Despite a decrease in the incidence of dental caries over the past four decades, it remains a widespread public health concern. The multifactorial etiology of dental caries complicates effective prevention and early intervention efforts, underscoring the need for the development of rapid predictive methods that account for multiple factors. In this study, we selected the activity of urease secreted by Streptococcus salivarius as a metabolic marker for dental caries. This activity was quantified by measuring the diffusion of hydroxide ions generated from the urease catalytic reaction on urea across a ZIF-8-modified nanoporous membrane. The choice of ZIF-8 was based on its preference in transporting hydroxide ions, enabling the accurate detection of urease activity at concentrations as low as 1 CFU/mL. Subsequently, we collected 287 saliva samples to determine the Michaelis constant (Km) of urease using this method. Logistic regression analysis revealed that both the Km of urease and the frequency of sugar intake are significant factors influencing the development of dental caries. Furthermore, we developed a machine learning methodology for identifying dental caries, achieving an accuracy rate of 81%. It is expected that increasing the sample size will further enhance the predictive accuracy of the model. This innovative approach provides valuable insights into early intervention strategies in the fight against dental caries.

A novel biosensor based on the direct electrochemistry of Salmonella paratyphi A immobilized on pretreated glassy carbon electrode (PGCE) was established. It was essential that the trans -membrane and trans-wall direct electron transfer of guanine (G) in DNA strand inside viable Salmonella paratyphi A was captured by microwave irradiation for melting double-stranded DNA(dsDNA) into single-stranded DNA (ssDNA). When the microwave irradiation condition reached 100 W for 9 s, the oxidation peak current reached maximal levels in pH 6.0 phosphate buffer solution (PBS). Meanwhile the typical surface controlled and irreversible electrode process of G was revealed by cyclic voltammetry (CV) with participation of 2 protons and 2 electrons respectively. In addition, A linear relationship for the oxidation current of G with the logarithm of Salmonella paratyphi A concentration was established with the range from 2.10 x 103 to 2.10 x 106 CFU center dot mL-1. The rapid quantification of viable Salmonella paratyphi A was achieved based on the direct electrochemical biosensor.

The direct electrochemistry of hepatitis B virus containing the covalently closed circular DNA (HBV cccDNA) is realized at pretreated glassy carbon electrode (PGCE). It is essential that the direct electron transfer of guanine (G) and adenine (A) on HBV cccDNA strand is captured by microwave irradiation to melt cccDNA into ssDNA. The irreversible adsorption and diffusion controlled processes of G and A are revealed by cyclic voltammetry with participating 2 protons and 2 electrons respectively. In addition, we found that there are two oxidation peaks of G and A in whole blood containing HBV. Nevertheless, there is only one oxidation peak of G in whole blood of normal people. According to this difference of oxidation peaks in whole blood sample, it can be used screen quickly HBV infection or carriers in clinic and large area of blood donors.

The direct electrochemistry of fresh tobacco RNA on the surface of the pretreated glassy carbon electrode (PGCE) is researched. Tobacco RNA immobilized at PGCE shows good electrochemical activity in 0.10 M pH 7.5 phosphate buffer solution. The typical surface-controlled & irreversible electrode process of tobacco RNA was achieved by cyclic voltammetry and differential pulse voltammetry with the participation of two elec-trons and two protons, providing a paradigm for the direct electrochemical study of RNA. In addition, cyclic voltammetry and amperometry techniques are employed to demonstrate that tobacco RNA displays the char-acteristics of peroxidase and exhibits excellent electrocatalytic oxidation to H2O2. The electrochemical H2O2 sensor based on the RNA exhibits a good response, which shows a range of 5.0 x 10-6-2.5 x 10-4 M with a low detection limit of 1.7 x 10-6 M (S/N = 3).

