Biosafety Assessment Research Articles

Targeting staphylococcal bone infections

A novel quinolone antibiotic was developed by Shiladitya Sengupta and colleagues using molecular-docking simulation, and one lead compound, VCD-077, was selected based on this strategy.1 Antimicrobial resistance is increasing, driven by widespread antibiotic overuse in medical and agricultural settings.2 Paradoxically, despite the urgent need to develop a new generation of antibiotics, their marketability is suppressed, partly because the new antibacterial drug may quickly develop new resistance and the development of new antibiotics is sluggish.3, 4 The ideal next-generation antibiotic should demonstrate excellent activity against drug-resistant bacteria, good biosafety, flexible drug delivery, and the ability to retard the development of resistance. In this regard, recently researchers have focused on developing novel antibiotics by improving drug performance, availability, targeted enrichment, and reducing systemic toxicity. Reporting in Nature Biomedical Engineering, Shiladitya Sengupta and colleagues now show that VCD-077 screened by molecular-docking simulations exhibits excellent activity against drug-resistant bacteria and its biofilms, reduces the development of bacterial resistance and is compatible with bone cement for local delivery and treatment of staphylococcal bone infections in rats (Figure 1).1 Bone infections are rising rapidly due to accidental fractures and the global aging population.5 Sengupta and co-authors designed a series of quinolone antibiotics using molecular-docking simulation. They selected VCD-077 from 17 candidate antibiotics, which can effectively against clinical drug-resistant staphylococcal and retard the development of resistance. The minimal inhibitory concentration (MIC) of ciprofloxacin, Staphylococcus aureus sensitive antibiotics, increased stepwise to 64.0 μg/ml by the 20th passage to S. aureus. While S. aureus were still sensitive to VCD-077 even at the 28th passage. Specifically, VCD-077 is potent against S. aureus and Staphylococcus epidermidis biofilms because it is a weak acid with a single pKa of 5.8, that is, it still maintains antibacterial activity at pH 5.5–7.4. In contrast, gentamicin lost part of its activity at acid pH 5.5. Therefore, VCD-077 has a unique advantage in the prevailing weakly acidic infected bone environment. Notably, VCD-077 is physicochemically compatible with polymethylmethacrylate bone cement, exhibits desired pharmacokinetics without loss of mechanical properties of bone cement. VCD-077-impregnated bone cement showed more powerful anti-infective activity compared with either FDA-approved rifampin or gentamicin-impregnated bone cement. Overall, the authors show that VCD-077-impregnated bone cement could be used as rational next-generation drugs or coatings to treat bone infections. The high efficacy of Sengupta and co-authors' VCD-077-impregnated bone cement suggests that flexible local administration can be achieved at ideal safe concentration, and is effective against resistant strains, as well as delaying the development of new resistance. However, before VCD-077-impregnated bone cement can be considered for the treatment of clinical bone infection, three main challenges were compelled to be discussed. First, the authors used rodents in this experiment, which may be differences between the efficacy of antibiotics-impregnated bone cement in rodents and human bones. Studies using larger animal infection models (such as pigs and monkeys) would employ to corroborate the impressive antimicrobial activity in rat models. Second, significant biosafety assessment under good laboratory practice guidelines should be performed. And third, new antibiotic development should focus on specific screening molecules and combinations with emerging nanoparticle-based delivery systems that can target both resistant and persistent bacterial populations.6 Developing novel antibacterial agent delivery systems to improve the bioavailability of antibiotics is a promising strategy for increasing the lifespan of newly developed antibiotics. Integration of such novel antibiotics and combinations into nanoparticle-based delivery systems or coating implants might transform the landscape of infectious diseases. Drafting the article: Zhang Xiangchun. Revising the manuscript: Xulin Hu and Hongping Chen. All authors have read and approved the final manuscript This research was supported by the National Key Research and Development Program of China (2021YFD1601102), Central Public-interest Scientific Institution Basal Research Fund (No. Y2022QC24), and Innovative Program of Chinese Academy of Agricultural Sciences (CAAS-ASTIP-2021-TRI, CAAS-ZDRW202011). The authors declare no conflict of interest. Not applicable. Not applicable.

