Novel Porphyrinic Covalent Organic Polymer with Polarity-Switchable Dual Wavelength for Accurate and Sensitive Photoelectrochemical Sensing.

Herein, we synthesized a novel porphyrinic covalent organic polymer (TPAPP-PTCA PCOP) for constructing a polarity-switchable dual-wavelength photoelectrochemical (PEC) biosensor with ferrocene (Fc) and hydrogen peroxide (H2O2) as regulator and amplifier simultaneously. Interestingly, this new PCOP possessed both n-type and p-type semiconductor characteristics, which thus enabled the appearance of a dual-polarity photocurrent at two different excitation wavelengths. Furthermore, Fc and H2O2 could readily switch the photocurrent of PCOP to the cathode and anode stemming from its efficient electron collection and donation function, respectively. Based on these, a PCOP-based PEC biosensor skillfully integrating dual wavelengths with reliable accuracy and polarity switch with high sensitivity was instituted. As a result, the developed PEC biosensor exhibited a low detection limit down to 0.089 pg mL-1 for the most powerful natural carcinogen aflatoxin M1 (AFM1) assay. Impressively, the target exhibited a completely opposite photocurrent difference to the interfering substances, and the linear correlation coefficient of the assay was improved compared to single-wavelength detection. The PEC sensing platform not only provided a basis for exploring multicharacteristic photoactive material but also innovatively developed the detection mode of the PEC biosensor.

Adsorption force of fibronectin on various surface chemistries and its vital role in osteoblast adhesion.

The amount, type, and conformation of proteins adsorbed on an implanted biomaterial are believed to influence cell adhesion. Nevertheless, only a few research works have been dedicated to the contribution of protein adsorption force. To verify our hypothesis that the adsorption force of protein on biomaterial is another crucial mediator to cell adhesion, fibronectin (FN) adsorbed on self-assembled monolayers (SAMs) with terminal -OH, -CH3, and -NH2 was quantified for FN adsorption force (F(ad)) by utilizing a sphere/plane adsorption model and parallel plate flow chamber. As revealed, F(ad) on SAMs followed a chemistry-dependence of -NH2 > -CH3 ≫ -OH. It is further demonstrated that F(ad) together with FN conformation could regulate the late osteoblast adhesion and the consequent reorganization of the adsorbed FN and fibrillogenesis of the endogenous FN. Our study suggests that protein adsorption force plays a key role in cell adhesion and should be involved for better biomaterial design.

Organic polymer/inorganic heterostructure coupled with efficient allosteric bicycle strand displacement for photochemical sensing.

In this work, a high-performance conjugated microporous polymer (CMP) decorated with BiOBr (Tr(PhXOD)3-CMP/BiOBr) is synthesized to application in construction of ultrasensitive photoelectrochemical (PEC) biosensor for sensing miRNA-122, by firstly coupling with efficient clip toehold-mediated allosteric bicycle strand displacement (ABSD). Notably, the Tr(PhXOD)3-CMP/BiOBr not only owns self-enhanced D-A-D structure that extremely shortens migration distance of photo-generated electron, but also forms Z-type heterostructure for accelerating electron-hole separation, thereby significantly enhancing the photocurrent with 10-fold higher than commonly used methods. Meanwhile, the clip toehold-mediated ABSD based on ternary linkage structure transformation avoids the attrition of invading strand, endowing the conservation of high concentration for undergoing rapid reaction with high-efficiency DNA amplification, which dramatically improves reaction time and superior target conversion. The experimental results indicate that proposed PEC biosensor had a high sensitivity to miRNA-122 with a detection limit of 0.49 fM, which provides a newly organic/inorganic photosensitive nanomaterials and efficient DNA strand displacement in bioanalytical and early clinical disease diagnosis.

A Charcot-Marie-Tooth-Causing Mutation in HSPB1 Decreases Cell Adaptation to Repeated Stress by Disrupting Autophagic Clearance of Misfolded Proteins.

