In this work, dynamic introduction of bioactive RGD peptide on a matrix was successfully demonstrated via reversible multicovalent interactions within PBA/cis-diol polymeric complexes. These reversible, stable multiple interaction sites, in addition to a long accessible polymeric linker, enabled "reversible" control of cell adhesion by specific biomolecular exchange (e.g., glucose or fructose). This biomolecule-triggered, noninvasive strategy shows great promise for use in real-time biological research and mimics natural biomolecular feedback systems, thus having potential application in medical diagnoses and regenerative medicine.

Cell sheet technology is a novel approach to preparing and harvesting monolayer cell sheets by using poly(N-isopropylacrylamide) (PNIPAAm)-modified surfaces as thermoresponsive cell culture substrates. [1] At lower temperatures the cultured cells detach spontaneously as the surface of the substrate changes from hydrophobic to hydrophilic. In this way, an intact cell monolayer can be harvested non-invasively together with its underlying extracellular matrix (ECM). As a frequently used way to achieve scaffold-free tissue engineering, cell sheet technology holds great promise in cell-based regenerative medicine. [2] Considering the limited availability of autologous cells and the timeliness requirement of clinical treatments, current attempts at improving the efficiency of thermo-responsive cell sheet harvest systems face a dilemma. On the one hand, the cell culture substrate must be very cell-adhesive to markedly promote rapid adhesion and proliferation of the limited autologous cells for a timely therapy. On the other hand, the same substrate should become very cell-repulsive after the formation of a confluent cell monolayer such that the mature cell sheet can be rapidly released without hurting the cells and their underlying ECM. Specifically, simple regulation of the chemical composition or the topography of the surface can only either promote cell adhesion or accelerate cell detachment [3] and these surfaces commonly have very low bioactivity. [4] Introducing cell-adhesive biomolecules by means of covalent binding or physical adsorption can improve the surface bioactivity but result in the inevitable deceleration of cell detachment [5] and serious leakage of the biomolecules, [4, 6] respectively. Thus far, no single method without additional auxiliary means can effectively enhance cell adhesion during culture as well as facilitate the rapid harvest of cell sheets.To conquer this long-standing problem, we conceive of introducing cell-adhesive biomolecules to a thermo-responsive cell culture substrate in a reversible way and modulating them through temperature-dependent interactions. In this case, biomolecules can be stably immobilized on the substrate at cell culture temperature (37 8C), while they can be released as the temperature drops (e.g., 20 8C), thus facilitating both the initial cell adhesion and the final detachment of the cell sheet. With this strategy in mind, we find that the reversible interaction known as "specific binding" in noncovalent molecular imprinting is very appealing. As is well known, polymeric receptors with tailor-made recognition sites and "specific binding" properties comparable with those of natural receptors can be easily prepared by molecular imprinting. [7] More importantly, molecularly imprinted polymers (MIPs) containing thermo-responsive recognition sites (i.e., the sites with temperature-dependent interactions between MIPs and targeted molecules) can be readily obtained using PNIPAAm-based materials. [8] We herein report a novel system for harvesting cell sheets which r...

Specific cell adhesion and osteogenicity are both crucial factors for the long-term success of titanium implants. In this work, two mussel-derived bioactive peptides were designed to one-step dual-biofunctionalization of titanium implants via robust catechol/TiO coordinative interactions. The highly biomimetic peptides capped with integrin-targeted sequence or osteogenic growth sequence could efficiently improve the biocompatibilities of titanium implants and endow the implants with abilities to induce specific cell adhesion and enhanced osteogenicity. More importantly, rationally combined use of the two biomimetic peptides indicated an enhanced synergism on osteogenicity, osseointegration and finally the mechanical stability of Ti implants in vivo. Therefore, the highly biomimetic mussel-derived peptides and the dual-functional strategy in this study would provide a facile, safe, and effective means for improving clinical outcome of titanium-based medical implants.

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Expansive laminoplasty is an effective treatment for cervical myelopathy. Since the design of classic open-door laminoplasty with the use of suture, the procedure has been modified to reduce complications such as restenosis, axial symptoms, and segmental motor paralysis. Expansive open-door laminoplasty with the use of titanium miniplate is becoming popular. It is effective in expanding spinal canal dimensions with good clinical efficacy. However, a lack of studies exist comparing titanium miniplate fixation with classical suture fixation.We performed a retrospective study of 54 patients with cervical myelopathy. Twenty-nine patients (4 women and 25 men) receiving expansive open-door laminoplasty by titanium miniplate fixation were classified as the modified group, and 25 patients (5 women and 20 men) fixed with suture served as the control group. Clinical and radiologic outcomes were assessed. No significant differences were observed in Japanese Orthopaedic Association scores and the recovery rate of C5 palsy. The incidence of axial symptoms in the modified group was significantly lower than that in control group. Radiologic examination showed that postoperative C2-C7 lordosis and range of motion of the cervical spine in the modified group were preserved. No significant differences were observed in mean anteroposterior diameter and open angle in the 2 groups. Both surgical protocols were effective in preventing reclosure of open laminae. Furthermore, the modified laminoplasty was superior in reducing the incidence of axial symptoms and loss of cervical lordosis and range of motion.

The pooled incidence of PSI in scoliosis was 25%. Risser sign, preoperative LC, postoperative RSH, correction rate of PTC at follow-up, correction rate of MTC at follow-up, and LC at follow-up were risk factors for PSI in patients with scoliosis. Adding-on might be a compensatory mechanism for PSI. It is recommended that (1) sufficient correction of PTC and moderate correction of MTC and LC in the operation should be performed; (2) PSI should be prevented not only for the patients' postoperative appearance, but also for preventing the adding-on phenomenon.

In this meta-analysis, we aimed to assess glycosylated hemoglobin (HbA1c) level and lower extremity amputation (LEA) risk in patients with diabetes. Systematic computerized searches of the PubMed and Web of Knowledge were performed. We compared HbA1c level between groups with LEA and without LEA by meta-analysis; we also examined the dose-response relationship between HbA1c level and LEA risk. Sixteen studies were included in the meta-analysis. Eleven studies with 43,566 patients compared HbA1c between groups with and without LEA. The mean HbA1c (%) ranged from 8.3 to 12.5 in the group with LEA and from 7.4 to 11.3 in the group without LEA. The pooled weighted mean difference was 1.110 (95% confidence interval = 0.510-1.709; Z = 3.63, P = .008). The funnel plot was symmetrical, and Begg's test (z = 0.00, P = 1.000) and Egger's test (t = -0.02, P = .984) suggested no significant publication bias. Six studies with 109,933 patients included in the dose-response meta-analysis. The LEA incidence ranged from 0.3% to 14.6% between different HbA1c levels. Dose-response meta-analysis showed statistically significant association between HbA1c and LEA risk (χ(2) = 65.51, P = .000). In linear model, the odds ratio for LEA incidence was 1.229 (95% confidence interval = 1.169-1.292) for every 1% HbA1c increase. In the spline model, the odds ratio of LEA risk increased with HbA1c levels, especially when HbA1c ranged from 5% to 9%. Our meta-analysis indicates that high level of HbA1c is an important risk factor for LEA in patients with diabetes. This evidence supports the strategy for lowering glucose levels to reduce amputation in patients with diabetes.