Aging of Nanoplastics Significantly Affects Protein Corona Composition Thus Enhancing Macrophage Uptake.

Nanoplastics (NPs), as emerging contaminants, have attracted increasing attention for their effects on human exposure and potential health risks. The protein corona formed on the surface of NPs affects the biological activity and fate of the NPs in vivo. However, how environmental aging, an inevitable process once NPs enter the environment, affects the formation of protein corona on NPs is still unclear. This study investigated the changes in the compositions of protein corona formed on photo-aged polystyrene (PS) NPs in human bronchoalveolar lavage fluid (BALF), corresponding to the inhalation exposure pathway. The results demonstrated that both the species and abundance of proteins in the BALF protein corona on the surface of PS NPs were altered by aging. In addition, the aged PS NPs are more hydrophilic and less electronegative than the pristine PS NPs; hence, there is an increased sorption of more negatively charged hydrophilic proteins. Moreover, aging-induced alterations in BALF protein corona enhanced the uptake of aged PS NPs by lung macrophages J774A.1 through phagocytosis and clathrin-mediated endocytosis. These findings highlight the importance of environmental aging processes in the biosafety assessment of nanoplastics.

Combinatorial Polydopamine-Liposome Nanoformulation as an Effective Anti-Breast Cancer Therapy.

Drug delivery systems (DDSs) based on liposomes are potential tools to minimize the side effects and substantially enhance the therapeutic efficacy of chemotherapy. However, it is challenging to achieve biosafe, accurate, and efficient cancer therapy of liposomes with single function or single mechanism. To solve this problem, we designed a multifunctional and multimechanism nanoplatform based on polydopamine (PDA)-coated liposomes for accurate and efficient combinatorial cancer therapy of chemotherapy and laser-induced PDT/PTT. ICG and DOX were co-incorporated in polyethylene glycol modified liposomes, which were further coated with PDA by a facile two-step method to construct PDA-liposome nanoparticles (PDA@Lipo/DOX/ICG). The safety of nanocarriers was investigated on normal HEK-293 cells, and the cellular uptake, intracellular ROS production capacity, and combinatorial treatment effect of the nanoparticles were assessed on human breast cancer cells MDA-MB-231. In vivo biodistribution, thermal imaging, biosafety assessment, and combination therapy effects were estimated based on MDA-MB-231 subcutaneous tumor model. Compared with DOX·HCl and Lipo/DOX/ICG, PDA@Lipo/DOX/ICG showed higher toxicity on MDA-MB-231 cells. After endocytosis by target cells, PDA@Lipo/DOX/ICG produced a large amount of ROS for PDT by 808 nm laser irradiation, and the cell inhibition rate of combination therapy reached up to 80.4%. After the tail vein injection (DOX equivalent of 2.5 mg/kg) in mice bearing MDA-MB-231 tumors, PDA@Lipo/DOX/ICG significantly accumulated at the tumor site at 24 h post injection. After 808 nm laser irradiation (1.0 W/cm2, 2 min) at this timepoint, PDA@Lipo/DOX/ICG efficiently suppressed the proliferation of MDA-MB-231 cell and even thoroughly ablated tumors. Negligible cardiotoxicity and no treatment-induced side effects were observed. PDA@Lipo/DOX/ICG is a multifunctional nanoplatform based on PDA-coated liposomes for accurate and efficient combinatorial cancer therapy of chemotherapy and laser-induced PDT/PTT.

