A disposable immunosensor array using cellulose paper assembled chemiresistive biosensor for simultaneous monitoring of mycotoxins AFB1 and FB1.

Due to the common contamination of multiple mycotoxins in food, which results in stronger toxicity, it is particularly important to simultaneously test for various mycotoxins for the protection of human health. In this study, a disposable immunosensor array with low-cost was designed and fabricated using cellulose paper, polydimethylsiloxane (PDMS), and semiconducting single-walled carbon nanotubes (s-SWCNTs), which was modified with specific antibodies for mycotoxins AFB1 and FB1 detection. The strategy for fabricating the immunosensor array with two individual channels involved a two-step protocol starting with the form of two kinds of carbon films by depositing single-wall carbon nanotubes (SWCNTs) and s-SWCNTs on the cellulose paper as the conductive wire and sensing element, followed by the assembly of chemiresistive biosensor with SWCNTs strip as the wire and s-SWCNTs as the sensing element. After immobilizing AFB1-bovine serum albumin (AFB1-BSA) and FB1-bovine serum albumin (FB1-BSA) separately on the different sensing regions, the formation of mycotoxin-BSA-antibody immunocomplexes transfers to electrochemical signal, which would change with the different concentrations of free mycotoxins. Under optimal conditions, the immunosensor array achieved a limit of detection (LOD) of 0.46 pg/mL for AFB1 and 0.34 pg/mL for FB1 within a wide dynamic range from 1 pg/mL to 20 ng/mL. Furthermore, the AFB1 and FB1 spiked in the ground corn and wheat extracts were detected with satisfactory recoveries, demonstrating the excellent practicality of this established method for simultaneous detection of mycotoxins.

Endodontic Microsurgery of Mandibular Second Molars Using the Bony Lid Approach: A Case Series.

Endodontic microsurgery is important for preservation of natural teeth with symptomatic apical periodontitis when conventional endodontic treatment is neither feasible nor effective. The thick buccal cortex, poor visibility, and potential neurovascular complications can make microsurgical procedures of mandibular second molars infeasible. With the aid of cone-beam computed tomography, the bony lid approach was applied in 10 cases of endodontic microsurgery of mandibular second molars at the VIP Center, Hangzhou Stomatology Hospital between 2019 and 2020. In all cases, the clinical and radiographic findings at the 24- or 36-month follow-up revealed complete healing of the periapical lesions. The bony lid technique contributed to precise root-end localization and helped avoid excessive postoperative pain or unfavorable healing that occurred in cases of excessive alveolar bone resection. Some clinical tips on preserving the cortical bone, obtaining precise access, and improving surgical efficiency have been proposed in this report.

Endodontic Microsurgery with Orthodontic Treatment in a Mandibular Left Molar with Symptomatic Apical Periodontitis.

Endodontic microsurgery has reduced the degree of treatment trauma compared with traditional apical surgery and further increased the success rate of natural teeth retention. However, when root apices of the mandibular posterior teeth are far from the buccal cortical bone surface or near to the inferior alveolar nerve, the operational difficulty of endodontic microsurgery increased greatly. Orthodontic treatments may be helpful to decrease the difficulties. In this case, the roots of a highly calcified mandibular molar diagnosed as previously initiated, symptomatic apical periodontitis were moved initially buccally by orthodontic treatment in 2 months. Then, endodontic microsurgery was completed. The tooth remained asymptomatic and functional with a radiographically healing periapical lesion at the 4-, 12-, and 24-month follow-ups.