Effects of glutaraldehyde and povidone-iodine on apoptosis of grass carp liver and hepatocytes.

Since disinfectants are used all over the world to treat illnesses in people and other animals, they pose a major risk to human health. The comprehensive effects of disinfectant treatments on fish liver, especially the impacts on oxidative stress, toxicological effects, transcriptome profiles, and apoptosis, have not yet been fully analyzed. In the current investigation, healthy grass carp were exposed to 80 µg/L glutaraldehyde or 50 µg/L povidone-iodine for 30 days. First, the findings of enzyme activity tests demonstrated that the administration of glutaraldehyde could considerably increase oxidative stress by lowering T-SOD, CAT, and GPx and raising MDA. Furthermore, KEGG research revealed that exposure to glutaraldehyde and povidone-iodine stimulated the PPAR signal pathway. To further elucidate the transcriptome results, the relative expressions of related DEGs in the PPAR signal pathway were verified. Glutaraldehyde induced apoptosis in liver tissue of grass carp; however, it activated cytotoxicity and apoptosis in grass carp hepatocytes when exposed to glutaraldehyde or povidone-iodine. According to the current study, disinfectants can cause the impairment of the immune system, oxidative stress, and attenuation of the PPAR signal pathway in the liver of grass carp, making them detrimental as dietary supplements for grass carp, particularly in the aquaculture sector.

Gender differences in oral health among prisoners: a cross-sectional study from Taiwan.

BACKGROUND: The prevalence of oral diseases among Taiwanese prisoners has rarely been investigated. This study aimed to estimate the gender-specific prevalence of oral disease in a sample of Taiwanese prisoners. METHODS: We included 83,048 participants from the National Health Insurance (NHI) Program. Outcomes were measured using the clinical version of the International Classification of Diseases, Ninth Revision (ICD-9-CM). For prevalence, we provide absolute values and percentages. We also performed a χ2 test to assess sex and age group differences in the percentage of disease in the oral cavity, salivary glands, and jaw. RESULTS: The prevalence rate of oral diseases was 25.90%, which was higher than that of the general population. The prevalence of oral diseases in female prisoners was higher than that in male prisoners (p < 0.001), and the prevalence of oral diseases in prisoners aged ≤ 40 was higher than that of prisoners aged > 40. Among all cases of diagnosed oral diseases, the top three diseases were dental hard tissue diseases (13.28%), other cellulitis and abscesses (9.79%), and pruritus and related conditions (2.88%), respectively. The prevalence of various oral diseases in female prisoners was significantly higher than that in male prisoners. CONCLUSION: Oral disease is common among Taiwanese prisoners. Female prisoners had a higher prevalence of oral, salivary gland, and jaw diseases than male prisoners. Therefore, early prevention and appropriate treatment are required and also a need for gender-specific oral disease products given the differences in the prevalence of oral disease among male and female prisoners.

Microfluidic-Based Single-Cell Study: Current Status and Future Perspective.

Investigation of cell behavior under different environments and manual operations can give information in specific cellular processes. Among all cell-based analysis, single-cell study occupies a peculiar position, while it can avoid the interaction effect within cell groups and provide more precise information. Microfluidic devices have played an increasingly important role in the field of single-cell study owing to their advantages: high efficiency, easy operation, and low cost. In this review, the applications of polymer-based microfluidics on cell manipulation, cell treatment, and cell analysis at single-cell level are detailed summarized. Moreover, three mainly types of manufacturing methods, i.e., replication, photodefining, and soft lithography methods for polymer-based microfluidics are also discussed.

Influence of Polymers on the Physical and Chemical Stability of Spray-dried Amorphous Solid Dispersion: Dipyridamole Degradation Induced by Enteric Polymers.