Biosafety assessment of lactic acid probiotic isolates obtained from the gastrointestinal tract of livestock, poultry and bees native to Iran

Probiotics are suitable substitutes to reduce the use of growth-promoting antibiotics and antibiotics used to treat livestock infections due to new international laws and consumers' expectations of livestock products. Although lactic acid bacteria, especially Lactobacillus, are safe strains (GRAS11Generally Recognized As Safe), a safety study of new probiotic strains is needed to evaluate their safety and pathogenicity parameters. Such investigations can reduce concerns about antibiotic resistance genes transfer and observe rare cases of infection caused by probiotic usage. In the previous project of Iran Animal Biotechnology Research Institute, several lactic acid species were isolated and identified from the gastrointestinal tract of different farm animals via phenotypic characteristics and 16S rRNA sequencing. These bacteria had probiotic properties and were assessed for acid resistance, antibiotic resistance, bile salts, and antimicrobial activity. In this study, the presence or absence of several genes, such as pathogenic genes, amine-producing genes, and genes associated with antibiotic resistance, were examined by PCR.22Polymerase chain reaction Furthermore, genes that lead to the emergence of antibiotic resistance through other mechanisms such as efflux pumps were also studied in the same way. These studies have led to the achievement of safe strains for the introduction to the large market of livestock, poultry, and aquatic probiotics.

Strengthening Biorisk Management Capacities in Burkina Faso: Contribution of the Global Health Security Agenda.

The Global Health Security Agenda and the International Health Regulations (2005) recommend that countries strengthen the capacity of their national laboratory systems to comply with the International Health Regulations. To efficiently and effectively direct these efforts, the US Centers for Disease Control and Prevention-in collaboration with the Ministry of Health Directorate of Laboratories, the African Society for Laboratory Medicine, and Integrated Quality Laboratory Service-assessed Burkina Faso's national laboratory system using the World Health Organization Laboratory Assessment Tool. Based on gaps observed in biorisk management, the Biosafety and Biosecurity Laboratory Assessment Tool (BSS LAT) was developed to assess 10 public laboratories handling dangerous pathogens. This tool uses a specific scoring matrix with quantitative output. Composite assessment scores for the 9 primary modules (capacity areas) were reported, with the highest scores reported in cleaning, disinfection, sterilization, waste management (42%), and good laboratory practices (40%), and the lowest scores in biosecurity/biosafety (33%), documents/regulations (18%), emergency management (16%), and risk management (5%). To address challenges identified in the assessments, a set of activities was planned with a focus on biorisk management. Results from an evaluation conducted 1 year later, using the BSS LAT, showed an increase in the average score of all indicators from 25% to 45% and an increase in the biorisk management module score from 5% to 35%. This evaluation process was a decisive step toward strengthening the capacity of the laboratory system in Burkina Faso. Global Health Security Agenda investments and activities have made a lasting impact on improving biosafety and biosecurity in public health laboratories. To ensure sustainability, a strong laboratory quality management program based on a mentorship system is greatly needed.

A Multilingual Tool for Standardized Laboratory Biosafety and Biosecurity Assessment and Monitoring.

Control of infectious diseases requires the handling of infectious materials by both clinical and public health laboratories with exposure risks for laboratory personnel and environment. A comprehensive tool for assessing the capacity to manage these risks could enable the development of action plans for mitigation. Under the framework of the Global Health Security Agenda action package for biosafety and biosecurity, the authors developed a tool dedicated to assessing laboratory biosafety and biosecurity. The Biosafety and Biosecurity Laboratory Assessment Tool (BSS LAT) assesses the status of all laboratory biosafety core requirements across 10 different modules. It consists of a standardized spreadsheet-based tool that provides automatic scoring. It is designed to support national, regional, and global efforts to strengthen biosafety in clinical, public health, and veterinary laboratories. The BSS LAT was first used in Burkina Faso in collaboration with the African Society for Laboratory Medicine and the US Centers for Disease Control and Prevention to support the country in strengthening their biorisk management system. Since then, it has been successfully used in other countries (ie, Armenia, Burundi, Cameroon, Ghana, Guinea, Kazakhstan, Liberia), various settings (medical and veterinary laboratories), and translated into several languages (eg, English, French, Russian). The BSS LAT is a multipurpose tool that assists with standardization of biosafety and biosecurity requirements for all laboratories working with infectious materials, serves as a self-assessment guide for laboratories to develop improvement plans and reinforce capacities, and serves as a training guide for individual laboratories and networks or at the national level. The BSS LAT can also be used as a monitoring tool for the assessment of biosafety and biosecurity across all laboratories working with infectious materials at the national, regional, and global levels.

