis in mice to test the effect and mechanism of dandelion tea. The visual manifestations of arthritis, histopathological conditions of spleen, serum inflammatory factors and gene expression of synovium of foot and ankle joints in mice were detected by the methods of arthritis index (AI), spleen index, enzyme linked immunosorbent assay (ELISA), hematoxylin-eosin (H&E) staining and quantitative polymerase chain reaction (qPCR). The compound components of dandelion tea were determined by high performance liquid chromatography (HPLC). The experimental results show that dandelion tea can reduce the AI value, spleen index and paw swelling degree of arthritis mice, reduce the pathological damage of spleen, and increase the serum IL-10 and TGF-β levels, and can up-regulate Foxp3 expression and down regulate ROR-γt expression in the synovium of ankle joint. At the same time, the results of component analysis showed that the efficacy of dandelion tea came from the contents of gallic acid, protocatechuic acid, chlorogenic acid, caffeic acid, p-coumaric acid, rutin, myricetin, isoquercitrin, isochlorogenic acid and luteolin. It can be seen that dandelion tea is a health drink with good intervention effect on arthritis. 

Effects of dandelion tea on type II collagen induced arthritis in mice by regulation of ROR-γt/Foxp3 signaling

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Target-independent hybridization chain reaction-fluorescence resonance energy transfer for sensitive assay of ctDNA based on Cas12a.

Evaluation of Biological Effects and Transcriptome Changes Induced by LED‐Based Narrow‐Band UVB Phototherapy

Multi-functional Dumbbell DNA Probe Design and Its Application in Signal Amplification Cascade -based Assay of Human Immunodeficiency Virus

Effects of dandelion tea on type II collagen induced arthritis in mice by regulation of ROR-γt/Foxp3 signaling