Amorphous solid dispersions (ASDs) are inherently unstable because of high internal energy. Evaluating physical and chemical stability during the process and storage is essential. Numerous researches have demonstrated how polymers influence the drug precipitation and physical stability of ASDs, while the influence of polymers on the chemical stability of ASDs is often overlooked. Therefore, this study aimed to investigate the effect of polymers on the physical and chemical stability of spray-dried ASDs using dipyridamole (DP) as a model drug. Proper polymers were selected by assessing their abilities to inhibit drug recrystallization in supersaturated solutions. HPMC E5, Soluplus®, HPMCP-55, and HPMCAS-LP were shown to be effective stabilizers. The optimized formulations were further stored at a high temperature (60 °C) and high humidity (40 °C, 75% RH) for 2 months, and their physical and chemical stability was evaluated using polarizing optical microscopy, FTIR, HPLC, and mass spectrometry (MS). In general, crystallization was observed in all samples, which indicated the physical instability under stressed storage conditions. Also, it was noted that the polymers in ASDs rather than physical mixtures, induced a dramatic drug degradation after being exposed to a high temperature (HPMCP-55 > 80% and HPMCAS-LP > 50%) and high humidity (HPMCP-55 > 40% and HPMCAS-LP > 10%). The MS analysis further confirmed the degradation products, which might be generated from the reaction between dipyridamole and phthalic anhydride decomposed from HPMCP-55 and HPMCAS-LP. Overall, the exposure of ASDs to stressed conditions resulted in recrystallization and even the chemical degradation induced by polymers.

Hierarchical Microspheres Constructed from Chitin Nanofibers Penetrated Hydroxyapatite Crystals for Bone Regeneration.

Chitin exists abundantly in crab and shrimp shells as the template of the minerals, which inspired us to mineralize it for fabricating bone grafting materials. In the present work, chitin nanofibrous microspheres were used as the matrix for in situ synthesis of hydroxyapatite (HA) crystals including microflakes, submicron-needles, and submicron-spheres, which were penetrated by long chitin nanofibers, leading to the hierarchical structure. The shape and size of the HA crystals could be controlled by changing the HA synthesis process. The tight interface adhesion between chitin and HA through the noncovanlent bonds occurred in the composite microspheres, and HAs were homogeneously dispersed and bounded to the chitin nanofibers. In our findings, the inherent biocompatibilities of the both chitin and HA contributed the bone cell adhesion and osteoconduction. Moreover, the chitin microsphere with submicron-needle and submicron-sphere HA crystals remarkably promoted in vitro cell adhesion and in vivo bone healing. It was demonstrated that rabbits with 1.5 cm radius defect were almost cured completely within three months in a growth factor- and cell-free state, as a result of the unique surface microstructure and biocompatibilities of the composite microspheres. The microsphere scaffold displayed excellent biofunctions and an appropriate biodegradability. This work opened up a new avenue to construct natural polymer-based organic-inorganic hybrid microspheres for bone regeneration.

Amniotic membrane and adipose-derived stem cell co-culture system enhances bone regeneration in a rat periodontal defect model.

BACKGROUND/PURPOSE: Periodontal disease is a chronic inflammatory process that potentially leads to alveolar bone destruction and tooth loss. Tissue engineering combined with stem cell therapy is a potential effective treatment for periodontal bone loss. Amniotic membrane (AM) is a potential scaffold enriched with multiple growth factors. It has the effects of anti-inflammation, antiangiogenesis, and immunosuppression. Herein, we used adipose-derived stem cells (ADSCs) and an AM co-cultured system to study bone regeneration in a rat periodontal defect model in vivo. METHODS: Human ADSCs were isolated from the infrapatellar fat pad, and characterized by flow cytometry, reverse transcription-polymerase chain reaction, and multipotent differentiation assays. The co-culture system was applied in the periodontal two-wall osseous defect in a rat model, and computed tomography was used to measure the effect. RESULTS: Human ADSCs isolated from the infrapatellar fat pad showed spindle-like morphology. Flow cytometry results demonstrated that ADSCs expressed a high level of CD90 and CD105, but not CD31, CD34, and CD45. ADSCs strongly expressed stemness genes, including SOX2, OCT4, NANOG, and KLF4 on different passages. Furthermore, ADSCs were able to differentiate into osteogenic, chondrogenic, and adipogenic cells. In the periodontal osseous defect rat model, ADSCs and the AM co-culture system significantly increased bone regeneration. CONCLUSION: This study provides the basis for using ADSCs with an AM co-culture system as stem cell therapy and scaffold transplantation in clinical periodontology.