Effects of Insect-Resistant Maize HGK60 on Community Diversity of Bacteria and Fungi in Rhizosphere Soil.

The influence of biotech crops on microbial communities in rhizosphere soil is an important issue in biosafety assessments. The transgenic maize HGK60 harboring the Bt cry1Ah gene enhanced the resistance to lepidopteran pests, while the ecological risk of HGK60 maize on rhizosphere microorganisms is unclear. In this study, we comprehensively analyzed the diversity and composition of bacterial and fungal communities in the rhizosphere soil around Bt maize HGK60 and the near-isogenic non-Bt maize ZD958 at four growth stages via a high-throughput sequencing technique. The results showed that HGK60 maize unleashed temporary effects on the bacterial and fungal diversity and richness during the study plant's development, which would be restored after one cycle of plant cultivation due to the application of the same agricultural management. The differences of bacterial and fungal communities were marked by seasonality, while the different growth stage was the important factor as opposed to the cultivar contributing to the shifts in the bacterial and fungal communities' structure. This study will provide useful information regarding the impact of Bt transgenic maize on the soil microbiome and a theoretical basis for the development of a safety assessment approach for Bt maize in China.

CEpiderm, a Canine Skin Analog Suitable for In Vivo Testing Replacement

Skin is one of the organs most tested for toxicity and safety evaluation during the process of drug research and development and in the past has usually been performed in vivo using animals. Over the last few years, non-animal alternatives have been developed and validated epidermis models for human and rat skin are already available. Our goal was to develop a histotypical canine skin analog, suitable for non-animal biocompatibility and biosafety assessment. Canine keratinocytes were seeded in an air-lift culture using an adapted version of the CELLnTEC protocol. Corrosion and irritation protocols were adapted from human EpiSkinTM. For histological analysis, sample biopsies were fixed in neutral-buffered formalin, and paraffin slices were routinely processed and stained with hematoxylin and eosin. A canine multilayer and stratified epidermal-like tissue (cEpiderm), confirmed by histological analysis, was obtained. The cEpiderm tissue exhibited normal morphological and functional characteristics of epidermis, namely impermeability and an adequate response to stressors. The cEpiderm is a promising canine skin model for non-animal safety testing of veterinary pharmaceuticals and/or cosmetics, significantly contributing to reducing undesirable in vivo approaches. cEpiderm is therefore a valid canine skin model and may be made commercially available either as a service or as a product.

Insecticidal efficacy and risk assessment of different neuropeptide analog combinations against the peach-potato aphid following topical exposure.

Insect neuropeptides control essential physiological metabolic activities. In our previous studies, Capability/CAP2b (PK/CAPA) analog 1895 applied alone or as a combination of CAPA analogs (1895 + 2315) was reported to decrease aphid fitness. While this was obtained with the combination of two peptide analogs of the same neuropeptide class, the effect of combining peptide analogs of different neuropeptide classes has not been explored so far. In this study, we assessed the effect of combinations of the PK/CAPA analog 1895 with neuropeptide analogs of four different classes [adipokinetic hormone (AKH) analog: 2271; myosuppressin analog: 2434; kinin analog: 2460; tachykinin-related peptide analog: 2463] on the fitness of aphids. We found that the combination of 1895 and AKH analog 2271 was the most effective one to control Myzus persicae. The triple combination 1895 + 2271 + 2315 provided a synergistic effect by further increasing aphid mortality and reducing reproduction relative to 1895 + 2315. Additionally, a biosafety assessment of the combination 1895 + 2271 + 2315 showed no significant lethal nor sub-lethal effects on survival rates and food intake for the pollinator (Bombus terrestris) and the two representative natural enemies (Harmonia axyridis and Nasonia vitripennis). These results could facilitate establishment of the triple combination 1895 + 2271 + 2315, and/or inclusion of second generation analogs, as alternatives to broad spectrum and less friendly insecticides. © 2022 Society of Chemical Industry.

