Magnetically-refreshable receptor platform structures for reusable nano-biosensor chips.

We developed a magnetically-refreshable receptor platform structure which can be integrated with quite versatile nano-biosensor structures to build reusable nano-biosensor chips. This structure allows one to easily remove used receptor molecules from a biosensor surface and reuse the biosensor for repeated sensing operations. Using this structure, we demonstrated reusable immunofluorescence biosensors. Significantly, since our method allows one to place receptor molecules very close to a nano-biosensor surface, it can be utilized to build reusable carbon nanotube transistor-based biosensors which require receptor molecules within a Debye length from the sensor surface. Furthermore, we also show that a single sensor chip can be utilized to detect two different target molecules simply by replacing receptor molecules using our method. Since this method does not rely on any chemical reaction to refresh sensor chips, it can be utilized for versatile biosensor structures and virtually-general receptor molecular species.

Internal Fixation of Osteochondral Lesion of the Talus Involving a Large Bone Fragment.

BACKGROUND: Internal fixation of an osteochondral lesion of the talus (OLT) can restore the congruency of the talus and maintain the subchondral bone and innate hyaline cartilage. However, OLT that is indicated for fixation is rarely encountered; hence, not many studies report on the results after the procedure. PURPOSE: To evaluate the clinical and radiological outcomes after internal fixation of chronic OLT involving a large bone fragment of at least 10 mm in diameter and 3 mm in depth on computed tomography (CT). STUDY DESIGN: Case series; Level of evidence, 4. METHODS: We retrospectively reviewed the data of 26 patients with OLT treated with internal fixation between August 2014 and April 2018. Of the patients, 15 were male and 11 were female, with a mean age of 16 years (range, 11-29 years). The primary radiological outcome measurement was bone union assessed on the 6-month postoperative CT scan. Clinical outcomes were assessed at a mean of 27.7 months postoperatively. RESULTS: Twenty patients (77%) achieved bone union on postoperative CT scan. The mean 100-mm visual analog scale (VAS) improved from 30.5 ± 8.5 preoperatively to 13.4 ± 9.7 postoperatively (P < .001). The mean Foot Function Index (FFI) improved from 30.5 ± 6.7 preoperatively to 13.7 ± 9.8 postoperatively (P < .001). A malleolar osteotomy was not necessary to approach the lesion in 88% of patients. A bone fragment with an irregular margin and low density on the preoperative CT scan was significantly associated with nonunion (odds ratio: 7.67, 95% confidence interval: 2.67 to 22.02, P = .008). The difference in clinical outcomes between patients with skeletally immature ankles and those with skeletally mature ankles was not statistically significant. Patient age did not correlate with postoperative 100-mm VAS (Pearson correlation coefficient, r = -0.07, P = 0.72) or the postoperative FFI (Pearson correlation coefficient, r = -0.05, P = .80). CONCLUSION: Internal fixation of an OLT involving a large bone fragment resulted in satisfactory clinical and radiologic outcomes. We found that patients with skeletally immature and mature ankles attained healing at comparable rates after the internal fixation of OLT.