Charcot-Marie-Tooth (CMT) disease is the most common inherited neurodegenerative disorder with selective degeneration of peripheral nerves. Despite advances in identifying CMT-causing genes, the underlying molecular mechanism, particularly of selective degeneration of peripheral neurons remains to be elucidated. Since peripheral neurons are sensitive to multiple stresses, we hypothesized that daily repeated stress might be an essential contributor to the selective degeneration of peripheral neurons induced by CMT-causing mutations. Here, we mainly focused on the biological effects of the dominant missense mutation (S135F) in the 27-kDa small heat-shock protein HSPB1 under repeated heat shock. HSPB1S135F presented hyperactive binding to both α-tubulin and acetylated α-tubulin during repeated heat shock when compared with the wild type. The aberrant interactions with tubulin prevented microtubule-based transport of heat shock-induced misfolded proteins for the formation of perinuclear aggresomes. Furthermore, the transport of autophagosomes along microtubules was also blocked. These results indicate that the autophagy pathway was disrupted, leading to an accumulation of ubiquitinated protein aggregates and a significant decrease in cell adaptation to repeated stress. Our findings provide novel insights into the molecular mechanisms of HSPB1S135F-induced selective degeneration of peripheral neurons and perspectives for targeting autophagy as a promising therapeutic strategy for CMT neuropathy.

Coxsackievirus A6 was the most common enterovirus serotype causing hand, foot, and mouth disease in Shiyan City, central China.

BACKGROUND: Hand, foot, and mouth disease (HFMD) has become one of the most common infectious diseases in China. Before 2016, the primary causal serotypes were enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16). Following the introduction of EV-A71 vaccines in China since 2016, the situation could change. CV-A6 has recently replaced EV-A71 and CV-A16 in some areas of China. However, the epidemiological characteristics of central China remain unknown. AIM: To investigate the clinical symptoms and pathogen spectrum of HFMD in Shiyan City, central China, in recent years. METHODS: The epidemiological, clinical, and laboratory data from HFMD cases reported to the Shiyan Center for Disease Control and Prevention between January 2016 and December 2020 were analyzed. 196 throat swab specimens were collected from hospitalized HFMD patients between January 2018 and December 2020. To detect and genotype enteroviruses, real-time reverse transcription-polymerase chain reaction and sequencing of the 5'-untranslated region were used. In Shiyan, 168 laboratory-confirmed HFMD cases were studied using a logistic regression model to determine the effect of predominant enterovirus serotypes. Based on the logistic regression model, the least absolute shrinkage and selection operator model was used to analyze the correlation between CV-A6 infection and various clinical characteristics in HFMD patients in Shiyan. RESULTS: From 2016 to 2020, 35840 HFMD cases were reported in Shiyan. The number of cases decreased by 48.4% from 2016 to 2017. Approximately 1.58-fold increases were found in 2018 and 2019 when compared to the previous year, respectively. In 2020, a decrease of about 85.5% was reported when compared to 2019. The most common serotypes shifted from EV-A71 and CV-A16 (about 60%-80% in 2016 and 2018) to others (more than 80.0% in 2017, 2019, and 2020). EV-A71 lost its dominance in 2017 in Shiyan. Among 196 confirmed HFMD cases, 85.7% tested positive for enterovirus, with CV-A6 being the most common serotype (121/168, 72.0%). The positive rates for CV-A16 and CV-A10 were 4.8% and 3.0%, respectively. There was no EV-A71 discovered. Infection with CV-A6 was linked to fever, myocardial damage, increased creatine kinase MB isoenzyme, and lactate dehydrogenase levels. CONCLUSION: CV-A6 was the most common enterovirus serotype in Shiyan City, replacing EV-A71 and CV-A16 as the HFMD pathogen. Developing vaccines against CV-A6 or multiple pathogens, as well as rising CV-A6 surveillance, will help prevent HFMD in central China.

SIRT2-knockdown rescues GARS-induced Charcot-Marie-Tooth neuropathy.

Charcot-Marie-Tooth disease is the most common inherited peripheral neuropathy. Dominant mutations in the glycyl-tRNA synthetase (GARS) gene cause peripheral nerve degeneration and lead to CMT disease type 2D. The underlying mechanisms of mutations in GARS (GARSCMT2D ) in disease pathogenesis are not fully understood. In this study, we report that wild-type GARS binds the NAD+ -dependent deacetylase SIRT2 and inhibits its deacetylation activity, resulting in the acetylated α-tubulin, the major substrate of SIRT2. The catalytic domain of GARS tightly interacts with SIRT2, which is the most CMT2D mutation localization. However, CMT2D mutations in GARS cannot inhibit SIRT2 deacetylation, which leads to a decrease of acetylated α-tubulin. Genetic reduction of SIRT2 in the Drosophila model rescues the GARS-induced axonal CMT neuropathy and extends the life span. Our findings demonstrate the pathogenic role of SIRT2-dependent α-tubulin deacetylation in mutant GARS-induced neuropathies and provide new perspectives for targeting SIRT2 as a potential therapy against hereditary axonopathies.