Background: Keloid, also known as connective tissue hyperplasia, is a benign proliferative disorder with a global distribution. The available therapeutic interventions are steroid injections, surgical removal of keloids, radiotherapy, compression therapy, the application of cryosurgery, and many other methods. Objectives: Existing treatments or approaches for keloids may lead to similar or even larger lesions at the site of keloid excision, leading to a high recurrence rate. Therefore, this study aims at identifying a new gene-based therapy for the treatment of keloids. Methods: An ASPN-siRNA/nanoparticle combination (si-ASPN) and a negative siRNA/nanoparticle complex (NC) was developed on the basis of bioinformatics studies and used in vitro and in vivo experiments. Results: The results showed a strong correlation between the development of keloids and high expression of ASPN protein. With the expression of ASPN protein greatly reduced in keloid fibroblasts and nude mice allografts after treatment with si-ASPN, the collagen and fibroblasts were also uniform, thinner, parallel and regular. Conclusion: All the above experimental results suggest that keloid and ASPN are closely related and both fibroblast growth and metabolism of keloid are inhibited after silencing ASPN. Therefore, ASPN-siRNA delivered via nanoparticles can serve as a novel intervention therapy for the treatment of keloids.

A sandwich-type electrochemical immunosensor was developed for sensitive detection of Salmonella Typhimurium (S. Typhimurium) in milk and eggs. According to the antigen-antibody specific binding, Anti-S. Typhimurium antibody was used to recognize the S. Typhimurium, while the HRP-Anti-S. Typhimurium antibody as signal probe was used to catalyze H2O2 with the assistance of thionine. The immunosensor showed wide linear range from 5.6x10(1) to 5.6x10(8) CFU/mL and low detection limit of 35 CFU/mL. The immunosensor also exhibited excellent specificity, reproducibility and stability, indicating that it had practicability in quality control of complex food samples and potential in clinical applications.

Exogenous insulin (INS) is critical for managing diabetes. However, owing to its short in vivo half-life, frequent injection of INS is un-avoidable, which is both painful and inconvenient, compromising the quality of life. Herein, we developed a laser-regulated INS release system (INS-ICG@ER hydrogel) that allowed an on-demand release of INS from the subcutaneous INS reservoir by remote laser control without the frequent injection of INS. The amino acid hydrogel functions as a hydrogel 3D scaffold material, which offers increased subcutaneous stability of drug loaded erythrocytes (ER). This INS-ICG@ER hydrogel would release INS due to the elevated content of reactive oxygen species (ROS), generated by ICG under laser irritation. Conversely, the ROS would be scavenged without the laser irradiation and stopped the release of INS from INS-ICG@ER hydrogel. Furthermore, the release of INS from INS-ICG@ER hydrogel could be regulated by laser irradiation. The INS-ICG@ER hydrogels could control the hyperglycemia within 2 h in diabetic mice and maintained their normal blood glucose level (BGL) for up to 6 days with laser irradiation 30 min prior to meals avoiding the frequent injection of free INS. This delivery system is an effective method that offers a spatiotemporally controlled release of INS to control the glucose level in vivo.

Failure to control blood glucose level (BGL) may aggravate oxidative stress and contribute to the development of diabetic nephropathy (DN). Using erythrocytes (ERs) as the carriers, a smart self-regulatory insulin (INS) release system was constructed to release INS according to changes in BGLs to improve patients’ compliance and health. To overcome the limited sources of ERs and decrease the risk of transmitting infections, we developed an in vitro, closed-loop autologous ER-mediated delivery (CAER) platform, based on a commercial hemodialysis instrument modified with a glucose-responsive ER-based INS delivery system (GOx-INS@ER). After the blood was drained via a jugular vein cannula, some of the blood was pumped into the CAER platform. The INS was packed inside the autologous ERs in the INS reactor, and then their surface was modified with glucose oxidase (GOx), which acts as a glucose-activated switch. In vivo, the CAER platform showed that the BGL responsively controlled INS release in order to control hyperglycemia and maintain the BGL in the normal range for up to 3 days; plus, there was good glycemic control without the added burden of hemodialysis in DN rabbits. These results demonstrate that this closed-loop extracorporeal hemodialysis platform provides a practical approach for improving diabetes management in DN patients.

