Temperature-Responsive Aldehyde Hydrogels with Injectable, Self-Healing, and Tunable Mechanical Properties.

Injectable and self-healing hydrogels with exemplary biocompatibility and tunable mechanical properties are urgently needed due to their significant advantages for tissue engineering applications. Here, we report a new temperature-responsive aldehyde hydrogel with dual physical-cross-linked networks and injectable and self-healing properties prepared from an ABA-type triblock copolymer, poly{[FPMA(4-formylphenyl methacrylate)-co-DEGMA[di(ethylene glycol) methyl ether methacrylate]-b-MPC(2-methacryloyloxyethyl phosphorylcholine)-b-(FPMA-co-DEGMA)}. The thermoresponsive poly(DEGMA) segments drive the dehydration and hydrophobic interaction, enabling polymer chain winding as the first cross-linking network, when the temperature is raised above the critical gelation temperature. Meanwhile, the benzaldehyde groups offer physical interactions, including hydrogen bonding and hydrophobic and π-π stacking interactions as the second cross-linking network. When increasing the benzaldehyde content in the triblock copolymers from 0 to 8.2 mol %, the critical gelation temperature of the resulted hydrogels dropped from 35.5 to 19.9 °C and the mechanical modulus increased from 21 to 1411 Pa. Owing to the physical-cross-linked networks, the hydrogel demonstrated excellent injectability and self-healing properties. The cell viabilities tested from MTT assays toward both normal lung fibroblast cells (MRC-5) and cancerous cervical (HeLa) cells were found to be 100 and 101%, respectively, for varying polymer concentrations up to 1 mg/mL. The 3D cell encapsulation of the hydrogels was evaluated by a cytotoxicity Live/Dead assay, showing 92% cell viability. With these attractive physiochemical and biological properties, this temperature-responsive aldehyde hydrogel can be a promising candidate as a cell scaffold for tissue engineering.

Preparation and Characterization of Thermoresponsive PEG-Based Injectable Hydrogels and Their Application for 3D Cell Culture.

We report here the synthesis of a series of ethylene glycol-based triblock copolymers containing a hydrophilic middle segment of poly(ethylene glycol) methyl ether methacrylate (PEGMA) and two temperature-responsive segments of diethylene glycol methyl ether methacrylate (DEGMA) at both ends via the reversible addition-fragmentation chain-transfer (RAFT) polymerization. While the corresponding temperature-responsive homopolymer (PDEGMA) and the diblock copolymer (PDEGMA-b-PPEGMA) could not form a gel, the triblock copolymers (PDEGMA-b-PPEGMA-b-PDEGMA) could form a physical gel at certain concentrations and at temperatures above the lower critical solution temperature (LCST). This sol-gel transition is fully reversible and can be repeated several times. Depending on the chain length of the middle block and two end blocks, a physical gel could be formed at a minimum polymer concentration of 5 wt %. In addition, a mechanically strong gel could be easily formed within 5 s at the maximum concentration of 20 wt % and at a temperature of 37 °C. Considering the good cell compatibility and soft rubbery nature of the triblock copolymers, they can potentially be used as injectable scaffold for cell culture and tissue engineering applications.

Advancing hyper-crosslinked materials with high efficiency and reusability for oil spill response.

Developing materials with high efficiency for recovering oil to mitigate the environmental impact of oil spills has always been a challenging task. A commercial melamine formaldehyde sponge was coated with an optimised superhydrophobic/superoleophilic hyper-crosslinked polymer and applied to the removal of crude oil from oil-in-water emulsions for the improvement of oil spill clean-up processes. The high surface area, porosity, hydrophobicity, and selectivity of oil over water made the hyper-crosslinked polymer coated sponge (HPCS) an ideal sorbent for efficient oil/water separation. The system was able to strip crude oil from water emulsions of 1000 ppm to a negligible level of 2 ppm oil with minimal amounts of the HPCS material. More importantly, the HPCS material could be reused via a simple mechanical compression process, and the uptake capacity was retained over ten cycles. For five cycles of oil adsorption/mechanical compression the HPCS was able to provide water filtrate with oil concentrations of under 15 ppm. This is an effective and economical recovery system, removing the need for consistent solvent washing and drying processes. These results suggest that the HPCS is a promising material for oil/water separation and recovery under challenging conditions.

Hyper-Cross-Linked Polymer-Decorated Surfaces with Ultrahigh Efficiency for Oil/Water Emulsion Separation and Recovery.

A novel superhydrophobic/superoleophilic surface has been developed by direct surface condensation of dichloroxylene that results in a controlled coating of hyper-cross-linked polymers. Specifically, the coating was successfully applied to a melamine formaldehyde sponge and optimized by fine-tuning the reaction variables. The resulting hierarchical porous sorbents stabilized by polydimethylsiloxane exhibited an increased surface area, good physiochemical stability, high selectivity, and adsorption capacities for a variety of oils and solvents. The composite can separate oil in water emulsions with ultrahigh separation efficiency >99% over 10 cycles in liter-scale experiments, wherein the highest separation efficiency was as low as 2 ppm even with a short period of filtration, suggesting strong potential for oil/water separation and recovery.

