Electrospray ionization (ESI) is a mass spectrometric technique widely used in various fields including chemistry, biology, medicine, pharmaceutical industry, clinical assessment, and forensic science. In this study, we report a simple and economical ESI-mass spectrometry (MS) technique, which makes use of disposable wooden tips (wooden toothpicks) for loading and ionization of samples. Samples could be loaded by normal pipetting onto the tip or simply dipping the tip into sample solutions. The hydrophilic and porous nature of wood allows effective adhesion of the sample solution for durable ion signals. The tip can be directly connected to nano-ESI ion sources of various mass spectrometers. Upon application of high voltage to the tip, desirable mass spectra could be obtained. We demostrated that this new technique is applicable for analysis of various samples, including organic compounds, organometallic compounds, peptides, proteins, and samples that cannot be directly analyzed by conventional ESI techniques, e.g., slurry samples and powder samples. The slim and hard properties of the wooden tip enable sampling from specific locations such as corners and small openings, indicating potential applications of the new technique in forensic investigations. The observation of electrospray ionization from wooden materials also allows us to get new insights into the materials that can be directly ionized for mass spectrometric analysis.

Food production in green crops is severely limited by low activity and poor specificity of D-ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) in natural photosynthesis (NPS). This work presents a scientific solution to overcome this problem by immobilizing RuBisCO into a microfluidic reactor, which demonstrates a continuous production of glucose precursor at 13.8 μmol g −1 RuBisCO min −1 from CO 2 and ribulose-1,5-bisphosphate. Experiments show that the RuBisCO immobilization significantly enhances enzyme stabilities (7.2 folds in storage stability, 6.7 folds in thermal stability), and also improves the reusability (90.4% activity retained after 5 cycles of reuse and 78.5% after 10 cycles). This work mimics the NPS pathway with scalable microreactors for continuous synthesis of glucose precursor using very small amount of RuBisCO. Although still far from industrial production, this work demonstrates artificial synthesis of basic food materials by replicating the light-independent reactions of NPS, which may hold the key to food crisis relief and future space colonization.

The luminescence sensing of histidine and histidine-rich proteins plays a pivotal role in biochemistry and molecular biology, in particular when both temporal and spatial resolution are required. An abnormal level of histidine-rich proteins is an indicator for many diseases, such as advanced liver cirrhosis, [1a,b] AIDS, [1c] renal disease, [1c] asthma, [1c] pulmonary disorders, [1d] thrombotic disorders, [1e, f] and malaria.[1g]Some analyses of histidine and histidine-rich proteins have been developed in conjunction with immunoassay [2a-d] and colorimetric detection methods.[2e] The most commonly used method for the detection of histidine and histidine-rich proteins in biological samples is chromatography, which is usually performed through the combination of an effective separation technique, such as thin-layer chromatography, gas chromatography, or HPLC, followed by UV/Vis or fluorescence spectroscopy.[2f-h] The use of high-performance capillary electrophoresis with a derivation reagent has also been reported.[2i] However, the aforementioned methods are generally tedious, laborious, and, most importantly, expensive for routine detection in a biochemistry laboratory.Although numerous studies have dealt with the detection of histidine or histidine-rich proteins, studies on the use of luminescent probes for this purpose remain sparse.[3] Notable examples include research by Fabbrizzi and co-workers, who developed competitive noncovalent fluorescence turn-on probes for histidine in the form of dizinc(II) or dicopper(II) macrocyclic complexes, which recognize histidine through the formation of an imidazolate bridge between the two dizinc(II) or dicopper(II) centers; [3a] however, the resulting noncovalent ensemble may be less stable than a covalently linking sensory system, and the complexity of the synthetic process makes it difficult to implement in a convenient manner.Photoluminescent iridium(III) complexes have emerged as a topical area of interest in inorganic photochemistry [4] and phosphorescent materials for optoelectronic [5] and luminescence signaling applications.[6] Significant changes in the photophysical behavior and emission properties of iridium-(III) complexes may be induced by the presence of biomolecules. Luminescent transition-metal complexes for protein staining, such as the luminescent ruthenium complex known as SYPRO Ruby dye, have been reported previously. [7] However, despite its high sensitivity and its broad dynamic range, the use of SYPRO Ruby dye is limited, as it is sold only as a formulated solution; therefore, it is not possible to optimize the dye for a particular electrophoresis protocol and protein. + , and the iridium complex is readily soluble and stable in aqueous staining solutions. In this study, [Ir(ppy) 3 ] (2) was also prepared for comparative studies, as its binding with proteins was expected to be largely hydrophobic in nature. Herein, we describe the luminescent switch-on probe [Ir(ppy) 2 (solv) 2 ] + (1) for histidine/histidinerich proteins and demonstrate...

Analysis of biological tissue at a molecular level is of great importance in biological, medical and clinical studies. In this manuscript, we report that both plant and animal tissues can be directly ionized and analyzed by mass spectrometry under ambient conditions. By adding some solvents and applying a high voltage, spray ionization can be induced at the tip of biological tissue and a mass spectrum can be observed. Various plant and animal tissues have been tested and compounds such as lipids, alkaloids, glucosides, lignans, pharmaceuticals and proteins could be detected in the spectra. This new technique provides a simple and rapid method for tissue analysis and allows observation of compounds that cannot be detected by other ionization techniques.