Assessment of biosafety and biorisk management practices among medical laboratory students in two institutions in Uganda

Medical laboratory workers handle clinical specimens, which are a threat of exposure to infectious agents. Notably, medical laboratory science students report for internships with only theoretical knowledge of biosafety and biorisk management practices, predisposing them to a higher risk of laboratory hazards. In this study, we assessed the influence of entry-level students' adherence to practices and attitudes towards biosafety and biorisk management during the Internship. An online survey tool was used to explore the practices and attitudes towards laboratory biosafety and risk management. Of the 96 students, 60 (62.5%) anonymous responses were received, and of these, 60.3% were direct entrants, and 32.8% were diploma entrants. Most (91.7%) of the students attended hospital internships, with 60.2% in Biosafety Level (BSL)-2 laboratories and 70.2% rotating in all the core areas of laboratory medicine. The 8.3% who did not attend any internship were under the direct entry category. Exposure to biohazards was not significantly associated with laboratory safety level and student entry category (P> 0.05). Recommended laboratory biosafety practices were not significantly associated with the safety level of the laboratory and student entry category (P> 0.05). Poor attitudes towards certain laboratory biosafety practices were not significantly associated with the biosafety level of the training laboratory (P> 0.05), whereas training (P = 0.021) and clean-up procedures (P = 0.048) were associated with laboratory safety levels, respectively. The direct entrants had no access to BSL-3 laboratories, and this category of students had a negative attitude towards internship attendance. Therefore, there is a need to create a multi-channel full range laboratory biosafety and biorisk management teaching reforms based on practical application, real case studies, and laboratory simulation to be incorporated into the curriculum to benefit the direct entrant.

MXene-Chitosan Composites and Their Biomedical Potentials.

Today, MXenes with fascinating electronic, thermal, optical, and mechanical features have been broadly studied for biomedical applications, such as drug/gene delivery, photothermal/photodynamic therapy, antimicrobials/antivirals, sensing, tissue engineering, and regenerative medicine. In this context, various MXene-polymer composites have been designed to improve the characteristics such as physiological stability, sustained/controlled release behaviors, biodegradability, biocompatibility, selectivity/sensitivity, and functionality. Chitosan with advantages of ease of modification, biodegradability, antibacterial activities, non-toxicity, and biocompatibility can be considered as attractive materials for designing hybridized composites together with MXenes. These hybrid composites ought to be further explored for biomedical applications because of their unique properties such as high photothermal conversion efficiency, improved stability, selectivity/sensitivity, stimuli-responsiveness behaviors, and superior antibacterial features. These unique structural, functional, and biological attributes indicate that MXene-chitosan composites are attractive alternatives in biomedical engineering. However, several crucial aspects regarding the surface functionalization/modification, hybridization, nanotoxicological analyses, long-term biosafety assessments, biocompatibility, in vitro/in vivo evaluations, identification of optimization conditions, implementation of environmentally-benign synthesis techniques, and clinical translation studies are still need to be examined by researchers. Although very limited studies have revealed the great potentials of MXene-chitosan hybrids in biomedicine, the next steps should be toward the extensive research and detailed analyses in optimizing their properties and improving their functionality with a clinical and industrial outlook. Herein, recent developments in the use of MXene-chitosan composites with biomedical potentials are deliberated, with a focus on important challenges and future perspectives. In view of the fascinating properties and multifunctionality of MXene-chitosan composites, these hybrid materials can open significant new opportunities in the future for bio- and nano-medicine arena.

