Copper (II)-catalyzed polydopamine mediated photothermal sensors for visual quantitative point-of-care testing.

BACKGROUND: Temperature sensing is commonly used in point-of-care (POC) detection technologies, yet the portability and convenience of use are frequently compromised by the complexity of thermosensitive processes and signal transduction. Especially, multi-step target recognition reactions and temperature measurement in the reaction vessel present challenges in terms of stability and integration of detection devices. To further combine photothermal reaction and signal readout in one assay, these two processes enable to be integrated into miniaturized microfluidic chips, thereby facilitating photothermal sensing and achieving a simple visual temperature sensing as POC detection. RESULTS: A copper ion (Cu2+)-catalyzed photothermal sensing system integrated onto a microfluidic distance-based analytical device (µDAD), enabling the visual, portable, and sensitive quantitative detection of multiple targets, including ascorbic acid, glutathione, and alkaline phosphatase (ALP). The polydopamine nanoparticles (PDA NPs) were synthesized by the regulation of free Cu2+ through redox or coordination reactions, facilitating the transduction of distinct photothermal response signals and providing the versatile Cu2+-responsive sensing systems. Promoted by integration with a photothermal µDAD, the system combines PDA's photothermal responsiveness and thermosensitive gas production of ammonium bicarbonate for improved sensitivity of ALP detection, reaching the detection limit of 9.1 mU/L. The system has successfully achieved on-chip detection of ALP with superior anti-interference capability and recoveries ranging from 96.8 % to 104.7 %, alongside relative standard deviations below 8.0 %. SIGNIFICANCE AND NOVELTY: The µDAD design accommodated both the photothermal reaction of PDA NPs and thermosensitive gas production reaction, achieving the rapid sensing of visual distance signals. The µDAD-based Cu2+-catalyzed photothermal sensing system holds substantial potential for applications in biochemical analysis and clinical diagnostics, underscored by the versatile Cu2+ regulation mechanism for a broad spectrum of biomarkers.

Targeted next-generation sequencing of deaf patients from Southwestern China.

BACKGROUND: Targeted next-generation sequencing is an efficient tool to identify pathogenic mutations of hereditary deafness. The molecular pathology of deaf patients in southwestern China is not fully understood. METHODS: In this study, targeted next-generation sequencing of 127 deafness genes was performed on 84 deaf patients. They were not caused by common mutations of GJB2 gene, including c.35delG, c.109 G>A, c.167delT, c.176_191del16, c.235delC and c.299_300delAT. RESULTS: In the cohorts of 84 deaf patients, we did not find any candidate pathogenic variants in 14 deaf patients (16.7%, 14/84). In other 70 deaf patients (83.3%, 70/84), candidate pathogenic variants were identified in 34 genes. Of these 70 deaf patients, the percentage of "Solved" and "Unsolved" patients was 51.43% (36/70) and 48.57% (34/70), respectively. The most common causative genes were SLC26A4 (12.9%, 9/70), MT-RNR1 (11.4%, 8/70), and MYO7A (2.9%, 2/70) in deaf patients. In "Unsolved" patients, possible pathogenic variants were most found in SLC26A4 (8.9%, 3/34), MYO7A (5.9%, 2/34), OTOF (5.9%, 2/34), and PDZD7 (5.9%, 2/34) genes. Interesting, several novel recessive pathogenic variants were identified, like SLC26A4 c.290T>G, SLC26A4 c.599A>G, PDZD7c.490 C>T, etc. CONCLUSION: In addition to common deafness genes, like GJB2, SLC26A4, and MT-RNR1 genes, other deafness genes (MYO7A, OTOF, PDZD7, etc.) were identified in deaf patients from southwestern China. Therefore, the spectrum of deafness genes in this area should be further studied.