Effects of Chitin Whiskers on Physical Properties and Osteoblast Culture of Alginate Based Nanocomposite Hydrogels.

Novel nanocomposite hydrogels composed of polyelectrolytes alginate and chitin whiskers with biocompatibility were successfully fabricated based on the pH-induced charge shifting behavior of chitin whiskers. The chitin whiskers with mean length and width of 300 and 20 nm were uniformly dispersed in negatively charged sodium alginate aqueous solution, leading to the formation of the homogeneous nanocomposite hydrogels. The experimental results indicated that their mechanical properties were significantly improved compared to alginate hydrogel and the swelling trends were inhibited as a result of the strong electrostatic interactions between the chitin whiskers and alginate. The nanocomposite hydrogels exhibited certain crystallinity and hierarchical structure with nanoscale chitin whiskers, similar to the structure of the native extracellular matrix. Moreover, the nanocomposite hydrogels were successfully applied as bone scaffolds for MC3T3-E1 osteoblast cells, showing their excellent biocompatibility and low cytotoxicity. The results of fluorescent micrographs and scanning electronic microscope (SEM) images revealed that the addition of chitin whiskers into the nanocomposite hydrogels markedly promoted the cell adhesion and proliferation of the osteoblast cells. The biocompatible nanocomposite hydrogels have potential application in bone tissue engineering.

Evaluation of the root and root canal systems of mandibular first premolars in northern Taiwanese patients using cone-beam computed tomography.

BACKGROUND/PURPOSE: Cone-beam computed tomography (CBCT) can provide valuable data for root canal systems of human teeth in vivo. This study used CBCT to evaluate the number of roots and canals of 300 mandibular first premolars in 150 northern Taiwanese patients. METHODS: The root canal systems of 300 mandibular first premolars in 150 northern Taiwanese patients with bilateral premolars were analyzed by CBCT. RESULTS: Of the 300 mandibular first premolars, 197 (65.7%) had one root with one canal (1R1C), 49 (16.3%) had one root with two canals (1R2C), 51 (17.0%) had two roots with one canal in each root (2R2C), and three (1.0%) had three roots with one canal in each root (3R3C). Statistical analyses showed that women had a significantly higher incidence of 1R1C mandibular first premolars (71.4%) than men (58.8%, p = 0.031), and men had a significantly higher incidence of 2R2C mandibular first premolars (27.2%) than women (8.5%, p < 0.001). One hundred and twenty-two (81.3%) of the 150 patients had a symmetrical root and root canal system between the right and left mandibular first premolars. Men had a significantly higher symmetrical rate of 2R2C mandibular first premolars (26.5%) than women (8.2%, p = 0.013). CONCLUSION: Approximately 82% of mandibular first premolars in northern Taiwanese patients have one root with either one or two canals. There are significant differences in the number of roots and canals and symmetry of the root canal system of bilateral mandibular first premolars between male and female northern Taiwanese patients.

[Preparation and performance evaluation of fast dissolving polymer microneedles piggybacked with sitagliptin].

