Embedding leaf tissue in graphene ink to improve signals in electrochemistry-based chemotaxonomy

Application of Solid-state Electrochemical Analysis in Ancient Ceramic Identification and Characterization: A Review

Background:

Ceramics can reflect ancient technology and art, therefore, it has a very important position in archaeology. However, it is far from enough just to study the shape of pottery and porcelain. It is necessary to use advanced scientific and technological means to conduct a comprehensive analysis of pottery and porcelain, so as to study the information hidden deep in the remains of ceramic objects.

Methods:

The solid voltammetric method can be used to obtain information about the composition of materials used in ancient ceramics. This new method can be applied to insoluble solids for example, providing qualitative and quantitative information and structural information with little soluble solids. The method requires only ng-μg sample.

Results:

In this review, we first describe the development of solid-state voltammetric method and our work in this field. Then, we describe in detail the application of this method in archaeology, especially in the analysis of ceramics. Finally, we describe the analytical applications of other electrochemical techniques for ceramics analysis.

Conclusion:

Due to the low demand for samples and the high-cost performance of analytical instruments, this method has been widely studied in Europe. To sum up, we propose to establish a microsampling method for ancient ceramics. A new method for the protection of fine ancient ceramics by the suitable carrier and the fixation on the surface of the electrode. These improvements can enable solid-state electroanalytical chemistry technology to achieve more comprehensive and accurate quantitative analysis of ancient ceramics particles. We also propose the current challenges and future directions of solid-state electroanalytical chemistry.

Can Electrochemical Sensors Be Used for Identification and Phylogenetic Studies in Lamiaceae?

Electrochemical sensors have shown potential in recent years for plant species identification and phylogenetic studies. These works have been used to investigate the affinities of different species in many genera. However, the ability of electrochemical sensors to study relationships between different genera within a family has not been investigated. In this work, we selected 31 species in the Labiatae and 5 exotaxa as subjects to investigate the feasibility of electrochemical sensors at the genus level. The results show that electrochemical sensors are still very effective for the identification of these plants. Different pattern recognition techniques can make the identification more efficient. Also, the fingerprint profiles collected by the sensors can be used for phylogenetic studies of Labiatae. The phylogram divides all the species into five clusters, where the exotaxa are in one cluster. Species in the Labiatae are mainly distributed in four other clusters. Importantly, the different genera of species all showed close affinities, representing that electrochemical fingerprinting can well distinguish the affinities between the different genera. The results of this work demonstrate the great potential of electrochemical sensors in the study of plant phylogeny. Its application is not limited to the study at the species level, but can be extended to the genus level.

Voltammetric Electrochemical Sensor for Phylogenetic Study in Acer Linn

Acer Linn. is a highly divergent species morphology in the maple family (Aceraceae). It is one of the genera facing a very difficult taxonomic situation. The phylogeny of the genus and the taxonomic system under the genus remain unclear. The use of electrochemical fingerprints for plant phylogenetic study is an emerging application in biosensors. In this work, leaves of 18 species of Acer Linn. with an exo-taxa were selected for electrochemical fingerprint recording. Two different conditions were used for improving the data abundance. The fingerprint of all species showed a series of oxidation peaks. These peaks can be ascribed to the oxidation of flavonols, phenolic acids, procyanidins, alkaloids, and pigments in plant tissue. These electrochemical fingerprints can be used for the identification of plant species. We also performed a phylogenetic study with data from electrochemical fingerprinting. The phylogenetic tree of Acer is divided into three main clades. The result is in full agreement with A. shangszeense var. anfuense, A. pictum subsp. mono, A. amplum, A. truncatum, and A. miaotaiense, belonging to the subsection Platanoidea. A. nikoense and A. griseum were clustered together in the dendrogram. Another group that fits the traditional classification results is in the subsection Integrifolia.