Assessment of Biosafety and Biosecurity Engagements among Workers in some Institutional Research Laboratories (Private and Public) in Abuja, Nigeria

This study aims to evaluate the biosafety and biosecurity engagements among workers in some selected institutional research laboratories in Abuja, Nigeria. A biosafety and biosecurity survey was carried out from October 2021 to March 2022 (6 months) among 280 workers such as laboratory technologists, veterinary clinicians in institutional research laboratories (Private and Public) in Abuja, research officers and graduate students. This study data was collected using a standardized and self-administered questionnaire that had 2 sections; Socio-Demographic and Criteria assessment (General knowledge on laboratory biosafety and biosecurity, Laboratory biosecurity Agenda, Laboratory Biosecurity Plan, Achieve Laboratory Biosafety, Attitude towards Laboratory Biosafety). The predictors of biosecurity and biosafety engagement effect on the workplace (Private or Public) was significant with Omnibus χ2 (5, N= 280) = 44.130, Hosmer-Lemeshow values χ2 40.954, DF=7, p< 0.05. The interaction (Sector*Biosafety level) effect [F (5, 266) =5.43, p<0.05] was also statistically significant with its effect on the general knowledge of laboratory biosafety and biosecurity among the respondents. The relationship between the gender and position occupied in the laboratory and the assessment criteria was statistically significant F (15, 737) = 10.899, p<0.05; Wilks’ Lambda=0.575 and partial eta squared=0.168. It was concluded that the laboratory biosecurity plan and attitude towards laboratory biosafety had a significant influence on the biosafety and biosecurity engagement of the workers based on where (private or public) they work. Also, general knowledge of the workers in the laboratory about biosafety and biosecurity is significantly dependent on the sector where they work and their various biosafety levels.

Self-assembled terbium-amino acid nanoparticles as a model for terbium biosafety and bone repair ability assessment

Terbium (Tb) has been widely applied in biomedical field due to its excellent physicochemical properties, and is mainly deposited in bone tissue. However, its effects on bone and long-term biosafety have not been investigated in detail yet. In this study, self-assembled terbium-cysteine nanoparticles (Tb-Cys NPs) are designed as a model for the biosafety and bone repair ability assessment of Tb, which eliminates the disturbance of other factors as much as possible. Through metabolism, Tb is excreted gradually without obvious damage to major organs. Interestingly, Tb-Cys NPs efficiently promote bone repair. This study confirms the preferable biocompatibility and bone repair property of Tb and provides a competent reference for Tb biosafety during clinical applications. Further, the form of metal-amino acid assembly can serve as a kind of suitable model for the reasonable assessment of the long-term biosafety and the functions on tissues of other rare earth elements.

Generation and Identification of the Number of Copies of Exogenous Genes and the T-DNA Insertion Site in SCN-Resistance Transformation Event ZHs1-2.

Soybean cyst nematode (SCN, Heterodera glycines Ichinohe) causes an estimated economic loss of about USD 3 billion each year in soybean (Glycine max L.) production worldwide. Overexpression of resistance genes against SCN provides a powerful approach to develop SCN resistance cultivars in soybean. The clarification of molecular characterization in transformation events is a prerequisite for ecological risk assessment, food safety, and commercial release of genetically modified crops. Here, we generated transgenic events harboring the BCN (beet cyst nematode) resistance Hs1pro−1 gene using the Agrobacterium-mediated method in soybean, evaluated their resistance to SCN infection, and clarified the molecular characterization of one of the transformation events. Five independent and stable inheritable transformation events were generated by an Agrobacterium-mediated transformation method. SCN resistance tests showed the average number of developed females per plant and female index (FI) in T4 ZHs1-1, ZHs1-2, ZHs1-3, ZHs1-4, and ZHs1-5 transformation events were significantly lower than that in the nontransgenic control. Among these, the ZHs1-2 transformation event had the lowest number of developed females per plant and FI. Southern hybridization showed the exogenous target Hs1pro−1 gene was inserted in one copy and the Bar gene was inserted two copies in the ZHs1-2 transformation event. The exogenous T-DNA fragment was integrated in the reverse position of Chr02: 5351566–5231578 (mainly the Bar gene expression cassette) and in the forward position of Chr03: 17083358–17083400 (intact T-DNA, including Hs1pro−1 and Bar gene expression cassette) using a whole genome sequencing method (WGS). The results of WGS method and Southern hybridization were consistent. All the functional elements of exogenous T-DNA fragments were verified by PCR using specific primer pairs in the T5 and T6 ZHs1-2 transformation events. These results demonstrated that the overexpression of Hs1pro−1 gene enhanced SCN resistance, and provide an important reference for the biosafety assessment and the labeling detection in transformation event ZHs1-2.