Laminectomy and fusion after spinal cord injury: national inpatient complications and outcomes.

There is little information about national in-hospital complication rates, adverse outcomes, and mortality after spinal fusion for spinal cord injury (SCI). The National Inpatient Sample (NIS) was utilized to identify 31,381 admissions of acute spinal cord injured patients who underwent spinal decompression with laminectomy and/or fusion (lam/fusion) in the United States from 1993 to 2002. Multivariate analysis was performed to analyze the effects of patient and hospital characteristics on outcomes such as mortality, complications, and discharge disposition, which were then stratified by age, level, and type of injury. The overall mortality was 3.0%, with a complication rate of 26.3% and mean length of stay (LOS) of 17 days. Pulmonary complications (14.4%) and postoperative hemorrhages or hematomas (3.8%) were the most common complications reported. One postoperative complication doubled the length of stay, increased the mortality rate by fivefold and added over $50,000 to hospital charges. Age and comorbidities were the main significant predictors of mortality on multivariate analysis. Patients aged >85 or 65-84 had a 44- and 14-fold greater risk of dying compared with patients in the 18-44 age group respectively. Patients with >3 comorbidities also had an increased risk of mortality (odds ratio [OR] = 1.8). Alcohol abuse was the most common medical comorbidity (present in 12% of patients treated). This study represents the first major national estimate of in-hospital mortality and complication rates after nonoperative and operative treatment for SCI.

Inpatient complications, mortality, and discharge disposition after surgical correction of idiopathic scoliosis: a national perspective.

BACKGROUND CONTEXT: Information about complications and mortality after surgery for correction of idiopathic scoliosis has been largely derived from single-institution series. Regional or national studies have been lacking. PURPOSE: To report inpatient mortality, complications, and discharge disposition after surgical correction of idiopathic scoliosis on a national level. STUDY DESIGN: Retrospective cohort study using National Inpatient Sample (NIS) administrative data. PATIENT SAMPLE: All patients in the NIS with the primary diagnosis of idiopathic scoliosis who underwent a spinal fusion between 1993 and 2002 were included. OUTCOME MEASURES: Inpatient complication rate, mortality rate, and adverse outcome defined by death or discharge to institution other than home. METHODS: Outcome measures were abstracted from the NIS. Univariate and multivariate analyses were performed to analyze the effects of patient and hospital characteristics on outcome measures. RESULTS: The NIS was used to identify 51,911 patients who underwent spinal fusion for idiopathic scoliosis in the United States from 1993 to 2002. The total inhospital complication rate was 14.9% for pediatric patients and 25.1% for adult patients. The inhospital mortality rate was 0.17% and 0.40% for pediatric and adult patients, respectively. Adverse outcome was noted in 2.3% of pediatric patients and 20.4% of adult patients. Pulmonary and postoperative hemorrhages/hematomas were the most common complications reported. Multivariate analysis for complications showed that morbidity was significantly lower for pediatric patients (odds ratio [OR] = 0.80; confidence interval [CI] = 0.68-0.94) and female patients (OR = 0.77; CI = 0.68-0.88). Patients with a preoperative comorbidity were 1.53 (CI = 1.32-1.76) times more likely to develop a complication. A single postoperative complication increased the mean length of stay by more than 2 days and increased the mortality rate, adverse outcome, and hospital charges significantly. CONCLUSIONS: We have provided a national perspective on inpatient complications, mortality, and discharge disposition after spinal fusion for idiopathic scoliosis in the United States. The significant negative effects of postoperative complications on mortality and resource utilization have been demonstrated. Furthermore, we have identified adult age, male gender, and preoperative comorbidity as important risk factors and defined their impact on patient outcomes.

Polysaccharides as protectants for paper-based analytical devices with antibody.

Paper with immobilized protein can provide a low-cost platform for diagnostics, but evidence is emerging that the instability of protein on paper during shipping and storage severely limits its commercial development. Of these, paper-immobilized antibody, though widely used, is in urgent need of improvement in the shelf life. Herein we provided a detailed investigation of a simple and versatile approach for achieving stable antibody on paper to improve bioassay performance. Anti-Blood Group A IgM was chosen as the model antibody and its activity was tested via agglutination reactions. Representative polysaccharides (i.e., chitosan, sodium alginate and dextran) were used as protectants and their ability to stabilize antibody under heat and desiccation stresses was investigated. It was found that the presence of dextran with high concentration markedly stabilized paper-immobilized IgM for at least 120 days. Our results indicate that dextran with good film-forming ability could be a protectant for paper-immobilized antibody.

Medically complex children and early intervention for comprehensive medical care at home.