Electrochemical Profile Recording for Pueraria Variety Identification

The rapid identification of plant variety is valuable in both academic studies and crop production. However, rapid and accurate identification has been difficult because many varieties have very similar morphological characteristics and are susceptible to the effects of the growing environment. In this work, we established an electrochemical method for recording the electro-active profile of compounds in plant tissue. Because the chemical composition of different varieties is largely controlled by their genes, rather than a growing environment, this method has considerable potential for variety identification. Three varieties of Pueraria with sixteen locations were collected for confirming the feasibility of the proposed methodology. Principal component analysis and peak ratio analysis have been used for grouping the sample data. The results indicate the electrochemical profiles of three varieties can be distinguished using their voltammetric data.

Electrochemical Sex Determination of Dioecious Plants Using Polydopamine-Functionalized Graphene Sheets

The rapid identification of sex has potential uses involving dioecious commercial plants. In this work, we first propose a rapid electrochemical analysis method for plant sex determination using the signal difference generated by the electrochemically active substances in plant tissue. Polydopamine-functionalized graphene was wrapped around plant tissue. The introduction of polydopamine-functionalized graphene could solve the problem of the instability of plant tissue immobilization and enhance the electrochemical signals from plant tissue. Taxus × media, Dioscorea zingiberensis, and Dioscorea bulbifera were deliberately selected as dioecious plant models due to their pharmaceutical applications. The sex of the plant was not obvious after simply comparing the electrochemical voltammograms. Scatter patterns and 3D surface patterns were generated based on the voltammograms recorded after different solvent extractions. Sex determination was successfully achieved by pattern recognition.

Infrageneric phylogenetics investigation of Chimonanthus based on electroactive compound profiles

Voltammetric scan can record the profile of electrochemical active substances in plant tissues. Because the distribution of chemical components in plants is controlled by genes, these profiles can reflect differences at the genetic level in different species. In this study, the voltammetric scan was applied to the investigation of macrophanerophytes taxonomy. All species of Chimonanthus with two exotaxa were deliberately selected due to their controversial infrageneric relationship. Electrode surface modification was excluded in this work to improve the convenience and accuracy of the fingerprint recording process. The dendrogram deduced from the electrochemical fingerprint data suggests that Ch. Zhejiangensis and Ch. grammatus are two groups of Ch. nitens, which may be only the ecotype of Ch. nitens, rather than independent taxonomic species. The small variations between the three species may be due to environmental factors and cannot be used for species formation. In addition, Ch. campanulatus and Ch. Praecox were clustered together with a close relationship.

An electrochemical method for plant species determination and classification based on fingerprinting petal tissue

The identification of plant species not only is a hobby but also has important application value in plant resources science. Traditional plant identification often relies on the experience of botanists. The infrageneric identification of plants is easily mistaken due to similarities in organ features. In this work, we propose an electrochemical method to obtain fingerprints of plant petal tissue. Fourteen species of Lycoris were used as a model for validating this methodology. Pattern and color recognition were established for visualization of electrochemical fingerprints recorded after various solvent extractions. In addition, the infrageneric relationships of these Lycoris species were deduced from the electrochemical fingerprints since the type and content of electroactive compounds in plants are controlled by genes. The results indicate that the electrochemical fingerprints of Lycoris petals are correlated with the infrageneric relationships of native Lycoris species.

High Sensitive Immunoelectrochemical Measurement of Lung Cancer Tumor Marker ProGRP Based on TiO₂-Au Nanocomposite

Progastrin-releasing peptide (ProGRP), which is known to be highly specific and sensitive to small cell lung cancer (SCLC), has been proven to be a valuable substitute for neuron-specific enolase in SCLC diagnostics and monitoring, especially in its early stages. The detection of ProGRP levels also facilitates a selection of therapeutic treatments. For the fabrication of our proposed biosensor, titanium (IV) oxide microparticles were first used, followed by dispersing gold nanoparticles into chitosan and immobilizing them onto a carbon paste electrode (CPE) surface. The developed immunosensor exhibits a much higher biosensing performance in comparison with current methods, when it comes to the detection of ProGRP. Therefore, the proposed CPE/TiO₂/(CS+AuNPs)/anti-ProGRP/BSA/ProGRP is excellent for the development of a compact diagnostics apparatus.