Assessment of biosafety and toxicity of hydrophilic gel for implantation in experimental in vitro and in vivo models.

BackgroundThe assessment of biosafety of pharmacologically active substances is crucial for determining the feasibility of their medical use. There are controversial issues regarding the use of substances of different origins as implants.MethodsWe have conducted the comprehensive studies to determine the in vivo toxicity and in vitro genotoxicity of new generation of hydrophilic gel for implantation (production name of the substance “Activegel”) to detail its characteristics and assess its biosafety.ResultsIn vivo studies have shown the absence of clinical manifestations of intoxication in animals and no abnormalities in their physiological condition, general and biochemical blood tests. Evaluation of the site of the gel application showed no inflammatory reaction and evidenced on normal state of tissues of animal skin. The results of the genotoxicity test indicated that the gel did not affect the parameters of DNA comets and the formation of micronuclei, accordingly, had no genotoxic effect on human peripheral blood lymphocytes. When studying the effect of the gel on malignantly transformed cells in vitro, it was found that the gel for implantation did not change the proliferative activity and viability of human breast cancer cells.ConclusionsComprehensive in vitro and in vivo study using various experimental model systems showed that the hydrophilic gel for implantation “Activegel” is non-toxic.Supplementary InformationThe online version contains supplementary material available at 10.1186/s40360-022-00577-3.

Ag2Se quantum dots damage the nervous system of nematode Caenorhabditis elegans.

Silver selenide quantum dots (Ag2Se QDs), as a novel type of QDs, are valuable in the biomedical application due to their low-toxic and excellent optical property in near infrared region, but the biosafety assessment of Ag2Se QDs is rare. In this study, the findings suggested that the accumulation of Ag2Se QDs in the body of nematodes decreased the lifespan and damaged normal neurobehaviors of Caenorhabditis elegan (C. elegans). Furthermore, Ag2Se QDs caused excessive reactive oxygen species (ROS) productions and altered expressions of several genes associated with redox equilibrium, which might contribute to neurotoxic outcomes in nematode C. elegans. According to this study, it is necessary and important for researchers to pay attention to the biosafety assessment of presumed low-toxic nanomaterials, like Ag2Se QDs, especially on sensitively toxic targets, i.e. the nervous system.

Comparison of cell viability between mouse-derived ES-D3 cells and Balb/c 3T3 cells using denture-base lining materials.

The study was done to compare cell viability between ES-D3 and Balb/c 3T3 cells, and evaluate the difference in cell viability between these cell lines using denture-base lining materials for prosthetic dentistry. To compare the cytotoxicity, three acrylic and three silicone dental materials were used. The cell viability was examined by MTT and lactate dehydrogenase (LDH) methods. The cell viability immediately after malaxation or light irradiation was lower only for the acrylic materials in 3T3 cells, and for both silicone and acrylic materials in ES-D3 cells. However, the cell viability determined 24 h after malaxation or light irradiation by the MTT and LDH methods did not significantly differ between samples. It was observed that ES-D3 cells are more sensitive depending on the type of material. The results suggest that ES-D3 cells can be used as in vitro systems for conducting biosafety assessment to predict embryotoxicity.