Shape recovery strain and nanostructures on recovered polyurethane films and their regulation to osteoblasts morphology.

Shape memory polyurethanes (SMPUs) have emerged as novel dynamic substrates to regulate cell alignment, in which recovery-induced change in substrates topography has been described as the major contributor. This work, for the first time, confirmed the pivotal roles of recovery strain and phase-separated nanostructures of SMPUs in regulating cell morphology. SMPU films with different stretching ratios (0%, 50%, 100%, and 200%) were found to produce an average recovery strain from 19.41% to 34.04% within 2 h in dulbecco's modified eagle medium (DMEM). Meanwhile, the assembly of hard domains was enhanced during shape recovery, leading to the reorientation of fibrillar apophyses (i.e., nanostructures). Further observation of osteoblast morphology revealed that recovery strain resulted in perpendicular orientation of osteoblasts to strain direction. With the extension of incubation time (24 h), however, the perpendicular orientation was transformed to follow the nanostructures on recovered films, suggesting that the nanostructures might become the determinant of the long-term cell orientation. This study provides a biomechanics-based perspective to understand the dynamic interactions between SMPU and cells, which can help to guide the design of SMPU for specific biomedical applications.

Stretching-induced nanostructures on shape memory polyurethane films and their regulation to osteoblasts morphology.

Programming such as stretching, compression and bending is indispensible to endow polyurethanes with shape memory effects. Despite extensive investigations on the contributions of programming processes to the shape memory effects of polyurethane, less attention has been paid to the nanostructures of shape memory polyurethanes surface during the programming process. Here we found that stretching could induce the reassembly of hard domains and thereby change the nanostructures on the film surfaces with dependence on the stretching ratios (0%, 50%, 100%, and 200%). In as-cast polyurethane films, hard segments sequentially assembled into nano-scale hard domains, round or fibrillar islands, and fibrillar apophyses. Upon stretching, the islands packed along the stretching axis to form reoriented fibrillar apophyses along the stretching direction. Stretching only changed the chemical patterns on polyurethane films without significantly altering surface roughness, with the primary composition of fibrillar apophyses being hydrophilic hard domains. Further analysis of osteoblasts morphology revealed that the focal adhesion formation and osteoblasts orientation were in accordance with the chemical patterns of the underlying stretched films, which corroborates the vital roles of stretching-induced nanostructures in regulating osteoblasts morphology. These novel findings suggest that programming might hold great potential for patterning polyurethane surfaces so as to direct cellular behavior. In addition, this work lays groundwork for guiding the programming of shape memory polyurethanes to produce appropriate nanostructures for predetermined medical applications.

The optimal combination of substrate chemistry with physiological fluid shear stress.

Osteoblasts on implanted biomaterials sense both substrate chemistry and mechanical stimulus. The effects of substrate chemistry alone and mechanical stimulus alone on osteoblasts have been widely studied. This study investigates the optimal combination of substrate chemistry and 12dyn/cm(2) physiological flow shear stress (FSS) by examining their influences on primary rat osteoblasts (ROBs), including the releases of ATP, nitric oxide (NO), and prostaglandin E2 (PGE2). Self-assembled monolayers (SAMs) on glass slides with -OH, -CH3, and -NH2 were employed to provide various substrate chemistries, whereas a parallel-plate fluid flow system produced the physiological FSS. Substrate chemistry alone exerted no observable effects on the releases of ATP, NO, and PGE2. Nevertheless, when ROBs were exposed to both substrate chemistry and FSS, the ATP releases of NH2 were upregulated about 12-fold compared to substrate chemistry alone, while the ATP releases of CH3 and OH was similarly increased 7-fold at the peak. Similar trends were observed for the releases of NO and PGE2. The expressions of ATP, NO, and PGE2 followed the pattern of NH2-FSS>Glass-FSS>CH3-FSS≈OH-FSS. ROBs on NH2 produced the optimal combination of substrate chemistry with the physiological FSS. The F-actin organization and focal adhesion (FA) formation of ROBs on various SAMs without FSS were examined. NH2 produced the best results whereas CH3 and OH produced the worst ones. Inhibition of FAs and/or disruption of F-actin significantly decreased the releases of FSS-induced PGE2, NO, and/or ATP. Consequently, a mechanism was proposed that the best F-actin organization and FA formation of ROBs on NH2 lead to the optimal combination of substrate chemistry with the 12dyn/cm(2) physiological FSS. This mechanism gives guidance for the design of implanted biomaterials and bioreactors for bone tissue engineering.