We present the case of a 4-year-old with multiple congenital anomalies. These included complete tracheal rings with agenesis of the right lung and missing right ribs. He was hospitalized from birth until he was age 3 years and 6 months. At age 4 years and 4 months he had yet to move to a family home or experience his first day of school because he was in a transitional care facility. The intensity of his care was initially high, slowly declined over time, and eventually entered the range where he would be potentially manageable in a home environment. Despite the countless medical teams treating him, he did not receive a referral either to the early intervention or educational services that he had a right to under the Individuals with Disabilities Education Act. While his case is extreme, there is a disconnect between the United States health care and educational systems, which negatively impacts both the health and development of children with chronic conditions who require frequent and prolonged hospitalizations.

Cervical spondylotic myelopathy: complications and outcomes after spinal fusion.

OBJECTIVE: There is little information about in-hospital complication rates, adverse outcomes, and mortality after spinal fusion for cervical spondylotic myelopathy (CSM). The aim of this study was to report inpatient mortality, complications, and outcomes on a national level. METHODS: We used the National Inpatient Sample to identify 58,115 admissions of patients with CSM who underwent spinal fusion in the United States from 1993 to 2002. Multivariate analysis was performed to analyze the effects of patient and hospital characteristics on outcomes such as mortality, complications, discharge disposition, and length of stay. RESULTS: A total of 58,115 patients with CSM underwent spinal fusion with an average mortality rate of 0.6%, a complication rate of 13.4%, and a mean length of stay of 4 days. Pulmonary (3.6%) and postoperative hemorrhages or hematomas (2.3%) were the most common complications reported. One postoperative complication led to a 4-day increase in mean length of stay, increased the mortality rate 20-fold, and added more than $10,000 to hospital charges. Multivariate analysis identified age, comorbidity, and admission type as the main predictors of mortality, complication rate, and adverse outcome. Patients aged > or =85 or 65 to 84 years had respective 44- and 14-fold increases in mortality, compared with patients in the 18- to 44-year age group. Patients older than 84 years had a 40-fold increase in adverse outcomes and a 5-fold likelihood of medical complications. Patients with three or more comorbidities had an increased risk of medical complications (odds ratio [OR], 1.98), adverse discharge (OR, 2.17), and in-hospital mortality (OR, 2.36). Elective admissions were associated with much lower rates of mortality (OR, 0.28), complication (OR, 0.68), and adverse outcome (OR, 0.26). Complications were greater for posterior fusion (16.4%) versus anterior fusion (11.9%) procedures. Anterior fusions were associated with a greater incidence of dysphagia (3%) and hoarseness (0.21%). Cervical spondylosis patients who presented without myelopathy had a much lower incidence of complications (6.3%). CONCLUSIONS: We provide a national estimate of inpatient complications and outcomes after spinal fusion for CSM patients in the United States. We demonstrate the impacts of age, complications, and medical comorbidities on the outcome of surgery for patients with this common disorder. We provide complication rates stratified by age and medical comorbidities for elderly patients who present with CSM who need spinal fusion.

Effects of age and comorbidities on complication rates and adverse outcomes after lumbar laminectomy in elderly patients.

STUDY DESIGN: This is a retrospective cohort study using the National Inpatient Sample database. OBJECTIVE: The objective is to report mortality and complications after lumbar laminectomy in the elderly. SUMMARY OF BACKGROUND DATA: As the population continues to age in the United States, it is important to consider the surgical complications and outcomes in the elderly. A review of the literature reveals controversy over the safety of lumbar laminectomy in the elderly and disagreement over estimates of risks in this population. METHODS: Outcome measures were abstracted from the National Inpatient Sample. Multivariate analysis was performed to analyze the effect of patient and hospital characteristics on outcome measures. RESULTS: A total of 471,215 patients underwent lumbar laminectomy without fusion for lumbar stenosis from 1993 to 2002. The in-hospital mortality rate was 0.17%, and the complication rate was 12.17%. Postoperative hemorrhage or hematoma (5.2%) and nonspecific renal complications (2.8%) were the most common complications. Complication and mortality rates increased with age and comorbidities with an 18.9% complication rate and 1.4% mortality rate in patients over the age of 85 with 3 or more comorbidities, 14.7% complication rate and 0.22% mortality rate in patients over 85 with no comorbidities, and only a 6% complication rate and 0.05% mortality rate in patient between 18 and 44 with no comorbidities. Multivariate analysis revealed increased odds of mortality with increasing number of comorbidities and complications in the greater than 85 year age group. Increasing age, number of comorbidities, complication rate, and female sex also increased the odds of discharge to institution other than home. CONCLUSION: Elderly patients with comorbidities are at a higher risk for complications and adverse outcome after lumbar spine surgery. The effects of age and comorbidities on patient outcomes have been quantified. This information is critical in counseling elderly patients about the risk of surgery in their age group.