The dramatic rise in the number of obese/overweight people is a global public health challenge that urgently requires novel and effective therapies. In this study, we designed a fast dissolving polymer microneedle array patch (SGN-PVP/PVA-MN) with sitagliptin as a model drug for treating obesity, focusing on the preparation process of the patch. We then characterized the morphology and dimensions of SGN-PVP/PVA-MN. Furthermore, we delved into the mechanical properties, solubility, skin-puncturing capability, and transdermal drug diffusion and release kinetics of SGN-PVP/PVA-MN. The results demonstrated that SGN-PVP/PVA-MN exhibited favorable morphology and mechanical properties, effectively penetrating the stratum corneum and creating microchannels for rapid transdermal drug diffusion. The in vitro transdermal diffusion assays revealed the release of 64.5% of the drug within 2 min and 95.7% within 10 min. With rapid dissolution and high drug diffusion efficiency, SGN-PVP/PVA-MN is poised to serve as an effective and safe treatment option for the individuals with obesity.

ROS-Responsive Nanoprobes for Bimodal Imaging-Guided Cancer Targeted Combinatorial Therapy.

Purpose: Chemotherapy mediated by Reactive oxygen species (ROS)-responsive drug delivery systems can potentially mitigate the toxic side effects of chemotherapeutic drugs and significantly enhance their therapeutic efficacy. However, achieving precise targeted drug delivery and real-time control of ROS-responsive drug release at tumor sites remains a formidable challenge. Therefore, this study aimed to describe a ROS-responsive drug delivery system with specific tumor targeting capabilities for mitigating chemotherapy-induced toxicity while enhancing therapeutic efficacy under guidance of Fluorescence (FL) and Magnetic resonance (MR) bimodal imaging. Methods: Indocyanine green (ICG), Doxorubicin (DOX) prodrug pB-DOX and Superparamagnetic iron oxide (SPIO, Fe3O4) were encapsulated in poly(lactic-co-glycolic acid) (PLGA) by double emulsification method to prepare ICG/ pB-DOX/ Fe3O4/ PLGA nanoparticles (IBFP NPs). The surface of IBFP NPs was functionalized with mammaglobin antibodies (mAbs) by carbodiimide method to construct the breast cancer-targeting mAbs/ IBFP NPs (MIBFP NPs). Thereafter, FL and MR bimodal imaging ability of MIBFP NPs was evaluated in vitro and in vivo. Finally, the combined photodynamic therapy (PDT) and chemotherapy efficacy evaluation based on MIBFP NPs was studied. Results: The multifunctional MIBFP NPs exhibited significant targeting efficacy for breast cancer. FL and MR bimodal imaging clearly displayed the distribution of the targeting MIBFP NPs in vivo. Upon near-infrared laser irradiation, the MIBFP NPs loaded with ICG effectively generated ROS for PDT, enabling precise tumor ablation. Simultaneously, it triggered activation of the pB-DOX by cleaving its sensitive moiety, thereby restoring DOX activity and achieving ROS-responsive targeted chemotherapy. Furthermore, the MIBFP NPs combined PDT and chemotherapy to enhance the efficiency of tumor ablation under guidance of bimodal imaging. Conclusion: MIBFP NPs constitute a novel dual-modality imaging-guided drug delivery system for targeted breast cancer therapy and offer precise and controlled combined treatment options.

External Electrons Directly Stimulate Escherichia coli for Enhancing Biological Hydrogen Production.

External electric field has the potential to influence metabolic processes such as biological hydrogen production in microorganisms. Based on this concept, we designed and constructed an electroactive hybrid system for microbial biohydrogen production under an electric field comprised of polydopamine (PDA)-modified Escherichia coli (E. coli) and Ni foam (NF). In this system, electrons generated from NF directly migrate into E. coli cells to promote highly efficient biocatalytic hydrogen production. Compared to that generated in the absence of electric field stimulation, biohydrogen production by the PDA-modified E. coli-based system is significantly enhanced. This investigation has demonstrated the mechanism for electron transfer in a biohybrid system and gives insight into precise basis for the enhancement of hydrogen production by using the multifield coupling technology.

Multi-step manipulations of PMMA submicron particles using dielectrophoresis.

