An Aggregation-Induced Emission-Based Dual Emitting Nanoprobe for Detecting Intracellular pH and Unravelling Metabolic Variations in Differentiating Lymphocytes.

Monitoring T lymphocyte differentiation is essential for understanding T cell fate regulation and advancing adoptive T cell immunotherapy. However, current biomarker analysis methods necessitate cell lysis, leading to source depletion. Intracellular pH (pHi) can be affected by the presence of lactic acid (LA), a metabolic mediator of T cell activity such as glycolysis during T cell activation; therefore, it is a potentially a good biomarker of T cell state. In this work, a dual emitting enhancement-based nanoprobe, namely, AIEgen@F127-AptCD8, was developed to accurately detect the pHi of T cells to "read" the T cell differentiation process. The nanocore of this probe comprises a pair of AIE dyes, TPE-AMC (pH-sensitive moiety) and TPE-TCF, that form a donor-acceptor pair for sensitive detection of pHi by dual emitting enhancement analysis. The nanoprobe exhibits a distinctly sensitive narrow range of pHi values (from 6.0 to 7.4) that can precisely distinguish the differentiated lymphocytes from naïve ones based on their distinct pHi profiles. Activated CD8+ T cells demonstrate lower pHi (6.49 ± 0.09) than the naïve cells (7.26 ± 0.11); Jurkat cells exhibit lower pHi (6.43 ± 0.06) compared to that of nonactivated ones (7.29 ± 0.09) on 7 days post-activation. The glycolytic product profiles in T cells strongly correlate with their pHi profiles, ascertaining the reliability of probing pHi for predicting T cell states. The specificity and dynamic detection capabilities of this nanoprobe make it a promising tool for indirectly and noninvasively monitoring T cell activation and differentiation states.

[Comparison of effectiveness of three surgical methods in treatment of Pauwels type â ¢ femoral neck fracture in young and middle-aged patients].

Objective: To compare the effectiveness of three surgical methods in the treatment of Pauwels type Ⅲ femoral neck fracture in young and middle-aged patients, in order to provide reference for clinical selection of appropriate surgical methods. Methods: The clinical data of 103 patients with Pauwels type Ⅲ femoral neck fracture who met the selection criteria between June 2018 and December 2021 were retrospectively analyzed. The fractures were fixed with hollow screws in an inverted triangular shape (37 cases, hollow screw group), hollow screws in an inverted triangular shape combined with eccentric shaft screw (34 cases, eccentric shaft screw group), and hollow screws in an inverted triangular shape combined with medial support plate (32 cases, support plate group). There was no significant difference in age, gender, cause of injury, body mass index, time from injury to operation, side of the fracture, and Garden classification, whether they were in traction preoperatively, and other baseline data between groups ( P>0.05). The operation time, intraoperative blood loss, the number of fluoroscopy, the length of hospital stay, early postoperative complication and postoperative weight-bearing time of the three groups were recorded. Harris score was used to evaluate joint function at 6 and 12 months after operation, and the difference between the two time points (change value) was calculated for comparison between groups. X-ray films were reviewed to evaluate the quality of fracture reduction (Garden index) and healing, as well as the occurrence of internal fixation failure and femoral head necrosis. Results: The patients of the three groups were successfully completed. Compared with the hollow screw group and the eccentric shaft screw group, the operation time and intraoperative blood loss of the support plate group significantly increased, the number of fluoroscopy reduced, and the quality of fracture reduction was better, the differences were significant ( P<0.05). The operation time, intraoperative blood loss, and the number of fluoroscopy of the hollow screw group were less than those of the eccentric shaft screw group, the differences were significant ( P<0.05). There was no significant difference in the length of hospital stay between groups ( P>0.05). All patients in the three groups were followed up 21-52 months, with an average follow-up time of 36.0 months, and there was no significant difference between groups ( P>0.05). The incisions of all patients healed by first intention. Imaging reexamination showed that there was no significant difference in the incidence of fracture nonunion between groups ( P>0.05). The fracture healing, partial weight-bearing, and full weight-bearing were significantly earlier in the eccentric shaft screw group and the support plate group than in the hollow screw group ( P<0.05). There was no significant difference in change value of Harris score, the incidence of postoperative deep venous thrombosis and femoral head necrosis between groups ( P>0.05); however, the incidence of internal fixation failure in the support plate group and the eccentric shaft screw group was significantly lower than that in the hollow screw group ( P<0.05). The incidence of postoperative lateral thigh irritation in the support plate group was significantly lower than that in the hollow screw group ( P<0.05); there was no significant difference between the eccentric shaft screw group and the other two groups ( P>0.05). The overall incidences of postoperative complications in the eccentric shaft screw group and the support plate group were significantly lower than that in the hollow screw group ( P<0.05). Conclusion: For young and middle-aged patients with Pauwels type Ⅲ femoral neck fracture, compared with simple hollow screw fixation in an inverted triangular shape, combined with medial support plate or eccentric shaft screw internal fixation can shorten the fracture healing time, reduce the incidences of postoperative complication, more conducive to early functional exercise of the affected limb; at the same time, the operation time and blood loss of combined eccentric shaft screw internal fixation are less than those of combined medial support plate internal fixation, so the hollow screw in an inverted triangular shape combined with eccentric shaft screw fixation may be a better choice.

Magnetic-responsive upconversion luminescence resonance energy transfer (LRET) biosensor for ultrasensitive detection of SARS-CoV-2 spike protein.

Upconversion nanoparticles (UCNPs) are ideal donors for luminescence resonance energy transfer (LRET)-based biosensors due to their excellent upconversion luminescence properties. However, the relatively large size of antibodies and proteins limits the application of UCNPs-based LRET biosensors in protein detection because the large steric hindrance of proteins leads to low energy transfer efficiency between UCNPs and receptors. Herein, we developed a magnetic responsive UCNPs-based LRET biosensor to control the coupling distance between antibody-functionalized UCNPs (Ab-UCNPs) as donors and antibody-PEG linker-magnetic gold nanoparticles (Ab-PEG-MGNs) as acceptors for ultrasensitive and highly selective detection of SARS-CoV-2 spike proteins. Our results showed that this platform reversibly shortened the coupling distance between UCNPs and MGNs and enhanced the LRET signal with a 10-fold increase in the limit of detection (LOD) from 20.6 pg/mL without magnetic modulation to 2.1 pg/mL with magnetic modulation within 1 h. The finite-difference time-domain (FDTD) simulation with cyclic distance change confirmed the distance-dependent LRET efficiency under magnetic modulation, which supported the experimental results. Moreover, the applications of this magnetic-responsive UCNP-based LRET biosensor could be extended to other large-size biomolecule detection.