Oxidative stress has been implicated in the pathogenesis of cognitive impairment. Lead (Pb) is a common environmental toxicant and plays a vital role in oxidative stress activation. In this study, a superoxide dismutase (SOD) and catalase (CAT) containing poly (lactic-co-glycolic acid) (PLGA) meso-particles (PLGA@SOD-CAT) were prepared to attenuate cognitive impairment via inhibiting oxidative stress in rats. It was prepared using a double emulsion (water/oil/water phase) technique to minimize the hazardous effects of Pb burden on cognitive impairment. The meso-particles antagonized the Pb-induced cognitive impairments. Behaviour, serum biochemical parameters and biomarkers of oxidative stress in rats were evaluated after they were subjected to intravenous injection with lead nitrate and PLGA@SOD-CAT. Moreover, the potential protective mechanism of PLGA@SOD-CAT was determined. Notably, PLGA@SOD-CAT appreciably agented memory impairment caused by lead nitrate and it could significantly inhibit Pb-induced oxidative stress in the blood. Furthermore, a remarkable reversion effect of cognitive impairments, including escape latency, crossing platform times and time per cent during the platform quadrant, after PLGA@SOD-CAT administration were noted. Therefore, these results suggested that the bi-enzymes platform was a superior product in eliminating Pb-induced cognitive impairments through reducing expression of Pb-associated oxidative stress, and it could potentially be applied in detoxifying heavy metals in blood circulation.

食品接触性塑料制品、可再生资源、汽车尾气中含有低浓度铅.铅等重金属体内蓄积严重影响机体健康,但机体长期暴露于铅环境的代谢依然未知.以低剂量含铅细颗粒物暴露为场景,探讨其在大鼠体内的生物转运及体内分布.通过比较每日吸入染毒(7.05±0.83)μg/m3及经口染毒0.42μg/d,连续染毒28 d.结果显示含铅细颗粒物入血的速度比经口途径快,在肺内蓄积浓度达(4.2±0.67)μg/g,与经口染毒组比较有显著统计学差异(P<0.01);排泄方面,吸入含铅细颗粒物以粪便、尿液形式排出为主,与经口染毒组比较具有体内蓄积量大、排泄慢、在股骨和肋骨内蓄积量大的特点.因此,吸入含铅细颗粒物暴露体内蓄积量大,代谢速度慢,暴露危害比经口途径更大.

This work proposed a novel and flexible immunosensor for highly selective and sensitive determination of cortisol in sweat. The flexible electrode was developed by transferring multi-walled carbon nanotubes (MWCNTs) film on polydimethylsiloxane (PDMS) substrate and subsequent electrochemical deposition of Au nanoparticles (AuNPs) on the MWCNTs surface. The obtained AuNPs/MWCNTs/PDMS electrode was then covalently immobilized with anti-cortisol monoclonal antibody (Anti-Cmab) and blocked with BSA. Scanning electron microscope confirmed that MWCNTs have been firmly combined with PDMS and AuNPs distributed uniformly on the surface of MWCNTs. The PDMS-based sensor possesses a good mechanical stability against stretching, bending and twisting, displaying stable electrochemical performance under deformation. After optimizing the analytical parameters, the developed immunosensor allowed a facile quantification of cortisol in the range of 1 fg/mL-1 μg/mL with a detection limit of 0.3 fg/mL. The cortisol immunosensor was further used to evaluate cortisol levels in human sweat, and the results corresponded closely with commercially available chemiluminescence immunoassay (CLIA) method. Results indicated that the new cortisol immunosensor could provide an effective tool for the noninvasive, point of care measurement of sweat cortisol levels and is promise to be a wearable biosensor for the healthy monitoring.

光热治疗偶联剂纳米硫化铜的临床应用,存在增加浓度、提高光热治疗效果的同时也增加毒副作用的矛盾.利用红细胞作为纳米硫化铜载体,体外激光照射控制其在肿瘤组织释放,增强光热治疗效果.采用改良低渗预膨胀法,将纳米硫化铜包载入红细胞,构建纳米硫化铜载药红细胞(CuS@ER);用小动物活体成像表征其肿瘤靶向效率,评价光热升温效果.40只荷瘤小鼠随机分为4组:对照组、单纯激光照射组、硫化铜+激光照射组和纳米硫化铜载药红细胞+激光照射组,每组10只,比较肿瘤体积变化率、生存率,并评价其安全性.结果 表明:已成功构建纳米硫化铜载药红细胞,载药率为17.24 ％±0.98％,包载后显著降低纳米硫化铜的细胞毒性.在0.44W/cm2的980 nm激光作用下,光热效率超过53％.荷瘤小鼠给药后,激光作用2 min,肿瘤内硫化铜浓度高达(0.061±0.007) μg/g,显著高于纳米硫化铜组的相应浓度(P＜0.01).纳米硫化铜载药红细胞给药组肿瘤内部温度达到60℃以上,与纳米硫化铜组相比具有显著统计学意义(P＜0.01);肿瘤体积变化比为0.91±0.02,与纳米硫化铜组相比具有显著性差异(P＜0.01);48 d荷瘤小鼠存活率达90％,显著高于纳米硫化铜组.所构建的纳米硫化铜载药红细胞具有高肿瘤靶向率及优良的光热治疗效果,可为临床光热治疗提供一种新思路.