A microfluidic chip for multi-step manipulations of polymethylmethacrylate submicron particles (PMMA-SMPs) based on dielectrophoresis (DEP) has been developed that includes four main functions of focusing, guiding, trapping and releasing the submicron particles. The structure of the DEP chip consists of a top electrode made of indium tin oxide (ITO), a flow chamber formed by optically clear adhesive (OCA) tape and bottom electrodes with different patterns for different purposes. The bottom electrodes can be divided into three parts: a fish-bone type electrode array which provides the positive DEP force for focusing the suspended nanoparticles near the inlet in the flow chamber; the second is for switching and guiding the focused nanoparticles along the electrode surface to the target area, like a flow passing along a virtual channel; and a trapping electrode in the downstream for trapping and releasing the guided nanoparticles. According to the simulation and experimental results, nanoparticles can be aligned along the electrode of the focusing electrode and guided toward the target electrode by means of a positive DEP force between the top and bottom electrodes, with the effects of Brownian motion and Stokes force. In order to demonstrate the sequence of DEP manipulations, a PMMA-NP suspension is introduced to the DEP chip; the size of the PMMA-SMPs is about 300 nm. Furthermore, a LabVIEW program developed for sequence control of the AC signals for the multi-step manipulations. Consequently, the DEP chip provides an excellent platform technology for the multi-step manipulation of submicron particles.

Interaction between microplastic biofilm formation and antibiotics: Effect of microplastic biofilm and its driving mechanisms on antibiotic resistance gene.

As two pollutants with similar transport pathways, microplastics (MPs) and antibiotics (ATs) inevitably co-exist in water environments, and their interaction has become a topic of intense research interest for scholars over the past few years. This paper comprehensively and systematically reviews the current interaction between MPs and ATs, in particular, the role played by biofilm developed MPs (microplastic biofilm). A summary of the formation process of microplastic biofilm and its unique microbial community structure is presented in the paper. The formation of microplastic biofilm can enhance the adsorption mechanisms of ATs on primary MPs. Moreover, microplastic biofilm system is a diverse and vast reservoir of genetic material, and this paper reviews the mechanisms by which microplastics with biofilm drive the production of antibiotic resistance genes (ARGs) and the processes that selectively enrich for more ARGs. Meanwhile, the enrichment of ARGs may lead to the development of microbial resistance and the gradual loss of the antimicrobial effect of ATs. The transfer pathways of ARGs affected by microplastic biofilm are outlined, and ARGs dependent transfer of antibiotic resistance bacteria (ARB) is mainly through horizontal gene transfer (HGT). Furthermore, the ecological implications of the interaction between microplastic biofilm and ATs and perspectives for future research are reviewed. This review contributes to a new insight into the aquatic ecological environmental risks and the fate of contaminants (MPs, ATs), and is of great significance for controlling the combined pollution of these two pollutants.

Decline in dental caries experience among schoolchildren in Taiwan, 2012-2020.

OBJECTIVES: This study investigated the association between the decline of the decayed, missing, and filled teeth (DMFT) index and several family-level and individual-level factors among 6- to 18-year-old Taiwanese children from 2012 to 2020. METHODS: This study used data from the 2012 and 2020 Taiwan National Oral Health Survey of Children and Adolescents. Both surveys used similar methods and were performed in the same study age group. A structured questionnaire was used to collect data on parents' sociodemographic background; the number of children in the family; oral health-related knowledge, attitudes, and behaviours; and children's dietary habits. Dental caries was recorded through standardized oral examinations. Multivariable multilevel zero-inflated negative binomial regression models were used to determine the association between family-level and individual-level factors and the DMFT index from 2012 to 2020. RESULTS: A total of 10 217 and 10 436 schoolchildren completed the oral examinations and questionnaires in the 2012 and 2020 surveys, respectively. The adjusted mean DMFT index of 12-year-old Taiwanese schoolchildren in 2020 was 2.01, denoting a significant decline from 2.50 in 2012 (adjusted mean ratio = 0.20, 95% confidence interval [CI] = 0.17, 0.23, p < .0001). Furthermore, children who often consumed sugar-rich drinks had a significantly higher risk (mean ratio = 1.05, 95% CI = 1.01, 1.10) of having DMFT than those who seldom consumed such drinks (p = .017). CONCLUSIONS: In the period of 2012-2020, the DMFT index among Taiwanese children significantly declined. Children who often consumed sugar-rich drinks had a higher DMFT index than those who seldom consumed such drinks. Our findings are valuable to paediatricians, dentists, nutritionists, and public health policymakers.

