Surface-Coated Probe Nanoelectrospray Ionization Mass Spectrometry for Analysis of Target Compounds in Individual Small Organisms

Analysis of target compounds in individual small organisms is of significant importance for biological, environmental, medicinal, and toxicological investigation. In this study, we reported the development of a novel solid-phase microextraction (SPME) based ambient mass spectrometry (MS) method named surface-coated probe nanoelectrospray ionization (SCP-nanoESI)-MS for analysis of target compounds in individual small organisms with sizes at micrometer-to-millimeter level. SCP-nanoESI-MS analysis involves three procedures: (1) modification of adsorbent at the surface of a fine metal probe to form a specially designed surface-coated SPME probe with probe-end diameter at several-micrometer level, (2) application of the surface-coated SPME probe for enrichment of target analytes from individual small organisms, and (3) employment of a nanospray tip and some solvent to desorb the analytes and induce nanoESI for mass spectrometric analysis under ambient condition. A SCP-nanoESI-MS method for determination of the perfluorinated compounds (PFCs) in individual <i>Daphnia magna</i> was developed. The method showed satisfactory linearities for analysis of real <i>Daphnia magna</i> samples, with correlation coefficient values (<i>R</i>²) of 0.9984 and 0.9956 for perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), respectively. The limits of detection were 0.02 and 0.03 ng/mL for PFOS and PFOA, respectively. By using the proposed method, the amount, bioaccumulation kinetics, and distribution of PFOS and PFOA in individual <i>Daphnia magna</i> were successfully investigated

CD44-Targeted Facile Enzymatic Activatable Chitosan Nanoparticles for Efficient Antitumor Therapy and Reversal of Multidrug Resistance

Nanoparticles are attractive platforms for the delivery of various anticancer therapeutics. Nevertheless, their applications are still limited by the relatively low drug loading capacity and the occurrence of multidrug resistance (MDR) against chemotherapeutics. In this study, we report that the integration of d-α-tocopherol succinate (VES) residue with both chitosan and paclitaxel (PTX) led to significant improvement of drug loading capacity and drug loading efficiency through the enhancement of drug/carrier interaction. After the incorporation of hyaluronic acid containing PEG side chains (HA-PEG), higher serum stability and more efficient cellular uptake were obtained. Due to HA coating, VES residues and the enzymatic responsive drug release property, such facile nanoparticles actively targeted cancer cells that overexpress CD44 receptor and efficiently reversed the MDR of treated cells, but caused no significant toxicity to mouse fibroblast (NIH-3T3). More importantly, with HA-PEG coating, longer blood circulation and more effective tumor accumulation were achieved for prodrug nanoparticles. Finally, superior anticancer activity and excellent safety profile was demonstrated by HA-PEG coated enzymatically activatable prodrug nanoparticles compared to commercially available Taxol formulation