Assessment of biosafety and implantation feasibility of novel phakic refractive lens

PurposeWe investigated the biosafety and implantation feasibility of a new phakic refractive lens (PRL) in rabbit eyes.MethodsShort PRLs (S-PRLs), large PRLs (L-PRLs), and large-grooved PRLs (LG-PRLs), were prepared by molding medical-grade liquid silicon. The cytotoxicity and cellular adhesion of the PRLs was assessed in vitro. To assess implantation feasibility, the S-PRL, L-PRL, and LG-PRL were implanted in the posterior chamber of rabbit eyes and the relative position was assessed by optical coherence tomography. The intraocular pressures (IOP) were compared between the S-PRL, L-PRL, LG-PRL, and control groups to evaluate the PRL biosafety after implantation.ResultsThe in vitro assays showed that cell viability and cellular adhesion in the S-PRL, L-PRL and LG-PRL groups was not significantly different to those in the control group throughout the study. After implantation into the posterior chamber of rabbit eyes, there were no obvious signs of inflammation or increases in IOP at each time point relative to the control group, demonstrating good biosafety of the PRL. The relative positions of the L-PRLs and LG-PRLs in the posterior chamber were appropriate and the retention frequencies were high.ConclusionsThe newly developed LG-PRL showed good biosafety with negligible in vitro cytotoxicity, ocular inflammation, or fluctuations in IOP. The LG-PRL provided the best implantation feasibility. The grooves on the LG-PRL provided channels for aqueous humor circulation. The LG-PRL is a promising type of PRL with an appropriate size and surface structure for effective correction of refractive errors in rabbit eyes.

Progress on the toxicity of quantum dots to model organism-zebrafish.

In vivo toxicological studies are currently necessary to analyze the probable dangers of quantum dots (QDs) to the environment and human safety, due to the fast expansion of QDs in a range of applications. Because of its high fecundity, cost-effectiveness, well-defined developmental phases, and optical transparency, zebrafish has long been considered the "gold standard" for biosafety assessment of chemical substances and pollutants. In this review, the advantages of using zebrafish in QD toxicity assessment were explored. Then, the target organ toxicities such as developmental toxicity, immunotoxicity, cardiovascular toxicity, neurotoxicity, and hepatotoxicity were summarized. The hazardous effects of different QDs, including cadmium-containing QDs like CdTe, CdSe, and CdSe/ZnS, as well as cadmium-free QDs like graphene QDs (GQDs), graphene oxide QDs (GOQDs), and others, were emphasized and described in detail, as well as the underlying mechanisms of QDs generating these effects. Furthermore, general physicochemical parameters determining QD-induced toxicity in zebrafish were introduced, such as chemical composition and surface coating/modification. The limitations and special concerns of using zebrafish in QD toxicity studies were also mentioned. Finally, we predicted that the utilization of high-throughput screening assays and omics, such as transcriptome sequencing, proteomics, and metabolomics will be popular topic in nanotoxicology.

Bio-based mesh-like pesticide carriers via copper ions chelation for prolonging pesticide retention and flush resistance on foliage

In the past few years, the development of smart pesticide-controlled release systems has emerged as an important strategy in modern precision agriculture, particularly to increase retention efficiency and improve the utilization of pesticides. In order to achieve effective retention of pesticide spraying formulations on foliage surfaces, the present study aimed to develop a novel bio‐based mesh‐like pesticide carrier (named PDA/HDA‐Cu/MEP@CNC), using polydopamine (PDA) and hexadecylamine (HDA) -coated cellulose nanocrystal (CNC), wherein copper ion was used for chelation. Fenitrothion (MEP) was used as a model pesticide in the study. The use of PDA/HDA‐Cu/MEP@CNC exhibited sustained stimuli‐response release behavior under an alkaline environment, which was attributed to the coordination of copper ions on CNC. The deposition efficiency of the prepared PDA/HDA‐Cu/MEP@CNC was enhanced owing to the presence of the PDA layer. In addition to this, the use of PDA/HDA‐Cu/MEP@CNC resulted in more than 75% enhancement in the antifungal activity towards Rhizoctoni solani (R.s.), as compared to commercial MEP. Further, the results for biosafety assessment demonstrated that the prepared pesticide carrier exhibited remarkable biosafety properties. Altogether, enhanced retention property, controlled release behavior, and biosafety activity of this modified nanocellulose based controlled release system highlighted its potential to be explored as a commercial formulation for pesticide spraying.