AI Aided Analysis on Saliva Crystallization of Pregnant Women for Accurate Estimation of Delivery Date and Fetal Status.

Saliva contains similar molecular components to serum. Analysis of saliva can provide important diagnostic information about the body. Here we report an artificial intelligence (AI) aided home-based method that can let pregnant women perform daily monitoring on their pregnant status and accurate prediction on their delivery date by the pattern analysis of their salivary crystals. The method was developed based on the information obtained from our investigation on the saliva samples of 170 pregnant women about the correlation of the salivary crystal pattern with pregnant age and fetal status. It demonstrated that the patterns of salivary crystallization could act as indicators of the pregnant age, fetal state, and some medical conditions of pregnant women. On this basis, with the aid of AI recognition and analysis of the fractal dimension and some characteristic crystals in the salivary crystallization, we performed estimation on the delivery date in both quantitative and qualitative manners. The accuracy of the prediction on 15 pregnant women was satisfactory: 100% delivering in the predicted week, 93.3% within the estimated three days, and 86.7% on the day as the prediction. We also developed a simple smartphone-based AI-aided salivary crystal imaging and analysis device as an auxiliary means to let pregnant women monitor their fetal status daily at home and predict their delivery date with adequate accuracy.

System-level biochip for impedance sensing and programmable manipulation of bladder cancer cells.

This paper develops a dielectrophoretic (DEP) chip with multi-layer electrodes and a micro-cavity array for programmable manipulations of cells and impedance measurement. The DEP chip consists of an ITO top electrode, flow chamber, middle electrode on an SU-8 surface, micro-cavity arrays of SU-8 and distributed electrodes at the bottom of the micro-cavity. Impedance sensing of single cells could be performed as follows: firstly, cells were trapped in a micro-cavity array by negative DEP force provided by top and middle electrodes; then, the impedance measurement for discrimination of different stage of bladder cancer cells was accomplished by the middle and bottom electrodes. After impedance sensing, the individual releasing of trapped cells was achieved by negative DEP force using the top and bottom electrodes in order to collect the identified cells once more. Both cell manipulations and impedance measurement had been integrated within a system controlled by a PC-based LabVIEW program. In the experiments, two different stages of bladder cancer cell lines (grade III: T24 and grade II: TSGH8301) were utilized for the demonstration of programmable manipulation and impedance sensing; as the results show, the lower-grade bladder cancer cells (TSGH8301) possess higher impedance than the higher-grade ones (T24). In general, the multi-step manipulations of cells can be easily programmed by controlling the electrical signal in our design, which provides an excellent platform technology for lab-on-a-chip (LOC) or a micro-total-analysis-system (Micro TAS).

Fabrication of chitin nanofiber-PDMS composite aerogels from Pickering emulsion templates with potential application in hydrophobic organic contaminant removal.