Development of reliable sensors for real-time quantification of dopamine is highly essential to understand various biological processes and still remains challenge. Here, we proposed a novel and ultrasensitive electrochemical sensing platform for the monitoring of cell-secreted dopamine based on Pt nanoparticles (PtNPs) decorated multi-wall carbon nanotubes (MWCNTs) nanocomposite, which is synthesized by in-situ reduction of platinum on poly (diallyldimethylammonium chloride) (PDDA) functionalized MWCNTs. The unique structure of the hybrid nanocomposite and the interconnectivity between PtNPs and carbon nanotubes endow the nanocomposite with the enhancing conductivity and electrochemical activity. The Pt-MWCNTs hybrid modified screen-printed electrode exhibited excellent electrocatalytic ability for the detection of dopamine with a wide linear range (5 nM to 1 mu M) and a low detection limit (2 nM). The developed sensor enables the real-time recording of dopamine released from PC12 cells induced by the stimulation of K+ saline. Also, this approach can be used to quantitatively evaluate the effects of antipsychotic drug (aripiprazole) on the dopamine release from cells treated with high K+. Results indicated that the sensor could provide an effective tool for the monitoring of extracellular neurotransmitters related to the exogenous agent and drug on the nervous system.

We developed a novel method of microwave irradiation to deal with Escherichia coli (E. coli), realized the trans-membrane and trans-wall direct electron transfer of Guanine in viable E. coli. Typical surface controlled irreversible electrode process of E. coli was achieved by cyclic voltammetry with the participating of two electrons and two protons. The method of bacterium culture and colony count showed that the direct electrochemistry of E. coli could be realized with its biological activity maintained. In addition, the electrochemical parameters of E. coli were further achieved, which provided a paradigm for direct electrochemical study of other bacteria.

One primary and critical issue in a photosynthesis process is the absorption, transfer, and conversion of light energy in chloroplast. Although previous studies have shown that the absorption, transfer and conversion of light energy are involved in a series of ordered pigment protein complexes, there is still lack of direct evidence on the electron transfer mechanism within a chloroplast. In this study, chloroplast, thylakoid, and photosystem II (PSII) were assembled on the chitosan modified glassy carbon electrodes to explore the corresponding photosynthetic properties. The scanning electron microscopic and UV-visible spectral analysis showed that the chloroplast, thylakoid, and PSII were successfully modified on the electrode surfaces with their photosynthetic activity. The electrochemical features of chloroplast, thylakoid, and PSII were investigated through cyclic voltammetry. The results showed that only chloroplast modified electrodes didn't present any electrochemical activity, while the chloroplast modified electrodes soaked in water (hypotonic treatment) for 1 to 3 hours presented a couple of quasi-reversible redox peaks. Both thylakoid and PSII modified electrodes without hypotonic treatment showed similar redox peaks as that of chloroplast modified one, suggesting that the electrochemical signal sources for chloroplast, and thylakoid are out of PSII. In summary, this study not only explained the direct electrochemical signal source of the chloroplast, but also provided a new strategy to study the electron transfer process inside an organelle or cell.