Natural polymers have aroused increasing attention in water treatment but their application in removing hydrophobic organic contaminants (HOCs) was limited due to their hydrophilicity. Herein, hydrophobic aerogels were successfully fabricated from Pickering emulsions stabilized by chitin nanofibers (ChNF) with polydimethylsiloxane (PDMS) as dispersed phase and glutaraldehyde as a crosslinking agent, and their performance in HOCs removal were evaluated. The Pickering emulsions with PDMS ratios of 2.5-20% v/v showed high stability, demonstrating great potential as aerogel templates. The solidified PDMS droplets were evenly distributed within the matrix, contributing to homogeneous and permanent hydrophobicity. The composite aerogels with water contact angles of over 130° could selectively remove non-aqueous phase HOCs from water. The CCl4 adsorption capacity was 521-2820 wt%, depending on PDMS contents. Meanwhile, the mechanical resilience of the composite aerogels was significantly improved, facilitating the adsorbent regeneration by simple mechanical squeezing. The adsorption capacity remained above 85% for 24 cycles. Moreover, the aerogels could also remove dissolved HOCs from water with a maximum adsorption capacity of 1.34 mg/g for 10 mg/L TCE. This work reveals the potential of Pickering emulsions in the fabrication of composite hydrophobic materials from natural biopolymers with promising application in HOCs related water treatment.

Key Markers and Epigenetic Modifications of Dental-Derived Mesenchymal Stromal Cells.

As a novel research hotspot in tissue regeneration, dental-derived mesenchymal stromal cells (MSCs) are famous for their accessibility, multipotent differentiation ability, and high proliferation. However, cellular heterogeneity is a major obstacle to the clinical application of dental-derived MSCs. Here, we reviewed the heterogeneity of dental-derived MSCs firstly and then discussed the key markers and epigenetic modifications related to the proliferation, differentiation, immunomodulation, and aging of dental-derived MSCs. These messages help to control the composition and function of dental-derived MSCs and thus accelerate the translation of cell therapy into clinical practice.

Underwater CAM photosynthesis elucidated by Isoetes genome.

To conserve water in arid environments, numerous plant lineages have independently evolved Crassulacean Acid Metabolism (CAM). Interestingly, Isoetes, an aquatic lycophyte, can also perform CAM as an adaptation to low CO2 availability underwater. However, little is known about the evolution of CAM in aquatic plants and the lack of genomic data has hindered comparison between aquatic and terrestrial CAM. Here, we investigate underwater CAM in Isoetes taiwanensis by generating a high-quality genome assembly and RNA-seq time course. Despite broad similarities between CAM in Isoetes and terrestrial angiosperms, we identify several key differences. Notably, Isoetes may have recruited the lesser-known 'bacterial-type' PEPC, along with the 'plant-type' exclusively used in other CAM and C4 plants for carboxylation of PEP. Furthermore, we find that circadian control of key CAM pathway genes has diverged considerably in Isoetes relative to flowering plants. This suggests the existence of more evolutionary paths to CAM than previously recognized.

Study on the fabrication and characterization of tip-loaded dissolving microneedles for transdermal drug delivery.

In order to increase the utilization rate of drug carried by microneedles and reduce waste, a two-step casting method was proposed to fabricate tip-loaded dissolving microneedles in this paper. The tip-loaded dissolving microneedles, also named layered microneedles, was consisted of two layers. The tip layer of the microneedles carried model drug, while the backing layer was fabricated with pure dissolving material. Polyvinyl alcohol, polyvinylpyrrolidone and hyaluronic acid were used as the base materials to fabricate the dissolving layers of the microneedle patches. Rhodamine B was chosen as the model drug to show the layered structure of tip-loaded microneedles. The material formulation and fabricating conditions of the tip-loaded dissolving microneedles and their transdermal insulin delivery efficiency were systematically studied. Nanoindentation testing showed that the tips of all three kinds of dissolving microneedles can bear the maximum loading of 50 mN with no damages, indicated sufficient mechanical strength for smooth skin puncturing as the minimum pressure required was 10 mN only. Moreover, our fabricated tip-loaded dissolving microneedles can greatly reduce the drug waste cause by unused backing layer in normal microneedles and realize a 30% enhancement of drug delivery efficiency after puncture treatment.