Radiotherapy (RT) is a widely explored clinical modality to combat cancer. However, its therapeutic efficacy is not always satisfied because of the severe hypoxic microenvironment in solid tumors and the high dosage of radiation harmful to the adjacent healthy tissue. Herein, Au nanoparticle-hemoglobin complex nanoparticle loaded platelets (Au-Hb@PLT) were fabricated. These Au-Hb@PLT would be activated by tumor cells, and the formed platelet-derivate particles (PM) could deliver Au nanoparticle-hemoglobin complex deeply into tumor tissue because of their small size and tumor homing ability. Hemoglobin acts as an oxygen carrier to relieve the hypoxia and gold nanoparticles work as radiosensitizers to potentiate the sensitivity of tumor cells to X-ray, thus, enhancing the in vivo therapeutic outcome even under a low-dose RT in tumor bearing mice. The enhanced antitumor effect and survival benefits endowed by the Au-Hb@PLT were confirmed in vitro and in vivo. These results demonstrate that these Au-Hb@PLT can work as an oxygen vehicle, offer a promising approach to mitigate hypoxia and improve RT efficacy with a low RT dosage.

Radiotherapy (RT) as one of the most powerful cancer treatment strategies has been greatly restricted by tumor hypoxia. A mounting effort has been devoted to develop oxygen delivery systems for boosting the RT effect. Unluckily, those systems only supplied modest oxygen, which could not afford more than once and long-time RT. Herein, we describe the development of a glucose-regulated drug release platform, allowing for a long-term tumor normoxic microenvironment and repeated RT for a long time. The repeated cycles resulted in sustained high Endostar plasma levels, which dramatically normalized the tumor vasculature and chronically reversed tumor hypoxia. Taking advantage of the inexhaustible supply of oxygen, Endo@GOx-ER enabled RT achieved an impressive cancer treatment output. To the best of our knowledge, our strategy is the initial attempt to overcome tumor-hypoxia-limited RT through the normalization of tumor vasculature by using an erythrocyte-inspired and glucose-activatable platform and it visually casts a light on the clinical development.

Plant roots play critical roles in absorbing nutrients for the growth and development of plants as well as adapting different environments. Currently, there is no satisfactory way to track dynamic information when studying roots at the high temporal and spatial resolution. Herein, a simple microfluidic device with crossed microchannels was utilized for a microscopic investigation of Arabidopsis thaliana roots in situ. Our experimental results showed that the microfluidic system combined with a microscope could be conveniently utilized for the quantification of primary roots and root hairs with a change of micrometers within a time of minutes. Using the same approach, the influences of high salinity stress could also be investigated on different parts of roots, including the root cap, meristematic zone, elongation zone, mature zone, and root hairs. More importantly, the growth of roots and root hairs could be quantified and compared in a solution of abscisic acid and indole-3-acetic acid, respectively. Our study suggested that the microfluidic system could become a powerful tool for the quantitative investigation of Arabidopsis thaliana roots.

The amounts of uric acid (UA) in non-invasive biological samples, such as saliva, are critical for diagnosis and therapy of gout, hyperuricemia, Lesch–Nyhan syndrome, and several other diseases. Here, disposable UA biosensors were fabricated with the screen printing technique on the substrate of flexible PET. The working electrode was modified with carbon nanotubes followed by uricase for UA detection with excellent selectivity. The biosensor showed good electrocatalytic activity toward UA with high sensitivity, low detection limit, and wide linear range, which covers the full range of UA levels in human saliva. We demonstrate that UA can be directly detected in human saliva with the biosensor and the experimental data were consistent with the clinical analysis. This study indicated that the non-invasive biosensor is an attractive and possible approach for the monitoring of salivary UA.

Plants encounter phytopathogens frequently and phytohormones (such as salicylic acid, SA) are critical for their corresponding defensive functions. Monitoring SA in real time could help us understand its regulation mechanisms more clearly. Previously we have demonstrated that carbon tape working electrodes modified with carbon nanotubes could be utilized for quantification of SA in tomato leaf samples with the weights at the level of micrograms. Herein inexpensive pencils were used to modify the carbon tape with the pencil trace as the working electrodes by hand drawing. The pencil types and the trace layers were optimized for screening SA, implying that the carbon tape could maintain the handed pencil trace with its nanostructure. The carbon tape electrodes modified with handed pencil trace were integrated in the paper-based devices for real time monitoring SA in tomato leaves infected by Pseudomonas syringae pv. Tomato DC3000 (pst DC3000). Our results showed that the contents of SA in the surrounding area of the infection center increased significantly after inoculation of pst DC3000 within 24 h. The modification of working electrodes with handed pencil trace provided a low cost and effective method for sensitive detection of SA. The similar approach and platform might be extended for more biochemical applications.